Twospotted spider mites have been spotted in fields across much of Iowa already this summer, as much of Iowa is in moderate or severe drought (D1-D2, US Drought Monitor). I encourage you to scout for twospotted spider mites in crops. Twospotted spider mites can increase whenever temperatures are greater than 85°F, humidity is less than 90 percent, and moisture levels are low.
Observations across several counties in southeast and south central Iowa show that, despite some recent rain events and high humidity, twospotted spider mites are persisting in both corn and soybean fields across the area. These insect-like pests can be very difficult to identify, so we’ve got a few points below to help you find them.
A few places in southeastern Iowa and surrounding states have already reported heavy twospotted spider mite populations with prolonged feeding in soybean this year. I recommend scouting corn and soybean fields for mite infestations this year because they thrive in hot and dry conditions. The U.S. Drought Monitor estimates about 70% of Iowa is abnormally dry or in severe drought as of June 28, 2016.
