The Weird Weather of Summer 2012

Drought impacts corn, beans, wheat and sugar beets across the state.

Published on: Aug 6, 2012

We've been inundated, and rightly so, with reports about Minnesota farmers dealing with drought in parts of the state and what various agencies and university specialists are doing to provide assistance.

We've assembled some of that information here for your perusal.

Spider mite outbreak
Two-spotted spider mites are making the most of this year's hot, dry weather, say entomologist Ken Ostlie and integrated pest management specialist Bruce Potter, University of Minnesota Extension.

For farmers and crop advisers not familiar with spider mites, the damage they cause may be mistaken for drought symptoms. Infestations usually begin on fields edges, particularly adjacent to cut grass or alfalfa.

The Weird Weather of Summer 2012
The Weird Weather of Summer 2012

If you see a discoloration of the lower leaves on your soybeans or corn, you need to get in the field and scout for mites. To do so:

1.Start at the field edge where symptoms occur.

2.Examine leaves from the bottom upwards. Look at the underside of leaves. Note yellow spots (stippling), webbing and how far up the plant the damage has progressed.

3.Tap damaged leaves over a white sheet of paper and look for mites with a hand lens or magnifying glass. They are very small—half the size of a soybean aphid nymph. 

4.If mite presence is verified, it's time to progress into the field. Move at least 100 feet into the field before making your first stop. Walk a "U" pattern, checking at least two plants at each of 20 locations.

5.Check fields every 4-5 days if drought persists.

Treatment is recommended only if damage and mites are detected throughout the field. Edge treatments are not effective since mites are usually spreading throughout the field before any visual symptoms are noticed.