With many of our cotton acres at or past cutout, wrapping up insect control is coming quickly. We’re beginning to see a general decline in plant bug populations but stink bugs continue to linger with numbers increasing.

Keep in mind that the average last effective bloom date is right around the corner (August 15-20^th). This is the average date that a white flower has a 50% chance of making a harvestable boll. It is a roll of the dice whether bolls set after this date have time to mature before a frost. For late maturing fields that are just now or have not reached NAWF5, it is still advisable to continue to good insect management practices for 2-3 weeks to allow these last bolls to accumulate enough heat units to be relatively safe from insect attack.

Once cotton reaches NAWF 5, accumulated heat units (DD60s) determine when individual insect pests no longer pose an economic threat. Recommended termination thresholds are:

• Tarnished plant bug: NAWF 5 + 350 DD60s
• Bollworm: NAWF 5 + 400 DD60s
• Spider mites: NAWF 5 + 350 DD60s
• Soybean looper: NAWF 5 + 350–400 DD60s
• Stink bugs: NAWF 5 + 450 DD60s
• Fall armyworm: NAWF 5 + 500–550 DD60s

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I’ve been receiving more calls about whiteflies over the past week. Fortunately, many of the fields are not at economically damaging levels. However, if large amounts of honeydew are accumulating and/or leaves are beginning to yellow, those fields deserve closer attention.

The whiteflies we are dealing with in Tennessee are bandedwinged whiteflies, not silverleaf whiteflies. Bandedwinged whiteflies do not transmit any viruses of economic concern in cotton. Drought-stressed cotton is at the greatest risk of injury, and insecticide applications may be warranted if whitefly populations are increasing plant stress—similar to how we approach aphid infestations. Continue reading →