Bean thrips

AVRDC International Cooperators'
Fact Sheet

Mungbean Insect Pests

Bean Thrips
Megalurothrips usitatus

Damage symptoms

Flowers and flower parts are brown, dried, or completely destroyed. The flowers drop early. The petioles and leaves have tiny holes surrounded by discolored areas. Pod production is low and pods are deformed.

Insect characteristics

Modified piercing-sucking mouthparts. These insects are very small and silver-shaped, about the size of a flea. They are just barely visible to the naked eye. The young are white, whereas adults are dark brown with a reddish tinge.

Damage

Where to look

Bean thrips prefer to feed on the flower. Inspect the flower, especially around its reproductive parts. These insects remove plant cell contents and also feed on pollen. Inspect the undersides of leaves that appear brown or dry. The areas around the mid-vein are likely to harbor thrips.

Technical information

Adults lay their eggs inside the leaf tissue. After the immatures have completed feeding, they drop form the plant and pupate in the soil. Generations are continual and populations are highest during warm and dry weather. Temperatures of around 20¢XC favor reproduction and survival.

Control

To be added later.

Last updated: 2001.
Information from: Field Guide: Insect Pests of Selected Vegetables in Tropical and Subtropical Asia. 1995. B.L. Parker, N.S. Talekar and M. Skinner. Publication 94-427.

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