The forests of South Carolina – like those throughout the United States – certainly have their share of pests. While most of these pests are native and typically only impact stressed or injured trees, several non-native species are present and established in South Carolina. And of those non-native species, a few are true invasives, capable of causing widespread economic and/or ecological damage. This article will give an update on invasive forest pests already established in our forests and some to be on the lookout for as well.
Two unregulated pests in South Carolina’s forests are the emerald ash borer and laurel wilt. The emerald ash borer is established in several Upstate counties and has been for several years. Adults are a bright green beetle, while larvae are whitish in color and feed on the phloem of a tree (just under the bark). Larval feeding is capable of killing mature trees in just a few months, as their winding feeding galleries cut off nutrient transport within the tree and essentially cause starvation. Little can be done to manage populations in natural areas, though there are several biological control agents that have been shown to help reduce beetle populations. These beetles only impact ash (Fraxinus) in our area, so if you have dying ash, it’s worth checking it out and notifying your local Extension agent or SC Forestry Commission forester. Laurel wilt, a devastating disease spread by the redbay ambrosia beetle, is present in most of the eastern half of the state and is making its way into the Upstate as well. This disease affects all species in the family Lauraceae, which includes redbay and sassafras. The beetles attack healthy trees and introduce fungal spores, which quickly grows and clogs the tree’s water-conducting tissues. Trees rarely survive once infected.
The Asian longhorned beetle is under federal and state regulation, and is (still) confined to an area in Charleston and Dorchester counties. This large black and white beetle primarily attacks maple (Acer), but can also use poplar (Populus), willow (Salix), birch (Betula), sycamore (Platanus), and elm (Ulmus). Larvae can get up to nearly 2” long and feed on the wood, causing branches and stems to break. The good news is that this pest can be eradicated! The bad news is that total host removal is necessary, which means removing and grinding the infested tree and stump.
The spotted lanternfly and elm zigzag sawfly aren’t known to be present in South Carolina yet, but both are established in our neighbor state, North Carolina. The spotted lanternfly is an insect that feeds on over 100 different host plants, including several smooth-barked hardwoods, like maples and young walnuts (Juglans). Spotted lanternfly hasn’t been shown to be a forest pest (yet), but feeding by this insect can negatively impact tree growth and health. There is a quarantine for spotted lanternfly, and we are asking anyone who sees this pest to report it immediately, as the impacts of this pest are both known and significant.
The elm zigzag sawfly is also present in North Carolina and is capable of defoliating elms of any species and size. Both of these pests are fairly distinctive in appearance, as spotted lanternfly is black with white and red coloration when young, and can be over ½ inch long. Elm zigzag sawfly larvae make characteristic feeding patterns in leaves, and can quickly defoliate entire trees. If you see either of these pests, please let your local Clemson Extension agent or SC Forestry Commission forester know right away.
Find out more about these pests at our state regulatory page (https://www.clemson.edu/public/regulatory/plant-industry/invasive/index.html) and report them if you see them!
Author(s)
Dave Coyle, Cooperative Extension, Forestry and Wildlife Specialist
This information is supplied with the understanding that no discrimination is intended and no endorsement of brand names or registered trademarks by the Clemson University Cooperative Extension Service is implied, nor is any discrimination intended by the exclusion of products or manufacturers not named. All recommendations are for South Carolina conditions and may not apply to other areas. Use pesticides only according to the directions on the label. All recommendations for pesticide use are for South Carolina only and were legal at the time of publication, but the status of registration and use patterns are subject to change by action of state and federal regulatory agencies. Follow all directions, precautions and restrictions that are listed.
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