Insects That Attack Cereal Grains

Corn

• Insects that cause problems for farmers growing corn in the U.S. include the maize billbug. This insect attacks corn seedlings just below the surface of the soil by piercing the stalk with its beaks and feeding on the tissue inside. It causes further damage by laying its eggs inside the stalk, the larvae of which will eventually hollow out the entire stalk and also part of the taproot. Other problematic insects include species of cutworm, wireworm and the armyworm.

Rice

• Insects damage rice plants by feeding on the stems, leaves, roots and grain. Those that attack the grain include the stink bug, named due to the odor produced by the scent glands on its abdomen. The sucking mouth-parts of stink bugs remove the white fluid from the grain, thus preventing its subsequent development. Bacteria and fungi further damage the rice by entering via the puncture points. Other potentially damaging insects include grasshoppers, aphids and rice water weevils.

Barley

• Barley is attacked by a number of different species of aphid, which are liable to spread Barley Yellow Dwarf Virus when they feed on the phloem of the leaf. Plants affected with the virus are less able to photosynthesize and become stunted, with yellowed leaves, lessened root growth and blackened heads. Other unwanted pests include the jointworm, green bug and barley thrips.

Millet

• Stemborer moths attack all types of millet by laying their eggs between a plant's leaves and its stem. The emerging caterpillars disrupt the flow of nutrients from the roots by boring into the plants' stems. The millet head miner moth attacks the pearl millet species. It lays its eggs on the head of the plant. The emerging caterpillars enter the millet seeds and damage the flower head where the grain is formed.