COTTON: Most cotton has accumulated enough heat units that the need for scouting and further insecticide applications has passed. Based on last effective bloom date for West Tennessee and the calendar, any insecticide applications in late maturing cotton should wrapped up within the next 4-5 days.
A short and sweet synopsis of the 2017 season is 1) plant bug pressure was generally lower than in recent years, 2) spider mite and aphid infestations were more common than usual, and 3) our bollworm flight was nothing extraordinary, but we took some hits in some fields. It’s clear we need to adjust our plans for managing bollworm in Bt cotton with growing tolerance to Bt toxins and pyrethroid insecticides.
SOYBEAN: September is an important month for scouting and managing insect populations in late maturing soybean fields. Loopers and stink bug are likely problems as the month progresses. It is fairly likely than some fields will need treating for redbanded stink bug. With two warm winters in a row, this insect has crept into Tennessee. Redbanded stink bugs are more damaging and more difficult to control than other stink bugs. I’ve included a couple of links to some resources to help you identify and manage redbanded stink bugs. Keep in mind that the threshold for redbanded stink bugs is lower than that for other stink bugs in soybean, and they can reduced test weight and seed quality as late as R7, resulting in potential dockage. Louisiana deals with the redbanded stink bug annually, and my LSU colleagues recommend the following.
- The suggested treatment threshold for redbanded stink bug is 4/25 sweeps … as opposed to 9/25 sweeps for other stink bug pests
- Don’t walk away from these fields too early
- Do not double the threshold at R6 … as we suggest for other stink bugs
- Do not terminate insecticide applications at R6.5 if redbanded stink bugs are present at threshold levels
I’ve included a photo gallery of the various life stages. Keep in mind that this insect is smaller than the green stink bug, and the red band on the adult varies in color and distinctiveness (and may actually be yellow or black).
When Can I Quit Treating Redbanded Stink Bug in Soybean? By Angus Catchot, Extension Entomologist, Don Cook, Research Entomologist and Jeff Gore, Research and Extension Entomologist