Includes alfalfa looper (Autographa californica)
Pest description and crop damage Alfalfa looper adults are brownish moths with distinctive silvery figures on the front wings. Eggs are ridged and dome-shaped and usually laid singly on the undersurface of leaves. Looper caterpillars can be distinguished from most other common caterpillars by their distinctive looping movement, in which they arch the middle portion of their body to bring the hind legs forward to meet the front legs. Loopers are smooth-skinned with only a few long bristles down the back. They are green, usually with a narrow white stripe along each side and several narrow lines down the back. They may grow up to 1.5 inches long. Mature larvae spin silken cocoons and pupate, usually attached to leaves. Alfalfa loopers tend to have more dark markings than cabbage loopers. They tend to do less physical damage to plants but are a serious source of contamination.
Biology and life history The alfalfa looper overwinters as a pupa either in the soil or in trash near the base of host plants. Moths begin emerging in late April and May, and adults lay eggs singly on weed hosts, usually wild crucifers, rarely on crops. Eggs hatch in 3 to 5 days, and larvae feed for about 2 weeks before pupating on the host plant or in trash. The total development time is about 30 days. Adults emerge in about 7 days, mate, and females deposit eggs as before about 3 days after emerging. There are three or four generations each year.
Pest monitoring A sweep net can be used to sample for large larvae. Take a minimum of 100 sweeps divided into groups of 10 in different parts of the field and along the margins. Sequential sampling that involves fewer samples, and presence-absence sampling that does not involve counting, also may be used.
Pheromone traps can be used to monitor for the emergence of adult male moths. Alfalfa loopers tend to be caught in traps more often than cabbage loopers, sometimes leading to misreadings of which looper is the primary pest. More than five cabbage looper moths per trap per day constitutes significant egg-laying pressure. More than two to five large looper worms per 100 leaves 2 to 3 weeks prior to harvest may justify an early spray program.
Management-biological control
Cabbage loopers have many natural enemies that may keep them below economic levels if they are not killed by insecticide treatments for other pests. These include several important, naturally occurring parasites. A nuclear polyhedrosis virus disease is also important under certain circumstances. Be sure to monitor for natural enemies. If looper populations are close to treatment thresholds, but you find a significant percentage of parasitized or disease-killed individuals, delay treatment for a few days to see if these natural controls will bring populations down on their own. If treatment is necessary, Bacillus thuringiensis insecticide minimizes injury to natural enemies.
Management-chemical control: HOME USE
- acetamiprid
- azadirachtin (neem oil)-Some formulations are OMRI-listed for organic use.
- Bacillus thuringiensis var. kurstaki (Btk)-Some formulations are OMRI-listed for organic use.
- capsaicin-Some formulations are OMRI-listed for organic use.
- carbaryl
- cyfluthrin
- permethrin
- plant-derived essential oils (rosemary, peppermint etc.)-Some formulations are OMRI-listed for organic use.
- pyrethrins-Some formulations are OMRI-listed for organic use.
- spinosad-Some formulations are OMRI-listed for organic use.
- zeta-cypermethrin
Management-chemical control: COMMERCIAL USE
- alpha-cypermethrin (Fastac EC) at 0.02 to 0.025 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.075 lb ai/a per season.
- azadirachtin (Neemix 4.5) at 0.18 to 0.25 lb ai/a. PHI 0 days. REI 4 hr. OMRI-listed for organic use.
- Bacillus thuringiensis (Javelin) at 0.12 to 1.5 lb/a. PHI 0 days. REI 4 hr. Acts slowly; may need multiple applications. Add an appropriate spreader-sticker to enhance control. Most effective on small larvae. Some formulations are OMRI-listed for organic use.
- beta-cyfluthrin (Baythroid XL) at 0.013 to 0.019 lb ai/a. PHI 0 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.1 lb ai/a per season.
- beta-cyfluthrin/imidacloprid (Leverage 360) at 0.07 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.1 lb ai/a beta-cyfluthrin or 0.2 lb ai/a imidacloprid per season.
- Burkholderia spp. (Venerate XC) at 1 to 4 quarts/a product. PHI 0 days. REI 4 hr. OMRI-listed for organic use.
- chlorantraniliprole (Coragen) at 0.045 to 0.098 lb ai/a a) at planting; b) via drip irrigation; c) as foliar. PHI 1 day. REI 4 hr. Retreatment interval 3 days for foliar and 10 days for chemigation. Do not exceed 0.2 lb ai/a per season.
- chlorantraniliprole/thiamethoxam (Voliam Flexi) at 0.1 to 0.175 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed or 0.172 lb ai of thiamethoxam or 0.2 lb ai of chlorantraniliprole per acre per growing season.
- Chromobacterium subtsugae (Grandevo) at 0.3 to 0.9 lb ai/a per 100 gal. PHI 0 days. REI 4 hr. OMRI-listed for organic use.
- cyantraniliprole (Exirel) at 0.065 to 0.11 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 5 days. Do not exceed 0.4 lb ai/a per year.
- cyfluthrin (Tombstone) at 0.025 to 0.038 lb ai/a. PHI 0 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.2 lb ai/a per season.
- emamectin benzoate (Proclaim) at 0.01 to 0.015 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.09 lb ai/a per season. Do not graze livestock.
- indoxacarb (Avaunt) at 0.045 to 0.065 lb ai/a. PHI 3 days. REI 12 hr. Do not exceed 0.44 lb ai/a per crop. Retreatment interval 3 days.
- malathion (Malathion 8) at 1.25 lb ai/a. PHI 7 days. REI 24 hr. Limit 2 treatments per year. Retreatment interval 7 days.
- methoxyfenozide (Intrepid 2F) at 0.06 to 0.12 lb ai/a for early season or 0.12 to 0.16 ai/a for mid to late season. PHI 1 day. REI 4 hr. Do not exceed 1 lb ai/a per season.
- permethrin (Loveland Permethrin) at 0.05 to 0.2 lb ai/a. PHI 1 day. REI 12 hr. Do not graze or feed. Retreatment interval 3 days. Do not exceed 2 lb ai/a per season.
- spinetoram (Radiant SC) at 0.039 to 0.078 lb ai/a. PHI 1 day. REI 4 hr. Retreatment interval 4 days. Do not exceed 0.266 lb ai/a per season. Limit 6 treatments per season. Do not apply to seedling leafy vegetables grown for transplant within a greenhouse, shade house, or field plot.
- spinosad (Success, Entrust SC) at 0.05 to 0.09 lb ai/a. PHI 1 day. REI 4 hr. Do not exceed three applications in any 21-day period. Do not exceed 0.45 lb ai/a per crop. Limit 6 treatments per crop. Entrust SC is OMRI-listed for organic use.
- tebufenozide (Confirm 2F) at 0.09 to 0.12 lb ai/a early year; 0.12 lb ai/a mid to late year. PHI 7 days. REI 4 hr. Do not exceed 0.12 lb ai/a per application or 0.625 lb ai/a per season. Retreatment interval 7 days. Use of a spreader-binder is recommended.
- thiamethoxam/chlorantraniliprole (Durivo) at 0.195 to 0.257 lb ai/a soil application. PHI 30 days. REI 12 hr. Do not exceed 0.172 lb ai of thiamethoxam or 0.2 lb ai of chlorantraniliprole per acre per growing season.
- zeta-cypermethrin (Mustang) at 0.04 to 0.05 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.3 lb ai/a per season.