As new cotton matures, growers need to be watching for the presence of fleahoppers, says Terry Pitts, Oklahoma State University Extension integrated pest management specialist.
“During the first three weeks of squaring, 30 to 45 fleahoppers per 100 plant terminals may cause economic damage and an insecticide treatment is warranted,” he says.
Fleahopper control is not justified after the first week of bloom. Cotton that is in the squaring stage across the area needs to be monitored for fleahoppers immediately, with numbers just detectable.
“The decision to apply an insecticide should be based on the number of fleahoppers present,” Pitts says. “As the first small squares appear (five to six-leaf stage), examine the main stem terminal buds of the plants. For each acre in a field, one plant should be examined. At each site or location in the field, 25 plants should be examined.
“For example, when scouting in a 100-acre field, four different locations should be scouted. At each location, 25 plants should be examined for a total of 100 plants. The number of fleahoppers found divided by the 100 plants examined will yield the percentage of fleahoppers in the field.”
Pitts says fleahopper adults and nymphs suck sap from tender portions of the plant, including small squares. “Pinhead size and smaller squares are most susceptible to damage. Fleahopper adults and nymphs feed on tender plant parts, including new terminal growth and small squares.
Their piercing, sucking mouthparts will penetrate small squares causing desiccation from sap removal. Pinhead size squares are the most vulnerable to this ‘blasting’ where squares turn brown and die.”
He says damage may not appear for one to three days, depending upon environmental conditions. Larger squares, flowers and bolls are not as vulnerable to fleahopper feeding damage. Fleahoppers inject saliva when feeding, causing abnormal growth patterns in plants that sustain heavy damage. Shorter internodes, "suckering" and generally "crazy" cotton can result from loss of terminal dominance. As plants increase in size and fruit load into the bloom stage, larger numbers of fleahoppers may be tolerated without yield reduction
Pitts recommends farmers consult chemical suppliers or OSU agricultural educator for suggestions on products used for fleahopper control.
He says bollworm adults were reported in cotton in the Altus and Tipton, Okla., areas during the week of June 7, 2010. He says bollworm egg-laying generally will coincide with the dark phase of the moon.
Pitts works out of the Southwest Research and Extension Center, 16721 South U.S. Highway 283, in Altus. Email is [email protected]. His office telephone is 580-482-8880, and his cell telephone is 580-318-0208 .
TALKIN' COTTON is produced by NTOK Cotton, a cotton industry partnership which supports and encourages increased cotton production in the Rolling Plains of North Texas, Oklahoma and Kansas. For more information on the cotton scene, see ntokcotton.org. and okiecotton.org. For questions or comments on Talkin' Cotton, contact [email protected].