General Information

Common name: Whorl maggot
Scientific name: Hydrellia philippina
Diptera:Ephydridae

Host plants

Rice and wild rice

Distribution

Bangladesh, Cambodia, India, Indonesia, Lao PDR, Malaysia, Philippines, Thailand, and Vietnam

Damage

Heavily damaged plants are stunted and have few tillers. The leaves have white and/or transparent patches and break easily when the wind blows. Slightly damaged leaves have pinholes. At the maximum tillering stage, these symptoms usually disappear.

Description

The eggs are whitish, elongate, and banana-shaped with a hard shell as a covering. The individual egg is laid on the leaf surface. It is found sticking on the leaves because of a gluey substance secreted by the female. Egg stage lasts from 2 - 6 days.

The larva is legless. A newly hatched larva is transparent to light-cream. The mature larva is yellowish and cylindrical with a pair of pointed spiracles. It is 4.4 - 6.4 mm long and 0.5-0.7 mm wide. The larva feeds on the unopened central leaves. Before pupation, the matured larva leaves the feeding site and pupates inside older tillers. Larval development is completed in 10 - 12 days.

The pupa is dark-brown with a tapered posterior end and has two terminal respiratory spines. The pupa is 4.8 mm long. Pupation is 5 - 10 days.

The adult is gray in color and has transparent wings. It has silvery-white frons and cheeks. Its abdomen is silvery-white to gray, and blackish-brown in the middle of the three basal segments. The adult has yellow legs apart from the thigh. It is active during the day and rests on rice leaves near the water. It prefers thick vegetation and is attracted to open standing water around seedbeds.