The caseload at the UW Insect Diagnostic Lab (IDL) has been high over the last two weeks.  Reports of fruit crop insect activity submitted to the IDL from the last two weeks are summarized below:

Eastern tent caterpillar activity should be wrapping up for the year, if it hasn’t already done so.  Large, mature caterpillars were observed in central Wisconsin approximately 3 weeks ago and mature caterpillars were spotted in northern Wisconsin within the last week and a half.  With only a single generation per year, this will be one less pest to have to scout for this season.

Grape flea beetle larvae are active with several recent reports of damage to grape leaves in south-central and central Wisconsin. The adult beetles are a concern early in the growing season when grape buds are expanding, but the larvae can cause conspicuous skeletonization type damage to foliage this time of the year.

Plants bugs such as the tarnished plant bug and others are regularly being reported from spots across the state.  Species like the tarnished plant bug can feed on a very wide range of fruit crop and other plants.

Plum curculio damage (scars) has been observed recently at the UW Insect Diagnostic Lab.  Recent samples with PC damage have come in from stone fruit and apples in southern Wisconsin.

Rose chafers have become active over the last two weeks, with a scattering of reports from around the state.  This species is associated with sandy soil, so activity can sometimes be patchy or localized.  This insect is native, but is a close relative of the Japanese beetle.  It feeds on many of the sample plants as Japanese beetles (including fruit trees, cane fruits, grapes, etc.), and causes similar skeletonization-type damage.  Luckily, the adults are typically active for only a few weeks in late spring and early summer.  Emergence seems delayed this year, likely due to the cool spring temperatures.

Japanese beetles are expected to become active any day now.  I have not had any reports yet this year at the UW Insect Diagnostic Lab, but adult Japanese beetles typically begin emerging in late June or early July. Growers should be scouting for this pest as it can cause significant damage to a range of fruit crops.

Spotted Wing Drosophila: The first detection of SWD was recently reported by the UW Fruit Team in La Crosse County.  Growers of caneberries should keep a close eye out for this pest.

Beneficial Insects: The IDL has been seeing an increase in reports of beneficial insects over the last two weeks, such as lady beetle larvae, lacewing eggs & larvae, and predatory wasps.  Growers should scout for these beneficials in addition to pests and be aware of their populations when considering management approaches.   

This article was posted in Apples, Berries, Grapes and tagged Beneficial insects, Japanese beeetles.