Rainfall, up to 3 inches in the Palacios area of Matagorda County, recently, has kept the cotton crop in remarkably good shape where this timely rainfall has been received, according to Texas AgriLife integrated pest management specialist Clyde Crumley, who works the Upper Coastal region of South Texas.
He recommends farmers keep close watch for insect populations.
Crumley says most of the crop is still at the 1/3 grown square stage. “With most of the cotton included in our IPM program in the 1/3 grown square stage to first flower stage, we are monitoring for bollworms, fleahoppers, aphids and Creontiades. Significant populations of adult fleahoppers were migrating in droves at the end of May and in some cases fruit sets dropped well below 80 percent.
“Aphid populations have increased markedly in many area cotton fields particularly where multiple sprayings have taken place.” He says a noticeable increase in egg laying activity by bollworm moths occurred in Jackson and Wharton Counties the last week of May. “We have observed few live worms, however. Beneficial (insect) numbers in cotton are moderate to high with lady beetle adults, big eyed bugs, minute pirate bugs, green lacewing eggs, and damsel bugs.”
He says as grain sorghum begins to flower growers need to be looking for sorghum midge in the heads.
Crumley says significant populations of adult fleahoppers were migrating in droves at the end of May resulting in fruit sets dropping well below 80 percent. “We can only speculate if this is the end of the migration or what really caused such a mass movement. On balance, most cotton in the area is beginning to be out of harm’s way from fleahoppers; however, if you were unfortunate enough to have a dramatic drop in fruit set, additional treatments may be necessary.”
He said effective insecticides include: Centric 40 WG at 1.25 ounces per acre; Intruder 70WR at 0.6 ounces per acre; Trimax Pro at 0.9 ounces per acre; and Vydate C-LV at 1 gallon per 15 to 20 acres.
“In more mature cotton, fleahoppers are considered food for predators or predators themselves and should be treated as such. In younger cotton—pre-bloom, first bloom or in cotton that has gotten off to a slow start—they can still cause damage.
“When plants are blooming, fleahopper control is rarely justified. Also, insecticides applied early in the blooming period may result in outbreaks of bollworms and tobacco budworms because of the destruction of predaceous insects and spiders. Use suggested higher application rates only when infestations are severe. If more information is needed please contact my office.”
Crumley says aphid numbers may increase to moderate or heavy levels and then decline for no apparent reason. “Although high populations can develop prior to bloom, most economically damaging infestations develop later in the season during the blooming period. Fields should be scouted twice per week since rapid increases in aphid numbers can occur in a short time. A total of 60 leaves divided between the top, middle and lower portion of the plant should be sampled from plants across the field to determine infestation levels.”
For more information contact Crumley at firstname.lastname@example.org or 979-532-8040, cell: 979-320-4102.