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 an IPM plan that is suitable for their 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 September 22
|Species||2021 Moth Numbers||This Time Last Year||A month ago|
|Lesser cornstalk borer||4120||7150||2910|
|Squash vine borer||1040||619||714|
Alabama Pest Alert #6 and Vegetable IPM Recommendations:
- USDA Drought Monitor doesn’t show any dry areas in Alabama. Higher moisture in the air and the soil helps insect pathogens and natural enemies that may suppress pest populations.
- Notice the comparison data in the columns. Fall armyworm (FAW) moths continue to be very active – they have nearly doubled in numbers from August 2021 and over five times the numbers from 2020. Beet armyworms are catching up to the FAW numbers and getting close to the activity levels last year. Southern armyworms and yellowstriped armyworms continue to increase slowly.
- Make sure to scout vegetable crops every week or more often under this high pest pressure condition! Fall crops (e.g., brassicas) are being planted in extremely high armyworm pressure – so the armyworms could be the first insect producers will encounter as they switch crops. Bt, natural pyrethrin, neem with azadirachtin and spinosadin are a good rotation or as tank-mix (e.g., Bt Xentari + Pyganic, Bt + neem) are effective for small caterpillars or when numbers are low. There are several effective conventional insecticides that can be used selectively. Choose long-persistence and translaminar products in this wet weather.
- Natural enemy activity has been good this year due to high moisture. Entomologists have seen more insect diseases (epizootics) this year in comparison to past years. Stay alert if we end up in a drought situation, as drought can change the pest situation dramatically.
- Other pest issues and educational resources:
- There have been many questions about melonworm outbreaks. Melonworms are different from squash vine borers and pickleworms. Melonworms also feed extensively on leaves and cause webbing, not just on the fruits. Get more information and pictures.
- There have been a number of fire ants questions. Other ants will follow the aphids for honeydew (see cartoon below for fun). Click for more info about fire ant control in vegetable crops.
- Early season pests of brassicas/crucifers: Watch for flea beetles, yellowmargined leaf beetles, armyworms and cabbage loopers. More information on pest scouting in crucifer crops is available on Extension’s website.
- Cabbage Insects 101 video.
- Yellowmargined leaf beetle video.
- Temporary and Permanent Pest Exclusion System: Great way to deter early season insect pests this fall – especially armyworm and looper moths!! Read more.
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 are 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 percent 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 September 23 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.