Tarnished Plant Bug IPM and Impact of the Transform Label Cancellation

We posted an article last spring about utilizing several best management practices in an overall IPM program to manage tarnished plant bug in cotton. We included a pdf that highlights all of the research we have conducted over the last few years that is here: Tarnished Plant Bug IPM

Adoption of this IPM program, or some variation of it, has been growing among growers and consultants over the last couple of years. One of the aspects of many of these practices is that they promote earliness in the cotton crop. We have found that getting the crop through the squaring and flowering periods as quick as possible can eliminate insecticide applications and minimize yield losses from tarnished plant bug.

Several of the practices, such as planting date, varietal maturity, nitrogen rate, and irrigation management, highlighted in the above reference can impact maturity of the cotton crop.  Other factors can also impact crop maturity. One of those is early season pest management, especially management of thrips. This is something that people don’t think about much, but the impact of thrips on cotton yield can be greatly magnified in areas where tarnished plant bug is the primary pest. That is because in addition to thrips causing yield reductions, they also delay maturity of the crop if not managed. This can result in additional insecticide applications for plant bugs.

Because of that, insecticide seed treatments are a vital component of the overall cotton IPM program from both a thrips and tarnished plant bug standpoint. Growers should utilize the best available seed treatment and manage thrips accordingly to promote earliness.

Figure 1. Insecticide rotation strategy for tarnished plant bug management in cotton with Transform included.

Although adopting at least some of these practices can provide significant benefits, scouting fields and spraying insecticides remains the most important component of this IPM approach. Figure 1 shows the overall insecticide rotation strategy for tarnished plant bug and cotton aphid management in Mississippi cotton. The horizontal blue bars are when each of the pests typically occurs at treatable levels. The dashed boxes represent use windows to effectively rotate the available classes of insecticides.

You will notice that we recommend the neonicotinoids during the first 2 weeks of squaring and then recommend Diamond during the late squaring/early flowering period. The Diamond application is based on research highlighted in the paper above. When Transform was first labeled, we began recommending 1-2 applications following the Diamond application because it was the most effective insecticide to manage both tarnished plant bug and cotton aphid. Transform was then followed by the organophosphates (acephate or dicrotophos) and pyrethroids, usually applied as tank mixes. Transform was brought back into the rotation around peak bloom to provide an overall rotation strategy.

The point of this is that, when available, Transform serves as the foundation of the overall IPM program because it provides effective control of both tarnished plant bug and cotton aphid, and because it is not as likely to flare spider mites as the other insecticides currently available.

With the recent cancellation of the Transform label discussed here, management of tarnished plant bug becomes more difficult. Most important is the fact that it basically eliminates the key rotational insecticide in the overall program. It also eliminates the one insecticide that provided effective control of both plant bugs and aphids in cotton.

Figure 2. Insecticide rotation strategy for tarnished plant bug management in cotton without Transform included.

Figure 2 shows the seasonal rotation strategy without Transform, which is basically not a rotation at all. In this scenario, we will have to rely on the neonicotinoids from first square to first flower and then rely on the OP’s and pyrethroids from first flower to well past peak flower.

Although this is not ideal, we will be able to manage tarnished plant bug with the overall IPM approach highlighted above. Perhaps the biggest benefit from a tarnished plant bug management standpoint would be a significant increase in cotton acres to dilute the population across more acres. Having Transform as the foundation of our insecticide rotation was making that possible. At this time, it is not clear what the availability of Transform will be. Growers that currently have Transform leftover from last year will be able to use it in 2016, but at this time it cannot be purchased. In the meantime, the key will be to manage the crop for earliness and do everything you can to reduce the number of applications needed to manage tarnished plant bugs.