Field Guide     Pest Management     Velvetbean Caterpillar

Velvetbean Caterpillar

CROPS IMPACTED: Soybeans

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Family: Erebidae

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About the Velvetbean Caterpillar

Reproduction and Life Cycle

The velvetbean caterpillar will overwinter as a moth in the tropical areas of America and the southern area of Florida. During the summer months, they will begin their migration back north towards the southeastern area of the United States. The adults will then begin laying their eggs on the underside of soybean plant leaves. The eggs are laid individually and will hatch after developing for 3 days. When the larvae first hatch in their first instar, they will eat the egg casing. Throughout the rest of the instars (6 all together) they will begin eating the soybean leaves, if available. The larvae stage lasts anywhere from 3 to 5 weeks, when they will pupate in leave crevices in the soil. They pupate for 7 days and then emerge as a moth. The velvetbean caterpillar will go through numerous generations each year.

Velvetbean Caterpillar Identification and Habitat

Identification

As an adult, this pest has a wingspan between 3 and 4cm in length. Their colour varies with different patterning types as well. The forewings tend to be any colour from gray to yellow-brown to red-brown. The hind wings are a lighter brown and have faded spots near its center. The wings will usually have a dark line that runs diagonally through both wings. These moths are active during the night and prefer to eat flower nectars. Their eggs are oval, ribbed, and will remain white until hatching, when it will turn a pink colour. The eggs are very small, only 1 to 2mm in length and are slightly flattened. The larvae have a large variety of colour and markings it goes through during its 6 instars. However, they usually have dark stripes running lengthwise down their body, along with thinner stripes of yellow, pink, or white. The larvae head is rounded and brown in colour. During the first instar, larvae will be a light green; they won’t develop the stripes until later stages of development. The pupa starts off as a green, and will later change to a brown. It has a smooth texture and is approximately 20mm long and 6mm wide.

Habitat

This pest tends to populate the western hemisphere, mainly in the southeastern United States. The larvae mainly feed on soybean plants, but are also a pest to velvetbean, peanut, alfalfa, cotton, cowpea, sesbania, white sweetclover, among others. They tend to prefer legume plants. This caterpillar is the most destructive soybean pest, possessing the ability to defoliate the entire plant when populations are high. Infestations usually take place later in the summer and will significantly lower your crop yield if they are not managed effectively. The caterpillar will first eat new leaves, then older leaves, and once those are damaged will move on to the stems, pods, and buds. It only takes the larvae 5 to 7 days to complete the defoliation process.

Velvetbean Caterpillar Management and Control Methods

Cultural Control

The velvetbean caterpillar can be controlled by natural enemies, such as parasitoids (Winthemia rufopicta), and wasp parasitoids (Euplectrus puttleri and Meteorus autographae). Ground beetles are another predator of this pest, along with frogs, birds, fungi, and rodents. If none of these predators are helping to control the velvetbean caterpillar, then it is advised to plant your soybeans early and to use plant varieties that mature early. This will allow the plant to grow strong for when the caterpillar begins feeding, thus helping the plant to withstand injury this pest may cause. You can also plant trap crops near your soybean fields to attract the velvetbean caterpillars to that area instead of your fields. It is important to note that proper management of this pest can be achieved through an integrated system involving both cultural and chemical control methods.

Chemical Control

It is advised to plant a variety of soybean plants that is resistant to velvetbean caterpillars. While this variety will not eliminate the pest’s population directly, it can slow the caterpillars’ consumption and will provide better results when combined with an insecticide, in comparison to varieties that are not resistant to the velvetbean caterpillars. Insecticides recommended for controlling this caterpillar include Baythroid, Dimilin, Arthene, Karate Z, Asana XL O, Intrepid, methyl parathion, and Prolex. Be sure to carefully read the insecticide labels for cautions and proper application.

Latin / Alternative Velvetbean Caterpillar Names

  • - Anticarsia gemmatalis

Sources

http://entnemdept.ufl.edu/creatures/field/velvetbean.htm

http://ipm.ncsu.edu/AG271/soybeans/velvetbean_caterpillar.html