Sugarcane Beetle
Euetheola rugiceps (LeConte), Scarabaeidae, COLEOPTERA


DESCRIPTION

Adult - This black, hard-shelled beetle is dome-shaped and faintly ribbed, has strong legs with coarse spines, and is about 13 mm long. Color plate.

Egg - When first deposited, the smooth, white egg is oval and about the size of a pinhead. Before it hatches, it gradually enlarges until it is spherical and about twice its original size.

Larva - Ranging from 4.8 to 31.8 mm in length, the dirty white grub has a brick red head, pale brown legs, and a dark abdomen.

Pupa - The pupa is about 19 mm long and changes from white to pale brown as it matures.


BIOLOGY

Distribution - The sugarcane beetle has been a problem on corn in all southern states except Oklahoma, Kentucky, and Florida. Even in these states, however, some damage is periodically reported. This beetle is also a pest of rice and sugarcane in Louisiana, Texas, and Arkansas. Damage in North Carolina occurs statewide but most frequently in the Piedmont counties.

Host Plants - Although the sugarcane beetle is primarily a problem on corn, sugarcane, and rice, it also infests cotton, strawberry, rose, and wild grasses.

Damage - The grubs feed on the roots of grasses; however, the adult beetles are responsible for damage to field crops. Feeding below the soil surface, the beetles chew into the outer walls of lower stalks leaving large ragged holes. Seedlings suffer the most damage and are often killed when the beetles destroy the growing point. Corn plants one meter (3 feet) or taller usually recover from sugarcane beetle injury. Damage occurs most frequently when corn is planted into a sod field or adjoining such a field. Damage occurs primarily from April 15 to June 15 in Gulf Coast states and from late April to late June in Virginia and North Carolina.

Life History - Adult beetles hibernate during the winter in the soil of well-drained sod land. Although they may become active on warm days in late fall or winter, they normally do not resume continual activity until late March or early April. After mating in the soil, females each deposit clusters of three or four eggs in earthen cells. Approximately 2 weeks later, larvae emerge and begin feeding on decaying vegetable matter. After 2 or 3 months, the mature larvae enter a 2-week pupal period. Emerging in August and September, the new generation of adults feeds for a short time before entering hibernation. One generation occurs each year.


CONTROL

Cultural practices are useful in controlling sugarcane beetles. Since most problems occur where corn is planted after or near sod, avoid growing corn or sorghum in these fields where possible. If planting corn in a former sod field cannot be avoided, use high quality certified seed, early planting, and proper fertilization. These practices will increase the vigor of the crop so the plants will grow rapidly and become more resistant to the beetles.

Sugarcane beetles can also be controlled chemically. Insecticides should be recommended when corn or sorghum is planned for a sod field established for 3 or more years. For specific information concerning cultural recommendations, insecticides and rates, consult the North Carolina Agricultural Chemicals Manual.