Image: Gyorgy Csoka, Hungary Forest Research Institute, Bugwood.org An elm zigzag sawfly (Aproceros leucopoda) larvae feeding on a leaf There’s a new invader in town! Elm zigzag sawfly, so called for its unique feeding pattern, has made its way down to North Carolina. The invasive forest pest was observed in Surry and Stokes county in August 2022. While it might look like a harmless little caterpillar when it’s young, the insect can be quite harmful to infested elm trees. Elm zigzag sawfly, or EZS for short, is a defoliating insect when in its larval stage, meaning it feeds on the leaves of trees. It infects various types of elm trees including American elm, winged elm, Chinese elm, and more. There is a lot that remains unknown about how EZS will behave in North Carolina right now, but researchers at NC State University and other institutions are currently working to find the answers we need. The effect of a warmer climate and how that could impact population growth is of particular concern. Elm Zigzag Sawfly's Journey Around the GlobeElm zigzag sawfly is native to eastern Asia, where it is a minor pest. However, in Europe, where it has been found since 2003, EZS can be quite damaging to host trees. EZS was first observed outside of its native range in Hungary and Poland, but has since been confirmed in at least 13 more European countries. In 2020, elm zigzag was documented to have made its way to North America for the first time. The small wasp-looking fly was actually first identified through the citizen science app iNaturalist in Quebec, Canada. The observation was then confirmed by professionals from the Canadian Food Inspection Agency in August 2020. Once in North America, EZS quickly began moving south. In 2021, it was confirmed in Virginia. In 2022, it was confirmed in Maryland, Pennsylvania, and North Carolina. As of this article being published, the infestation in North Carolina seems to be localized, meaning it is contained to one area that spans the border of Surry and Stokes county. Adult elm zigzag sawflies are strong fliers, which allows them to spread to new regions relatively quickly. In addition to flying, they can also spread via transport accidentally facilitated by human activity. EZS builds cocoons that can be attached to objects that people might relocate to areas not yet infested; they can also hide in soil or on plants being moved by people, all of which contributes to their spread. What's So Bad About a Little Green Caterpillar?When in the larval stage (the green caterpillar looking insect pictured above), elm zigzag sawfly is a prolific defoliator. Defoliation doesn’t always threaten the health of the tree; sometimes, it is simply an aesthetic issue that is typically remedied during a late-season period of growth or during the next growing season. However, after multiple seasons of intense defoliation from dense populations of pests, the health of the host tree can be severely diminished. Extended intense defoliation can lead to branch dieback and eventually the death of the tree. As of 2021, no tree deaths have been directly linked to EZS. However, researchers are concerned that the warm climate of the Southeastern United States will allow EZS populations to skyrocket, reaching dangerous levels for the elm trees they infect. Additionally, elm trees across the United States are already being threatened by Dutch elm disease, a fungal infection that can be quite damaging. Elm zigzag sawfly is wildly successful at reproducing, which is another factor that makes this insect so good at invading new regions. No male EZS have been observed, meaning this species is likely entirely made up of female sawflies. Female EZS reproduce without males, so when they travel to new areas they don’t need to find a mate to lay fertilized eggs. EZS have also been recorded to have up to six generations during a single year in the wild. The number of generations could be higher in areas where temperatures get warmer earlier in the year and colder later in the year. A longer period of warm weather gives EZS a longer time to reproduce. Not needing a mate and the potential for many generations in a single year are indicators that this invasive pest could be quite a problem for North Carolina. How Can We Stop It?One way you can help prevent the spread of elm zigzag sawfly is by checking for cocoons (pictured below) when leaving areas where their presence has been confirmed. The cocoons can be attached to objects that are transported, which can lead to the accidental introduction of EZS to a new region. Unfortunately, the cocoons can be quite difficult to spot. The most important thing you can do to prevent the spread is report any sightings of EZS or indicators that they might be nearby. Images: Kelly Oten, NC State University EZS Cocoons attached to a fence post and a leaf respectively How to Identify Elm ZIgzag SawflyLarval elm zigzag sawflies emerge from the egg a pale gray-green color but turn a bright green color as they grow. The larvae are quite small, only growing to be slightly more than 1 cm long. They have 6 true legs on the upper part of their body. The second and third pair of legs have a dark T-shape marking on them. The larvae also have a dark band on their head. Image: Matt Bertone, NC State University An elm zigzag sawfly larvae Adult elm zigzag sawflies are also quite small at about 1 cm long. Their white-green legs and white patch underneath the thorax (the middle body segment of insects) can be used to identify them. Image: Gyorgy Csoka, Hungary Forest Research Institute, Bugwood.org A mature elm zigzag sawfly Adult EZS and larval EZS can be quite difficult to identify without a trained eye. The feeding pattern of EZS larvae, on the other hand, can be quite easy to spot. When the larvae are young, they feed in a zigzag pattern between leaf veins. As they age, they begin to eat the entire leaf tissue, while still leaving behind the mid-vein, meaning they no longer create that characteristic zigzag. Image: Gyorgy Csoka, Hungary Forest Research Institute, Bugwood.org The characteristic zigzag feeding pattern of young EZS larvae So You Think You've Identified Elm Zigzag Sawfly... Now What?If you think you’ve found elm zigzag sawfly or evidence of its presence, it's important to report it to the right people. Reporting potential sightings is crucial to slowing, and hopefully stopping, the spread of invasive pests. You can report your findings to your local NC Forest Service county ranger, your local extension office, or you can email Dr. Kelly Oten ([email protected]) with NC State University. ReferencesElm zigzag sawfly (Aproceros leucopoda). 2023 Feb 14. Forest Research. [accessed 2023 Feb 21]. https://www.forestresearch.gov.uk/tools-and-resources/fthr/pest-and-disease-resources/elm-zigzag-sawfly-aproceros-leucopoda/#:~:text=Origins%20and%20background. Martel, V., O. Morin, S. Monckton, C. Eiseman, C. Béliveau, M. Cusson, and S. Blank. 2021. Elm zigzag sawfly, Aproceros leucopoda (Hymenoptera: Argidae), recorded for the first time in North America through community science. Can. Entomol. 154(1): E1. Oten K, Bertone M. 2022 Aug 31. Elm Zigzag Sawfly | NC State Extension Publications. NC State Extension Publications. [accessed 2023 Feb 21]. https://conte nt.ces.ncsu.edu/elm-zigzap-sawfly#:~:text=The%20elm%20zigzag%20sawfly%20. AuthorsDelaney Serpan, Courtney (Smith) Johnson
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![]() Many homeowners plant Bradford pear to show off its beautiful white flowers, but it is actually an invasive species! Image: Dow Gardens, Dow Gardens, Bugwood.org Many people in the Carolinas have Bradford pear trees, cultivars of Callery pear (Pyrus calleryana), decorating their yards. And we can’t blame them for being attracted to these trees! Their beautiful, snowy white flowers land them spots in many yards. However, many people don’t realize that they are actually invasive species. While these trees are sure to add some beauty to your yard, they also cause many ecological issues, so it is important to plant native trees instead. Luckily, there are plenty of native look-a-likes that can spruce up your yard. What is Callery 'Bradford' pear? Callery pear is a deciduous tree. It has light gray bark along with white flowers that appear before leaves from April to May. It also has olive-brown fruits that are present from May to July. Native to China, this tree was introduced to the United States in 1917. It was originally introduced for hybridization experiments that were meant to improve the disease resistance of fruiting pear trees. Many cultivars of the Callery pear exist, each of which have different characteristics that contribute to the “invasive” status. In the 1950s, the Bradford cultivar was planted in many areas across the U.S., and many other cultivars have been created since then. Why is Bradford pear invasive? It was originally thought that the trees were sterile, but they have recently spread. Even though individual cultivars are considered self-sterile, different cultivars that are planted near each other can cross-pollinate and produce viable fruits and seeds! As a result, these fertile fruits can spread when birds and other animals eat and distribute them, effectively increasing the range of the species. The tree can spread quickly, forming dense groups and outcompeting native plants. In the forest, these trees produce leaves earlier than native trees, allowing Bradford pear to shade out wildflowers. The tree is adapted to many conditions like drought and heat, allowing it to escape cultivation. It grows best in the sun but can tolerate some shading. Not only does the tree cause harm to our native ecosystems, but it also impacts people. The tree is structurally weak, breaking readily from weather conditions like ice, snow, or wind. Homeowners are often annoyed when their Callery pear trees fall after a storm. Further, the tree produces large thorns that can cause significant damage to equipment when people try to remove them. Many land managers have spent large sums of money replacing popped tires on their tractors or other equipment as a result of Callery pear. Bradford pear is often structurally weak and prone to falling or splitting after a storm. Image:Rebekah D. Wallace, University of Georgia, Bugwood.org What can you do to help? Considering all of the damage it causes, it may be time for Bradford pear to go! There are many beautiful native trees that can replace your Bradford pear trees. Save yourself the annoyance of dealing with downed Bradford pear trees and help out our native ecosystem in the process by planting native species. Replacements for Bradford pear may include flowering dogwood (Cornus florida), eastern redbud (Cercis canadensis), American plum (Prunus americana), fringetree (Chionanthus virginicus), hawthorn (Crataegus spp.), and more. To help out, learn more about designing a native plant landscape and check out a list of native trees in NC. ReferencesMissouri Department of Conservation. (2018, January). Callery Pear. Retrieved December 02, 2020, from https://mdc.mo.gov/sites/default/files/downloads/callerypearinvasive.pdf#:~:text=Callery%20pear%20(Pyrus%20calleryana)%20is,of%20the%20common%20fruiting%20pear.
Missouri Department of Conservation. (n.d.). Callery Pear (Bradford Pear). Retrieved December 02, 2020, from https://nature.mdc.mo.gov/discover-nature/field-guide/callery-pear-bradford-pear NC State University. (n.d.). Invasive, Exotic Plants of the Southeast: Callery 'Bradford' Pear. Retrieved December 02, 2020, from https://projects.ncsu.edu/goingnative/howto/mapping/invexse/bradfor.html Shaughnessy, D., Polomski, B., Coyle, D., & Williamson, J. (2020, January 09). Bradford Pear. Retrieved December 02, 2020, from https://hgic.clemson.edu/factsheet/bradford-pear/ In August 2020, it was confirmed that an argentine black and white tegu was sighted in South Carolina. This isn’t the first time a species has migrated from its natural habitat and moved northward towards the Carolinas; even armadillos have been recently spotted in the area. The sightings of the tegu lizard, however, are especially alarming because their native range is actually in South America. Tegus originate from Brazil, Argentina, Paraguay and Uruguay. That’s what’s so fascinating about their arrival to South Carolina. Why Are They Showing Up? There’s not a lot of research surrounding how the tegu moved from its native range to the United States, but it’s likely due to the exotic pet trade. The trading of exotic animals can be very problematic, and this case is a great example of that. Due to trading, there are already sizable tegu populations living in Florida and Georgia. It’s probable that the tegu lizard was brought to the United States because it was purchased as an exotic pet, and its current populations in the southeastern U.S. are the result of pet owners releasing these lizards into the wild. When exotic pets are released, they can do significant harm to the ecosystems because they are outside of their native range. Burmese pythons are an example of how the release of exotic pets can damage the environment. These pythons have infested parts of Florida and are harming populations of native species. They have been found to feed on over 20 species of birds, many of which are classified as endangered. How Did They End Up in South Carolina? The exotic pet trade explains how the tegu lizard arrived in the United States, but it doesn’t explain why the wild populations seem to be moving north. A black and white tegu was spotted in Lexington County, SC in August, and just a few weeks later, 8 more sightings were confirmed in the state. So why do they seem to be moving here? There still isn’t a lot of research surrounding the spread of the tegu lizard, so we can’t be certain what is causing them to move and spread to surrounding states. However, there are a few possibilities. It’s important to keep in mind that these lizards are invasive to the United States, so they don’t have any natural competition or predators in the wild. Since we know that they already have established populations in nearby states, it’s likely that they are able to spread to more states in a short amount of time because they aren’t meeting any resistance. Controlling the spread of an invasive species is very difficult, especially once they already have a stable population. There are plenty of native species for the tegu to hunt and prey on, so they have several food sources as well. These lizards are predators, and their presence in SC provides a threat for native populations like turkey and quail. Since the species seems to specifically be moving northward, another possible explanation is climate change. Let’s look back at the example of armadillos appearing in the Carolinas. Over the past few decades, it has been observed that armadillo populations have been expanding further north, even appearing as far north as Illinois. This is mostly due to the fact that the climate has warmed to the point where these regions have become habitable for the armadillo, so they are able to expand their natural range. It’s possible that this is also why the tegu lizard has been seen in South Carolina. The warming climate means that the area has become more suitable for the lizard, so its wild populations are beginning to expand outside of where they were originally released. What Can We Do? Issues like climate change and the exotic pet trade are huge problems that need to be faced and dealt with. Although combating these issues may seem daunting, there are some small ways that people can help keep our ecosystems safe and healthy. One of the biggest lessons to be learned from the tegu lizard situation is that people shouldn’t release their exotic pets into the wild. Exotic pets can quickly become invasive if they are able to form a stable population, and the native animals in the surrounding environment have no natural defenses against them. Better yet, this is a lesson of why people shouldn’t be buying exotic animals to keep as pets. Exotic animals don’t need to be taken out of their natural habitat, and the spread of the tegu lizard has shown that buying and releasing these animals can have serious consequences. Works Cited Armadillos On The Move To North Carolina. (2019, June 06). Retrieved from https://www.wfdd.org/story/armadillos-move-north-carolina Everglades Cooperative Invasive Species Management Area. (n.d.). Retrieved from https://www.evergladescisma.org/the-dirty-dozen/tegu-lizards/ Exotic Pet Trade. (n.d.). Retrieved from https://www.nhes.org/exotic-pet-trade/ First sighting of black and white tegu lizard confirmed in Midlands. (2020, August 21). Retrieved from https://www.dnr.sc.gov/news/2020/aug/aug_21.php Mallory, L. (2020, September 10). 8 more non-native tegu lizard sightings in SC have wildlife officials concerned. Retrieved from https://www.wistv.com/2020/09/10/more-non-native-tegu-lizard-sightings-sc-have-wildlife-officials-concerned/ Ronald Driggers, Orges Furxhi, Gonzalo Vaca, Veerle Reumers, Milad Vazimali, Robert Short, Prashant Agrawal, Andy Lambrechts, Wouter Charle, Kathleen Vunckx, and Carl Arvidson, "Burmese python target reflectivity compared to natural Florida foliage background reflectivity," Appl. Opt. 58, D98-D104 (2019) Taulman, J.F. and Robbins, L.W. (2014), Range expansion and distributional limits of the nine‐banded armadillo in the United States: an update of Taulman & Robbins (1996). J. Biogeogr., 41: 1626-1630. https://doi-org.prox.lib.ncsu.edu/10.1111/jbi.12319 United States, South Carolina Department of Natural Resources, National Wildlife Control Training Program. (n.d.). Armadillos. Retrieved from https://www.dnr.sc.gov/wildlife/publications/nuisance/armadillos.pdf Photography: Hillsborough County Parks, Recreation and Conservation Department , Bugwood.org At first glance, the spotted lanternfly, Lycorma delicatula, is quite exquisite, but their looks are deceiving. As a more recent invasive, they are considered one of the most aggressive pests in the Mid-Atlantic region and pose a severe threat to our forests and agricultural industry. Most plants, animals, and insects are equipped with at least one defense mechanism to help them survive, but these pests have four that can change seasonally. With cryptic forewings, defensive chemicals, and multiple behavioral defenses such as jumping, running, and death feigning (pretending to be dead or injured) when captured, the spotted lanternfly is a force to be reckoned with. Surprisingly, Changku Kang, a professor in the Department of Biology at Carleton University in Canada, discovered that adult lanternflies are more likely to jump and run away from potential threats in the spring and summer, while death feigning seems to be the preferred tactic in late summer and fall. How did the Lantern Fly get here?In 1844 the spotted lanternfly was first described in Nankin, China. Unfortunately, very little was known about them until they began to cause significant problems in South Korea and Japan in the early 2000s. It is suspected that egg masses were unintentionally transported to the U.S. in a shipment of stone. The first sightings in the United States occurred in 2014 in Berks County, Pennsylvania, and they quickly spread across the state. Currently, invasions of the spotted lanternfly have been documented in Virginia, New Jersey, Delaware, New York, Massachusetts, and Maryland. Why is it a threat?The spotted lanternfly is highly polyphagous, meaning they can eat a wide variety of foods, and they are known to have a voracious appetite. Think Eric Carle’s 'The Very Hungry Caterpillar' on steroids. Both adults and the 4 nymphal stages, called instars, suck sap from trees and vines, draining them of the essential sugars they need to survive. Instars seem to be the most destructive as they feed on a broader range of plants and will consume leaves and stems in addition to the sugary sap. As they reach adulthood, they typically reduce their range of host plants just before reproducing. Incidentally, the tree-of-heaven, which is also a problematic invasive species here in the Carolinas, is thought to be the spotted lanternflies’ host tree. However, they are also known to nearly drain the life out of many of our native and agricultural crop trees, including; birch, maple, beech, sassafras, oak, tulip, black cherry, black gum, white ash, serviceberry, apple, peach, and walnut trees. In Pennsylvania, grapevines are being hit hard, which may have a significant economic impact on their local wineries. How to Identify the Spotted Lantern Fly?Though it looks more like a moth and has fly in its name it’s actually neither. The spotted lanternfly is a planthopper in the order Hemiptera and is more closely related to aphids, cicadas, and brown marmorated stink bugs. Adults may be present from late summer through November. They are approximately 1 inch in length by ½ inch wide. Their forewings are grey with black spots, and their wingtips have a black block-like pattern. The hind wings have contrasting patches of red and black with a white band. Their legs and head are black; the abdomen is yellow with broad black bars across each segment. Egg masses can be seen from mid-October to early spring and are commonly laid along smooth tree trunks like the tree-of-heaven. However, they can be found on nearly any smooth outdoor surface. Their egg masses are grayish-brown in color and look like dry mud or putty. They can contain anywhere from 30-50 eggs each. Spotted lanternfly nymphs emerge in late spring or early summer. They are black with white spots and develop patches of red as they grow. What is being done to manage the spotted lanternfly in areas impacted by them?![]() The bad news is that this invasion is relatively new, and there is still a lot to learn about these pests. The good news is that they don’t seem to be very resilient against common insecticides. Researchers have found that Chlorpyrifos, a chemical commonly used in agricultural pesticides, effectively kills 100% of treated spotted lanternfly egg masses, while thiamethoxam and bifenthrin are found to be lethal to adults in less than two weeks. More commonly used products containing neem oil and insecticidal soap seem to be very effective as well. The greatest challenge though, is that spotted lanternflies are feeding on so many things in the surrounding landscape that even after an orchard or vineyard is treated, they may re-infest the area within a few days. Sticky bands placed on tree trunks are a great way to catch spotted lanternfly nymphs. They can be purchased at your local garden shop, or you can make your own by wrapping duct tape around the trunk of your tree with the sticky side facing outwards and securing it with push pins. |
If you’re a gardener, then you’re probably familiar with the Japanese beetle, Popillia japonica. First discovered in the United States in southern New Jersey in 1916, these small, metallic-green beetles are destructive plant pests that have spread well beyond their entry point. In fact, these beetles are present in most states east of the Mississippi River, and partial infestations occur in states like Arkansas, Iowa, and Kansas. Like any invasive species, the Japanese beetle lacks the natural “checks” that keep it at bay in its home, Japan. As a result, it has become a serious plant pest and threat to agriculture in the United States. Still, methods of controlling the pest have been developed over the years, and strict regulations and monitoring have prevented the pest’s establishment in some southern and western states.
What makes the Japanese beetle so destructive?
Japanese beetles are damaging both as adults and immatures (called larvae or grubs). The immature beetles develop in soil. These hungry grubs feed on roots of vegetation like grasses and other plants. Grubs often destroy turf grass in areas like golf courses and parks. They are quite efficient at destroying turf – the Japanese beetle is the most widespread turf-grass pest in the United States. Shockingly, it is estimated to cost over $460 million a year to control the beetle of which $234 million is spent on the immature stage alone.
When these grubs grow into adults, they become no less destructive! Adult Japanese beetles feed on the fruits and foliage of a wide range of plant species. In fact, Japanese beetles attack over 300 species of plants. Examples include shrubs, fruit trees, field crops, and ornamental trees. As adults satiate their hunger with this vegetation, they create skeletonized leaves along with large holes in leaves.
How can we control the Japanese beetle?
Control of the Japanese beetle is tricky. As a homeowner, there is no easy or quick fix to get rid of this bothersome beetle. Still, scientists at the USDA have created an integrated pest management (IPM) program that homeowners can utilize. As long as homeowners monitor the beetle populations (both as adults and immatures) and collaborate with neighbors, the program can be effective.
IPM is a control method that uses many different tactics to keep pest populations below damaging levels. Rather than eradicate pests, IPM seeks to control them, keeping in mind that reducing pest populations can have a damaging effect on beneficial organisms and the ecosystem as a whole. Therefore, IPM works to minimize impacts on the environment by using many control methods, including biological, cultural, mechanical, and chemical tactics. IPM also includes surveying the pests to keep track of their population size. Because it is clear that the Japanese beetle isn’t going anywhere, IPM allows us to realistically manage the pest. Simply applying chemical pesticides can be wasteful and environmentally damaging, so IPM is a great way to manage the beetle while minimizing environmental harm.
So, what does the IPM program for the Japanese beetle entail? Aside from using survey methods like trapping to keep up with the population size, the IPM plan also includes biological controls. This refers to using other organisms to kill the Japanese beetle. Some biocontrol agents include parasites, nematodes, and bacteria. Several of these are commercially available to homeowners. For example, milky spore, Bacillus papillae, refers to the spores of a bacterium that will infect the gut cells and enter the blood of Japanese beetles. Other methods for controlling the beetle include chemical controls (insecticides) and mechanical controls, such as hand-picking the beetles or using traps. It may be possible to simply shake beetles off plants each morning (due to their aggregation behavior) or pick them off by hand and knock them into a jar of soapy water. If choosing to use chemicals, make sure to follow all instructions and read labels carefully. Secondly, if you have any questions about these methods or would like more information, make sure to contract your county extension office.
Lastly, there are many plants that are resistant to the Japanese beetle that you can grow. Examples include hickory, red maple, tulip popular, ash, coreopsis, and more. For a more complete list, check out the USDA’s homeowner handbook to Japanese beetle (page 13) or contact your county extension office.
So, while the Japanese beetle causes a large amount of damage and is just plain annoying to many gardeners, there are control methods to combat it. They may seem like the bane of your garden, but there are several strategies besides pesticides that you can utilize with the help of neighbors and local extension agents!
References
Brandenburg, R., & Billeisen, T. (n.d.). Japanese Beetle. Retrieved November 3, 2020, from https://www.turffiles.ncsu.edu/insects/japanese-beetle-in-turf/
Daughtry, M., & Gaster, R. (2019, July 05). Japanese Beetles. Retrieved November 3, 2020, from https://lee.ces.ncsu.edu/2019/07/japanese-beetles-4/
United States, US Department of Agriculture, Animal and Plant Health Inspection Service. (2015, August). Managing the Japanese Beetle: A Homeowner's Handbook. Retrieved November 3, 2020, from https://www.aphis.usda.gov/plant_health/plant_pest_info/jb/downloads/JBhandbook.pdf
Mimosa (Albizia julibrissin) or silktree is native to the Middle East and Asia. It was introduced to the United States in the 1700’s, and since then it has invaded most of the southern half of the United States and some of the North Eastern states. Mimosa has been planted as an ornamental tree along roads and in yards because many people enjoy its summer time appearance. People are drawn to its pink pom-pom shaped flowers that appear from May to July and their fern-like leaves. Mimosa can be very large, growing as tall as 40 feet. It will produce green pods in the summer that will stay on the tree until the winter.
mimosa, Albizia julibrissin, Flower(s), photo by James H. Miller, forestryimages.org
Threat to our Native Species
Mimosa spreads very easily, it produces many seeds that can be dispersed by animals or water, and the seeds remain viable for many years. It prefers direct sunlight, so it tends to grow along road sides, on forest edges, vacant lots, old fields, and other open areas. Mimosa out competes our native flora for sunlight and resources. It grows very fast so it is able to outgrow our native plants easily. It can grow individually or form a dense colony and can create a monoculture disrupting our native species diversity.
Mimosa spreads very easily, it produces many seeds that can be dispersed by animals or water, and the seeds remain viable for many years. It prefers direct sunlight, so it tends to grow along road sides, on forest edges, vacant lots, old fields, and other open areas. Mimosa out competes our native flora for sunlight and resources. It grows very fast so it is able to outgrow our native plants easily. It can grow individually or form a dense colony and can create a monoculture disrupting our native species diversity.
How to Eradicate
Young saplings can simply be pulled out of the ground, but for larger trees the best way is to cut down the tree and treat the outer 2 inches with undiluted glyphosate concentrate. If the pods are on the tree they need to be collected and bagged so that they are not able to sprout.
If you are looking to plant or replace mimosa trees, two native alternative species are Red Buckeye (Aesculus pavia) and Eastern Redbud (Cercis canadensis).
Young saplings can simply be pulled out of the ground, but for larger trees the best way is to cut down the tree and treat the outer 2 inches with undiluted glyphosate concentrate. If the pods are on the tree they need to be collected and bagged so that they are not able to sprout.
If you are looking to plant or replace mimosa trees, two native alternative species are Red Buckeye (Aesculus pavia) and Eastern Redbud (Cercis canadensis).
Red Buckeye Eastern Redbud
red buckeye, Aesculus pavia, Tree(s), Photo by John Ruter, Forestryimages.org eastern redbud, Cercis canadensis, Cultivar, Photo by James Chatfield, forestry images.org
red buckeye, Aesculus pavia, Tree(s), Photo by John Ruter, Forestryimages.org eastern redbud, Cercis canadensis, Cultivar, Photo by James Chatfield, forestry images.org
References
Meyer, Rachelle. 2010. Albizia julibrissin. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: https://www.fs.fed.us/database/feis/plants/tree/albjul/all.html [ 2020, October 29 ].
NC Forest Service. (2010, January 3). Invasive Species Leaflet: Alibizia julibrissin (Mimosa). https://www.ncforestservice.gov/publications/Forestry%20Leaflets/IS13.pdf
NCSU Extension. (n.d.). Invasive, Exotic Plants of the Southeast: Mimosa. https://projects.ncsu.edu/goingnative/howto/mapping/invexse/mimosa.html
Meyer, Rachelle. 2010. Albizia julibrissin. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: https://www.fs.fed.us/database/feis/plants/tree/albjul/all.html [ 2020, October 29 ].
NC Forest Service. (2010, January 3). Invasive Species Leaflet: Alibizia julibrissin (Mimosa). https://www.ncforestservice.gov/publications/Forestry%20Leaflets/IS13.pdf
NCSU Extension. (n.d.). Invasive, Exotic Plants of the Southeast: Mimosa. https://projects.ncsu.edu/goingnative/howto/mapping/invexse/mimosa.html
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If you read our previous blog post about hemlocks, then you know that the eastern hemlock and Carolina hemlock are currently being destroyed across the Appalachian region due to an invasive pest known as the hemlock woolly adelgid. There have been many efforts to conserve the hemlock tree and protect it from extinction, including insecticides to kill the pest, and biocontrol, where another organism is released into the ecosystem to prey on the invasive species. There is another method currently being used for hemlock conservation, which involves the use of biotechnology.
To understand how biotechnology can be used to conserve the hemlock trees, we need to look at another case study from a few years ago: the American chestnut tree. In the early 1900s, the chestnut blight began destroying chestnut trees across the United States. The chestnut blight, Cryphonectria parasitica, is a fungus that essentially suffocates the tree through formation of cankers, inhibiting it from growing more than a couple of feet high. The chestnut blight drove nearly all American chestnut trees to functional extinction in less than 50 years.
This problem had two major solutions that were explored, with the first solution being to cross the American chestnut with a similar species that is resistant to the blight. In this case, that other species would be Chinese chestnut. The cisgenic organism that would result from this hybridization would be mostly American chestnut with a few Chinese chestnut genes, hopefully including the gene(s) that help give the tree resistance against the blight.
Another solution is to create a transgenic American chestnut. Transgenic trees are genetically modified using genes from an unrelated species, while cisgenic trees are genetically modified with genes from a related species. Scientists found that they could genetically modify the American chestnut and insert a gene from wheat called oxalate oxidase, which gives the tree resistance against the chestnut blight without having to cross it with the Chinese chestnut.
There have also been more recent advancements in the field of biotechnology that make the process of genetic modification faster and easier, like CRISPR. CRISPR stands for clustered regularly interspaced short palindromic repeats, and it is a relatively new tool that can be used for genetic engineering, and can potentially be used for species conservation for trees like hemlocks.
How does that work?
Since this is a complex topic, I’ve reached out to PhD student Bárbara Machado Marques, who is currently doing research with CRISPR at the Forest Biotechnology Group at NC State, to ask for her insight surrounding genetic engineering and its applications for conservation.
“In general,” Bárbara began, “biotechnology can be defined as the use of any living organism or biological process for an application. This often involves the manipulation of genetic material. So for example, beer is the oldest biotechnological product made by humans because we take advantage of the fermentation process. Also, insulin is a product isolated from bacteria cells. We’ve genetically engineered this bacteria to produce something we need.”
How does CRISPR work, and how does it fall under the category of biotechnology?
“The CRISPR system works like DNA scissors,” she explained. “We use a piece of RNA to guide this nuclease called Cas9 into our target DNA in the genome. When you find this target sequence, it is able to clip this piece of DNA and it breaks the two strands of DNA. And because eukaryotic cells have a really cool tool for DNA repair, when it breaks, the cell is able to repair it. And when it does, something happens that usually changes the DNA. In other words, it inserts one or two bases. It often deletes bases, and when it changes this DNA region, usually the gene doesn’t have function anymore.”
So, what does this have to do with hemlock trees?
“I am currently working with the application of CRISPR technologies into conifer species, which includes Fraser fir, Christmas trees, and hemlock trees,” Bárbara explained. “We use somatic embryogenesis, which is a really cool tool for engineering conifers with all the constraints involved in the transformation of trees. I’m trying to design a protocol for the use of CRISPR on these trees.”
It may seem as though genetic engineering for hemlock trees is unnecessary, especially when considering the other methods that are being used to control the HWA spread. Unfortunately, it is possible that those methods may not be enough to protect the hemlock trees on a long term scale.
“From what you’ve seen in your research, do you think hemlock trees are in danger of going extinct within the next few years?” I asked Bárbara.
“I, unfortunately, think so,” she replied. “Because of climate change, this is a serious issue. The woolly adelgid is actually sensitive to cold, so that’s why the most resistant hemlock trees are located up in the mountains. And it’s the same for Fraser fir. So with climate change, it raises the temperature of everything and it actually helps to spread the woolly adelgid or any other insect. It becomes impossible to control.”
I asked, “So when you’re using CRISPR on hemlocks, what genes are you targeting?”
“That’s the problem with conifers,” she answered. “Because their genome is not sequenced, so we don’t know which genes regulate pathogen resistance or cold resistance. We don’t know much about the genome of conifers. So the first step of applying CRISPR is to see if it works. We’re targeting a particular gene right now. Once this gene is targeted, the plants turn white because they are unable to produce chlorophyll anymore. So when we target this gene, we can actually see if the CRISPR system is working or not. But other genes that are more relevant for conservation, we don’t know yet. This is more functional characterization of the genes.
“The questions are ‘What are the differences between the Chinese hemlock and the Carolina hemlock? What things on the genomes of the Chinese hemlock make it resistant, and how can we use that with CRISPR to introduce this resistance to the [eastern and Carolina] hemlock too?’ And it could be a lot of genes, or it could be only one single base pair.”
“How do you feel like your research is going to help conserve hemlock trees and other tree species?”
“So, what happened to the hemlock trees here, the Carolina hemlock and the eastern hemlock, is that they didn’t coevolve with this woolly adelgid insect. So, they didn’t get any resistance like the Chinese hemlock. The Chinese hemlocks are resistant because they coevolved with this insect, so they were selected to have some tool inside them to be able to survive with this insect. And because of climate change, there is no time for the eastern hemlock and Carolina hemlock to evolve and be able to naturally develop resistance against this insect.
“Here’s where CRISPR is important, because CRISPR can accelerate this process,” she continued. “We can induce mutations that could easily occur naturally, but in a shorter amount of time. Tree breeding programs, artificial selection of traits through crossing of resistant individuals and native individuals, usually take decades to generate good results. By establishing methods for the use of CRISPR as a genome editing tool in trees, the selection of resistant individuals is straightforward, saving the time hemlock trees do not have. So that’s what CRISPR could give to the hemlocks -- time. That’s the main point of using CRISPR.”
So, if we look back at the American chestnut case, scientists were successful in using this genetic engineering to take a gene from wheat and insert it into the genome to create a transgenic tree. It appears that as more research on conifers is collected, there is a possibility that something similar to what was done for the chestnut could be done for the hemlocks, whether that means a gene from the Chinese hemlock or a gene from a completely unrelated species is utilized in the process. But will this experiment be well received?
“Public reception for the American chestnut wasn't great,” Bárbara noted. “You know, we have a plant that is resistant to the disease, we could apply it to forests, and it’s not there because it’s transgenic. For many years, and even now, transgenics have a very negative image on the general public, for many reasons. Everybody has heard that word and associates it with something bad. So the public acceptance for a plant that was transformed with CRISPR could be greater than it was with the American chestnut because CRISPR is new. It always depends on the public acceptance. If technology has potential, and you do not do the work of explaining and combating fake news, you’ll never be able to apply it.”
I asked, “Do you think that being more transparent and upfront about what’s being done will make people feel more accepting of it?”
“I think the most important thing for people to know is that we are not doing this without safety and without thinking through what we’re doing,” she replied. “It is scary at some points because there is so much you can do with CRISPR, but we’re not going to throw a genetically engineered tree into the forest without seeing how it interacts with other organisms and what disruptive consequences it could have. It’s important to be clear that there are ethics involved. CRISPR brings a new opportunity for scientists to develop products that do not use transgenic techniques, and are new to the public. Even so, I believe that a main effort has to be made to inform the public about how this technology works and what its potential is.”
Works Cited
Barakat, A., DiLoreto, D.S., Zhang, Y. et al. Comparison of the transcriptomes of American chestnut (Castanea dentata) and Chinese chestnut (Castanea mollissima) in response to the chestnut blight infection. BMC Plant Biol 9, 51 (2009). https://doi.org/10.1186/1471-2229-9-51
Interview with Bárbara Machado Marques [Online interview]. (2020, October 27).
Zhang, B., Oakes, A.D., Newhouse, A.E. et al. A threshold level of oxalate oxidase transgene expression reduces Cryphonectria parasitica-induced necrosis in a transgenic American chestnut (Castanea dentata) leaf bioassay. Transgenic Res 22, 973–982 (2013). https://doi-org.prox.lib.ncsu.edu/10.1007/s11248-013-9708-5
Photography:
Dr. Benjamin Smith, Forest Restoration Alliance, threatenedforests.com
Joseph OBrien, USDA Forest Service, Bugwood.org
To understand how biotechnology can be used to conserve the hemlock trees, we need to look at another case study from a few years ago: the American chestnut tree. In the early 1900s, the chestnut blight began destroying chestnut trees across the United States. The chestnut blight, Cryphonectria parasitica, is a fungus that essentially suffocates the tree through formation of cankers, inhibiting it from growing more than a couple of feet high. The chestnut blight drove nearly all American chestnut trees to functional extinction in less than 50 years.
This problem had two major solutions that were explored, with the first solution being to cross the American chestnut with a similar species that is resistant to the blight. In this case, that other species would be Chinese chestnut. The cisgenic organism that would result from this hybridization would be mostly American chestnut with a few Chinese chestnut genes, hopefully including the gene(s) that help give the tree resistance against the blight.
Another solution is to create a transgenic American chestnut. Transgenic trees are genetically modified using genes from an unrelated species, while cisgenic trees are genetically modified with genes from a related species. Scientists found that they could genetically modify the American chestnut and insert a gene from wheat called oxalate oxidase, which gives the tree resistance against the chestnut blight without having to cross it with the Chinese chestnut.
There have also been more recent advancements in the field of biotechnology that make the process of genetic modification faster and easier, like CRISPR. CRISPR stands for clustered regularly interspaced short palindromic repeats, and it is a relatively new tool that can be used for genetic engineering, and can potentially be used for species conservation for trees like hemlocks.
How does that work?
Since this is a complex topic, I’ve reached out to PhD student Bárbara Machado Marques, who is currently doing research with CRISPR at the Forest Biotechnology Group at NC State, to ask for her insight surrounding genetic engineering and its applications for conservation.
“In general,” Bárbara began, “biotechnology can be defined as the use of any living organism or biological process for an application. This often involves the manipulation of genetic material. So for example, beer is the oldest biotechnological product made by humans because we take advantage of the fermentation process. Also, insulin is a product isolated from bacteria cells. We’ve genetically engineered this bacteria to produce something we need.”
How does CRISPR work, and how does it fall under the category of biotechnology?
“The CRISPR system works like DNA scissors,” she explained. “We use a piece of RNA to guide this nuclease called Cas9 into our target DNA in the genome. When you find this target sequence, it is able to clip this piece of DNA and it breaks the two strands of DNA. And because eukaryotic cells have a really cool tool for DNA repair, when it breaks, the cell is able to repair it. And when it does, something happens that usually changes the DNA. In other words, it inserts one or two bases. It often deletes bases, and when it changes this DNA region, usually the gene doesn’t have function anymore.”
So, what does this have to do with hemlock trees?
“I am currently working with the application of CRISPR technologies into conifer species, which includes Fraser fir, Christmas trees, and hemlock trees,” Bárbara explained. “We use somatic embryogenesis, which is a really cool tool for engineering conifers with all the constraints involved in the transformation of trees. I’m trying to design a protocol for the use of CRISPR on these trees.”
It may seem as though genetic engineering for hemlock trees is unnecessary, especially when considering the other methods that are being used to control the HWA spread. Unfortunately, it is possible that those methods may not be enough to protect the hemlock trees on a long term scale.
“From what you’ve seen in your research, do you think hemlock trees are in danger of going extinct within the next few years?” I asked Bárbara.
“I, unfortunately, think so,” she replied. “Because of climate change, this is a serious issue. The woolly adelgid is actually sensitive to cold, so that’s why the most resistant hemlock trees are located up in the mountains. And it’s the same for Fraser fir. So with climate change, it raises the temperature of everything and it actually helps to spread the woolly adelgid or any other insect. It becomes impossible to control.”
I asked, “So when you’re using CRISPR on hemlocks, what genes are you targeting?”
“That’s the problem with conifers,” she answered. “Because their genome is not sequenced, so we don’t know which genes regulate pathogen resistance or cold resistance. We don’t know much about the genome of conifers. So the first step of applying CRISPR is to see if it works. We’re targeting a particular gene right now. Once this gene is targeted, the plants turn white because they are unable to produce chlorophyll anymore. So when we target this gene, we can actually see if the CRISPR system is working or not. But other genes that are more relevant for conservation, we don’t know yet. This is more functional characterization of the genes.
“The questions are ‘What are the differences between the Chinese hemlock and the Carolina hemlock? What things on the genomes of the Chinese hemlock make it resistant, and how can we use that with CRISPR to introduce this resistance to the [eastern and Carolina] hemlock too?’ And it could be a lot of genes, or it could be only one single base pair.”
“How do you feel like your research is going to help conserve hemlock trees and other tree species?”
“So, what happened to the hemlock trees here, the Carolina hemlock and the eastern hemlock, is that they didn’t coevolve with this woolly adelgid insect. So, they didn’t get any resistance like the Chinese hemlock. The Chinese hemlocks are resistant because they coevolved with this insect, so they were selected to have some tool inside them to be able to survive with this insect. And because of climate change, there is no time for the eastern hemlock and Carolina hemlock to evolve and be able to naturally develop resistance against this insect.
“Here’s where CRISPR is important, because CRISPR can accelerate this process,” she continued. “We can induce mutations that could easily occur naturally, but in a shorter amount of time. Tree breeding programs, artificial selection of traits through crossing of resistant individuals and native individuals, usually take decades to generate good results. By establishing methods for the use of CRISPR as a genome editing tool in trees, the selection of resistant individuals is straightforward, saving the time hemlock trees do not have. So that’s what CRISPR could give to the hemlocks -- time. That’s the main point of using CRISPR.”
So, if we look back at the American chestnut case, scientists were successful in using this genetic engineering to take a gene from wheat and insert it into the genome to create a transgenic tree. It appears that as more research on conifers is collected, there is a possibility that something similar to what was done for the chestnut could be done for the hemlocks, whether that means a gene from the Chinese hemlock or a gene from a completely unrelated species is utilized in the process. But will this experiment be well received?
“Public reception for the American chestnut wasn't great,” Bárbara noted. “You know, we have a plant that is resistant to the disease, we could apply it to forests, and it’s not there because it’s transgenic. For many years, and even now, transgenics have a very negative image on the general public, for many reasons. Everybody has heard that word and associates it with something bad. So the public acceptance for a plant that was transformed with CRISPR could be greater than it was with the American chestnut because CRISPR is new. It always depends on the public acceptance. If technology has potential, and you do not do the work of explaining and combating fake news, you’ll never be able to apply it.”
I asked, “Do you think that being more transparent and upfront about what’s being done will make people feel more accepting of it?”
“I think the most important thing for people to know is that we are not doing this without safety and without thinking through what we’re doing,” she replied. “It is scary at some points because there is so much you can do with CRISPR, but we’re not going to throw a genetically engineered tree into the forest without seeing how it interacts with other organisms and what disruptive consequences it could have. It’s important to be clear that there are ethics involved. CRISPR brings a new opportunity for scientists to develop products that do not use transgenic techniques, and are new to the public. Even so, I believe that a main effort has to be made to inform the public about how this technology works and what its potential is.”
Works Cited
Barakat, A., DiLoreto, D.S., Zhang, Y. et al. Comparison of the transcriptomes of American chestnut (Castanea dentata) and Chinese chestnut (Castanea mollissima) in response to the chestnut blight infection. BMC Plant Biol 9, 51 (2009). https://doi.org/10.1186/1471-2229-9-51
Interview with Bárbara Machado Marques [Online interview]. (2020, October 27).
Zhang, B., Oakes, A.D., Newhouse, A.E. et al. A threshold level of oxalate oxidase transgene expression reduces Cryphonectria parasitica-induced necrosis in a transgenic American chestnut (Castanea dentata) leaf bioassay. Transgenic Res 22, 973–982 (2013). https://doi-org.prox.lib.ncsu.edu/10.1007/s11248-013-9708-5
Photography:
Dr. Benjamin Smith, Forest Restoration Alliance, threatenedforests.com
Joseph OBrien, USDA Forest Service, Bugwood.org
The air is crisp, leaves are turning brilliant shades of yellow, orange, and red, and pumpkin spice is everywhere. This is also that time of year when Autumn olive, Elaeagnus umbellata is exploding with ripe red berries. Once a plant reaches 2-3 years of age a single shrub can produce up to 80 pounds of fruit annually. These red berries are highly desired by much of our native wildlife including raccoons, skunks, opossums, black bears, and songbirds such as thrushes, cardinals, cedar waxwings, sparrows, and northern bobwhite, consequently aiding in the dispersal of seeds through their excrement.
Growing best in full sun, Autumn olive, also referred to as Japanese silverberry, can persist in the low light conditions of the forest canopy. It is drought tolerant and well adapted to grow in sandy, loam, or clay-based soils. Because of its versatility of growing conditions and the aid of seed dispersal from our native wildlife, Autumn olive has been able to become well-established throughout the Eastern U. S., ranging from Maine and Wisconsin in the North to Florida and Louisiana in the South, and as far west as Nebraska. It has successfully invaded grasslands and woodlands, though it is most prevalent in recently disturbed areas, pastures, and fields.
How did autumn olive get here?
It’s important to note that the concept of alien or invasive species didn’t take hold until the mid-1900s. In the 1800s severe erosion, sedimentation, and landslides were significant concerns in the United States. Autumn olive, a deciduous shrub native to eastern Asia, seemed to be the perfect solution as it is drought, disease, and insect resistant and can grow in a variety of environmental conditions. Additionally, it had the potential to restore deforested and degraded lands, provide windbreaks and highway barriers, and served as wildlife cover and food.
Although Autumn olive was first introduced into the United States from Asia in 1830, the real expansion of its spread occurred between 1940-1970 when soil conservation districts introduced it through their spring plant sales. They released a variety called ‘Cardinal’ that was known for its prolific red berries, which is the one most commonly encountered today (Voyle 2011).
Although Autumn olive was first introduced into the United States from Asia in 1830, the real expansion of its spread occurred between 1940-1970 when soil conservation districts introduced it through their spring plant sales. They released a variety called ‘Cardinal’ that was known for its prolific red berries, which is the one most commonly encountered today (Voyle 2011).
Why is Autumn olive a threat?
The USDA categorizes Autumn olive as a problematic invasive plant species. As mentioned above Autumn olive thrives under a wide variety of environmental conditions, and a single plant can produce up to 80 pounds of viable seeds dispersed by wildlife annually. Additionally, it is a fast-growing shrub that can often reach up to 20 feet tall in as little as a few years, shading out and ultimately outcompetes our native wildflowers and tree saplings. As a nitrogen-fixing plant (plants that have bacteria living around their roots used to extract nitrogen from the air and convert it into a form required by plants for their growth), Autumn olive can also adversely affect the nitrogen cycle of the native plant communities that depend on infertile soils.
How to identify Autumn Olive
![Picture](/uploads/1/3/3/5/133509311/published/img-2689.jpeg?1603482399)
Autumn olive is easily identified during the spring because it develops leaves while most of our native vegetation is still dormant. Its bell-shaped, cream to pale yellow flowers bloom in early spring through late summer. Late summer through fall (August- November) offers another optimal time to identify Autumn olive by their fruit which ripens to a showy bright red.
Autumn olive is a large shrub growing 3.5 to 5m tall and up to 6m across. The leaves are dark green on top with a silvery-white underside. They are oval to lance-shaped and arranged in an alternate pattern on the stem. The leaves also have a wavy appearance, which is much different from any of our other native foliage. New growth stems typically have a rusty colored appearance, while older branches sometimes develop thorns.
You can also email a photo to your local university extension office or use a plant app like LeafSnap or iNaturalist to help you confirm an identification if you’re unsure.
Autumn olive is a large shrub growing 3.5 to 5m tall and up to 6m across. The leaves are dark green on top with a silvery-white underside. They are oval to lance-shaped and arranged in an alternate pattern on the stem. The leaves also have a wavy appearance, which is much different from any of our other native foliage. New growth stems typically have a rusty colored appearance, while older branches sometimes develop thorns.
You can also email a photo to your local university extension office or use a plant app like LeafSnap or iNaturalist to help you confirm an identification if you’re unsure.
What can we do to manage autumn olive?
Repeat pruning and prescribed fire have been found to not be the most effective methods in controlling and eradicating Autumn olive. The most effective way to control this plant is with a combination of mechanical and chemical treatments. Small plants can be eradicated by hand pulling in the spring when the ground is moist. For shrubs around 3-5ft. tall we recommend using a weed wrench to ensure you have removed the deep taproot.
For larger shrubs, we recommend killing the taproot with the cut-stump method and applying either glyphosate, triclopyr, or picloram herbicide like RoundUp, Vastlan® herbicide (Garlon® 3A), or Garlon® 4 directly to the stump. The Missouri Department of Conservation suggests that Roundup herbicide (a formulation of glyphosate) has been effective in controlling autumn olive when used as a 10-20% solution and applied directly to the cut stump as described above. Although the RoundUp label specifies a higher concentration for cut-stump application (50 to 100 percent), this lower concentration has proven effective. The best time for the cut-stump method is from July-October, during the late growing season. Cut the plant down as close to the main stem as you can, and apply the herbicide directly to the cut stump. We recommend using a sponge applicator to apply the herbicide directly to the stump rather than a spray nozzle as the herbicide will cause damage to any other plants it comes in contact with. A sponge applicator can be purchased in the paint area of your local hardware store. If you are treating Autumn olive near a wetland, use an herbicide that is safe for use around water like RoundUp Rodeo®. As always, when using herbicides please read and follow the directions carefully.
For larger shrubs, we recommend killing the taproot with the cut-stump method and applying either glyphosate, triclopyr, or picloram herbicide like RoundUp, Vastlan® herbicide (Garlon® 3A), or Garlon® 4 directly to the stump. The Missouri Department of Conservation suggests that Roundup herbicide (a formulation of glyphosate) has been effective in controlling autumn olive when used as a 10-20% solution and applied directly to the cut stump as described above. Although the RoundUp label specifies a higher concentration for cut-stump application (50 to 100 percent), this lower concentration has proven effective. The best time for the cut-stump method is from July-October, during the late growing season. Cut the plant down as close to the main stem as you can, and apply the herbicide directly to the cut stump. We recommend using a sponge applicator to apply the herbicide directly to the stump rather than a spray nozzle as the herbicide will cause damage to any other plants it comes in contact with. A sponge applicator can be purchased in the paint area of your local hardware store. If you are treating Autumn olive near a wetland, use an herbicide that is safe for use around water like RoundUp Rodeo®. As always, when using herbicides please read and follow the directions carefully.
As the title suggests, if you can’t beat them, eat them!
Although I hope we can, we might not be able to ever completely eradicate Autumn olive from North America. The berries produced are edible, and if you’re fast enough to beat out our native wildlife, why not put them to good? As a bonus, researchers found that Autumn olive berries contain high levels of lycopene, a powerful antioxidant also found in tomatoes, watermelon, guava, papaya, and pink grapefruit. The time is right for foraging Autumn olive berries, and we found some excellent recipes, and urge you to try them out! Foraging is an ancient art and should be done with extreme caution. If there is the slightest feeling of doubt on a plant ID, it’s best to just move along.
Lemon Autumn Olive Berry TartePrep Time: 15 minutes Cook Time: 15 minutes Yield: Makes 1 pie Ingredients 1 cup unbleached all purpose flour 1/2 cup softened butter1/4 cup icing sugar 2 large eggs 1 cup organic cane sugar 1/2 tsp baking powder 2 tbsp fresh squeezed lemon juice 1 to 1 1/2 cups of autumn olive berries Instructions 1. Heat oven to 350°F 2. Thoroughly mix the flour, butter and icing sugar. Press in an ungreased pie plate or 8x8x2 baking pan. Build up the edges so that there is a half inch edge. 3. Bake pie crust for 15-20 minutes, remove when lightly golden brown. 4. Beat remaining ingredients except the berries until the mixture is light and fluffy. Fold in the berries. Pour over the cooked hot crust. 5. Bake about 20 minutes until set, or no imprint remains when lightly touched. Autumn Berry Fruit LeatherYield: 2 fruit roll trays in an average dehydrator Ingredients 6 cups of Autumn olive berries, rinsed & strained 2 tablespoons honey (or to taste) Instructions 1. Stir berries in pot over medium-high heat until berries have burst and begin to bubble in their own pulp. Some berries will still be unbroken but burst easily when pressed between the side of the pot and a spoon. 2. Remove from heat and ladle into a food mill, passing them through the food mill into another pot or container. Put the seeds and pulp from the food mill aside. (You can use these to feed chickens or wildlife, the seeds are no longer fertile since they have been boiled. Use in your compost if you like.) 3. Add honey to the pulp to taste. If you harvested your berries early in the season you may have to add more honey. Be sure to put in at least some honey or your fruit leather will not be very flexible and will stick to the tray when dehydrating. 4. Oil your fruit roll trays with vegetable or olive oil (thin coating). Dehydrate at 57°C (125-135°F). If you do not have a dehydrator, a cookie sheet with parchment on it will do; dry in the oven at 57°C (135°F) for 6 hours or until fruit roll is no longer sticky. 5. Cut roll into serving-sized slices (or bits to be used as salad topping, etc.) and store in an airtight container. If still tacky/sticky in some areas you can store in the refrigerator or freeze for long-term storage. | Autumn Berry CookiesPrep Time: 15 minutes Cook Time: 15 minutes Yield: 12 servings Ingredients 1/2 cup butter 1/4 cup organic cane sugar 1/3 cup light or dark brown sugar 1 egg 1 tsp vanilla extract 2 tbsp milk 1/2 tsp salt 1/4 tsp baking soda 1/2 tsp baking powder 1 1/4 cups unbleached flour 2 cups autumn olive berries Instructions 1. Preheat oven to 350°F. 2. Line a baking sheet with parchment paper. 3. Cream sugars with the butter. Add the egg, vanilla extract and milk then mix well. 4. In a separate bowl combine all dry ingredients. Then, slowly add the wet mixture into the dry mixture and continue to stir until completely mixed. 5.Once all ingredients are blended fold in the autumn olive berries. 6. Drop by spoonfuls onto the baking sheet leaving about 1” between cookies. 7. Bake 12-15 minutes until thoroughly baked (test with a toothpick to ensure the centre is dry). |
Recipes courtesy of ediblewildfood.com & thecookscook.com
Resources
Autumn olive control. Missouri Department of Conservation (n.d.). Retrieved from https://mdc.mo.gov/trees-plants/problem-plant-control/invasive-plants/autumn-olive-control
Black, B. L., Fordham, I. M., & Perkins-Veazie, P. (2005). Autumnberry (elaeagnus umbellata): A potential cash crop. Journal of the American Pomological Society, 59(3), 125-134. Retrieved from https://proxying.lib.ncsu.edu/index.php/login?url=https://www-proquest-com.prox.lib.ncsu.edu/docview/209776248?accountid=12725
Oliphant, A. J., Wynne, R. H., Zipper, C. E., Ford, W. M., Donovan, P. F., & Li, J. (2016;2017;). Autumn olive (elaeagnus umbellata) presence and proliferation on former surface coal mines in eastern USA. Biological Invasions, 19(1), 179-195. doi:10.1007/s10530-016-1271-6
Voyle, G. (December 1, 2011). Autumn olive: one invasive shrub. https://www.canr.msu.edu/news/autumn_olive_one_invasive_shrub
Black, B. L., Fordham, I. M., & Perkins-Veazie, P. (2005). Autumnberry (elaeagnus umbellata): A potential cash crop. Journal of the American Pomological Society, 59(3), 125-134. Retrieved from https://proxying.lib.ncsu.edu/index.php/login?url=https://www-proquest-com.prox.lib.ncsu.edu/docview/209776248?accountid=12725
Oliphant, A. J., Wynne, R. H., Zipper, C. E., Ford, W. M., Donovan, P. F., & Li, J. (2016;2017;). Autumn olive (elaeagnus umbellata) presence and proliferation on former surface coal mines in eastern USA. Biological Invasions, 19(1), 179-195. doi:10.1007/s10530-016-1271-6
Voyle, G. (December 1, 2011). Autumn olive: one invasive shrub. https://www.canr.msu.edu/news/autumn_olive_one_invasive_shrub
The emerald ash borer, Agrilus planipennis, may have a beautiful, metallic green color, but its looks are deceiving. This invasive beetle, which was first discovered in the United States near Detroit, Michigan in 2002, destroys our ash (Fraxinus) trees. In fact, the emerald ash borer has killed tens of millions of ash trees since it was introduced into the U.S. The pesky beetle has traveled from its entry point to many central and eastern U.S. states as well as eastern Canada. In North Carolina, the beetle was initially found in Granville, Person, Vance, and Warren counties in 2013, but it has since spread to about 60 counties. The pest is moving quickly and killing our ash trees in the process.
How did the emerald ash borer arrive?
The emerald ash borer hails from Asia. It is native to Japan, China, Korea, and parts of Russia. Since this beetle is a wood-borer, it likely entered near Detroit, Michigan through wood packing material made of ash. The beetle is capable of flying to a new host tree after it emerges, but it only moves a few miles per year in this manner. It is transported long distances through ash products. So...we’ve said it before and we’ll say it again: don’t move firewood! Even transporting firewood across county lines can move wood-boring pests significant distances.
What’s the big deal?
Adults of the emerald ash borer lay eggs on our ash trees. Once these eggs on the bark of the ash trees hatch, the new immature beetles bore beneath the bark and feed on the inside of the tree. Since these hungry beetles eat the tissues that transport food and water within the trees, the movement of water and nutrients is disrupted, and the trees die.
The emerald ash borer may kill many of our ash species in North Carolina, including white ash, green ash, Carolina ash, and pumpkin ash. Unlike our native wood-boring beetles, the emerald ash borer will attack either healthy or unhealthy trees, so many of our ash trees are vulnerable. The pest may also attack white fringetree.
Even though ash trees make up a small part of our native forests and pure stands of ash are rare in North Carolina, these trees are important. The wood is strong and elastic, so it is very useful and of high value. The wood may be used in products like baseball bats, furniture, bows, and more. In urban areas, ash is particularly important as a street tree, and it can provide benefits to cities by cooling them. Many animals feed on ash leaves and seeds.
The loss of ash in the United States would cause many issues. Researchers found that the loss of ash could have significant effects on the productivity of forests and the ability of forests to store carbon (which mitigates climate change). Forests with high numbers of ash will experience large losses of productivity that are not likely to be replaced by the growth of other tree species. There are even human health implications. After studying 15 states in the U.S., researchers found that the death of ash trees caused by emerald ash borer increased human mortality from cardiovascular and lower respiratory illnesses!
What are the current management practices?
Research is actively being conducted on the best management practices to combat emerald ash borer. For example, at NC State University, scientists are studying ash stands to pick out the trees that survive in the wake of emerald ash borer infestations. Their hope is to figure out if some sort of genetic resistance occurs in certain ash trees, which may help in restoring ash trees.
For now, the best management practice is to reduce the spread of emerald ash borer. This may involve quickly detecting the beetle and then cutting down infested trees. The entire state of North Carolina is also under quarantine for emerald ash borer, meaning firewood or other materials that could be infested with emerald ash borer cannot be moved outside of the quarantine area. Insecticides may be used to protect trees when emerald ash borer is closeby. Chemicals may also be used to help individual trees recover, but the recovery is slow and re-treatment must take place each year or two, so this method can be costly.
Interestingly, there are three species of parasitoid wasps from China that have been released in the U.S. to combat emerald ash borer (a management practice called biocontrol). These tiny wasps kill emerald ash borer by laying eggs inside or on the beetles’ larvae or eggs. The wasps then consume the immature beetles and kill them. Extensive research was conducted before these wasps were released to ensure they would have no adverse effects on the ecosystem. The NC Forest Service releases the wasps at four different sites.
What are the signs and symptoms of emerald ash borer?
Signs and symptoms of an emerald ash borer infestation within an ash tree include cracks in the bark, dieback, D-shaped exit holes, epicormic sprouting (sprouting occurring from the main stem of the tree), and increased woodpecker activity (woodpeckers enjoy emerald ash borer as a snack). When the bark is peeled back, tunnels created by emerald ash borer larvae are visible.
If you think you have spotted emerald ash borer, you can contact your county ranger through the NC Forest Service or your county extension office. Above all, make sure that you do not transport wood that could be infested!
How did the emerald ash borer arrive?
The emerald ash borer hails from Asia. It is native to Japan, China, Korea, and parts of Russia. Since this beetle is a wood-borer, it likely entered near Detroit, Michigan through wood packing material made of ash. The beetle is capable of flying to a new host tree after it emerges, but it only moves a few miles per year in this manner. It is transported long distances through ash products. So...we’ve said it before and we’ll say it again: don’t move firewood! Even transporting firewood across county lines can move wood-boring pests significant distances.
What’s the big deal?
Adults of the emerald ash borer lay eggs on our ash trees. Once these eggs on the bark of the ash trees hatch, the new immature beetles bore beneath the bark and feed on the inside of the tree. Since these hungry beetles eat the tissues that transport food and water within the trees, the movement of water and nutrients is disrupted, and the trees die.
The emerald ash borer may kill many of our ash species in North Carolina, including white ash, green ash, Carolina ash, and pumpkin ash. Unlike our native wood-boring beetles, the emerald ash borer will attack either healthy or unhealthy trees, so many of our ash trees are vulnerable. The pest may also attack white fringetree.
Even though ash trees make up a small part of our native forests and pure stands of ash are rare in North Carolina, these trees are important. The wood is strong and elastic, so it is very useful and of high value. The wood may be used in products like baseball bats, furniture, bows, and more. In urban areas, ash is particularly important as a street tree, and it can provide benefits to cities by cooling them. Many animals feed on ash leaves and seeds.
The loss of ash in the United States would cause many issues. Researchers found that the loss of ash could have significant effects on the productivity of forests and the ability of forests to store carbon (which mitigates climate change). Forests with high numbers of ash will experience large losses of productivity that are not likely to be replaced by the growth of other tree species. There are even human health implications. After studying 15 states in the U.S., researchers found that the death of ash trees caused by emerald ash borer increased human mortality from cardiovascular and lower respiratory illnesses!
What are the current management practices?
Research is actively being conducted on the best management practices to combat emerald ash borer. For example, at NC State University, scientists are studying ash stands to pick out the trees that survive in the wake of emerald ash borer infestations. Their hope is to figure out if some sort of genetic resistance occurs in certain ash trees, which may help in restoring ash trees.
For now, the best management practice is to reduce the spread of emerald ash borer. This may involve quickly detecting the beetle and then cutting down infested trees. The entire state of North Carolina is also under quarantine for emerald ash borer, meaning firewood or other materials that could be infested with emerald ash borer cannot be moved outside of the quarantine area. Insecticides may be used to protect trees when emerald ash borer is closeby. Chemicals may also be used to help individual trees recover, but the recovery is slow and re-treatment must take place each year or two, so this method can be costly.
Interestingly, there are three species of parasitoid wasps from China that have been released in the U.S. to combat emerald ash borer (a management practice called biocontrol). These tiny wasps kill emerald ash borer by laying eggs inside or on the beetles’ larvae or eggs. The wasps then consume the immature beetles and kill them. Extensive research was conducted before these wasps were released to ensure they would have no adverse effects on the ecosystem. The NC Forest Service releases the wasps at four different sites.
What are the signs and symptoms of emerald ash borer?
Signs and symptoms of an emerald ash borer infestation within an ash tree include cracks in the bark, dieback, D-shaped exit holes, epicormic sprouting (sprouting occurring from the main stem of the tree), and increased woodpecker activity (woodpeckers enjoy emerald ash borer as a snack). When the bark is peeled back, tunnels created by emerald ash borer larvae are visible.
If you think you have spotted emerald ash borer, you can contact your county ranger through the NC Forest Service or your county extension office. Above all, make sure that you do not transport wood that could be infested!
Left: The emerald ash borer spreads quickly and kills ash trees. In this stand in Garner, NC, it is difficult to find a living ash tree. Image: Courtney Smith
Right: After peeling back the bark on an ash tree, the emerald ash borer larvae's galleries are visible. Image: Courtney Smith
Right: After peeling back the bark on an ash tree, the emerald ash borer larvae's galleries are visible. Image: Courtney Smith
References
Donovan, G. H., Butry, D. T., Michael, Y. L., Prestemon, J. P., Liebhold, A. M., Gatziolis, D., & Mao, M. Y. (2013). The relationship between trees and human health: evidence from the spread of the emerald ash borer. American journal of preventive medicine, 44(2), 139-145.
Flower, C. E., Knight, K. S., & Gonzalez-Meler, M. A. (2013). Impacts of the emerald ash borer (Agrilus planipennis Fairmaire) induced ash (Fraxinus spp.) mortality on forest carbon cycling and successional dynamics in the eastern United States. Biological Invasions, 15(4), 931-944.
North Carolina Forest Service. (2017, January 17). Emerald Ash Borer Frequently Asked Questions. Retrieved October 21, 2020, from https://www.ncforestservice.gov/forest_health/fh_eabfaq.htm
Oleniacz, L. (2020, September 17). Scientists Pilot Drones in Effort to Save Trees From Invasive Beetle. Retrieved October 21, 2020, from https://news.ncsu.edu/2020/09/scientists-pilot-drones-in-effort-to-save-trees-from-invasive-beetle/
Flower, C. E., Knight, K. S., & Gonzalez-Meler, M. A. (2013). Impacts of the emerald ash borer (Agrilus planipennis Fairmaire) induced ash (Fraxinus spp.) mortality on forest carbon cycling and successional dynamics in the eastern United States. Biological Invasions, 15(4), 931-944.
North Carolina Forest Service. (2017, January 17). Emerald Ash Borer Frequently Asked Questions. Retrieved October 21, 2020, from https://www.ncforestservice.gov/forest_health/fh_eabfaq.htm
Oleniacz, L. (2020, September 17). Scientists Pilot Drones in Effort to Save Trees From Invasive Beetle. Retrieved October 21, 2020, from https://news.ncsu.edu/2020/09/scientists-pilot-drones-in-effort-to-save-trees-from-invasive-beetle/
Japanese stiltgrass, Microstegium vimineum, Infestation, photo by John M. Randall
Background
Japanese stiltgrass (Microstegium vimineum) is a grass native to Japan, Korea, China, Malaysia, and India. It first arrived in Tennessee in 1919, when it was used as packing material for porcelain shipped from Asia. It has currently invaded 16 states from New York to Florida and is found throughout North Carolina. It has not only invaded the United States, but it is also established in Mexico, Europe, Australia, New Zealand, Africa, and South America. While Japanese stiltgrass can thrive in many different environments, it prefers forest edges, wetlands, disturbed areas, and moist soils with high nitrogen content, but it can also tolerate areas that are dryer and have full sunlight.
Japanese stiltgrass, Microstegium vimineum, Foliage, photo by Bruce Ackley
Identification
Japanese stilt grass is bright green and can grow to be 2 to 3 feet tall. Leaf blades are flat, long, thin, lance-shaped, and about 3 inches long. The mid-vein is white and off center and the leaves are asymmetrical.
Threat
Japanese stiltgrass out competes our native grasses and other understory plants. It is a major threat to the diversity of our native ecosystems. It is a very fast spreader as a single plant can produce 100 to 1,000 seeds, and the seeds can stay in the seed bank for 3 to 5 years. It can be dispersed by machinery, animals, humans, wind, and water. Deer and other foraging animals do not eat it, giving it an advantage over our native forage plants. It has adapted to low light conditions, which gives it the ability to spread in the understory of the forest. Farmers also have trouble with Japanese stiltgrass invading their pastures, because their livestock do not like to eat it and it out competes the preferred grasses.
Prevention
Japanese stiltgrass is a big threat to the diversity of our ecosystem. It can be hand pulled or mowed before flowers are visible in late September, but this will need to be continued for at least three years until it is out of the seed bank. When hand pulling, the entire plant needs to be removed including the roots. Plants can be removed while it is fruiting, but they need to be bagged and disposed of off site. An effective method to reduce the seed production would be to mow once it starts developing seed heads, but before they drop their seeds in August or late September. Another way that has been found to prevent the invasion of an adjacent infestation of Japanese stiltgrass from continuing to spread is to put down a 4-6 inch layer of much, to prevent it from growing. Herbicides need to be applied late in the growing season but before it seeds in October. Roundup Pro, which contains an herbicide called glyphosate, is an effective method for Japanese stiltgrass control. However it can kill any plant that it comes in contact with, so use with caution. If you are treating Japanese stiltgrass in a wetland, use a herbicide that is safe to use in wetlands like Rodeo and ALWAYS READ AND FOLLOW THE LABEL.
Sources
Fryer, Janet L. 2011. Microstegium vimineum. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). https://www.fs.fed.us/database/feis/plants/graminoid/micvim/all.html#225
Invasive.org.(2010,November11).ControlOptions.https://www.invasive.org/alien/pubs/midatlantic/control-grassesandsedges.htm
Invasive.org(2010,November11).JapaneseStiltgrass. https://www.invasive.org/alien/pubs/midatlantic/mivi.htm
NCForestService(2010,March).InvasiveSpeciesMicrostegiumvimineum. https://www.ncforestservice.gov/publications/Forestry%20Leaflets/IS04.pdf
NC State Extension. (2013, February 18). Japanese Stiltgrass Identification and Management. https://content.ces.ncsu.edu/japanese-stiltgrass-identification-and-management
PennStateExtension.(2019,October8). Japanese Stiltgrass in Pastures. https://extension.psu.edu/japanese-stiltgrass-in-pastures
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We are a group of NC State University students committed to spreading awareness about the invasive species that inhabit or threaten North Carolina.
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