Scouting and Control for Tarnished Plant Bugs in Cotton

tpb.jpg thumbnailPlant bugs are destructive insect pests of cotton. In Louisiana, the term "plant bugs" encompasses a group of closely related pests, including the tarnished plant bug, the cotton fleahopper, and the clouded plant bug. Both adult and immature plant bugs possess piercing, sucking mouthparts and feed on squares, flowers, and bolls. The feeding injury inflicted by plant bugs on small squares and bolls lead to reductions in size, quality, and yields and delays in maturity. To minimize economic losses resulting from plant bug infestations, it is crucial to scout and treat both at pre- and post-bloom stages of cotton.

At the pre-bloom stage, the objective is to maintain a first-position square retention rate of 70-85%. If squares are shedding before bloom, plant bugs are likely the culprit. Use a sweep net to monitor for plant bugs prior to bloom, and the threshold for treatment is eight or more plant bugs per 100 sweeps and square retention of 80% or less. Neonicotinoids generally provide better performance during pre-bloom. To manage resistance, it is advisable to avoid using pyrethroids, organophosphates, and carbamates during this stage.

Sampling methods and plant bug thresholds change once the cotton plants enter the bloom stage. The threshold for treatment at this stage is the detection of 2-3 plant bugs per drop cloth sample (equivalent to 0.6 per row foot). During the early bloom, both sweep nets and drop cloths can be utilized to monitor plant bug populations. There are several insecticides available that effectively control plant bugs during the post-bloom period, but selection should be based on individual field conditions. For instance, growth regulators such as Diamond only target immature plant bugs and should be tank-mixed with other insecticides if significant numbers of adults are present. Regular scouting and rotation of insecticides are key factors for long-term success in managing plant bugs.

LSU AgCenter Insecticide recommendations for plant bugs in cotton (cotton fleahoppers, tarnished plant bugs, and clouded plant bugs).


Amount per Acre (fl oz)

Pounds Active Ingredient

Acres Treated per Gallon or Pound SP


Carbine (50)

2.3 – 2.8

0.072 – 0.089

7.0 – 8.0


Centric (40)

2.5 – 3.0

0.0625 – 0.075

6.4 – 5.3


Admire Pro (4.6)

0.9 – 1.7

0.032 – 0.062

142.0 – 75.0

Imidacloprid (2)

2.0 – 4.0

0.032 – 0.062

64.0 – 32.0

Imidacloprid (4)





Strafer Max (70)

1.7 – 2.3

0.075 – 0.10

9.4 – 7.0


Transform (50)

1.5 – 2.25

0.047 – 0.071

10.7 – 7.1


Belay (2.13)

3.0 – 6.0

0.05 – 0.1

42.7 – 21.0


Vydate C-LV (3.77)

11.2 – 17.0

0.33 – 0.5

11.4 – 7.5


Diamond (0.83)

6.0 12.0

0.039 – 0.078

21.3 – 10.6

*Note – based on previous field trials, the number of insecticide applications for tarnished plant bugs is reduced with the recently released ThyrvOn Cotton.

7/12/2023 3:23:17 PM
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