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 outbre ak 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 agribusines s professionals perceive the crop production risks posed by European c orn borer, and (ii) explore how these perceptions are reflected in man agement options they use or recommend. Farmers and agribusiness profes sionals completed 851 surveys, The survey results provided insights in to yield loss perceptions, management tactics used, and research needs for European corn borer management, Economic yield losses caused by E uropean corn borers during the first and second generations, respectiv ely, 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 d uring the second generation, Although two-thirds of the farmers percei ved the European corn borer as a serious pest, only 35% had ever scout ed their fields and used economic thresholds, and only 28% had ever us ed 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 re commendation from ag-chemical professionals (68.3%), crop consultants (88.5%), and educator/agronomists (54.0%). The second most common reco mmendation was using an insecticide by ag-chemical professionals (57.9 %) and educator/agronomists (41.4%), whereas crop consultants were mor e likely to suggest early harvest to prevent ear droppage (73.8%). The survey results suggest that many farmers don't manage European corn b orer because of historic inaction, hidden yield losses, reluctance to scout, logistical burnout, capital doubts, cultural competition, insec ticide concerns, and a failure to recognize the problem. The results a lso suggest a strong need to educate farmers and agribusiness professi onals regarding biology, crop damage, and management options for the E uropean corn borer.