Cotton and Soybean Insecticide Termination

Cotton:

• Tarnished plant bugs and bollworms: NAWF 5 + 350 Heat Units
• Spider Mites: NAWF 5 + 350 Heat Units
• Soybean looper: NAWF 5 + 350-400 Heat Units
• Stinkbugs: NAWF 5 + 450 Heat Units
• Fall Armyworms: NAWF 5 + 500-550 Heat Units

NAWF, node above white flower, 5 or cutout, is the point when the terminal growth slows and the fifth node from the unfurled terminal leaf has a first position white flower.  Based on research, this is the last point in the growth and development of the plant that will produce bolls that  contribute to yield. The additional heat unit requirement after cutout allows for the boll to develop enough that the probability of sustaining economic damage from insects is low. Based on some preliminary graduate student data, NAWF 5 + 350 heat units for tarnished plant bug, bollworm, and spider mite termination, is roughly NAWF 2. DD60’s will vary depending on location within the state. Generate DD60’s across the state using the Mississippi State University Delta Agricultural Weather Center.

Soybean:

• Podworm: R6
• Stinkbugs: R6 + 7 Days (R6.5), Redbanded: R7, unless adverse environmental conditions exist that would promote poor seed quality.
• Soybean Looper, greenclover worms, velvetbean caterpillar, saltmarsh caterpillar: R6 + 7 Days (R6.5)
• Armyworms: R6 + 7 Days (R6.5)
• Bean leaf beetles: R6 + 7 Days (R6.5)

Remember that observations taken to determine plant growth should be taken from the pods in the upper four nodes on an indeterminate variety and anywhere on a determinate. R6 is the point that seed has completely filled the pod cavity. Roughly 7 to 10 days later, R6.5, is the point that seed has separated from the protective membrane within the pod. For redbanded stink bugs, unless there are adverse conditions, insecticide termination is R7 or when one pod is mature in color.