UW-Madison/Extension Insect Diagnostic Lab Update July 22, 2021
Caseload at the UW Insect Diagnostic Lab has been high over the last two weeks. A summary of recent fruit crop insects reported to the UW Insect Diagnostic Lab can be found below:
Japanese beetles: Japanese beetles are active and common in many parts of Wisconsin. Reports coming in to the UW Insect Diagnostic Lab suggest that Japanese beetle activity is below average in many parts of the state this year. Nonetheless, the IDL has recently received reports of damage from around the state on tree fruits (both pome and stone fruits), caneberries (especially raspberries), strawberries, and grapes. Japanese beetle adults can be fairly long lived, and adults can be found into September so growers should continue to monitor the situation.
Spotted Wing Drosophila: Since professional fruit growers are well aware of SWD and how to identify its damage, I usually don’t see many reports of SWD at the UW Insect Diagnostic Lab compared to several years ago. Nonetheless, I’ve had several recent cases of raspberry damage from home fruit growers. These reports have been scattered around the state.
Pearslug sawfly: The slug-like larvae of this pest can be found on pear, other fruit trees, and certain landscape plants from mid-summer onwards. The larvae skeletonize leaves and cause browning of leaf tissues. I’ve recently had some of my first reports for the year in southcentral and central Wisconsin. There are two generations per year.
Gypsy Moth: This year has turned out to be a strong year for gypsy moth in many areas. By now, caterpillars have finished feeding on plants and have pupated. In southern Wisconsin, adult gypsy moths are currently being spotted. Adult females cannot fly and use a pheromone to attract males (which can fly). Females lay egg masses (beige, velvety texture, ~1-2 inches long) on trees and other surfaces. Each egg mass can contain upwards of 1,000 eggs, which won’t hatch until next spring. Growers that saw gypsy moth in their area this year should keep an eye out for egg masses. These can be physically removed (scraped off into a container of soapy water) or treated with horticultural oils such as Golden pest spray oil in fall when temperatures are lower.
Brown Marmorated Stink Bug: While brown marmorated stink bug adults are currently scarce, I’ve continued to receive reports of BMSB nymphs from southern Wisconsin over the last two weeks. Recently, 1st, 2nd, and 3rd instar nymphs have been spotted. Growers with a history of BMSB in their area should monitor for activity.
This article was posted in Insects and tagged Brown Marmorated Stink Bug, gypsy moth, Insect Diagnostic Lab, insects, Japanese Beetles, Pearslug Sawfly, Spotted Wing Drosophila.