Help! Bagworms!

Asked July 29, 2016, 1:23 PM EDT

My evergreen tree has a dead spot. My neighbor says it's bagworms. What do I do? I read online to pull them off and put them in a bucket of soapy water. Then transfer that to a ziplock bag and throw it out. Is that right? Then how/what do I use to treat the tree? Or am I too late. Everything said May/June to treat with insecticides? My husband said it wasn't like that on Sunday. Today is Friday! Oh my! I don't want to lose my tree!

New Castle County Delaware

1 Response

The picture is not entirely clear as to what the problem is; however, it looks like it could be bagworms. They have been there since June. Insect feeding like this does not occur quickly, but the easily visible signs can suddenly appear (as the portions of the plant finally succumb to the damage). You can still treat but would need to happen within the next week for any efficacy. They are about to pupate (form cocoons) and no longer will be feeding. You have to obtain good coverage of the foliage otherwise you will not obtain control. The pesticide you use will not penetrate the bags. There are a number of products available at garden centers or box stores to treat for this pest; however, it is too late for the more reduced-risk type products. You will need to use a broad-spectrum product like a pyrethroid (active ingredient ends in "-thrin") or carbaryl. Alternatively, you could pick off all bags you can reach by hand and destroy the bags. This will reduce the population you have next year. The optimal time for treatment is mid- to late June and using B.t. kurstaki or spinosad products.