The Ohio State University

Home LandscapeNotes I'm always pretty conservative about making any real predictions concerning future insect or mite populations, but I'm going to break out of this timidity and predict that we are going to experience some major grub populations this September and October!

Two weeks ago, my crew and I sampled our billbug control trial and we found lots of billbug larvae, but what was very evident was lots of Japanese beetle and masked chafer eggs in the soil! It was common to find one to several eggs in each of our 4.25-inch diameter turf and soil plugs. If these eggs successfully hatch (which they should because the soil moisture has been great this July), this means that we may have anywhere from 10 to 40 grubs per square foot! Frankly, I'm worried that my billbug "ranch" may be destroyed by grubs, not billbugs. My dilemma is that if I apply a grub insecticide, I'm likely to destroy my billbugs!

Even if you live in the southern third of Ohio where the Japanese beetle and masked chafer populations were dramatically lowered by last year's drought, ALL the adult females are finding good places to lay eggs, and the Japanese beetle females are obviously making multiple eating and egg laying trips.

Central and northern Ohio is experiencing normal to higher than normal adult beetle flights, so egg laying will be off the scale this season. Even lawns that are not normally irrigated and golf course roughs that normally go dormant in the summer will be at high risk this year for grub populations.

Posted by Dave Shetlar