Wednesday, June 20, 2018

Heavy Plant Bug Season May be Becoming a Reality

Last week, aphids began to build in spots in fields statewide. Ordinarily, I would recommend to let the natural fungus take out the aphids. However, each field and season presents a different picture. The fungus always works, however sometimes it is a week to 10 days later than we would like. Since we have a lot of late maturing cotton this season, I don’t feel we need to let aphids set our cotton back any further. Even if aphids do not cause yield losses, when an entire field is drooped down from aphid stress, we are likely seeing some maturity delay. For this reason, in 2018, I am suggesting that if a grower is going over a field for weed control or PGR application, then I would add an aphid control insecticide in the spray. We have some very economical choices for aphid control when they can be piggy backed with a trip over the field for another purpose.

Now on to plant bugs – I say plant bugs because we could easily have both the tarnished and the clouded species in some fields. In fact, I picked up some clouded species in sweeps in cotton last week in central AL. Historically, we have had more clouded in wet springs. Maybe because we get a better growth on button bush, a wild host for clouded in wet seasons. Button bush is a plant that likes low, swampy habitat, and excessive rainfall gives us that. No matter whether it is TPB or CPB, our scouting thresholds and controls are the same.

Now let’s talk about the TPB. The rainfall in the past month has kept their primary wild host, daisy fleabane, fresh and it appears that 2 generations have developed on fleabane. In mid May, we had mostly adults here in Central and South AL. Now, in both South and North AL (including the TN Valley), we have another generation that was just mid aged immatures the second week of June. This means that we will likely have a migration from fleabane into cotton that will last for 3-4 weeks. Therefore, feeding and egg laying in cotton by these migrating adults will last 3-4 weeks. This will result in a long emergence of immatures in cotton beginning about first bloom.

We may need multiple applications pre bloom in some fields to control migrating adults. Then we may also need multiple applications post bloom for the immatures as they hatch. I hope I am over estimating what could be a bad plant bug year. This is not what we needed on 2 gene cotton. Multiple plant bug sprays just before the CEW flight comes from corn will result in more escape bollworms in mid-late July.

One thing we can do if this scenario happens is to use a plant bug application for adults about first bloom and add the IGR Diamond to the tank mix. Diamond will add residual control on hatching immature plant bugs for 10-20 days, depending on the rate used.

I will be focusing and making observations on plant bugs for about the next 3-4 weeks, and I will keep everyone updated on what we are seeing. The first report of high numbers of adult TPBs in cotton came from west central AL on June 19.

An Extension publication overviewing plant bugs was prepared by Barry Freeman, our resident plant bug expert in 1999 and can be found online at Life cycles, damage, scouting, and management have not changed over the years. Every season and field are different, which requires close monitoring in order to make the proper management decisions.

2018 Treatment thresholds and control recommendations can be found in ACES publication # ANR-0415, “Cotton IPM Guide” available online at

If fieldmen, growers, or consultants have plant bug observations, please call or text and share with me at 334-332-9501. You may email me at