Crop Update: Insect activity running ahead of the summer season

Posted: Jun. 19, 2011 12:25 am Updated: Nov. 29, 2014 7:16 am


Summer officially begins on June 21, but based upon insect activity to date, you'd think we were in the middle of summer. This may be a good year for our flying friends.

We started out with those darn buffalo gnats or black flies, which are still with us (but not for much longer). These are those annoying pests that like to hover around your head, ears and nose on calm days. These hatch from running water sources, and the females have to feed on a meal of blood. They will soon disappear (as water temperatures increase, it signals an end to hatch) but none too soon.

Then we had the cicadas emerge. This was the year of the 13-year brood. As you drive around the countryside or in developed parts of town during the day there is no mistaking their presence. They will be around for another couple of weeks, and then we won't notice them for another 13 years.

Black cutworm was probably more noticeable this year than they have been for a while. And although not everyone saw problems, there were a number of individuals who had corn populations affected to the point that treatment or replanting became necessary. This is an insect that is difficult to predict if injury may occur because they are dependent upon southerly storm fronts to bring them into our area.

The last two weeks or so I've been noticing lightning bugs, which also signal the time of corn rootworm (CRW) hatch. The past few years we've noticed an absence of CRW, most likely due to unfavorable conditions (extremely wet soils) during hatch that adversely affect their survival. This year the soils are much drier during hatch. So will CRW be troublesome this year? We'll know soon enough. But because populations were so low for the past few years, it's doubtful if widespread problems occur. There just weren't many females around last year to lay eggs.

I've noticed that European corn borer (ECB) is present now as well. Scouting non GMO corn fields, it's not uncommon to find evidence of their presence in whorls. Populations will vary across the region depending upon emergence, egg laying and Bt. But until you get half of the plants infested, control is probably not economical even with $7 corn. You can estimate potential economics of control in non-Bt corn via the IPM ECB calculator online at

Corn earworm moths also have made their presence known. Mike Vose at the Orr Center called to say they trapped numerous moths around June 10. I've also caught a number of moths. There certainly aren't any ears of corn to feed upon, but I've seen instances where the larvae will feed on leaves and in whorls of corn plants. The adults are here, and they will lay eggs, so as the larvae hatch, they will feed on leaf tissue in the absence of ears. Some of the Bt strains will have an effect on their tissue feeding, but scouting of non-Bt corn should begin.

True armyworms may be present in the area; they certainly are west of us in Missouri. It's been six years or so since we've seen much in the way of this insect. At that time we could find them damaging corn, wheat and pasture/hay ground. The moths prefer to lay eggs into lush grass growth and larvae can severely defoliate their food source in a short amount of time.

I'm not sure what other insect pests will occur this summer. Time will tell. But it would seem to me that the above list certainly seems like it doesn't really need any additions.



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