European corn borer management in field corn: A survey of perceptions and practices in Iowa and Minnesota

The European corn borer (Ostrinia nubilalis Hubner) is a major pest of field corn (Zea mays L.) in the midwestern states. In 1991, an outbreak of this insect caused yield losses as high as 32.6 bu/acre in Iowa and averaged 14 bu/acre in Minnesota. Following this pest outbreak, a questionnaire was developed to: (i) assess how farmers and agribusiness professionals perceive the crop production risks posed by European corn borer, and (ii) explore how these perceptions are reflected in management options they use or recommend. Farmers and agribusiness professionals completed 851 surveys. The survey results provided insights into yield loss perceptions, management tactics used, and research needs for European corn borer management. Economic yield losses caused by European corn borers during the first and second generations, respectively, were thought to occur only by 65 to 69% of farmers, 78 to 81% of ag-chemical professionals, 84 to 89% of crop consultants, and 68 to 70% of educator/agronomists. Respondents that perceived economic losses caused by European corn borers thought that the average loss was 15.3 to 16.6 bu/acre during the first generation and 15.2 to 18.1 bu/acre during the second generation. Although two-thirds of the farmers perceived the European corn borer as a serious pest, only 35% had ever scouted their fields and used economic thresholds, and only 28% had ever used an insecticide to control the pest. Farmers' primary and secondary options for managing the European corn borer or reducing yield losses were to harvest the fields early before ears drop onto the ground (63.4%) and to plant hybrids with known resistance (39.0%), respectively. In contrast, scouting and using economic thresholds was the primary recommendation from ag-chemical professionals (68.3%), crop consultants (88.5%), and educator/agronomists (54.0%). The second most common recommendation was using an insecticide by ag-chemical professionals (57.9%) and educator/agronomists (41.4%), whereas crop consultants were more likely to suggest early harvest to prevent ear droppage (73.8%). The survey results suggest that many farmers don't manage European corn borer because of historic inaction, hidden yield losses, reluctance to scout, logistical burnout, capital doubts, cultural competition, insecticide concerns, and a failure to recognize the problem. The results also suggest a strong need to educate farmers and agribusiness professionals regarding biology, crop damage, and management options for the European corn borer.