By Ross Greene, UGA Extension ANR Agent, Evans and Candler Counties
Cotton growers in Georgia are facing increasing pressure from cotton jassid (Amrasca biguttula biguttula). Updated scouting thresholds and new efficacy trial results are now available to help producers make timely, informed management decisions.
Scouting Guidelines
When scouting for jassid:
- Examine the 3rd, 4th, or 5th mainstem leaf below the terminal (the 4th leaf is most commonly infested).
- Look for nymphs and cast skins (exoskeletons), especially on the undersides of leaves.
Updated Preliminary Threshold
- 1–2 jassid nymphs per leaf or
- Early visible symptoms such as slight hopperburn, particularly in the inner portion of the field.
Current Field Observations
- The highest jassid populations have been reported in earlier planted cotton.
- As cotton defoliation begins, jassids are expected to move into lush, green cotton, raising concern for late-planted fields.
- This is an evolving situation, and injury levels may increase in coming weeks.
Common Grower Questions
How long before retreatment is needed?
- This depends on the insecticide used and reinfestation pressure. Some fields have already required a second application. Regular scouting is critical.
How long should cotton be protected from jassids?
- Green leaves are needed to fill top bolls.
- Based on field observations, jassids can damage a field in as little as two weeks.
- Protect cotton until about 14 days before the earliest possible defoliation date, when the field is at least 60% open and still green. This typically corresponds to 20–25% open boll.
Should I treat if the field is yellowing?
- If the field is yellowing but still green and symptoms are developing, treatment is recommended even at 20–25% open boll.
- If leaves are already red and brown, treatment may not provide economic benefit.
Insecticide Selection
- Bidrin – Consistently effective in both small plots and commercial fields.
- Argyle and Assail – Less consistent than Bidrin, but good options when whiteflies are present.
- Carbine – Strong results in small plots and larger test blocks.
- Centric, Transform, Sefina, and Sivanto – Remain options, with further evaluation ongoing.
- Bifenthrin and other pyrethroids – Do not provide acceptable control.
Insecticide Trials and Research Updates
UGA Extension is conducting 14-day after treatment efficacy counts and initiating additional trials across Georgia.
View the updated Jassid slides with trial results here :
Final Notes
This remains an evolving pest management issue. Producers should continue scouting fields and be prepared to act promptly when thresholds are met.
UGA Extension will continue to provide timely updates as more information becomes available. Please report noteworthy field observations to your local Extension office.
Evans County Extension Office – 912-739-1292
Candler County Extension Office – 912-685-2408
