Early detection, best for control of army worms

By Bett Kipsang’

Army worms are green-striped caterpillar larvae of the adult army worm moth; they are among the most destructive crop pests and a common pest of grass. Army worms will also eat corn, beets, beans, clover, flax, millet and other grains. Mature caterpillars can ruin an entire crop field in only a few days. The name “Army worm” is derived from its feeding habits; they travel in small armies, eating everything in their path.

At larvae stage, the moths feed very heavily and can wreak havoc on crops if left to multiply; they eat everything in an area until the food supply is exhausted, then the entire “army” moves to the next available food source.

Once its wings are fully dried and expanded, the adult butterfly or moth can fly in search of a mate. Mated females lay their fertilized eggs on appropriate host plants, beginning the life cycle anew.  

Noah Koinett inspecting an army worm trap

Some of the signs that of army worms infestation is an increase of the number of birds in your yard. Birds eat the caterpillars, but usually do not eat enough of them to keep the infestation under control. Brown spots on your lawn are often the first sign that army worm are about to strike.

Look for holes in the leaves or pieces missing off of leaf edges where the army worms have eaten them. Look under the plants for army worms or signs of their droppings. You may also find larvae under plant debris lying in the field. If you are growing barley or wheat, you may find worms inside of the heads.

Control measures.

Army worms are hard to detect as the caterpillars migrate at night in search of new feeding areas. The best way to control Army worms starts with understanding and looking for early signs of army worm damage. The earlier you treat the problem, the easier it is to control and the lesser the damage crops will sustain.

Cut the grasses short, then collect and burn or water it well to move the caterpillars out of the thatch. Spraying the grass heavily with a liquid insecticide kills the pest; make sure to follow the manufacturer’s directions. Leave the sprayed lawn alone for at least 3 days without mowing or watering to give the insecticide time to work.

The ministry of agriculture has developed a method of detecting the signs of Army worms in an area. A trap with pheromones substance is placed in an open field to attract female moths to the trap; the substance producing male like scent also has tranquilizing effects that makes the insect immobile. If a female moth is seen in the trap, it is a clear indication that army worms are visiting the area.

 ‘‘We check the trap every week, and we raise the alarm quickly in case we find the moths’’ said Noah Koinett, an agriculture extension officer in Rumuruti ward. Noah told the Ng’arua Maarifa centre that the government is always on high alerts for any sign of migratory pests.