Cool Invasive On the Horizon: Winter Moth. June 26th

Winter Moth Adult

Researchers have been surveying coastal Connecticut and Central Massachusetts for winter moth with pheromone traps each year for quite a few years. They have now documented the spread of winter moth from isolated eastern orchards to the western edge of both states, specifically Stamford CT and North Adams, MA. Densities in these regions, so far as we know, have remained low.

The introduction of the biological control parasitoid Cyzenis albicans, successfully controlled outbreak populations of winter moth in eastern Massachusetts, Maine and Rhode Island. However, populations in the western regions of MA and CT or in the Hudson Valley of New York are very far from our populations where the biological control has been confirmed as established. The potential for Winter Moth to cause outbreaks in these regions is a concern. Apples in particular, are a favored host.

Winter moth larval feeding to apple foliage.

Blueberry and apple growers in the mid-Hudson Valley bordering CT and MA should be on the lookout for high densities of the larva (little green inchworms) in the early spring. When possible, photo image and or collect them while they are still available, and place them in in a container with apple foliage.

We will arrange to pick them up and determine whether they are winter moths or Bruce spanworm, the native species. Research will conduct DNA analysis to determine species and will be begin introduction of the biological control parasitoid Cyzenis albicans next fall in locations where Winter Moth populations warrant control.

Biology: The winter moth (Operophtera brumata L.; Lepidoptera: Geometridae) is an inchworm caterpillar that hatches coincident with bud-break on its hosts and feeds on a wide range of deciduous trees. It is one of a group of geometrid species that feed in early spring and then pupate in the top layer of the soil or litter beginning in mid-May.

Winter moth late instar larva ‘looper’

UMass Fact Sheet on Winter Moth.