identification of worm/larvae?

Asked October 24, 2017, 3:28 AM EDT

Today, while working in my yard, I walked into a dangling cobweb or spider thread and when I wiped it from my face, I saw a cluster of tiny bright green worms snared in the strands. At first I thought it was just leaf matter, but my friend pulled some off my hair and noticed this stuff was moving. I put the clump in a covered plastic cup. They have since crawled apart and are clearly some type of worm or pupae. They are about the length of a grain of rice, thin, and bright chartreuse green. Do you know what this might be? Should I send it to your labs? It is so tiny I cannot photograph.

Oakland County Michigan

4 Responses

Hello,

Without a clear picture I can only give you some possibilities. This time of year when trees are going dormant, it is unlikely they are doing any damage unless they were falling from your evergreens. Fall webworm, inch worms or oak leafrollers are possibilities. Our warm fall has allowed some insects to have an extra generation develop.This may be why you have these caterpillars relatively late in the season. They are using the long, thin web thread to drop to the ground so they can overwinter in the soil. These caterpillars are harmless to humans and are the larvae of different moths.

Yes, you may submit samples to MSU Diagnostic lab and, for a small fee, they will I.D. them for you. Package your whole, undamaged samples in a small waterproof unbreakable container in a small amount of white vinegar. Place this in a small mailing box padded with newspaper. Here is their website with instructions and submittal form---

https://pestid.msu.edu

Thank you for using Ask an Expert



I did get a picture. The pupae is smaller than rice. More like a fat eyelash.. I am not an amateur gardener. I have never seen these before so I am concerned for my large landscaped organic garden and yard. I use organic fertilizers and simple natural methods when dealing with bugs and disease. Do you know what this is and should I be concerned?

Hello,

Sorry, the picture came through blurry. For ID it is important to be able to see how many legs and prolegs they have, any stripes, dots, hair, and color of eyes,etc. Often a hand lens is necessary.

That said, these appear to be an inchworm of some sort, perhaps a spring cankerworm. They drop to the ground and spend the winter in the soil as larvae, developing into adults in the spring. Infestations typically go in cycles, with populations peaking for two or three years and then declining for a few. Inchworms move to new host plants by dropping silken threads and hitching rides on the wind. They don't harm humans or animals.

They also don't cause permanent damage to trees that drop their leaves in fall. They are leaf eaters.

Organic control, should it be necessary in spring, is a Bt spray on trees that have high populations and noticeable damage on leaves.

Monitor your trees as leaves open next spring and treat then, if you see a lot of inchworms on leaves.

Thank you for submitting your picture.



Thank you for the info. I'll be on the lookout in spring.