Pest Management Practices of Crop Consultants in the Midwestern USA

A mail survey was conducted of independent crop consultants in 12 midwestern U.S. states working in corn (Zea mays L.), soybeans [Glycine max (L.) Merrill], wheat (Triticum aestivum L.), and grain sorghum (Sorghum bicolor L. Moench.) during 1993. The survey was conducted to document the acreage of crops monitored by crop consultants, and some of their operational characteristics. Kansas and Nebraska had the greatest reported acreage of crops scouted, over 3 million and 1 million acres, respectively. Total acres scouted were highest for corn, followed by soybeans, wheat, alfalfa (Medicago sativa L.), and sorghum. Acres contracted with crop consultants varied from 0.4 to 40.0% of the total 1993 harvested cres, depending on state and crop. The most common interval reported between field visits was once a week. Averaged over all states, the highest consulting fees were charged for alfalfa ($4.80), with less charged for corn ($4.31), sorghum ($4.26), soybeans ($4.07), and wheat ($3.74). There was a great range in fees within crops across the region (e.g., corn fees varied from S3.21-6.13/acre). Planting time application of insecticides was the most commonly used corn rootworm (Diabrotica virgifera virgifera LeConte and D. barberi Smith & Lawrence) control. Postemergence applications of insecticides for larval rootworms (cultivation time applications and chemigation) were used primarily in Kansas and Nebraska. Foliar sprays for adult corn rootworm control were also most common in these states. Use of crop rotation varied greatly across the region (23.8–83.7% of acres were corn after another crop). Additionally, across all states except Missouri, there was a significant correlation between frequency of rotation in corn and insecticide use against corn rootworms; i.e., states with higher frequencies of rotated corn treated a lower percentage of corn acreage for corn rootworm control. The diversity of crop consultant activity across the region has implications for future adoption of IPM practices on midwestern field crops. Research QuestionThe Clinton administration has set a goal of having integrated pest management (IPM) programs implemented on 75% of the managed acres in the USA by the year 2000. Crop consultants are a major group influencing adoption of IPM practices. This study's objectives were to document practices of crop consultants working on corn, soybeans, wheat, alfalfa, and grain sorghum in the midwestern USA during 1993. Literature SummaryIn 1993, nationally, 65% of corn acres and 69% of soybean acres were reported by growers to be scouted for all pests (weeds, insects, diseases), and growers used economic thresholds for decisions on use of pesticides 29% of the time for corn insecticides, 53% of the time for corn herbicides, and 59% of the time for soybean herbicides. However, often it is difficult to interpret the intensity of scouting reported by growers. Crop consultants have become increasingly important in implementation of IPM. Data from USDA-ERS for 1993 indicate that, in 10 midwestern states, from 1.9% to 29.9% of corn acres were scouted by crop consultants who charged fees from $2.89 to 5.50/acre. Study DescriptionA questionnaire was mailed to 571 crop consultants in the midwestern USA (Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, and Wisconsin). A total of 294 usable questionnaires was returned (51.5%). This survey was conducted to document the practices of crop consultants working on corn, grain sorghum, soybeans, alfalfa, and wheat during 1993. Selected data related to insect management and crop consultant practices are reported here. Applied QuestionsHow does the acreage contracted with crop consultants vary over the North Central region? Kansas and Nebraska had the greatest reported acreage of crops scouted and the greatest number of crop consultants. Across the region, total acres scouted were highest for corn, followed by soybeans, wheat, alfalfa, and sorghum. Acres contracted with crop consultants represented from 0.4 to 40.0% of the total 1993 harvested acres, depending on state and crop. How do crop consultant practices vary over the midwestern USA? The most common interval between field visits reported was once a week; 68% reported making visits once a week or more frequently. States where insect scouting is commonly a component of crop consultant services (Kansas and Nebraska) rarely reported scouting less frequently than once a week. Other states, where insect scouting was less commonly offered as a service, were more likely to report scouting intervals greater than once a week. Consulting fees per acre varied with crops; averaged over all states, the highest fees were charged for alfalfa ($4.80), with less charged for corn ($4.31), sorghum ($4.26), soybeans ($4.07), and the least charged for wheat ($3.74). There was a great range within crops across the region (e.g., corn varied from $3.21-6.13/acre). How did practices used for corn rootworm management vary across the region? Planting time application of insecticides was the most commonly used corn rootworm control. Postemergence applications of insecticides directed at larval rootworms (cultivation time applications, chemigation) were used primarily in Kansas and Nebraska. Foliar sprays for adult corn rootworm control were also most common in these states but some use occurred further east also. Use of crop rotation varied greatly across the region (23.8–83.7% corn grown after another crop). Additionally, across all states except Missouri, there was a statistically significant correlation between frequency of corn planted after another crop and insecticide use against corn rootworms; i.e., states with higher fiequencies of corn planted after another crop tended to treat a lower percentage of corn acreage for corn rootworm control.