UW-Madison/Extension Insect Diagnostic Lab Update June 2, 2022
Caseload at the UW Insect Diagnostic Lab (IDL) has greatly increased over the last two weeks and is now at levels of a typical busy “summer season” with 100+ cases per week at the lab. A summary of recent fruit crop insects reported to the UW Insect Diagnostic Lab as well as important insects to scout for can be found below:
Spongy moth (formerly known as “gypsy moth”): I’ve continued to see plenty of cases of spongy moth caterpillars over the last two weeks—mostly from southeastern and southcentral parts of the state. By now, caterpillars have increased in size and are between 3/4” – 1” long in many cases. Keep in mind that these caterpillars can get to be 2+” long, meaning that they’ll continue to grow in size over the next few weeks. Over 80-90% of the damage caused by the caterpillars is caused by the final two caterpillar stages (i.e., 5th and 6th instars), so I’m expecting to see an uptick in reports of caterpillars and damage over the coming weeks.
Eastern tent caterpillars: Eastern tent caterpillars are now larger and more noticeable and I’ve had many cases over the last two weeks from around Wisconsin. Tents are now readily visible in many cases. Managing individual silken tents can be a useful approach in orchard and landscape settings. Most of my reports have been from backyard fruit tree settings and landscape plants.
Humped green fruitworm: I’ve now had a few reports of humped green fruitworms from southern Wisconsin. Both humped green fruitworms and speckled green fruitworms can be common in spring and feed on a wide range of fruit and landscape trees. They are generally minor pests, but occasionally cause notable defoliation.
Tortricid Pests: Over the last two weeks, I’ve had many cases of Tortricid caterpillars and their damage at the IDL. This family includes many species relevant to tree fruits, such as the oblique banded leafroller, redbanded leadfroller, Oriental fruitworm, and many other related species. The WI DATCP Pest Survey Program also reports monitoring/trapping efforts for adult moths, which can give an indicator of activity and potential egg laying throughout the state.
Green pug: An occasional/minor pest of tree fruit. These inchworm-type caterpillars are pale greenish with a distinctive reddish stripe running down the back of mature caterpillars. They tend to feed on buds of fruit trees early in the year. Recent reports came in from northeastern Wisconsin.
Plant bugs & aphids: I’ve had a number of reports of plant bugs and aphids on fruit crops over the last two weeks from around the state. The commonest plant bug reported has been the tarnished plant bug, which can attack a wide range of fruits (fruit trees to strawberries).
Reminder about diagnostic support from the IDL: Growers and consultants in need of insect diagnostic services are always welcome to submit a sample to the UW Insect Diagnostic Lab. Lab services are provided free of charge. You can find additional information about the IDL here: insectlab.russell.wisc.edu
This article was posted in Insects and tagged aphids, eastern tent caterpillar, green pug, humped green fruitworm, Insect Diagnostic Lab, insects, PJ Liesch, plant bugs, spongy moth, tortricid pests.