John K. Saichuk | 1/26/2012 12:36:05 AM
Click on the links above to go to the Rice Insect Fact Sheets page or to go to the Rice Insects home page.
Common Name: Smaller rice leafminer Scientific name: Hydrellia griseola (Fallen)
Adults are metallic blue-green to gray flies with clear wings (1/4 inch long). They fly near the water and lay eggs on rice seedling leaves. Transparent or cream-colored larvae emerge in less than one week and feed between the layers of the rice leaf. Larvae become yellow to light green while feeding for one to two weeks before pupation. Adults emerge and live two to four months. The life cycle is completed in two weeks to one month.
Damage caused by larva: Larvae tunnel between the layers of the leaf, attacking and killing leaves closest to the water. Larvae move up the plant, killing additional leaves, and under heavy infestations the entire plant may die, reducing stands severely. The larvae are legless, transparent or cream-colored. Larvae become yellow to light green as they feed. The larvae or pupae can be found by separating the layers of the leaf.
Facts: Leafminers attack rice fields in early spring in the same vicinity year after year. Infestations usually occur where water is deepest on the upper side of levees. Leafminers are not usually a problem in shallow water. Leafminers are more severe in continuously flooded than in periodically flooded rice. Larvae tunnel between the leaf layers (mining the interior), attacking and killing leaves closest to the water before moving up the plant, killing additional leaves and possibly the entire seedling.
What should you look for: Walk through flooded rice fields and draw leaves between your thumb and forefinger. Bumps in leaves indicate leafminer larvae or pupae. The larvae or pupae can be found by separating the layers of the leaf.
How you can manage rice leafminer: Maintain water depth at 4-6 inches. Lower the water level in fields so that rice leaves can stand up out of the water. Treat if plant numbers are reduced to less than 15 per square foot.