We are getting reports of sugarcane beetles in seedling corn in some areas. Right now we are seeing them in southwest Arkansas, but growers in other areas should be watching for these pests. Adult sugarcane beetles are hard, shiny black beetles found in seedling corn feeding at or just below the soil level. Larvae can be found in mid-season corn through late summer. Larvae are cream colored grubs also found in the soil. However, it is the adult stage that causes most of the damage. Seedling corn is burrowed into at the base of stems generally at the soil line by the adult beetles. Plants are weakened and may not fully develop or may die. Sometimes small seedlings are cut completely off making the damage look like that caused by cutworms. The greatest threat is generally in fields recently converted from pastures to corn and in reduced tillage systems with substantial grasses.
Where do these beetles come from? Adult beetles overwinter in soil, particularly in grassy areas. With warm spring temperatures, adults are attracted to emerging corn seedlings and begin to cut a small chamber in the stem near or just below the soil level. Eggs are laid in soil in corn fields, and developing larvae feed on corn roots but cause little damage. The adults emerge and in late summer head to overwintering sites. Only one generation occurs each year in Arkansas.
Insecticide treated seed (Cruiser, Poncho) and soil applied insecticides at planting will aid in suppressing these pests. If considerable damage is occuring in a field, a foliar insecticide application may be necessary. Applying a pyrethroid at the higher recommended cutworm rate or chlorpyrifos (Lorsban, Nufos) will also help in reducing damage. See the cutworm section under field corn in MP 144 “Insecticide Recommendations for Arkansas” for a full list of recommended insecticides and rates. These beetles can be difficult to control.