By Anders Huseth, North Carolina State Extension Specialist

As we enter squaring stage cotton, growers should be mindful of tarnished plant bug movement into fields. Large plant bug populations have been reported in other parts of the Cotton Belt this season.

However, we do not know if high pressure will occur in North Carolina. A major concern is that cool early season conditions set the crop back this season. Managing TPB to maximize square retention will be critical in 2023.

Where are plant bugs?

Key sources of TPB are weedy field boundaries, cut overs, and senescing corn. Weedy field boundaries surveys detected high TPB adult counts in several NC counties earlier this season (Northampton, Halifax, Wayne, Sampson). We are unsure if these will translate in to management challenges in cotton, however, counts did suggest that this could be a good TPB year because weeds were healthy late into June. This could mean additional TPB reproduction and greater population sizes.

How to scout

Squaring cotton (pre-bloom) should be sampled using a standard sweep net. TPB are often unevenly distributed in cotton fields, scouting stops need to be spaced across the entire field if possible. Keying in on local landscape features (e.g., corn) can identify hot spots in the field. Be sure to average across all sampling stops. Remember to switch to a drop cloth after the crop begins blooming.

Related:There’s more to a fungicide program than the fungicides

When to treat

Squaring cotton (pre-bloom) should be treated if square retention drops below 80% AND 8 TPB per 100 sweeps. There is no need to protect cotton from square loss above 80%, even with the delay this season. Once cotton blooms, switch to 2-3 TPB per drop cloth sample (5 foot of row).

What to treat with

July is a time in the season where we need to preserve beneficial insects for bioresidual. Select insecticides based on our regional recommendations for a given time in the growing season.

An overview of plant bug management through the season can be found here.

A guide to managing plant bugs on ThryvOn cotton can be found here.

Some plant bug insecticides can have unequal impacts on beneficial insects. An overview of that can be found here.