Green cloverworm larvae.
Most recently reviewed by: Suhas Vyavhare (1970)
Common Name(s): Black snout moth, Green Cloverworm
Description
Newly hatched larvae are about 0.5 mm long at hatching and are pale and yellow. Older larvae are light green and have two yellowish-white stripes on the side of the body. Green cloverworms have four pairs of prolegs (three pair under the center of the body and one pair at the end of the abdomen), and this makes them easy to differentiate from soybean loopers because loopers have only two pairs of prolegs. Another distinguishing characteristic is that when disturbed, green cloverworms usually exhibit a rapid flopping or squirming behavior. Loopers do not exhibit this behavior.
Adults are triangular-shaped and brownish to grayish, about 1 – 1.4 inches in length. They have a relatively long snout. Females have more silver coloration than do males.
Green cloverworm adult. Patrick Porter
Origin and Distribution
North America.
Habitat & Hosts
Green cloverworm is a defoliator and capable of removing large amounts of leaf tissue very quickly when present in significant numbers. It is usually a sporadic pest in Texas. Eggs are about 0.5 mm in diameter and are laid singly on the undersides of leaves. Small larvae may only eat the lower tissue of a leaf and leave the upper tissue intact; this is known as skeletonizing. Larger larvae chew all the way through leaf tissue and can eat all of the leaf blade except the larger veins. Green cloverworms are usually not pod feeders, but can damage pods (depending on pod maturity), especially when all available leaf tissue has been consumed.
Green cloverworm damage to soybean. Patrick Porter
Life Cycle
Green cloverworms have complete metamorphosis. There is an egg stage, six larval stages (instars), a pupal stage and an adult stage. In Texas there are at least three generations per year. Overwintering occurs along the Gulf Coast.
Management
If you live in the State of Texas, contact your local county agent or entomologist for management information. If you live outside of Texas, contact your local extension for management options.Significant yield loss in soybean can occur at 20% defoliation in the podfill stage. Control decisions should be made on leaf damage because there are several defoliating pests of soybean and they may all be contributing to yield loss. In addition to green cloverworm, these species can include soybean loopers, cabbage loopers and velvetbean caterpillars. Soybean growers are referred to Managing Soybean Insects in Texas.
There are several diseases, especially granulosis virus, that help control populations, and beneficial insects (predators and parasitoids) help in control as well.
Registered insecticides include several pyrethroids like esfenvalerate, cyfluthrin, bifenthrin, zeta-cypermethrin and lambda-cyhalothrin. Other insecticides include carbaryl, spinosad, acephate and methomyl. Bacillus thuringiensis and Beauveria bassiana can be used for control.