Here’s a “tangled web” of a thought process on soybean aphids…

It’s HOT, so the aphid sprays won’t work as good….

• But, it’s HOT so the aphids are multiplying quickly!
• But, it’s a LITTLE TOO HOT, so they might not multiply as quickly!

It’s DRY, so the aphids are under stress, and won’t do as much damage….

• But, the soybeans are under stress, too!

We’re putting on the last spray of glyphosate, so it would be nice to mix the insecticide spray in…

• But, the glyphosate spray should have coarse droplets and the aphid spray should have finer droplets!

We’re pretty sure that our aphid populations will need to be sprayed….

• But, if we spray too soon we may have to spray a second time!

Corn Hybrids and Worms

Making proper insect control recommendations can be a challenge if one doesn’t have the exact planting maps of the various corn hybrids from the growers.

For example, western bean cutworm is controlled by Herculex Bt hybrids but not by the other Bt events. One makes the decision to treat when the corn is tasseling. If the grower plants various strips of different hybrids and events in the same fields, it becomes very difficult to make sure the proper hybrids are treated.

A 20% refuge is needed with non Bt corn for resistant management. However, if the other Bt events are mixed in the same field, misapplications will happen if a very detailed map is not available for both the consultant and the aerial applicator.

Likewise, the decision for treating second generation corn borer is usually decided prior to egg hatch. One cannot wait to determine survivability of the small worms before treating. Without a detailed map, some Bt corn may get treated if the consultant finds treatable numbers of corn borer eggs.

Growers and consultants need to coordinate hybrid selection and planting maps to make correct treatments for western bean cutworm and corn borers. Misapplications can be costly by treating hybrids that have the proper insect resistant Bt events or the non Bt refuges may be missed if numerous hybrids are planted in the same fields.

Leave a Comment

Name (required)

Email (will not be published) (required)

Website