Locust borers are a common pest that can cause severe damage to beautiful, mature trees like black locusts. These wood-boring beetles lay their eggs in the bark and trunks of locust trees, leading to weakened branches and potential tree death if left untreated.
While it might seem daunting to tackle this problem, there are certain measures one can take to prevent and control locust borer infestations. These methods include regular monitoring, tree care practices like proper pruning and thinning, and chemical controls when necessary to protect your treasured locust trees.
Some effective strategies for dealing with locust borers involve removing infested trees and peeling or burning the bark to kill larvae during dormancy. Remember, the best approach combines multiple tactics suited to your specific situation, ensuring the health and longevity of your trees.
Identifying Locust Borers
Physical Appearance
Locust borers are a type of long-horned beetle, with adults measuring about one inch in length. They are black with bright yellow markings, including a distinctive “W” across their wing covers, and have reddish legs1. Their larvae are white and legless, featuring a large prothorax2.
Host Tree Identification
Locust borers specifically target black locust trees3. Being aware of these trees in your area can help you identify potential infestations early on.
Signs and Symptoms
- Presence of holes in the bark1
- Reddish frass (insect waste) in bark crevices or around holes1
- Cracks or knotted areas on branches4
It is essential to regularly inspect black locust trees for these symptoms to catch locust borer infestations early and take appropriate action.
Prevention and Treatment Methods
Maintaining Tree Health
Keeping trees healthy is key in preventing locust borer infestations. A well-maintained tree can resist pests and diseases more effectively. Some measures to maintain tree health are:
- Adequate watering during drought conditions
- Providing nutrient-rich soil to ensure strong growth
- Regular pruning of dead or damaged branches
For example, if you have a healthy locust tree, it’s less likely to be attacked by locust borers than a stressed or weakened tree.
Chemical Insecticides
Using chemical insecticides can help control locust borers. One option is applying a carbamate or pyrethroid insecticide to the tree bark in late July or early August, before eggs are laid1. However, there are pros and cons to consider:
Pros:
- Effective in controlling the locust borer population
- Can easily be applied to tree bark
Cons:
- Possible risk to non-target insects and the environment
- Might require multiple applications for full effectiveness
Alternative Treatment Methods
Alternatively, non-chemical treatment methods can be used to control locust borers. For example, physically removing infested wood or branches and subsequently chipping or burning them can help manage the pest population2. Another method is using safe biological controls, like introducing predators or parasites that attack the locust borer.
Comparison between Chemical and Alternative Treatment Methods:
| Treatment Method | Pros | Cons |
|---|---|---|
| Chemical | Effective, easy to apply | Environmental concerns, multiple applications required |
| Non-Chemical | Safe, eco-friendly, physical removal of pests | Can be time-consuming, some methods may not be as effective as chemicals |
Remember that proper tree health management and a combination of these methods can provide the best defense against locust borers.
Dealing with Infestations
Inspecting for Infested Trees
Identifying infested trees is crucial in dealing with locust borer infestations. Look for:
- Holes in the bark
- Reddish frass in bark crevices or around the base of the tree
- Signs of larval feeding, such as branches with sawdust-like material1
To inspect the trees, focus on the trunks and large branches since these are where locust borer larvae usually tunnel2. Consult with a tree specialist if you’re not sure about potential infestation.
Removing and Destroying Infested Trees
Killing the locust borer larvae is essential for successful infestation management. Remove infested trees or branches, and choose one of these disposal methods:
- Chipping the removed wood to destroy larvae
- Burning the infested material to ensure effective extermination2
Keep in mind that prompt removal may prevent further infestation to other trees.
Protecting Unaffected Trees
Proactively protecting unaffected trees can help control locust borer infestations. To maintain overall tree health:
- Provide appropriate care, such as watering, fertilizing, and pruning
- Apply a carbamate or pyrethroid insecticide to the bark on the tree’s trunk and large scaffold branches2
| Pros | Cons |
|---|---|
| Prevents further damage to unaffected trees | Chemicals might have adverse effects on beneficial insects |
Remember that maintaining the health of your garden and trees is essential in avoiding locust borer issues and other destructive pests like emerald ash borer and grasshoppers.
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Locust Borers and Their Impact on Agriculture
Crop Damage and Economic Losses
Locust borer is a destructive insect, Megacyllene robiniae, that tunnels into the wood of locust trees. They create holes and weaken the tree structure, leading to crop damage and economic losses in agriculture.
- Holes in the trunk and branches weaken the tree
- Sawdust-like frass indicates infestation
For example, locust borer infestation in black locust trees can decrease their value as timber and honey producers.
Management Strategies for Agricultural Settings
Effective management strategies for locust borers include maintaining tree health and applying timely insecticides.
- Tree Health: Improve or maintain overall tree health to make them less susceptible to infestations.
- Insecticides: Apply carbamate or pyrethroid insecticides to the bark on the trunk and large scaffold branches in late-July/early-August, prior to egg-laying.
Here is a comparison table of the two strategies:
| Management Strategy | Pros | Cons |
|---|---|---|
| Tree Health | Natural approach, better long-term solution | Requires regular care and maintenance |
| Insecticides | Quick and effective | Potential harm to beneficial insects and the environment |
Pruning infested wood and branches, then chipping or burning them, can also help control locust borer populations.
Footnotes
15 Comments. Leave new
ty i know now what was all over the outside of my house. and coming from the roof even. i haved lived at this apt. for 4 years and have never seen them.
Dear ladyakita0701,
Though you did not submit a photo nor indicate your location, we suspect that you actually saw Hickory Borers, an insect in the same genus as the Locust Borer, and also very difficult to distinguish from the Locust Borer. The Hickory Borer appears in the spring, and the Locust Borer appears in the fall. We just posted a letter with a blurry photo of a Hickory Borer, part of a large emergence in Kentucky.
I have the locust borer in my house and I don’t know the best way to get rid of it
If you have Locust Borers in your house, they most likely came in on firewood. They will not damage your homes or its furnishings. Calling an exterminator is unnecessary.
Can they swim
They do not swim, but they will float.
can they do any thing that can harm?
We don’t understand your question. Fear can cause even the most benign creature to do harm. If someone was driving and a harmless Locust Borer entered the car, the driver might freak out and drive off the road.
can they see good the one i found flew into me
I have discovered Locust Borers in my house the last few days. We burn firewood, but I believe they are coming from the numerous black locust trees surrounding my house. My question is, do they bite? Are they dangerous to people or animals?
Locust Borers do have strong mandibles, and they may bite if carelessly handled, but we do not believe a bite would draw blood. Barring some freak accident, like a person choking to death after swallowing a Locust Borer or wrecking the car if a Locust Borer distracts the driver, they are not considered dangerous to people or pets.
We have a pond and woods around our home and we have a wood burning fireplace. We have seen either Locust or hickory beetles for the first time ever this spring and inside! Last year boxwood beetles arrived and year before stink bugs. What’s next in Western NY?
Does the locust borer only eat locust, I stumbled across a couple in North Texas yesterday after we cleared out a bunch of mesquites. To my knowledge there are not any black locusts anywhere around here.
You might have seen the similar looking Hickory Borer that is active in spring. The Mesquite Borer, which is pictured on BugGuide, also looks very similar.
I found one in Chapultepec, México.