Jerry Mathis (Sales Agronomist, Region 1 – South Dakota)
The continued lack of rain has really taken a toll on the corn crop. I have looked at a number of plots and noticed that there are some big differences among varieties. We have a number of new varieties in the lineup, which will be a good test in the plots to see what stands out. I look forward to sharing this information as harvest begins.
With the dry, dusty conditions, spider mites tend to flare up. Spider mites like it hot, dry and dusty. The most common is the two-spotted spider mite. Generally the first place to look for them is on the edges of a field on the bottom side of the lower leaves. They tend to work their way up the plant as populations increase. Since they are extremely small, you can usually see the webbing or the stippling of the leaves. You can also shake a leaf over a white piece of paper and look for a few black dots moving around.
Spider mites can be usually be controlled by an organophosphate insectide. I recommend a sulfur product be added to this as an irritant to the mites, which will get them to move around from under the leaf to increase control. You may find thrips in your soybeans as well; these are a natural predator that feed on the spider mite eggs helping to keep populations down. If there are no eggs for the thrips to eat they will feed on the plants, so keep an eye on them.
With the drought conditions and the corn firing up from the bottom, the appearance of spider mites tends to increase and the plant shows even more stress. As we get close to corn denting, it’s generally not feasible to spray for them.
As the crops get pushed along with the increase in heat units we have had (1-2 weeks ahead of normal), harvest is just around the corner. With this in mind please be safe.
Remember Dakotafest is coming up quick (August 21-23). Stop by the booth and see what we have new for next year. Hope to see you there!
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