UMass Extension Turf Program

Late-Season Chinch Bug Activity

October 24, 2002
Late-Season Chinch Bug Activity

We received numerous calls from turf managers (mostly in lawn care) during the month of October asking about chinch bugs. With the dry conditions we experienced through much of the summer, chinch bugs thrived - and probably completed two generations in many areas of Massachusetts and the rest of southern New England. In many locations chinch bug damage was not diagnosed until September, when dormant grass did NOT start to grow out of the dormancy. (As we have mentioned previously, chinch bug damage often resembles drought stress, and is often misdiagnosed.)

Some turf managers asked us about the wisdom of treating for chinch bugs in September or early October. I do not recommend such action, in part because the insecticides normally used for chinch bugs appear to be markedly less effective as ambient temperatures drop. I have not conducted such field trials myself, but I am not aware of any field testing that indicates late season applications of insecticides (i.e., mid-September to mid-October) can reduce chinch bug populations.

Philosophically I would not support such an application. Because our cool season turfgrasses are growing vigorously now, they can withstand virtually any chinch bug feeding during September or October. Quite often we encounter winter conditions (in particular, cold dessicating winds and low snow cover) that kill many chinch bugs, and we often have cool wet springs that further reduce their numbers.

For those who had chinch bugs - or suspected their presence once the grass was slow to recover in September - be prepared to monitor for chinch bug activity next year, beginning in late May or June. In general chinch bugs prefer sunny exposed locations and soils that drain well, but conditions have been fovorable for at least two consecutive years so they could show up anywhere.

The easiest way to monitor for chinch bugs is to cut a square of turfgrass (perhaps four inches on a side) and put it in a bucket. Fill the bucket with water (using some pressure to "stir things up") and watch for chinch bugs as they float to the surface. This method is a variation on the old coffee can technique and enables you to take samples even in areas with dense thatch.

Submitted by: Dr. Pat Vittum


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