The dry weather has provided the perfect opportunity for spider mite flares. We have reports of infested soybean fields in Charles City County and some in the Suffolk/Southampton County area. Miticide options are limited in soybean to bifenthrin (Capture, Brigade, and others), dimethoate, and Lorsban 4E. Bifenthrin is a pyrethroid so products will provide knock down of adults and nymphs, but not control of eggs. If there are a lot of eggs present at the time of application, they will hatch and could require a second application within 5 days or so of the first. Dimethoate is a foliar systemic but must be absorbed and translocated by the leaf tissues to provide residual action; otherwise, it undergoes rapid photodecomposition from sunlight. This leaf absorption process is greatly reduced in drought-stressed plants that have “shut-down” physiologically. According to Dr. Whalen (Univ. of Del), another important factor that plays a role in the performance of dimethoate is the pH of the water used as the carrier. Many pesticides, especially dimethoate, are subject to breakdown by alkaline hydrolysis. In alkaline water (high pH), dimethoate break down can result in poorer than expected field performance. Dimethoate degradation is also accelerated by the mineral content of the water, especially the presence of iron. If a high pH situation exists, you can lower the alkalinity of the water in the spray tank by adding an acid-based buffer. The buffer must be added to the spray tank first, before the addition of dimethoate. Lorsban 4E is somewhat effective against mites and offers the advantage of also having good activity against grasshoppers and some other pests. The very best control for spider mites is rain. I wish I could ‘recommend’ that but I reckon my ‘connections’ are not quite that good, yet!