Application of decision-support software for postemergence weed control

GESTINF (Berti and Zanin, 1997) is a decision tool for post-emergence weed control based on the equivalent density approach (Berti and Zanin, 1994). Based on the observation of 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 economic weed control solution. Each treatment is also characterized by an environmental pollution index. GESTINF has been tested on wheat and soybean crops. Trials were done on a farm in north-eastern Italy, considering a total cropping area of about 60 ha of wheat and 40 ha of soybean. For both crops in those areas, weed control followed the suggestions of GESTINF, while the remaining cropping areas were treated according to the standard farm weed control practices. To compare the two weed control systems, the extra time required for scouting and treatments, as well as weed control efficacy and average crop yield 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 following the standard farm weed control practices. In most cases GESTINF selected treatments with a lower environmental impact. The most critical point was the time required to scout the weed population which, in low value crops and/or when very cheap treatments were available, reduced the weed control economic return. In wheat, GESTINF indicated that less fields are 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 non-treated areas. For soybean the treatments adopted by the farm were based on a combination of pre- and post-emergence practices. In this case GESTINF identified cheaper but still efficacious treatments, significantly reducing the total cost of weed control.