- You will see the most green worm activity at the end of spring to early summer, May through June, although activity into August is not uncommon. Depending on the pest, outbreaks may be an annual occurrence or can occur in time frames as long as a decade, with the outbreak itself lasting two or three years. This makes identifying the specific type in question important to choosing what types of control are needed.
- Most green worms found on oak trees will occur across the continental United States. They are extremely common and aren't unusual to find on oaks or other hardwood trees. As climates change and animals are introduced to different areas, new types of green worms may appear.
- The more dangerous pests to your tree are rarely green. Most likely any green worm you're seeing is a Linden Looper, a Fall Cankerworm, or a Spring Cankerworm. These worms eat the tree's foliage, leaving holes in the leaves, and have unsightly nests. While occasionally these pests can severely defoliate trees, such outbreaks are rare and take many worms. This doesn't mean you shouldn't keep an eye on the health of your tree, simply be aware of the problem and be ready to act if necessary.
- While there are no prevention options, most outbreaks of green worms are best controlled by Mother Nature. These caterpillars have many natural enemies, such as birds and wasps, which will take care of the problem for you. If you have a more extensive problem, consider spraying your tree with a standard insecticide. This can be found at any hardware store, especially during the summer months when these pests are at their most common.
Wednesday, April 13, 2011
Walking today, I noticed loads of green worms suspended by silk threads hanging from the oak trees. Nothing unusual, certainly not in the Oak City. I'm familiar with finding them in the house, on the dog, clinging to your clothing; but I had never seen so many just hanging from the oaks as I did today.