Alabama Cotton: Options for Plant Bug Control

Photo: Lisa Ames, University of Georgia,

A concern of many cotton farmers now is plant bugs especially if their cotton is near a corn field. I would dare to venture that a significant portion of our cotton crop in north Alabama is not scouted on a regular basis. Plant bugs can have a devastating impact on cotton so growers need to stay on their toes.

A plant bug application should be made from the third week of squaring through bloom (where most of our crop in north Alabama is now) when three plant bugs are found per six feet of row with a drop cloth or 15 plant bugs are collected per 100 sweeps with a net.

Many growers are making growth regulator applications and it would be prudent to put a plant bug treatment, if needed, with this application.

Good options for plant bug control include Centric at two ounces per acre; Transform WG at 1.5 ounces per acre; Orthene at .5 pounds per acre (several growers have told me that Orthene is in short supply); and Bidrin at 3.2-5.3 ounces per acre. Bidrin can only be used after first bloom. Its use is prohibited from pinhead square to first bloom.

I would also rotate my mode of action to help avoid insecticidal resistance. Bidrin and Orthene are the same mode of action (1B) so if either of these are used I would rotate to another mode of action (Centric-4A or Transform-4C) if another plant bug application is needed.

Most growers are also concerned about stink bugs as the cotton begins to set bolls. Bidrin is very good on both the brown and green stink bug. Orthene is good on both stink bugs and Centric will give fair-to-good control of stink bugs. Transform will not control stink bugs.

The concern to preserve beneficial insects also plays a role in which insecticide to use. Bidrin and Orthene are very hard on beneficial insects and Centric is hard on beneficial insects. Transform is easy on beneficial insects and if used should help maintain their populations.

Growers may remember in 2014 when cotton was rank and they had trouble killing plant bugs in the lush growth. We have had plenty of rain so far and there is a concern that cotton could be rank. Diamond, an insect growth regulator, at six ounce per acre may be a good investment with our first plant bug application. It is only active on immature plant bugs and will not control the adults but will help extend plant bug control.

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