The Alabama Vegetable IPM program conducts the statewide insect monitoring program as a special service to specialty crop producers and other farmers. Pest alerts are based on moth counts from sticky wing traps. However, there is no shortcut to direct crop scouting to look for caterpillars and other insects. High moth activity usually leads to the increase in caterpillar pressure within 10 to 14 days after detection. Beginning or experienced producers should monitor insects, keep good records, and develop their own IPM plan that is suitable for the farm. For an insect and disease image library, download the Farming Basics mobile app. Producers can also use the app to contact a regional Extension agent.
The following table shows the latest results of moth numbers from trap location around Alabama.
Pest Monitoring Report from July 23
|Species||2021 Moth Numbers||This Time Last Year|
|Lesser cornstalk borer||1510||4290|
|Squash vine borer||316||203|
The following pest alerts/recommendations are based on sticky wing pheromone counts and outbreak reports from across the state:
- Fall armyworm moths continue their strong migration into crop fields this year- almost five times more activity compared to this time last year. FAW caterpillars are dark with a Y-shaped mark on the head and four spots at the tail end. FAW is a native species that overwinters in the Deep South. See more information below.
- Beet armyworm activity is catching up to the fall armyworms. Their caterpillars are green with a pair of black dots behind the head on their thoracic segment.
- Wet weather and cooler temperatures, resulting in high humidity, creates an extremely suitable environment for insect pathogens and natural enemies. Producers may see caterpillars dying upside down because of infection.
- Lesser cornstalk borer moth numbers are dramatically lower compared to 2020. The threat to crops from larvae should be low in areas with high rainfall.
- Cabbage looper activity is six times higher than soybean looper at present.
- Corn earworm/tomato fruitworm activity is four times higher than tobacco budworm.
- Southern armyworm moth activity is nine times higher than yellow-striped armyworm.
- Continue to look for stink bug and leaffooted bug feeding on tomatoes and okra. On tomatoes, growers will be able to see yellow areas and uneven fruit ripening. Fruits tend to rot faster after being fed on by leaffooted bug. On okra, growers can feel the bumps and blackened areas from stink bug feeding. Leaffooted bugs love okra for feeding and egg-laying (like a trap crop), so be cautious and treat with insecticides if needed.
- Vegetable producers should switch to using longer-persistence (translaminar action) and selective insecticides for caterpillar and stink bug/squash bug control in high rainfall conditions. Examples include Rimon, Intrepid or Intrepid Edge, Senstar, Coragen, Venom/Scorpion, etc.
- Spider mites have not been a concern in open field crop because of the amount of rain. Scenarios might be different for greenhouse and high tunnel producers. They should stay alert, and use a hand lens to identify spider mites correctly. Do not kill off the beneficial mites.
Fall Armyworm Management in Vegetable Crops
Systems-based (Cultural Control) Practices
- Monitor armyworms using pheromone traps for catching moths and direct crop scouting for caterpillars.
- Timely crop planting and harvest. Armyworms get worse on late crops because they have a 30-day life cycle and can establish four to five generations.
- Conserve natural enemies. Don’t overspray with conventional or organic insecticides.
- Reduce plant stress that affect plant vigor. Strong plants can compensate for loss of vegetative parts.
- Remove debris from previous crop after harvest. Don’t carry over insects.
Pest Exclusion Systems
- Temporary exclusion system. Use Super Light Insect Barrier or AgroFabric Pro (figure 1) immediately after transplanting or after seed germination to block moths. Remove the fabric after the insect threat is over and pollinators are needed.
- High Tunnel Pest Exclusion (HTPE) System. Use a 50% shade cloth with wide openings around high tunnels to block moths and significantly reduce caterpillar numbers (figure 2).
- Release natural enemies that will feed on egg masses and small caterpillars under the fabric or inside netted tunnels.
Biorational Insecticides for Organic/Naturally Grown Farms
- Bacillus thuringiensis or Bt (Xentari, Dipel)
- Natural pyrethrin (PyGanic, Azera)
- Spinosad (Entrust)
- Neem with Azadirachtin (Neemix)
- Leap (Bt + disease control premix)
Note. Develop a written IPM plan. Apply biorationals at 3 to 5 day intervals in high pressure and rotate insecticides. Follow all insecticide labels.
Synthetic Insecticides for Conventional Farms
- Chlorantraniliprole (Coragen, systemic – early season)
- Insect growth regulators (Intrepid, Rimon)
- Spinosad (Radiant)
- Carbaryl (Sevin)
Note. Rotate insecticides and protect natural enemies. Follow all insecticide labels.
The July 20 Alabama Drought Monitor map from the USDA shows no drought conditions for the state. Drought conditions generally increase pest activity on crops, so scout crops weekly or more often.
Use the following IPM resources for insecticide choices related to specialty crops.
- Southeastern U.S. Vegetable Crop Handbook
- Home Garden Vegetable: Insect Control IPM Guide
- Organic Vegetable IPM Slide Chart
- Urban Farm IPM Slide Chart
The Alabama Beginning Farmer playlist on the Alabama Extension YouTube channel have several IPM videos. One of the new field IPM videos, Integrated Pest Management (Overview), provides an overview of all three levels of pest management.
- Quick Overview of Conventional Insecticides
- Bioinsecticide 101
- Botanical Pesticides
- Basics of Organic Insecticides
- Insect Predator 101
- Tomato Insect Pests 101
- How to Manage Yellowmargined Leaf Beetles in Brassicas
- Cabbage Insect Pest 101
- Spider Mite Outbreak During Drought
- Cowpea Curculio Management – Part 1
- Cowpea Curculio Management – Part 2
- Yellowmargined Leaf Beetle IPM
Trade names are used only to give specific information. The Alabama Cooperative Extension System does not endorse or guarantee any product and does not recommend one product instead of another that might be similar.
Special thanks to Rudy Yates, Olivia Fuller, David Lawrence, Jacob Kelley, Chip East, and Eric Schavey for contributing data from multiple locations. Supported by funds from the USDA-NIFA BFRD (Phases 1 & 2), SARE Research & Education/PDP, CPPM/EIP, OREI, and ADAI Specialty Crops Block Grant Programs.