Spider Mites and Rootworms Peanut Notes No. 118 2019

— Written By

The following summary is based on discussions with Rick Brandenburg and Barbara Shew.

Late planted peanuts are at greater risk of southern corn rootworm damage than earlier planted peanuts because pods are less well developed and can be more easily damaged by insect feeding. Lorsban is our only control option. Diamond and Prevathon provide no benefit against rootworms. Chlorothalonil and Lorsban can flare spider mites. Lorsban likely triples the chances of spider mites and tools are very limited to control spider mites. Just because Lorsban flares spider mites, there is no justification for using Diamond and Prevathon against rootworms. They will not work. Given the mediocre performance of spider mite products, their cost, and often the lack of availability, farmers should do everything possible to avoid spider mite outbreaks. Weather patterns this year have promoted the buildup of spider mites in corn and along field edges. It is a problem waiting to happen. Therefore, use the Southern Corn Rootworm Index to make a decision on Lorsban. Apply fungicides only if needed and based on local advisories. See more details in 2019 Peanut Information on these issues.