Producer Perceptions and Pest Management Practices in Iowa Alfalfa

In June 1997, 1900 self-administered surveys were sent to Iowa alfalfa (Medicago sativa L.) producers. The sample was split into early adopter and general populations. Early adopters were those producers who purchased potato leafhopper [Empoasca fabae (Harris)) resistant alfalfa seed during the first year it was available commercially. The general population was randomly selected and no producer was present in both populations. Producers were asked questions on pest perceptions, management practices, and perceptions of leafhopper-resistant alfalfa. Seven hundred forty-seven usable surveys were returned. Results showed that the early adopter population farmed larger production systems and produced more alfalfa per acre than the general population. Overall, producers from the early adopter population had greater fundamental knowledge of serious alfalfa pests than producers from the general population. The potato leafhopper was reported as the most important pest in both populations. Producers seemed confused between the injury symptoms of potato leafhopper and alfalfa weevil [Hypera postica (Gyllenhal)] injury, and it was apparent that leafhopper injury symptoms were often confused with drought stress. Positive relationships were found between the frequency of scouting, the frequency of insecticide use, and alfalfa yield. The majority of producers expected leafhoppers to avoid resistant alfalfa varieties, resulting in smaller pest infestations. Adoption of leafhopper-resistant alfalfa probably will be limited by producers' knowledge of previous yield loss from this pest. Results of this survey will be used to develop improved educational materials on insect pest management in alfalfa. Research QuestionAn understanding of the fundamental knowledge of Iowa farmers in alfalfa pest management is lacking. In fact, many alfalfa and pest management experts seriously doubt the ability of farmers to accurately identify symptoms, scout, and effectively manage insect pests in alfalfa. Several seed companies released alfalfa varieties with resistance to the potato leafhopper. These resistant varieties will require a new set of leafhopper management guidelines, namely new economic thresholds. The objectives of this study were to learn producers' knowledge of alfalfa pests and their management, and their perceptions of leafhopper-resistant alfalfa. This information will be combined with new management guidelines to develop improved educational literature. This literature will focus on important topics where producer knowledge was lacking and integrate the changes in pest management practices that will accompany leafhopper-resistant alfalfa. Literature SummaryRecent surveys of production and pest management practices in alfalfa have been reported for states other than Iowa. This survey is unique because of its detail on insect pest management and producer perceptions of leafhopper-resistant alfalfa in Iowa. In general, the survey provided current information on producers' knowledge of insect pests and how they are being managed. More specifically, results were used to predict the rate at which leafhopper-resistant alfalfa would be adopted and who will probably benefit from this new management tactic. Producer perceptions of this new management tactic are especially important because researchers are still deciphering the resistance mechanisms. Study DescriptionA survey was conducted through the Iowa Agricultural Statistics Service. During June 1997, 1900 self-administered questionnaires were mailed to alfalfa producers. Of these, 577 were mailed to people who had previously purchased leafhopper-resistant alfalfa. These respondents were considered a sample of the early adopter population. Questionnaires were also mailed to 1323 randomly selected alfalfa producers who could have purchased leafhopper-resistant seed. This is a sample of the general population. No respondents were present in both populations. There were 229 usable replies from the early adopter mailing and 518 from the general mailing. Applied QuestionsHow knowledgeable are producers of insect pests in alfalfa and their potential to cause loss? Overall, producers from the early adopter population had greater fundamental knowledge of serious alfalfa pests, compared with producers from the general population. The potato leafhopper was reported as the most important pest in both populations. Producers from the early adopter and general populations seemed confused about the difference between the injury symptoms of potato leafhopper and the alfalfa weevil. It was also apparent that leafhopper injury symptoms were often confused with drought stress. Not all producers who scouted understood how key pests caused loss and how to identify pest injury symptoms. It seems greater knowledge of alfalfa pests and their management could increase alfalfa productivity in Iowa. How important are insecticide applications targeting the potato leafhopper in Iowa alfalfa? Insecticides were used by 46.9% of the respondents who ranked potato leafhopper as the most important pest of alfalfa. This was the most popular tactic for the early adopter population, and significantly more early adopters used insecticides than the general population. Additionally, results showed that yield increased as the frequency of pest scouting and insecticide application increased. These results confirm that insecticides are important for the management of insect pests in alfalfa, and show that an alternative tactic, such as leafhopper-resistant alfalfa, may reduce their use. How do Iowa alfalfa producers expect the potato leafhopper population to change in fields of leafhopper-resistant alfalfa? Most producers expect smaller populations of potato leafhopper in leafhopper-resistant alfalfa, compared with traditional alfalfa. Additionally, most expected leafhoppers to avoid resistant alfalfa and less than 10% thought resistant alfalfa would kill the pest. Producer expectations are largely inconsistent with the research findings. It will be important to warn producers that only small changes in the pest population will result from using resistant alfalfa. RecommendationsDeficiencies in fundamental knowledge of alfalfa pests were highlighted, and it was evident that well-informed producers are profiting from greater knowledge. Therefore, future educational material could benefit Iowa producers by focusing on areas where fundamental knowledge was lacking. Some of these areas are: identifying and differentiating symptoms of key pests, describing how to scout for key pests, and characterizing the response of the insect community to resistant alfalfa. Moreover, leafhopper-resistant alfalfa requires new scouting guidelines, specifically economic thresholds. It would be efficient to couple updated management guidelines with this broader information on insect pest management in alfalfa.