Application of decision-support software for postemergence weed control

GESTINF is a decision tool for postemergence weed control based on the equivalent density approach. Using observed weed densities just before treatment, the program estimates the economic return from the treatment, thus indicating whether to treat or not and, if a treatment is needed, the most economical weed control solution. Each treatment is also characterized by an environmental pollution index. GESTINF has been tested in wheat and soybeans on a farm in northeastern Italy with a total cropping area of 60 ha of wheat and 40 ha of soybean. For both crops, weed control followed the suggestions of GESTINF, whereas the remaining cropped areas were treated according to standard farm weed control practices. To compare the two weed control systems, weed control efficacy, average crop yield, and the extra time required for scouting and treatments were measured. In both crops, the treatments suggested by GESTINF showed good efficacy, and yields proved to be no different from those obtained in the fields treated with standard farm weed control practices. In most cases, GESTINF selected treatments with a lower environmental effect. The most critical point was the time required to scout the weed population that, in low-value crops or when very cheap treatments were available, reduced the weed control economic return. In wheat, GESTINF indicated that fewer fields needed to be treated than did the conventional system. However, extra costs due to both scouting and more expensive treatments balanced the savings obtained from nontreated areas. For soybean, the treatments adopted by the farm were based on a combination of pre- and postemergence practices. In this case, GESTINF identified cheaper but still efficacious treatments, significantly reducing the total cost of weed control.Nomenclature: Soybean, Glycine max (L.) Merr.; wheat, Triticum aestivum L.