According to the U.S. Drought Monitor, most of Iowa is still considered abnormally dry. Twospotted spider mites are erratic pests in some corn and soybean fields right now, particularly in southern Iowa. I’ve been getting a lot of questions about how to manage mites, including what products are active on the eggs. Robert Wright and Julie Peterson from the University of Nebraska-Lincoln summarized a list of pesticide groups labeled for twospotted spider mites in corn and soybean:
Mode of action class 1B; organophosphates
- Dimethoate in soybean and corn. E.g., Dimethoate 4E, 4EC, 400, Dimate 4E, 4EC.
- Chlorpyrifos in soybean. E.g., Lorsban 4E, Lorsban Advanced, Chlorpyrifos 4E, Govern 4E, Hatchet 4E, NuFos 4E, Warhawk 4E, Yuma 4E.
Mode of action class 3A; pyrethroids
- Bifenthrin in soybean and corn. E.g., Bifenture 2E, Brigade 2E, Discipline 2E, Fanfare 2E, Sniper 2E, Tundra 2E.
Mode of action class 6; chloride channel activators
- Abamectin in soybean, including spider mite eggs. E.g., Agri-Mek SC.
Mode of action class 10B
- Etoxazole in soybean and corn, including spider mite eggs and immatures. E.g., Zeal.
Mode of action class 12C
- Propargite in corn. E.g., Comite.
Mode of action class 23; tetronic and tetramic acid derivatives
- Spiromesifen in corn, most effective on spider mite eggs and immatures. E.g., Oberon.
- Hexythiazox in corn; does not control adult spider mites. E.g., Onager.
- Hero (zeta-cypermethrin and bifenthrin) labeled for soybean and corn.
- Cobalt (chlorpyrifos and gamma-cyhalothrin) labeled for soybean.
- Swagger (bifenthrin and imidacloprid) labeled for soybean.
- Tundra Supreme (chlorpyrifos and bifenthrin) labeled for soybean and corn.