Monday, July 13, 2020

Thoughts and Tips for Bollworm Scouting on 2 Gene Cotton for 2020

·       If monitoring 2 gene cotton in 2020, take note of the corn planting window in your area. This plays a large role in the emergence and movement of corn earworm (bollworm) moths to cotton in July and August. The more corn planting is spread out, the wider the emergence window of bollworms.

·       Bollworm moth activity is not constant throughout the season. Instead, it occurs in cycles especially through July. By August, generations of bollworms and tobacco budworms overlap. Fieldmen should detect the start of these peaks by focusing on eggs and newly hatched larvae in terminals/white blooms.

·       Scouting intervals for bollworms may be reduced to 3-4 days during critical windows on 2 gene cotton in 2020. Fieldmen could spot check select sentinel fields of similar variety and planting date on alternate visits to detect increased activity.

·       When monitoring for bollworm larvae or eggs on 2 gene cotton in 2020, be more concerned about detecting population increases early, and reacting if necessary, than quantifying exact numbers—for example: 18 vs. 28 per whatever.

·       Fieldmen should consider damaged fruit on 2 gene cotton in 2020, but treatment decisions will be more timely if primary focus is on eggs and/or newly hatched larvae.

·       Based on my observations during the Bt cotton era of the past 20 plus years, escape bollworm larvae do not feed on or damage as many fruiting sites per worm as they did in the pre Bt era.

·       In order to stay on schedule in 2020, fieldmen should consider only staying in a field long enough to make confident treat or not treat decision.

·       Pest Patrol Updates on cotton/soybean insects in Alabama are available again in 2020. To sign up for the Syngenta Pest Patrol Updates for Alabama, register online at or register via text message by texting pestpat11 to 97063.

Monday, July 6, 2020

Tarnished Plant Bug Alert for Cotton

Due to abundant rainfall over most of the state in recent weeks, the migration of adult plant bugs from wild host (daisy fleabane) has been slow and extended over several weeks. This makes it difficult to make treatment decisions since the adult numbers may be below threshold level (8 per 100 sweeps) for several consecutive weeks. It is for this reason that we also use a pinhead square retention count (need 80% retention) in making treatment decisions. It is possible that a sub-threshold number for consecutive weeks will do economic damage. Large farmers spread over a wide geographical area (multiple counties) do not have the ability to treat individual fields on a particular day. As the result, when PGR and boron applications are being made, a plant bug insecticide is included.

               Plant bugs tend to go to the earliest planted cotton first. As we move through July, all fields will eventually reach the blooming stage. When cotton reaches the blooming stage, we will begin to find immature plant bugs that have hatched from the eggs that were deposited by the adults that migrated from wild host. In blooming cotton, we can no longer use the pinhead square loss in making treatment decisions. Immature plant bugs move deeper into the canopy and feed on large squares, which results in damaged “dirty” blooms. The treatment threshold for these immature plant bugs is 3 per 5 row feet using a black drop or shake cloth. The product Diamond is a great plant bug suppression tool when immatures occur at threshold level in blooming cotton. Diamond at 6 to 9 oz. per acre will give 2-3 weeks control of immatures. Diamond can be mixed with an insecticide such as Bidrin, Centric, imidacloprid (Admire Pro or generic), pyrethroid or Transform. The number of adult plant bugs usually begins to decline (natural mortality) after first bloom as the immatures increase. In fields where plant bugs go uncontrolled for weeks, the immatures eventually reach the adult stage. If this situation is allowed to develop, a field may have plant bug populations that include all life stages from eggs in plant stems, immatures to adults. When this situation is allowed to develop into an imbedded population, multiple applications on a schedule are required to being plant bugs under control. It should be noted that clouded plant bugs have made up part of the plant bug population since mid-June. Damage, treatment thresholds and controls remain the same for both plant bug species.

Clouded Plant Bug Immature

Clouded Plant Bug adult