Fruit insect cases have decreased at the UW Insect Diagnostic Lab (IDL) over the last two weeks with the cooler temperatures.  Reports of fruit crop insect activity submitted to the IDL in late August and early September are summarized below:

Japanese beetles: Japanese beetle reports have dropped off substantially around the state.  Small numbers of adult beetles continue to be spotted, although Japanese beetle season is soon drawing to a close.

Red-humped Caterpillars (Schizura concinna) were recently reported by a home fruit grower in Bayfield County.  These distinctive caterpillars feature a prominent reddish hump just behind the thorax and distinctive black, white, and yellow stripes running down the body.  This species isn’t particularly common, but can feed on a wide range of trees, including apples.

Giant Silk Moth Caterpillars such as cecropia moth caterpillars can be somewhat common in late summer and are more of a curiosity than a threat to plants.  They have been reported several times in the last few weeks from the southern half of Wisconsin.

Bald-faced hornets and other yellowjackets are being reported around the state.  Such insects are secondary scavengers that readily go to fruits damaged by other insects, disease, or physical injury.  They can be a general nuisance and could pose sting risks to workers at the time of harvest.

Brown marmorated stink bug: Reports of BMSB nymphs and adults have increased in southern Wisconsin over the last two weeks.  In many cases, juveniles (including late instar nymphs) continue to be reported, although reports of adults are increasing as well.  Growers should continue to monitor for this invasive stink bug.

This article was posted in Insects and tagged bald-faced hornets, BMSB, Japanese Beetles.