General Information

Common name: Bean pod borer
Scientific name: Maruca vitrata, M. testulalis, Crochiphora testulalis
Lepidoptera:Pyraustinae

Synonyms: Legume pod borer, Lima bean pod borer, Maruca, Mung moth (CABI, 2000)

Host plants

Beans and legumes, lablab, and kudzu

Distribution

Asia, Europe, Africa

Damage

The larval feeding causes round holes in the corolla of the flowers, distorted pods associated with the inflicted holes, webbed flowers and young pods, and presence of frass. Damaged flowers become a mass of brownish-frass a day after infestation (Parker; Talekar; Skinner, 1995).

Description

The eggs are ovate, clear, and pale yellowish-white in color. Eggs are either laid individually or in small batches on flowers or flower buds, and on terminal shoots of young plants. A single egg looks like a small droplet of water and is seldom recognized as a pest egg. The egg development lasts for about 3 days.

The larva has a whitish to pale-green or pale-brown body with irregular brownish-black spots. These spots become indistinct immediately before pupation. Its head capsule is light to dark-brown with a dark-brown prothoracic plate which is divided dorsally. Newly hatched larvae are found clustered together in the flowers. They later disperse singly to feed from one flower to the next. A larva can consume 4-6 flowers. Matured larvae web together flowers and young pods, feed, and pupate inside the webs. When fully fed, they reache a length of 1.7-2.0 cm. A larval stage has five instars.

The pupa is enclosed with a silken cocoon found inside the web. The pupal stage lasts for 5-7 days.

The adult has brownish-black wings with a clear-white marking. It rests during the day with its outspread wings under the lower leaves of the host plant. An adult has a life span of 6-10 days.