Researchers’ Objective: Control Lygus Problem

By Brent Murphreee
Maricopa, Ariz.

The Third International Lygus Symposium was held in Scottsdale, Ariz., in October and brought together the most important players in lygus research, with an impressive showing by Western cotton pest researchers.

The objectives of the previous symposiums were to enhance collaboration, exchange current research, find solutions to research issues and determine a management approach for lygus control. Eighty-three participants represented six countries – United States, Mexico, China, Canada, France and Great Britain – and 13 states, most in the Cotton Belt.

Organizers and sponsors from USDA-ARS, Cotton Incorporated, Dow AgroSciences, FMC, Monsanto and the University of Arizona put together a comprehensive program addressing a wide range of subjects related to lygus and the control of the pest.

With the Western Cotton Belt’s control of whitefly and pink bollworm, lygus has emerged as arguably cotton’s costliest pest.

“All of my customers address it as the number one pest,” says Ryan Tregaskes, a pest control advisor in Central Arizona. Tregaskes believes the most effective management for lygus in cotton is awareness of the pest and staying on top of control so the
numbers don’t get out of hand.

Increase In Pressure

Lygus pressure was higher this year than it was in the past two or three years, according to Tregaskes. He relates the increase to this year’s high monsoonal activity. Thunderstorms in late summer dropped twice as much rain as normal in some areas.

Researchers agree. Water availability and pest interaction were mentioned by several presenters during the symposium. Water deficit plants yield fewer lygus, according to the most recent mapping studies.

According to Dr. Pat O’Leary of Cotton Incorporated, several presenters emphasized a whole-farm concept of landscaping and management for pest control and other agronomic issues. Precision tools can now effectively map farms to help advise for best management practices.

Peter Ellsworth, Extension specialist and University of Arizona professor of entomology, has developed a tool that can simulate how pests run through a farm system. The demonstration shows producers how advance spatial planning can positively affect their operations.

For other pests, such as pink bollworm and whitefly, insect specific control products have made big impacts in their management. The same is true for lygus. Flonicamid, a feeding inhib-itor, controls lygus well without affecting populations of beneficial insects.

Another Control Tactic

Dow will release Sulfoxaflor in 2013. It is also effective against lygus, although it has a different mode of action than Flonicamid and has little or no effect on beneficials. It will be effective in the Mid-South where there are chemical resistance issues.

Waseem Akbar of Monsanto reported that the company is moving forward on effective lygus-active Bt proteins. According to their data, efficacy is getting better and targets lygus hesperus, the major lygus pest in the West.

While current pest control products work well to keep the pest numbers down, researchers who took part in the symposium will continue research to find ways to control pest populations. Advancing discoveries will become increasingly valuable as the understanding of the pest increases.

For instance, USDA-ARS researcher Jeffrey Fabrick presented collaborative research that looks at how insects digest plant tissue after injection of saliva. Natural plant extracts contain blocking agents that can be used to prohibit insect feeding. The resear-chers are hoping to enhance those extracts to become another tool for pest management from within the plant.

“It’s great to have a gathering of people with such a focus on an issue,” says Ellsworth.

And, organizers agree, the meeting of minds in Scottsdale generated new ideas for lygus research.

Brent Murphree is the Cotton Board’s Regional Communication Manager for the West. He resides in Maricopa, Ariz.

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