Injection of Insecticide in Irrigation Water To Control Corn Earworm and Fall Armyworm on Corn

ABSTRACT A scaled one-nozzle irrigation system was con-structed and tested for injecting insecticide into irrigation water for control of insects attacking corn. In-secticide was injected either inside the sprinkler nozzle or at the intake of the irrigation pump. The two injection methods gave equal insect control. Also, the injection of water-soluble and non-soluble materials into the system gave equal results. A formulation composed of 2 L of oil plus 1 L of Sevin-4 oil resulted in the same insect control as Sevin-4 oil alone. Application of 0.36 cm of irrigation water after completion of insecticide treatments did not significantly affect kill of corn earworm, Heliothis zea (Boddie). Field tests indicated that corn treated with water-soluble methomyl had significantly more wormfree ears than corn treated with stirofos (tested as Gardona 80 per-cent in oil). Oil used by itself resulted in significantly less wormfree ears than Gardona in oil.