Armyworms

• Beet Armyworm
• Southern Armyworm

Cooperseeds.com recommends Talstar One Liquid Insectide. Talstar is a great concentrated insecticide for ants, mites, mole crickets and many others. Use inside or out. Talstar F is virtually odorless and keeps killing for up to six weeks! Contains 7.9% Bifenthrin.

You can also use Generic brand Bifen and save money. It has the same ingredient as Talstar One.

Southern Armyworm, Spodoptera eridania (Cramer)

Description

Adult moths have a wingspan of 1 1/2 in. The fore wings are streaked with cream, gray, light brown, and black, and have an elongate white mark across the rear outer corner. A dark kidney-shaped spot is present near the middle of the fore wings. Hind wings are white with a few dark marks on the margins. Females produce large egg masses of 100 to 200 eggs covered with scales from their abdomens. Eggs are usually deposited on the undersides of leaves. The larvae are often very colorful and grow to 2 in. long at maturity. Head color is light to reddish-brown. Their bodies have a narrow, almost continuous white to orange stripe down the center of the back. A yellowish to orange broad band runs backward from the first abdominal segment below the spiracles. Some to all abdominal and some thoracic segments have dark triangular markings near the center of the back. Darker specimens exist where bands and markings are very faint. Each thoracic segment and first two abdominal segments are larger than previous segment giving a distinctive swollen or hump-backed appearance to larvae, particularly in late instars. Sutures on front of head form an inverted "Y." Larvae have three pairs of true legs and five pairs of prolegs . Brown 3/4 to 1 in long pupae are found in the soil.

Biology

Adults feed on nectar and other moisture sources. Larvae emerge from egg masses in 3 to 4 days. They feed in groups during their first instar and then disperse on the wind using silken threads. All age larvae feed near leaf edges and may move down into the crowns and into heads near the base of the plants as they get older. Larvae enter the soil to pupate after 2 to 3 weeks feeding. Adults emerge from soil in 7 to 8 days.

Recommendation

Fields should be monitored at least weekly for damage by caterpillars feeding on leaves. Pheromone traps can be used to monitor occurrence of moths. Young plants are more susceptible to leaf feeding than middle age plants before cupping and head formation. Look for egg masses on the leaves. The dark bodied larvae are usually visible feeding on the leaves. Treat if you find one second or third instar larva per 10 plants from germination to heading. After head formation, treat if average count is >1 per 25 plants. Best time to treat for this pest is in early morning or early evening.

Insecticides are most effective against the younger instars with higher rates and more frequent applications needed to try to control later instars. Insecticides are available for foliar applications. Coverage and penetration are important in treating for all of the moth species. Use of surfactants to increase head penetration and surface coverage increase insecticidal control.

Insect predators and parasitoids, as well as pathogens aid in earworm control, but generally do not exert enough pressure to prevent yield loss.

Field disking and destruction of crop residues are important for control of all caterpillar, aphid and leafminer pests of leafy vegetables to reduce their migration into nearby crops. Southern armyworms develop well on several weeds in the Amaranth group, so weed control on ditch banks surrounding fields can help reduce populations before they invade fields.

Cooperseeds.com recommends Talstar One Liquid Insectide. Talstar is a great concentrated insecticide for ants, mites, mole crickets and many others. Use inside or out. Talstar F is virtually odorless and keeps killing for up to six weeks! Contains 7.9% Bifenthrin.

You can also use Generic brand Bifen and save money. It has the same ingredient as Talstar One.