Severe gypsy moth outbreak

Asked June 17, 2018, 12:27 AM EDT

I'm having a gypsi moth outbreak in my area. How concerned should I be? What can i do?

Washtenaw County Michigan insect issues gypsy moth

1 Response

We are near the end of the time gypsy moth caterpillars will be feeding this year. Soon they will enter a stage where they change to a moth to lay eggs. Their populations go up and down in nature due mainly to a pathogen, Entomophaga maimaiga, which is a fungus that kills them during their caterpillar stage. The trouble is it was too dry in 2016 and 2017 in late spring and the fungus was not as active allowing populations to climb. This year is different with weekly rain periods allowing the fungus to grow. Though many callers are already reporting caterpillars dying (hanging straight down on trees) from the fungus this year, the feeding was serious in some areas. Trees like oaks and maples can rebound from being stipped of their leaves, while pines and spruce often do not. *Trees that were defoliated will work to put out a new set of leaves and as they do this make sure they are not also stressed by any droughts that may occur. At this stage do not let them feed on spruce and pine and watch for the dying caterpillars. If rain was timely we can have a very large die-off of caterpillars preventing them from reaching their adult stage and laying more eggs. This has happened in Washtenaw County numerous times since the late 1990's. Nature is too unpredictable but in most years we do not need to worry about them. If droughts do occur at the right time the insects population can quickly develop over the next year. See the following article which includes links for how to protect trees: