Regional Insecticide Recommendations for Plant Bugs

(Updated: July 5, 2022, 8:27 a.m.)

Article by D. Reisig and A. Huseth

A recent survey of commercial fields in North Carolina provided data verifying the long-known regional nature of tarnished plant bug (aka Lygus bug). Furthermore, recent studies have demonstrated that higher minimum temperatures and a greater area planted to wheat and soybean has likely contributed to the increase of tarnished plant bugs in North Carolina cotton. Unfortunately, we expect tarnished plant bug to continue to be a major pest in North Carolina cotton based on these results.

Because of the regional nature of this pest, some growers can count on multiple sprays for tarnished plant bug a year, while others might only spray once, or some not at all. Furthermore, insecticide efficacy varies across the year, with some insecticides becoming less effective as the year progresses. In addition, growers need to be cautious using more broad-spectrum insecticides early in the season to preserve beneficial insects. Also important, is that we have documented pyrethroid resistance in North Carolina. So these should only be used as a tank mix partner and with caution (bifenthrin is an example of a pyrethroid). We have formulated a set of recommendations to reflect these expectations.

Three figures of cotton plants at different stages of development, along with the brand time to spray.
For growers expecting to spray one time during the season, select one of these insecticides if the spray is made in June, July through early August, or mid-August through September. If additional sprays are needed, do not follow with the same insecticide class (see Table 1 at end).
Three figures of cotton plants at different stages of development, along with the brand time to spray.
For growers expecting to spray up to three times during the season, select these insecticides if the spray is made in June, July through early August, or mid-August through September. If additional sprays are needed, do not follow with the same insecticide class (see Table 1 at end). fb = followed by
Three figures of cotton plants at different stages of development, along with the brand time to spray.
For growers expecting to spray up to three times during the season, select these insecticides if the spray is made in June, July through early August, or mid-August through September. If additional sprays are needed, do not follow with the same insecticide class (see Table 1 at end), except in July and August. Try to tank mix neonicotinoids (Admire Pro or Centric) or Diamond with Transform during this period. fb = followed by

Before you spray for tarnished plant bug in cotton, be sure you have reached the economic threshold. North Carolina research shows that the most consistent way to maximize economic returns when managing tarnished plant bug is to scout weekly and to treat when the economic threshold is reached (prior to bloom, 8 adults in 100 sweeps AND <80% square retention; post-bloom, 2-3 immatures per drop cloth sample).

Table 1. Insecticide trade name, active ingredient, and action classification

 

Trade name Active ingredient Mode of action classification Notes
Admire Pro imidacloprid 4a A poor stand-alone insecticide, but good as a tank mix
Bidrin dicrotophos 2b Harsh on beneficials
Centric thiamethoxam 4a Not as effective after June
Diamond novaluron 15 Only active on immatures
Orthene acephate 2b Harsh on beneficials
Transform sulfoxaflor 4c Considered a different MOA from 4a
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