Managing Thrips in Louisiana Cotton

Tobacco ThripsTobacco thrips as seen under the microscope (Photo by J. Villegas)

Thrips management is crucial to successful cotton production and requires proactive measures from the outset. Thrips possess a unique biology that makes precise timing of insecticide applications difficult without seed treatments. Their eggs are typically deposited in the cotyledons, and as the first true leaf emerges, immature thrips hatch and prefer to feed within the furl stage. Unfortunately, they are well-protected within the furl, making it extremely challenging to reach them with insecticides. Consequently, the first true leaf often sustains damage before it fully expands. Effective thrips management requires realistic expectations for sprays and consideration of the thrips' life cycle.

  • Insecticide Seed Treatments (ISTs): ISTs are the primary strategy for controlling thrips. Their effectiveness varies based on the prevailing weather conditions and the level of thrips infestations. In low to moderate-pressure situations, ISTs can effectively control thrips. However, supplementary foliar treatments may be necessary under high pressure or unfavorable growing conditions.
  • In-Furrow (IF) Applications: In-furrow treatments provide another effective method for thrips management. Several options include acephate (note that pockets of acephate-resistant thrips have been detected in portions of the state), imidacloprid, and aldicarb (AgLogic). Additional foliar applications for thrips control are typically unnecessary when cotton is treated with aldicarb.
  • ThryvOn: ThryvOn, a new Bt trait, offers an exciting at-plant option for thrips management. ThryvOn demonstrates high efficacy against thrips and may eliminate the need for supplementary foliar treatments. Furthermore, ThryvOn exhibits efficacy against tarnished plant bugs, albeit to a lesser extent than thrips.

Supplemental foliar insecticides for thrips management - if additional foliar insecticides are required to manage thrips, several options can be considered:

Foliar Insecticide/Active Ingredient)

Rate (fl oz/acre


Orthene (acephate)


-effective and cost-efficient choice, but it may result in secondary pest outbreaks like spider mites and aphids

Bidrin (dicrotophos)


- effective alternative and less likely to flare spider mites and aphids

Dimethoate (dimethoate)


-cost-effective, good efficacy at high rates, minimizes the risk of spider mite issues compared to acephate

Radiant (spinetoram)

1.5 – 3.0

-effective, requires adjuvant, least likely to flare spider mites or aphids

Intrepid Edge (spinetoram + methoxyfenozide)


effective, similar activity to Radiant, an adjuvant may be necessary to enhance the efficacy

To ensure a fast and vigorous start for cotton, effective thrips management is crucial. The recommended approach involves utilizing suitable at-plant insecticides, such as ISTs or in-furrow treatments, or considering the adoption of ThryvOn cotton. Notably, foliar insecticides should be used as supplementary measures to at-plant treatments, rather than replace them. For more information on thrips management, please check out the LSU AgCenter Insect Pest Management Guide.

5/29/2023 6:28:31 PM
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