This post will serve as my annual, early-season reminder about thrips and Tomato Spotted Wilt Virus management.
- First, there is nothing new when it comes to thrips and TSWV management. If someone tries to tell you or sell you something different, call your local UGA County Extension agent.
- Every peanut field in Georgia will have thrips. Thrips injury is most likely to result in yield loss when plants are under additional stress from herbicide injury, drought, cool temperatures, etc. I strongly encourage growers to use an at-plant insecticide to reduce the risk of losses to thrips injury.
- Thrips transmit TSWV. The only way peanut plants can acquire the virus is from thrips feeding.
- The most important factors that affect TSWV risk in peanut are:
- Cultivar resistance: planting a cultivar with resistance to TSWV is the critical first step to reducing risk.
- Planting date: planting before 10 May puts peanut at increased risk for TSWV because it exposes young plants to higher levels of thrips pressure.
- Phorate in-furrow: Phorate (Thimet) is the only insecticide that can be applied to peanut that reduces the risk of TSWV. Mixing other insecticides doesn’t do it; applying foliar insecticides doesn’t do it.
- Twin row pattern: twin row peanuts are at reduced risk for TSWV compared to single row.
- Plant Stand: Skippy stands or stands with fewer than 3 plants per foot are at increased risk for TSWV.
- Planting into residue: Thrips don’t like to land on peanuts when they are growing in small grain residue (like wheat or rye).
Research has shown that for every 1% TSWV found in a peanut field at harvest time, we can expect about a 20 pound reduction in per-acre yield. TSWV management is over when the furrow closes. Making good management decisions now, based on knowledge from years of research at UGA, will help reduce the likelihood of significant losses from the disease.
If you have questions about thrips and/or TSWV management, please contact your local University of Georgia Extension agent.
