Depending on the growth stage of the rice grain, the feeding can result in empty grains or small, shriveled, deformed grains with a spotty discoloration, sometimes with an offensive smell. Panicles appear erect.
Rice bugs occurs sporadically during milking to grain filling stage only and emanate foul smell in the evening hours. Immature and adult rice bugs both feed on rice grains. Rice bugs suck out the contents of developing grains. They are actually found in all rice environments. Woodlands, extensive weedy areas near rice fields, wild grasses near canals, and staggered rice planting favors high population densities. They are more active when monsoonal rains begin. Warm weather, overcast skies, and frequent drizzles favor its population build-up. They are less active during the dry season. The symptoms resemble the damage of Bacterial Panicle Blight.
Spray aromatic (like lemongrass) soap solution to expel the rice bug. Use “prahok” (local ‘cheese’ in Cambodia) near the field to attract the rice bug and kill it. Use a mosquito net in the early morning or late afternoon to remove the rice bug, crush it and put it in water then spray it to expel other rice bugs. Encourage biological control agents: some wasps, grasshoppers, and spiders attack rice bugs or rice bug eggs.
Always consider an integrated approach with preventive measures together with biological treatments if available. The benefits of using an insecticide must be weighed against the risks to health and the environment. Spray chlorpyriphos 50 EC at 2.5 ml + dichlorvos at 1ml/l in the evening hours by starting from the field edges to the center in a circular manner. This brings the bugs to the center and allows to manage them effectively. Alternatively you can also use abamectin. Indiscriminate insecticide use disrupts biological control, resulting in pest resurgence.