Granular organophosphate insecticides such as Lorsban 15G and Counter 15G applied in the seed furrow or banded across the row can reduce sugarcane beetle infestations in field corn.

Seedling injury has also been reduced in field plots treated with a variety of different insecticides as rescue treatments including Capture 2EC, Lorsban 4EC and Baythroid 2EC. In spite of these treatments, however, significant plant injury and ultimate yield losses still occur. 

In corn fields with large infestations of the insect, growers in both Virginia and North Carolina saw severe damage to the corn root system. Young plants are the most susceptible and several fields with damaging populations of sugarcane beetle in corn were reported this year.

Adult beetles mate in the ground during the spring. The female beetle deposits the eggs into groups of three or four eggs in earthen cells. After hatching, the grubs feed upon decaying plant matter in the soil.

After larva develop into an adult beetle, the food preference changes. Adult beetles attack the stems of young corn plants, feeding at or below the soil line. Damage to young corn plants can cause plants to wilt and die. A single beetle can destroy several plants in a row.

As it feeds, the adult sugarcane beetle chews a large gouge in the stem at the base of the plant. Eventually the damage to corn shows up as dead plants, plants with a dead heart, or stunted plants.

The ultimate result of having these little pests in your corn field is going to be reduced yield. How much yield loss is likely to be more dependent on how many beetles are in the field than what a grower does after he finds the insects.

Once you see damage from these beetles there is little a grower can do, says Virginia Tech IPM Leader Ames Herbert.

“These insects feed mostly below the soil surface; they come out for only a few hours at night or in the early daylight hours. While there are plenty of insecticides that will kill them, getting the product to the insect and at the right time is very difficult,” he says.

The best option is to plan ahead, including scouting fields that are planted to corn behind corn, poorly drained and/or near sod fields or planted on ground with a history of sod production.

“In the research plots where I found sugarcane beetle I had 10 pounds of Counter on my corn, and it didn’t seem to make a difference. So, I guess the best management strategy may be to use high rates of an insecticide seed treatment and expect to see some damage in high infestations,” Reisig concludes.

rroberson@farmpress.com