common name: Rice gall midge
Scientific name: Orseolia oryzae
Synonym: Asian rice gall midge
Rice and corn
Bangladesh, Bhutan, Cambodia, China, India, Indonesia, Lao PDR, Myanmar, Nepal, New Guinea, Pakistan, Sri Lanka, Thailand, and Vietnam.
The infested rice plant has a hollow cavity or a tubular gall
at the base of a tiller
which does not bear panicle
. Its feeding damage also causes elongation of leaf sheaths called 'Onion leaf or Silvershoot'. The gall is a silvery-white hollow tube which has a size of 1 cm wide and 10-30 cm long.
Eggs are elongate and tubular. The newly laid eggs vary from white to pink, red, and yellow colors. The eggs turn like shining-ambers before hatching. They are laid either singly or in groups of 3-4 at either on the base of the plant, the ligule
, the leaf blade, or on the leaf sheath. The egg development lasts for 3-4 days.
The larva is maggot-like, about 1 mm long, and is grayish-white in color. It situates itself at the growing point of the apical or side buds of a node in order to feed. One larva occupies a single tiller. The larval feeding damage causes the formation of a tubular gall at the base of the tiller and inhibits growth of the leaves and the panicle. The gall enlarges at the base of the tiller as a result of the larva's continuous feeding. There are 3-4 larval stages, which last for 15-20 days.
The pupa is light-pink with abdominal spines and it turns red before emergence. It is 2-2.5 mm long and 0.6-0.8 mm wide. Pupation is 2-8 days. Both the larval and the pupal developments are completed inside the gall.
The adult looks similar to a mosquito. The female midge has a bright
red abdomen while the male has a yellow-brown body. The male is generally smaller than the female. It has a wing expanse of 3.0-3.5 mm. Both adults have bead-like antennae with more than 10 segments. The adults are nocturnal. They are easily collected using light traps. They mate soon after emergence. A female midge mates only once. It can lay as many as 100-200 eggs in its lifespan of 4 days. The male midge lives only 12 to 18 hours.