Home 5 Ag Stories Prolonged heat welcomes twospotted spider mites

Prolonged heat welcomes twospotted spider mites

Photo by Iowa State University Extension and Outreach

The latest U.S. Drought Monitor indicates western Iowa still faces moderate drought conditions, while a section of west-central Iowa remains under the D2 level of intensity, or severe drought. Some of those areas have since received timely rains. Dryness, however, does not appear to be the only problem they face.

Prolonged heat and drought stress often present twospotted spider mites, shares Erin Hodgson, Iowa State University Extension & Outreach entomologist

“Twospotted spider mites usually flare up when you have 90 plus degree days for an extended period of time. They attack a lot of different plants, including corn and soybeans,” Hodgson said.

Twospotted spider mites can be difficult to detect. Hodgson shares how to best identify the rather small pest.

“If you’re scouting for spider mites, no matter the plant, take a leaf or part of the plant and shake it on top of a white piece of paper. If you see little dust specks moving around, they’re probably spider mites,” Hodgson said. “If you’re in crops, I’d encourage (you) to look at edge rows first and the upper part of the canopy.”

Twospotted spider mites cause injury when feeding and are capable of reducing soybean yield by 40 to 60 percent when left untreated, according to Iowa State University Extension and Outreach. Hodgson recommends being proactive in your treatment, as management becomes more difficult with field-wide outbreaks.

“Catching them early, when they’re on the field perimeters is important. If the plants are starting to suffer, you want to take action sooner rather than later. We would recommend using something that would be active on the egg, nymph and the adult,” Hodgson said.