Abundant populations of the adult sugarcane beetle can destroy whole corn stands.
Photo courtesy of Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org
Although an occasional insect pest, the sugarcane beetle (Euetheola humilis) can significantly damage corn yields. A pest native to North America, the most common outbreaks in corn seedlings have been documented in the southern states of Louisiana, Alabama, Tennessee, Mississippi, Virginia and North Carolina. The sugarcane beetle typically is not an economically significant threat to corn north of Virginia or Kentucky.
Usually problems from sugarcane beetles occur when corn is rotated after a grass crop, such as pasture or sod. Some corn fields show they are more susceptible to infections from this pest than others. The beetle is not only a pest for corn but is also a pest of cotton, rice, sugarcane and sweet potatoes as well as other crop hosts.
Identification and Lifecycle
Adult sugarcane beetles are plump, black and about 1.5 inches in length. With sturdy front legs and rough spines, they are designed for digging. Females deposit eggs in the soil, and grubs grow and pupate in 85 days. Each female sugarcane beetle lays 100 eggs in the soil during spring.
The larvae appear as white grubs, with a curved head shield that is red or brown in color. The emerging adults move into grasses to overwinter and migrate to corn in the spring. This insect pest produces one generation per season.
Sugarcane beetles feed below the soil on corn roots. Sometime within 45 days after corn planting, the adults can infest corn. Most corn seedling damage occurs from adults feeding at the base of the corn plant. Seedlings are very susceptible to damage, sometimes dying from extensive feeding. Older plants may have a weak stalk. Other symptoms include stunted plants.
According to North Carolina State University, corn plants above 3 ft. tall can recover from sugarcane beetle feeding damage. The university also reports that corn damage most frequently occurs from mid-April to mid-June in Gulf Coast states and from late April to late June in North Carolina and Virginia.
Begin scouting for sugarcane beetles as soon as seedlings emerge. A sign to note is that beetles easily fall to the ground during movement in the corn leaves. Sugarcane beetles are nocturnal insects and drawn to light, so night scouting can help. Farmers can also dig around plants that appear weaker than the rest of the corn crop to see if there is insect feeding. Corn fields should be scouted for sugarcane beetles twice weekly from seedling stage to 12-inch-tall plants.
Sugarcane Beetle Management Options
In no-till or limited-till situations, sugarcane beetles may become established in the soil, overwinter and feed on newly planted seedlings. For best results managing sugarcane beetles, remove existing crop residue and control weeds through tillage, a burndown herbicide and residual preplant herbicides.
Taking out existing vegetation prior to planting will also provide better penetration of insecticide spray or granules. Season-long weed control helps prevent sugarcane beetles from causing crop damage and harming yields and will help improve the effectiveness of in-season insecticide treatments. Crop rotation continues to be one of the most economical and effective cultural practices for controlling a wide range of crop pests.
According to Mississippi State University, there are no effective rescue treatments for sugarcane beetles. Therefore, the best approach to managing sugarcane beetles in corn is prevention, starting with seed selection.
Hybrids and seed traits
Farmers should consult with their seed dealer and review University Extension field trials for their area to evaluate Bt corn and non-Bt hybrid options to help control sugarcane beetles.
A broad-spectrum seed treatment provides a significant head start to prevent and suppress insect pressures during early corn seedling growth and should be included among the essential best management practices for establishing a healthy stand that leads to optimal yield outcomes.
The Bayer portfolio of seed treatment products offers some of the best seed-applied solutions, including seedling disease protection and early-season insect and nematode control, available on the market today.
Poncho®/VOTiVO® is an excellent seed treatment to help fight against sugarcane beetles and other important early-season pests, including wireworm, white grubs and black cutworms. Poncho 1250 + VOTiVO enhances the length of efficacy against many of the secondary insects that damage corn like black cutworm and adds billbug and corn rootworm protection under low-to-moderate pressure. Poncho, the systemic insecticidal component, is absorbed by new roots immediately, providing control of many critical early-season insect pests. VOTiVO, with its unique bacterial strain that lives and grows on young roots, creates a living barrier that prevents damage from all soilborne plant pathogenic nematodes. This dual protection results in healthier plant establishment and a more uniform crop, positively impacting yields.
In addition to seed treatments, farmers need to use granular insecticides, in-furrow sprays or combinations of these. Follow IPM guidelines to effectively use insecticides and manage resistance in combination with other control practices.
Visit our corn section to learn more about insect control options in corn including Poncho/VOTiVO, or contact your local Bayer representative.