Once again we have an invasion of spongy moth. In 2018 I would go out when the caterpillars were coming down the trees at night and brush them off ...
Knowledgebase
Spongy moth invasion #872403
Asked June 10, 2024, 11:48 AM EDT
Once again we have an invasion of spongy moth. In 2018 I would go out when the caterpillars were coming down the trees at night and brush them off in the hope of eliminating at least some of them. Generally I had large numbers.. This time, especially in the morning I am finding mostly dead ones. I read the question and answer article on your site and learned there is a virus that kills the caterpillars. Is this caused by the virus or some part of the life cycle of the moth?
Cass CountyMichigan
Expert Response
It sounds like the outbreak in your area is beginning to collapse. On the MSU gypsy moth website, there is a short write-up about the NPV pathogen (the virus) and the E. maimaiga fungus. Both cause caterpillars to die but NPV is more reliable than the fungus. Take a look at the images of the cadavers. The virus killed larvae will hang down, often in an V shape, liquify and the brown liquid smells nasty. As they disintegrate, the virus particles get into the environment and hopefully infect caterpillars next year. The fungus cadavers will be hanging head down. They are stiff and desiccated - like stale potato chips. The disintegrate and release fungal spores into the soil - which is a good thing!
Deb, Thank you for the quick response and the info. Our trees have mostly v shape which you said is good news and I totally agree. Anyway to get rid of them is welcome. Thanks again.
Good afternoon -- Deb and her teammates have put together an extensive webpage that will answer many of your spongy moth questions. Please check it out if you haven't already:
