Pigweed in particular is more abundant than formerly, and this weed is a favored host of the beet armyworm.Sporadic starvation of herbivorous insect pests, such as the beet armyworm Spodoptera exigua (Hübner), often occurs due to host plant scarcity and dislodgement from host plants resulting from inclement weather, enemy attack, and other perturbations. This might be due to use of minimal tillage in nearby soybean fields. In recent years, beet armyworms have become an increasing problem to Arkansas spinach producers. The gregarious larvae often produce spotty damage only in certain areas of a field. They are a pest in cotton fields, with young larvae skeletonizing leaves and older larvae feeding in foliage, squares, flowers, and bolls. They tend to develop large populations in soybean fields late in the season, feeding on flowers, beans, and leaves. In Arkansas, beet armyworms tend to be abundant under drought conditions. Beet armyworm is rarely a pest in the most northerly parts of its range, but it is a serious pest in southern states, including Arkansas. The reinvasion reaches as far north as the line from Maryland to Colorado to northern California.
Those areas are reinvaded by adult moths in the spring. However, it does not survive the winter in areas where its host plants freeze. In Arkansas, several generations occur annually.īeet armyworm can winter in warm areas, such as Florida, Texas, and Arizona, where all life stages can be found year round. Adults emerge in 6–7 days in warm weather and live for only about 10 days. Larvae develop in about 10–20 days and burrow in the ground to pupate. They have a wingspan of about one inch, but living adults at rest hold their wings draped over the sides of the body in a tent-like fashion.įemales deposit eggs in scaly clusters of 50–150, usually on undersides of leaves. Adults are small, drab, mottled brown and grey moths. Mature caterpillars are about 1 ¼ inches long. Unlike fall armyworms, they lack stout, black setae on the body. The caterpillars consume buds and new growth, preventing flowers, leaves and vegetables from developing.Īlthough coloration can be quite variable, the caterpillars are typically pale green with darker, lateral, longitudinal stripes, and they often have a diagnostic small dark spot behind the head laterally, above the second pair of true legs. They also have a habit of burrowing into thick areas of plants- ininto a head of lettuce, a maturing tomato, or an onion leaf, for example. Larger larvae are solitary and eat holes in foliage. Young larvae feed gregariously on leaf parenchyma, leaving behind only the epidermis and veings. The beet army worm is a serious pest of a wide range of crops, including various table vegetables, cotton, cereals, flowers and tobacco.
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