Caseload has been high at the UW Insect Diagnostic Lab the last two weeks and is expected to remain high for another month or longer as harvest season approaches.  A summary of recent fruit crop insects submitted to the IDL can be found below:

Key tree fruit pests—plum curculio, apple maggot, and codling moth. I’ve recently seen many samples at the lab of damage from plum curculio, apple maggot, and codling moth.  These samples have come in from around the state and damaged fruits have typically come in from backyard fruit growers or orchards that missed a spray application.

Spotted wing Drosophila: With late-season raspberries ripening in some areas, I’ve had a number of cases of damage from spotted wing Drosophila.  Recent reports of damage have come in from southern and west-central Wisconsin.

Japanese beetle: While many parts of southern Wisconsin have had a reprieve this year from Japanese beetles, large numbers of adults and damage have been reported from northern areas.  Northwestern and north-central Wisconsin stand out in particular.

Pearslug sawfly:  This insect can be a common pest of pears and other tree fruit in late summer.  Larvae cause lace-like damage (“windowpane damage”) that only goes part-way through the leaf.  I’ve seen recent samples from southcentral and west-central Wisconsin.

Social wasps: Colonies of social wasps (yellowjackets, bald-faced hornet, and paper wasps) are reaching peak size and workers are scavenging furiously for food to bring back to the colony.  This can lead to increased encountered and stings this time of the year.  These insects will readily forage upon diseased or damaged fruits and can be a concern during harvesting operations.  Expect social wasp activity to further increase statewide over the coming weeks.

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 Insect Diagnostic Lab, insects, PJ Liesch.