A beltwide herbicide survey was conducted in 1990 by state universities and the USDA under the National Agricultural Pesticide Assessment Program (NAPIAP). Extension weed specialists and/or university researchers were asked to provide information for their respective states to develop a national data base including (1) use patterns of herbicides including rates, application timing and acreage treated; (2) chemical and non-chemical alternatives it individual herbicides or groups of herbicides were cancelled; (3) impact of the cancellation of individual herbicides or herbicide groups on yield with and without the use of alternative weed control methods and (4) secondary effects if alternatives are used.

Computer summarization of the assessment information has led to the preliminary interpretations included in this paper. Final assessment results will be published later in 1992-

Twenty herbicides were mentioned by the 14 states reporting, with acreage treated ranging from 0.04% to 59.8%. Application timings included preplant incorporated, preplant foliar, preemergence, postemergence, layby, preharvest and spot treatment. Herbicide groups with respective percentages of acreage treated included acetanilids 2.5; dinitroanilines - 88.0; organic arsenicals - 33.3, substituted ureas - 33.2 and triazines 38.2.

Projected yield losses due to cancellation of individual herbicides with the use of alternative chemical and non-chemical weed control methods ranged from 0 to 4.0% and without the use of alternative methods ranged from 0.004 to 13.1%.

Secondary effects if alternative methods are used included increased herbicide carryover, greater harvesting losses, poor grass, broadleaf or nutsedge control, reduced lint quality, greater cotton injury. grassy bales, increased lint discounts and increased costs.

Projected yield losses due to the cancellation of groups of herbicides With the use of alternative chemical and non-chemical methods were acetanilids - 0.03%, dinitroanilines 7.0%, organic arsenicals - 2.7%, substituted ureas - 4.5%, triazines - 9.4% and all herbicides - 27.4%. Alternative methods if all herbicides were eliminated included cultivation, hand hoeing, crop rotation and flame cultivation. Without the use of alternative methods predicted losses increased to 0.47% for acetanilids, 21.4% for dinitroanilines, 8.8% for organic arsenicals, 15.9% for substituted ureas, 13.3% for triazines and 76.6% for all herbicides. Secondary effects if all herbicides were lost included acreage reduction, disk too great, increased erosion, hoe labor not available, increased costs and cotton production would cease.