The top goals in effective insect management in cotton are to preserve yield potential and improve the stability and consistency of control, says Phillip Roberts, University of Georgia Extension entomologist.
Reaching the goals is best achieved through the combined use of current and future technologies.
“There is no question that insect control technology including foliar insecticides, seed treatments, and traits will continue to get better,” said Roberts during the General Session at the 2012 Beltwide Cotton Conferences in Orlando, Fla., on Jan. 4.
Yet Roberts says it is not sustainable to depend on new technologies alone as few new methods have evolved in recent years.
“We must preserve existing technologies,” Roberts said. “Much pressure exists on current insecticides for bug control. History has shown that insect pests are resilient. There are no silver bullets.”
Roberts spoke during a Beltwide panel discussion on “Managing cotton with a changing arsenal of tools.”
Insecticide use has dropped dramatically in the Cotton Belt over the last 25 years. Five-to-six insecticide applications were required on average annually from the late 1980s to the early 1990s. Over the last decade, spray use has fallen on average to two-to-three sprays annually – about a 50-percent reduction.
Roberts credits reduced spray use to the boll weevil eradication program and the commercialization of Bt cotton.
“Bt cotton was a game-changing technology,” Roberts said.
In Georgia, cotton growers averaged 15.8 insecticide applications prior to the boll weevil eradication program. The elimination of boll weevils allowed growers to reduce sprays to four or five annually. Bt cotton further reduced the need.
Another breakthrough to improve insect management for Georgia growers was the introduction of Integrated Pest Management (IPM) in the state in 1972. Early on, IPM included scouting and treatments based on thresholds, plus appropriate insecticide selection for insect pest prevention.
“(Today) IPM is much more than that,” Roberts explained. “IPM uses all available control tactics to minimize economic losses and harmful environmental side effects. IPM is ‘informed pest management’.”
Best insect management strategy
The best insect management strategy is knowledge based on a good understanding of the crop; the pest - whether an insect, weed, or disease; the insecticide or trait; and the impact of cultural practices. This understanding paves the way to better informed decisions.
“We must truly understand the system and how the incorporation of new technology or a loss of technology can impact IPM programs,” Roberts said.
Roberts says Southeastern cotton growers this year will find a shortage of aldicarb, the active ingredient in the insecticide Temik, a standard at-plant insecticide. Temik is used to combat thrips and other insects.
Some growers will use alternative methods including neonic seed treatments. Roberts says growers should understand the issues associated with any product technology.
“Decisions made in thrips management could influence pest dynamics during the mid season,” Roberts said. “A foliar spray for thrips could flare aphid numbers … Multiple plant bug sprays could flare spider mites. The treadmill continues.”
Roberts says IPM is a proven program with good resistance management. IPM can reduce the need for insecticides thus reducing selection pressure for resistant pest populations. Efficacious insecticides are a vital component of IPM programs.
“We are managing a complex of insects. The potential of flaring non-target pests, suppressing sub-economic pests present at the time of application, and resistance management must all be considered when selecting insecticides.”
Cotton growers have a good arsenal of insect control tools. Improved control of true bugs is needed, says Roberts. Growers can expect the registration of new active ingredients including Sulfoxaflor with good activity on sucking pests.
In closing, Roberts said, “We must do all we can to preserve current tools. Resistance management must be a priority … IPM should be used to the fullest extent possible.”