Worms – By Mark Govan, Host “Florida Gardening”

Well the temperatures are warming up, the grass is starting to grow, ornamental plants are starting to bloom, and the trees are putting on their new leaves. Unfortunately, with all this new growth the pollen count is climbing and many of us with allergies are feeling the pain. Itchy eyes, stuffy noses, and coughing are all part of this springtime show. To make matters worse, the caterpillars have arrived and they are covering our trees with their webbing, raining down upon us by their silken webs, and defecating on our homes, walks, and cars. I have had at least a hundred calls to my office asking what can be done to alleviate this problem. Today, I will tell you why the caterpillar is here and what you can do about it.
 


 
 
 

There are several types of caterpillars that infest oak trees in the spring, the Leaf rollers caterpillar, the Leaf tiers, and the Oak Tree defoliators. Each of these caterpillars does similar damage to our trees. They feed on the early spring growth of our trees as the leaves emerge. As they feed they grow and feed more. When they become dislodged from the tree you may see them hanging from a single silken thread. This is the point many of us encounter them. Unfortunately, some of us do not see them until much later and when we sit down and feel something crawling on us. We call this the Ick-Factor. At this point we try to figure out where we picked up the caterpillar. When we retrace our footsteps of where we have been, we find numerous caterpillars hanging from our trees.

Here is the good news, the caterpillars are harmless to people. In fact this is a good time for the birds as they love to feed upon the caterpillars and because there are so many of them they can fill their bellies. Well, this does not sound too bad. Just wear a big hat, long sleeved shirts, and shoes because they will not harm people. Also, birds love them, and they are free food so sounds like no problem right? Well it would be if they were not feeding on our trees. The leaves they are eating are needed by the tree.

Here is the bad news. As the caterpillars feed on the new growth of the oak trees, the trees becomes stressed because the leaves are the trees source of food production. Leaves are the factories where photosynthesis occurs. When the leaves are stripped from the tree, the trees ability to create carbohydrates diminishes. This opens the tree to being susceptible to other insects and diseases which could attack the weakened tree. Wood boring insects can sense stressed trees and are drawn to them in numbers. Once these wood boring insects invade the tree, the tree loses its ability take up nutrients which the tree needs to survive. Further, repeated defoliation of the tree caused by second generation worms’ causes trees to use up their stored carbohydrates which can lead to the ultimate death of the tree. Trees only have so much stored energy which is used to produce their first flush of growth. As the tree produces its second flush of growth necessary because of the caterpillars feeding, the tree becomes weakened. This puts the tree under stress allowing other insects to invade. This is why control of these pests is so important.

Controlling these caterpillars is a little complicated so let me explain. In the old days homeowners would mix up a batch of pesticides and hook the spray mixture up to a spray gun and spray their tree with the product to kill the caterpillars. This type of application is old-fashioned, environmentally unfriendly, and rarely did the homeowner have the ability to make sufficient coverage to the tree to control the caterpillars. If the tree was very large, even a professional would have a hard time spraying the tree and getting sufficient coverage when you had to worry about spraying into the air. Remember, what goes up, must come down. If the tree was large enough and covered the neighbor’s homes or cars on a street, you could not spray. Now there is an environmentally friendly application technique called a tree injection. Tree injections deliver a measured dose of insecticide directly into the trees vascular system which directs the product throughout the tree eliminating drift or contamination of adjacent areas.

This environmentally friendly treatment is used by professional applicators and can control these pests for a full year. Many customers of my company, ABC Pest Control, have their trees injected in February so that the product is in the tree before the caterpillars start to feed. Once they feed upon a treated tree the caterpillar dies. This treatment is done only once per year as the product is stored in the tree and released slowly to the leaves. ABC also includes a micro-nutritional package with each injection which helps the tree by providing nutritional supplements which may be needed during the spring growth months.  

If your trees have not been affected yet you still have time to get them treated. Not only can you kill the caterpillars before they start eating but you can eliminate the mess they cause on your car and property. I have seen some people have to have cars repainted due to the excrement left behind on their cars. Call a professional today!  I hope you enjoyed this section on Leaf roller caterpillars! Thank you for your support and until next time, remember without plants we wouldn’t be here!

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