Have you noticed silky webs appearing in trees across the state? Well don’t worry, we are not being invaded by large spiders but rather the webs contain small caterpillars commonly known as fall webworms or simply webworms.
They are a common occurrence across Oklahoma, but some years they are more noticeable than others and this year it appears their population is on the rise. There may be several generations per season and their preferred species are pecan and persimmon but sometime you will also find them on other trees including hickory, walnut, mulberry, redbud, American elm, cottonwood and even baldcypress.
They may look bad, but they usually do not impact a tree's health. Trees may be totally defoliated by the caterpillars this year and have enough stored energy through photosynthesis to come back next season.
On small trees or low hanging webs you can remove them by hand or with a stick but there are a variety of readably available sprays to help with those you cannot reach. A sprayer with enough pressure to penetrate the webbing will be necessary to make sure that what you spray comes in contact with the caterpillars. Bacillus thuringiensis commonly referred to as (Bt) is a spray that can be applied that only targets the caterpillars and does not harm beneficial insects like honey bees or other pollinators. Other more broad ranging insecticides could be used and we always recommend closely following all label instructions.
Webs will stay attached until wind and rain washes them away.
Posted on Tue, July 19, 2016
by Communications filed under