Caseload at the UW Insect Diagnostic Lab (IDL) has been high over the last two weeks. A summary of recent fruit crop insects reported to the lab as well as important insects to scout for can be found below:
Spongy moth (formerly known as “gypsy moth”): Spongy moth remains one of the biggest issues being reported to the UW Insect Diagnostic Lab this spring and early summer. Most of the reports have ranged from Walworth County west to Green and Iowa Counties and up towards Monroe and Jackson Counties. Some good news is that the end is in sight and caterpillars should be wrapping up in the next few weeks. In some cases, large caterpillars (2 – 2 ½ inch) are being reported which are nearly ready to pupate. However, I’m still getting reports of caterpillars that are between ½ – 1 inches long and those will likely continue to feed and cause damage for several more weeks. For additional details of how 2022 has shaped up and how the rest of the season may go, check out this recent post on the IDL website: bit.ly/3OV8FAN
Clearwing borers (moths): We have a number of clearwing species that can be concerns in fruit crop systems (e.g., dogwood borer, peachtree borer, lesser peachtree borer, etc.). There are also many related clearwing moth species that occasionally show up in pheromone traps, but are not a concern for fruit growers. I’ve recently received a number of photo submissions of clearwing moths on pheromone sticky traps, but species-level confirmation is often best confirmed by examining a physical sample under the microscope. If you’re looking for assistance with identifying clearwing moths on pheromone traps, consider submitting a physical sample to the UW Insect Diagnostic Lab.
Lecanium scales: I’ve seen a few cases of European fruit lecanium at the UW Insect Diagnostic Lab over the last two weeks from central and west-central Wisconsin. These scales are known to be associated with a wide range of hardwood trees and shrubs, including fruit trees. We’re at the time of the year where crawlers may be active in southern parts of the state, so growers with a history/presence of this insect should scout for crawlers to inform management actions.
Japanese beetle & rose chafer: Reports of these two insects have been scarce thus far. Rose chafer (Macrodactylus subspinosus) is a native scarab pest that attacks many of the same fruit crops as Japanese beetles, such as tree fruit and grapes. This species is associated with parts of the state with sandy soil and they’re active mostly in June into the first half of July. I recently received my first report of Japanese beetle for the season from southwestern Wisconsin, but activity has been quiet thus far. Expect adult activity to pick up around Wisconsin over the next two weeks.
Stink bugs: Over the last two weeks, I’ve received a number of reports of adult brown marmorated stink bugs and a green stink bug from southcentral and southeastern Wisconsin. BMSB nymphs are generally spotted from July onwards, so growers should be on the lookout if they have a history of BMSB in their area.
On the radar—Apple Maggot: Based on growing degree days models, we’re at the time of the year that apple maggot activity should be kicking off in southern Wisconsin in the near future. Growers should be on alert for this pest. The National Phenology Network (NPN) has some helpful maps to forecast activity of apple maggot and other pests: www.usanpn.org
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.eduThis article was posted in Insects and tagged Apple maggot, clearwing borers, Insect Diagnostic Lab, insects, lecanium scales, moths, PJ Liesch, spongy moth, stink bugs.