Controlling early-season cotton insects is one of the best tools producers can use to manage their crop for early maturity and harvest, according to a Texas Cooperative Extension cotton entomologist.
“We need to protect the crop up through squaring, so we need to scout for early-season pests on a regular basis,” said Jim Leser, Extension cotton entomologist based at Lubbock. “Before you spray, ask yourself…will it pay? Timing is everything in making an insecticide application work, and in making more profit to cover the application cost.”
Leser was one of eight featured speakers at the Jan. 28 Caprock Cotton Conference here. More than 100 producers attended the conference for updates on cotton insects, weevil eradication, national and state legislation, alternative crops, crop water use efficiency and market prices.
Thrips are one of the most important early-season pests to watch for in irrigated cotton. Growers seldom increase yields by controlling thrips in dryland fields where water is a limiting factor, the entomologist noted.
“Western flower thrips are the chief culprit on the Texas High Plains.
Their feeding damages both leaves and squares on the plant. Research studies have shown that we can boost yields by as much as 21 percent if we control early-season thrips,” Leser said. “We can achieve good control by putting Temik down at planting. Or we can make one or two later applications of Orthene, Bidrin or dimethoate — as thrips move into the field.
“Foliar insecticides are a good, cost-effective choice for thrips control — especially in narrow-row cotton. Foliar applications should based on the number of mature and immature thrips in the field, and timing is crucial since thrips generally disappear once the plants set squares.”
Selecting varieties with insect resistance can also help offset damage from early-season pests. Bollgard and Bollgard II varieties seem to hold up very well against pests such as bollworms and caterpillars, Leser said.
Lygus bugs can threaten late-planted, stress-susceptible cotton if the field borders areas where mustard, thistle and alfalfa are growing. Lygus bugs live in these plants and in roadside weeds during the spring. In summer, sunflowers and sweet clover also harbor this pest. When young cotton plants emerge nearby, Lygus bugs move from these host plants into cotton, he added.
“Lygus bugs feed on cotton squares and immature bolls, so we must watch for them and be prepared to apply a control treatment up through squaring and boll initiation. Their damage potential declines once the plants accumulate 350 heat units after the first white flowers appear,” Leser said.
Growers who plant stress-tolerant varieties, manage their crop for early fruit-set, and aggressively control early-season insects pests will come out ahead at harvest, he added.
“Early squares make our lint crop, so we have to protect against insect damage right up through squaring and flowering. Managing for early plant maturity and protecting plants from early-season insects also makes the crop less vulnerable to later-season boll-feeding insects,” Leser said. “Spraying late is not profitable.
“Regardless of which pests they face, growers who base control decisions on a realistic target yield, and then spray to make money instead of simply spraying to eliminate pests, will come out ahead.”
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