Project Underway to Battle Cotton Pest in Delta

Concern about another major cotton pest that cost growers $75 million last year has led to an intensive Agricultural Research Service study over a 36-square-mile area in the Mississippi Delta region.

Scientists have begun a three- to four-year project to find ways to combat the tarnished plant bug. The study consists of four 9-square-mile areas in the Delta region, with a possibility of future expansion.

ARS research entomologist Gordon L. Snodgrass, with ARS’ Southern Insect Management Research Unit (SIMRU) in Stoneville, Miss., discovered in 1993 that tarnished plant bugs (Lygus lineolaris) had become resistant to pyrethroids, a class of insecticides commonly used to control them.

Tarnished plant bugs are a particular problem, because there are more than 100 different weed species on which they can feed and reproduce. In the winter, they lay dormant in weeds surrounding cotton fields. Then, from February or mid-to-late March, they emerge and begin laying eggs in the weeds. In late spring, they move into cotton crops when the weeds mature.

ARS scientist are investigating several different approaches to controlling plant bug populations, including controlling weeds and using biological controls and developing a chemical lure called a pheromone.

In field tests last summer, ARS scientists discovered that the males may produce a perfume-like pheromone that attracts both sexes--probably to signal food sources--but they are repeating the test this summer to make sure.

It’s the only major pest in cotton for which scientists don’t have a sex pheromone, according to Snodgrass. Once they develop a pheromone, they’ll be much closer to banishing the pest from cotton fields.

A longer article on this research appears in the July issue of Agricultural Research magazine. The story is also on the World Wide Web at:

http://www.ars.usda.gov/is/AR/archive/jul99/bugs0799.htm

Scientific contact: Gordon L. Snodgrass, ARS Southern Insect Management Research Unit, Stoneville, Miss. phone (601) 686-5231, fax (601) 686-5421, gsnodgra@ag.gov.