With continued dry weather, the pest we’ve been getting the most calls about is the spider mite. This is just a reminder that vigilant scouting for this pest is a good idea right now.
It is also important to re-scout five days after treatment because many products will not kill the eggs, and populations can resurge. Any necessary follow-up treatment should be made with a product with a different mode of action to reduce resistance development. So, for example, if you used something with bifenthrin the first time, you might switch to Lorsban the second time, or vice versa.
There are two miticides that are newly labeled for spider mite management in soybean and/or some types of corn: Agri-Mek from Sygenta and Zeal from Valent. We at OSU have not tested these products yet, but are currently running trials with both of them in northwestern Ohio.
Economic thresholds based on the number of mites per plant have not been established for spider mites on soybeans.