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Published June 02, 2014, 09:57 AM

Crop pests are coming

Here come the bugs and weeds.

By: Jonathan Knutson, Agweek

Here come the bugs and weeds.

The warmer temperatures that arrived across much of the Upper Midwest in late May were needed badly. They warmed and dried fields, allowing the sluggish planting pace to pick up.

But the warmer temperatures also will accelerate the development of weeds and insects. Experts offer two general suggestions on how farmers should deal with the potential pest onslaught:

n Scout fields early and often for insects.

“Get out into fields often because things will be changing quickly,” says Janet Knodel, North Dakota State University Extension Service entomologist.

n Consider using pre-emergent herbicides to fight weeds.

“We really want to see people bring back pre-emergent herbicides into their programs,” says Phillip Glogoza, crops educator with University of Minnesota Extension in Moorhead.

Applying herbicides before weeds emerge helps combat the spread of chemical-resistant weeds. It also provides “a wider window of opportunity” to combat weeds in general and complements the use of post-emergent herbicides, he says.

Trouble is, many farmers are so busy planting crops that they have little, if any opportunity, to apply pre-emergent chemicals, he acknowledges.

Traditionally, many farmers turn to aerial ag applicators, or crop sprayers, to apply pre-emergent herbicides in wet years like this one.

Glogoza notes that there are restrictions on which herbicides can be applied by air, so farmers interested in aerial application should check labels and talk with their chemical specialists.

Every growing year is different, and it’s too early to predict which weeds might become the biggest problems this summer, he says.

It’s also too early to predict which insects might be particularly troublesome this summer, Knodel says.

In general, though, the cool spring held down the development of most insects, including grasshoppers, she says.

Sometimes, though not always, “Insects don’t do as well in a cool, wet year,” she says.

Even so, “Insects are temperature-dependent and they can reproduce quickly. So with this hotter weather, I expect we’ll see a lot of activity,” she says.

Shorter window

When the weather turns warm relatively quickly, as was the case in late May, insects develop faster, Knodel says.

“In a year like this, there’s a shorter window in which they can come out. We may get them emerging more together (than is normally the case), so they can do more damage in a short period,” she says. “So it’s good to get out and scout your fields,” she says.

A few insects, such as corn seed maggots, generally do better in the cool, wet conditions, she says.

But seed treatments usually protect against those insects, she says.

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