Warm And Wet Spring Fuels Pest Pressures In Texas

KARN DHINGRA

COLLEGE STATION, TEXAS

A warm, wet spring has created near-ideal conditions for several damaging insects across parts of Texas, said a Texas A&M AgriLife Extension Service expert.

David Kerns, Ph.D., AgriLife Extension statewide integrated pest management coordinator, professor and associate department head for the Texas A&M Department of Entomology, said pest outbreaks were primarily impacting producers managing pastures, rice, corn and cotton.

“I’d say the biggest issue we’re facing currently is with the pasture mealybug,” Kerns said. “It’s really taken off in the last month. It has skyrocketed as an issue.”

A devastating newcomer in pastures

Unlike many pasture pests that cause temporary damage, the pasture mealybug can kill grasses outright, a serious blow for producers whose livestock depend on Bermuda hay, Bahia grass and native rangeland bluestems for forage.

The pest thrives in hot, wet weather and thus far has been detected throughout South Texas, along the Gulf Coast, Central Texas and as far west as Gillespie County. Drier conditions to the west may naturally limit further spread, Kerns said.

Treatment options remain limited. No currently labeled pasture insecticides have proven effective, though researchers are evaluating candidates, Kerns said.

Producers in affected areas should monitor closely and contact their local AgriLife Extension office if they suspect an infestation, he said.

Rice and corn crops impacted

In Southeast Texas’ rice country, Kerns expects rice delphacid populations to build and move into fields by mid-June. The sucking insect can kill plants or result in reduced grain weights. Fortunately, Texas has recently received an emergency Section 18 label for Courier SC insecticide. This insecticide is an insect growth regulator and will be active primarily on the nymphs.

“You don’t want them to get ahead of you,” he said. “It really is going to take close monitoring to make that insecticide more valuable.”

Corn producers face two concerns. The corn leafhopper, which vectors damaging plant pathogens, remains confined to South Texas for now. But North Texas and Panhandle fields could be reached as populations move northward. 

“We are recommending protecting corn from corn leafhoppers through R1,” Kerns said.

Corn leaf aphid is a second worry as a recent outbreak in Central Texas often signals trouble further north, and Panhandle producers should begin scouting before their corn tassels, Kerns said. The most critical period for corn leaf aphids is from just before tassel through R1. Producers should treat during this period when 10-20% of the plants have 100 or more aphids.

Cotton producers should stay vigilant

Texas cotton producers have one positive development to report. The two-spot cotton leafhopper, or cotton jassid, which can devastate cotton by injecting toxic saliva, has been detected only in nurseries where it is infecting hibiscus and not in commercial cotton fields so far this year.

“We haven’t detected any in our cotton to date, and that’s really good news,” Kerns said. 

Producers should continue scouting and report any unusual leaf yellowing or reddening to their AgriLife Extension county agent, Kerns added.   ∆

KARN DHINGRA

TEXAS AGRILIFE