Tarnished plant bug

With an above-average amount of rain this growing season, there are more factors constraining the CA cotton crop than usual. Wet conditions have created a stunted crop alongside increased insect pressure. In some cases, fallow fields have high weed pressure, which can increase lygus and other plant bug populations. To combat these challenges, growers should revisit their pest monitoring and control practices.

“Plant bugs” refer to a group of cotton insects that include the tarnished plant bug, western tarnished plant bug, cotton fleahopper, clouded plant bug and the verde plant bug. Plant bugs have a piercing, sucking mouth and damage cotton crops before they bloom by feeding in tender terminals and small squares. Their needle-like mouthparts cause squares to abort.

Once blooming occurs, plant bugs begin feeding on larger squares. Feeding on larger squares just before opening causes dirty blooms, or white blooms with darkened pollen anthers and occasional circular deformities on the petals.

University of California suggests early season monitoring for plant bug activity, especially retention counts of small squares. If square retention remains high, greater than or equal to 80%, comprehensive sampling for live plant bugs probably isn’t necessary.

After cotton blooms, you can assess plant bug presence by continuing fruit examinations, evaluating dirty blooms and using a black beat cloth. Research has found that small plant bug nymphs are easier to identify on black beat cloths than standard white cloths.

Centric® foliar insecticide and Endigo® ZC insecticide can help cotton growers control plant bugs and their subsequent damage. Centric provides fast-acting, long-lasting control of yield-robbing pests such as plant bugs. As an effective rotational product for insect resistance management, Centric consistently controls target insects in both Bt and conventional cotton. Endigo ZC combines 3 industry-leading technologies for quick knockdown and extended residual control, resulting in higher potential yield.

Other Pests to Monitor

The increased rain has the potential to jumpstart other pest populations in the coming months. Whether your operation is faced with lygus, worms, aphids or other pests, there are several management practices which can help mitigate these threats.

Lygus bugs, for example, move to cotton fields from other locations. More attractive crops such as alfalfa have the potential to reduce damaging migrations of these pests in your cotton fields. Uncut strips of alfalfa can serve as a border to slow lygus bug migration. Other pests, such as aphids, can be controlled by natural predators such as lady beetles and aphid-killing fungi. Additionally, if you planted early or used insecticide-treated seed, your cotton may not experience high pest populations.

If these management techniques need to be coupled with insecticides, there are several options to choose from depending on which pests need to be treated.

• Lygus: consider Centric, Endigo ZC or Warrior® II with Zeon® Technology insecticide.
• Lygus and Aphids: Centric or Endigo ZC.
• Lygus and Worms: Besiege® insecticide or Besiege tank mixed with Centric.
• Worms and Aphids: Centric, Besiege tank mixed with Centric, or Endigo ZC tank mixed with another worm material.

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