2/14/2012 12:30:17 AM
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Common Name: Aphids Scientific name: Aphididae (family)
Aphids are small, soft-bodied insects with piercing sucking mouthparts. Both adults and nymphs move slowly and often are observed in groups feeding together. This aggregation is caused by a reproductive phenomenon called “parthenogenesis,” in which unmated female aphids give birth to living young. Several species of aphids can damage rice in Louisiana and Texas: Bird cherry-oat aphid, Rhopalosiphum padi, English grain aphid, Sitobion avenae; greenbug, Schizaphis graminum; and yellow sugarcane aphid, Sipha flava.
Damage caused by mite: Aphids suck the juices from rice and cause stunting and chlorosis. Young rice is particularly vulnerable and stand reductions can occur under severe aphid pressure. Damage is usually more pronounced in rice that is stressed due to dry conditions.
Facts: Both adults and nymphs move slowly and often are observed in groups feeding together. Aphids suck the juices from rice. The feeding injury can cause stunting and chlorosis. Young rice is particularly vulnerable and stand reductions can occur under severe aphid pressure.
What should you look for: The key to aphid management is scouting. Generally, aphids are more of a threat to seedling rice, so be sure to scout fields carefully and frequently after rice emergence. When searching for aphids, remember to inspect the collar region (the junction of the leaf blade and sheath) of rice plants. Aphids are often found here because the relative humidity is high, the plant tissue is tender and concealment from natural enemies is possible. Lady beetles are predators of aphids. Presence of these beetles usually indicates high populations of aphids (Texas Rice Production guidelines, 2012).
How you can manage aphids: No economic thresholds are available for aphids, but if the stands are threatened, or the rice is yellow/reddish or stunted, and aphids are present, treat the rice with an approved insecticide.
Four practices that discourage aphid populations and damage: 1. flushing or flooding, which drowns the insects and forces them to move up the plant, where they are more vulnerable to natural control; 2. Controlling weeds, which prevents aphids from building up on alternate hosts; 3. establishing a healthy, uniform stand of rice; 4. reducing early-season stress caused by inadequate soil moisture, herbicide injury, nutrient imbalances and damage from other pest insects and diseases (Texas Rice Production guidelines, 2012). Natural enemies such as lady beetles and parasitic wasps can keep the aphids under control. Before applying insecticide for aphid, consider that insecticides will reduce the effectiveness of these natural enemies.