Corn leafhoppers have re-emerged in some Texas regions and other states, threatening both yields and grain quality.
David Kerns, Texas A&M AgriLife Extension Service statewide integrated pest management coordinator and associate department head for the Department of Entomology, says corn producers need to become familiar with the insect and learn more about management strategies.
“Certainly, growers need to be aware of this going into the next growing season,” he says. “It’s a big issue. Corn leafhoppers could transmit pathogens, which can lead to diseases and other problems associated with growing a good, healthy corn crop.”
Be Aware Of This Pathogen-Transmitting Pest
Corn leafhoppers were reported as far north as Ohio in 1981. In 2016, it re-emerged as a pest in South Texas. This year, outbreaks were reported in Tamaulipas, Mexico, and became widely distributed in Texas, Oklahoma, eastern New Mexico, Kansas, Missouri, Georgia and Arkansas. They were reported in Illinois, Indiana, Nebraska, Minnesota and Wisconsin late in the season.
Corn leafhopper produces a sugary substance called honeydew that can grow on stalks and leaves and lead to the growth of sooty mold, which may block leaf photosynthesis.
The biggest concern is red stunt disease due to the four main plant pathogens corn leafhoppers transmit. Symptoms include yellowing and reddening leaves, rapid dying of lower canopy, dying of ear leaf and corn husks, poor pollination and extensive blank ear tips, incomplete kernel fill, stunted or excessively thin and tall plants, formation of multiple deformed ears from the primary ear position and abnormal tillering.
Corn leafhoppers can survive at temperatures of 50 degrees Fahrenheit to 68 degrees. Kerns says corn is the best host, but the insects can survive on grass species such as eastern gamagrass when corn is not available. Corn is needed for the insect pest to reproduce. “It can also survive on sorghum and johnsongrass and may survive as long as one month,” Kerns says.
Farmers can follow these suggestions to lessen the leafhopper threat:
■ Plant a corn hybrid that is less affected than others. A resistant hybrid is not currently an option. Research is ongoing to determine hybrids that are least sensitive.
■ Manage volunteer corn. In areas that do not experience freezing temperatures, it is essential to eliminate volunteer corn that can serve as a host.
■ Plant as early as possible. Early planted corn has been shown to escape corn leafhopper infestations and subsequent issues during the critical infestation period, emergence through stage V8.
■ Use an insecticide during emergence through V8 when corn leafhoppers are detected, especially for late-planted corn or second-crop corn. Kerns says insecticides such as Sivanto Prime and Transform are options, although the effectiveness of these products has not been fully evaluated. CS