03/08/1993

Auburn Research Helping Fight Peanut Leafspot and Protect the Environment

AUBURN, Ala. - Part of the charm of a peanut butter and jelly sandwich lies in its simplicity. That same simplicity is the basis of a new peanut pest management system that sandwiches two simple tools between some expert logic.

Auburn University researchers have developed a pest control system for peanuts that uses a rain gauge and a weather forecast to help producers decide when to spray for leafspot. Leafspot is a major yield reducing disease affecting peanuts.

This leafspot module is part of a larger pest management system known as AU-Pnuts that is being developed by the Alabama Agricultural Experiment Station at Auburn and will eventually provide predictions and recommendations for managing a variety of peanut pests.

According to Paul Backman, one of several scientists who have been developing this system, AU-Pnuts is an "expert system," or a management system that employs the logic an expert might use to make management decisions. It is based on the integrated pest management (IPM) concept, which encourages the integration of all types of pest control into one overall system so that treatments are more efficient and effective.

Environmental concerns have been driving much of the interest in this type of pesticide management. "There is a general vision coming from the Environmental Protection Agency (EPA) and the U.S. Department of Agriculture (USDA) that we are going to have to evolve to prescription or predictive use of pesticides," explained Backman, a professor of plant pathology at Auburn.

Presently, many peanut producers use a "calendar" system for leafspot control that instructs them to spray fields every 14 days. Though this has been effective, it does not provide the flexibility for producers to skip sprays if they are unnecessary or to spray early if an outbreak occurs.

"Government agencies are concerned that calendar systems are causing producers to treat at incorrect times and may not be the most efficient way to apply chemicals," said Backman. "For that reason EPA is evolving to predictive or therapeutic programs."

Backman noted that such practices to reduce pesticide use may soon be mandated in the United States, and already have been in several other countries.

"How do you reduce chemicals and still produce? You make what you do use count," said Backman. "And that's what our system is all about."

Based on their initial research, the Auburn scientists received a USDA Southern IPM grant to develop the system. The first step in establishing a system for leafspot management was to determine the ideal spray intervals based upon weather conditions and incidence of disease. Jim Jacobi, research associate in plant pathology who conducted much of the preliminary work, said the initial model has been effective.

"We've tested it several years since then at numerous locations and we also have tested the incorporation of some newer fungicides," said Jacobi.

"The rules saved sprays and did as well if not better than more sophisticated computerized management systems. Our rules used only a rain gauge and a weather forecast, and they seemed to work pretty well," added Backman.

The next step was to test the system on farms to see if it would work in the "real world." Phil Brannen, an Alabama Cooperative Extension Service research assistant in plant pathology, conducted these on-farm validation tests.

"We found that farmers can use this without too much trouble," said Brannen. "It does take a little training to explain the rules, but once they understand the program, it is not too difficult to grasp."

"Almost all locations in all years have shown that we can get equal or better control, and usually with less fungicide usage," said Brannen. "Last year it only saved us an average of half a spray, but we received better control from our sprays because we had more timely applications.

"We found that this system actually did better than the 14-day schedule," Brannen added. "One reason we think we did better is that this gives a farmer a trigger of when to start spraying. It makes a big difference in the amount of disease control you get if you spray in a timely manner with your first spray."

Another reason Brannen believes the system has been effective is that it allows farmers to spray ahead of a weather front. "A lot of times farmers are spraying after a rain, when infection already has taken off. This system lets you treat before rain so you get better control."

"Using AU-Pnuts does require some record keeping," said Brannen. "That may be a drawback for farmers who don't like to keep records, but record keeping is becoming increasingly important for any chemical use."

Jacobi noted that leafspot advisories such as this system are nothing new to peanut production. Similar systems are now being effectively used in Virginia and the Carolinas.

Information on the leafspot module of AU-Pnuts is available now to producers through the county Extension Service office.

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News from:

Office of Ag Communications & Marketing

Auburn University College of Agriculture
Alabama Agricultural Experiment Station
3 Comer Hall, Auburn University
Auburn, AL 36849
334-844-4877 (PHONE) 334-844-5892 (FAX)

Contact Jamie Creamer, 334-844-2783 or jcreamer@auburn.edu
Contact Katie Jackson, 334-844-5886 or smithcl@auburn.edu

March 8, 1993