Corn Delphacid, Peregrinus maidis
(Hemiptera: Delphacidae)
The corn delphacid is distributed throughout the world in tropical areas and is best known from subtropical areas such as southern Florida and Texas. Weeds that serve as alternate hosts include barnyard grass, itchgrass, and goosegrass. Several natural enemies are reported that help keep populations under control. A complete generation of the corn delphacid requires about 30 days and several overlapping generations occur during the summer or growing period. The eggs are normally found around the midrib of leaves and are inserted into a slit cut by the female. Eggs are curved in shape, white, and resemble a banana in form. The nymph is whitish and becomes yellowish as it ages. The nymphs have red eyes. The adult is greenish or brownish-yellow and the forewings are greenish or brownish and darker at the ends. The abdomen is smoky with lateral yellow stripes.
Host plants that are generally attacked by the corn delphacid are corn and sorghum. The corn delphacid damages corn both directly and indirectly. Direct injury includes plant sap removal, tissue damage, and the production of honeydew that supports the growth of sooty mold. Indirect damage is caused by the transmission of plant viruses. Populations of the corn delphacid can be detected by sampling techniques that focus on the outer edges of the field where insect densities are usually highest. Insecticides are used to prevent corn delphacid populations from exploding in cornfields. Contact and systemic insecticides are commonly used and are relatively effective. Cultural control practices include crop rotation and removal of alternate host plants.
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