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Management Updates: Jun 25, 2018

White Grubs
June 25, 2018

Japanese beetle and masked chafer adults were reported flying in southern Ohio last week. This is pretty nearly "on schedule" for that region. Don't be surprised if you see a few early Japanese beetles flying in southern New England in the next week. (We often consider July 4th as a typical date to become aware of Japanese beetle adults, but recently they have been emerging a little earlier than that most years.)

While I have not had any reports so far this spring/summer, European chafer adults should already be flying in many parts of their New England range. European chafers are primarily night fliers, and can be seen congregating in trees at dusk. They are problematic from Boston north through mid-coast Maine, and have spread through much of Massachusetts and southeastern New Hampshire.

Oriental beetles will be flying soon as well. They are often described as night fliers, but in fact we have often seen large populations flying very actively in the middle of the day. They are a problem throughout coastal New England as well as towns bordering the Connecticut River in Connecticut and Massachusetts.

A reminder - for those who are planning to use a neonicotinoid to control white grub populations, the applications should be made "when the adults are laying eggs". For many of you in southern New England, European chafers may be laying eggs as early as early July. Most Japanese beetles and oriental beetles will not start laying eggs until around the second week of July. I normally suggest making neonicotinoid applications for Japanese and oriental beetles between 10 July and 10 August, and it looks like that should work pretty well for most of you in southern New England again this year. Be sure to follow best practices to protect pollinators when applying neonicotinoids for white grub control.

Submitted by: Dr. Pat Vittum