I have a ton of little bright green worms coming out of my oak tree on little silk strings. It is really bad this year as they are cocooning my other plants and even my car! How do I get rid of them and will they hurt my other plants?
The caterpillars are oak leafrollers or oak leaftiers. There is one generation of these caterpillars per year, lasting about one month. Although these caterpillars are present in the area to some extent every year, many people are reporting very high populations of them this year.
Usually It is not necessary (or practical) to attempt control them on trees, since the feeding damage is usually not life threatening to the trees. There have been reports of them sometimes feeding on other kinds of plants. If this occurs on landscape ornamentals you could spray with a product containing Bt (Bacillus thuringiensis). The caterpillars must feed on some of the treated foliage for the material to be effective. After feeding on treated leaves the caterpillars stop feeding and die in a few days.
Even without treatment the caterpillars will be gone in about one month and they will not reappear until about this time next year.
Please contact (727) 582-2100 if you have additional questions.