Evaluating New Repellents for Bird Management

Birds commonly cause damage to newly planted seeds, germinating seeds, or emerging seedlings of crops in many agronomic and horticultural crops causing economic loss. In Arizona, a variety of vegetables are grown throughout the year with planting occurring from the early fall (July to September for fall melons and leafy vegetables) through the winter (October to December for early spring vegetables) and into early spring (February to March for late spring vegetables and melons). Hybrid vegetables, including lettuce, are often planted to a stand and when bird damage occurs, quality and yield of the harvestable crop are significantly reduced. The experiment investigated the potential use of nine compounds, such as Mesurol 50% (Gowan Company, Yuma, AZ) as potential bird repellents for lettuce seedling protection. The experiments conducted, evaluated and determined the efficacy of over-sprays, seed coatings, and treated deterrent applications in protecting germinating seed and seedlings of lettuce during the period of stand establishment. Untreated cage studies determined that the rate of seedling consumption after 2 consecutive days was 26%. During a similar time frame, cage studies using Mesurol as a treated deterrent application using raw lettuce seed showed significant reductions in lettuce seedling consumption. When Mesurol was applied as a treated deterrent application, significant decreases in seedling consumption were observed when compared to the repellent being directly applied to the surface of the lettuce seed before planting. In all deterrent treated lettuce seedlings, lettuce consumption was reduced by a factor of between 2 and 5 when compared to non-deterrent treated lettuce. In addition to conducting caged studies, the research protocols were developed using Mesurol in a field trial. Results showed that Mesurol used as a treated deterrent before lettuce seedling emergence, significantly reduced seedling consumption by 29% relative to untreated controls. Determining the chemical residuals in lettuce seedlings via High Pressure Liquid Chromatography will be used to evaluate the effectiveness and field longevity of the repellents in the future.  This project addresses some of the technical issues relating to the efficacy of chemical repellents and suggests future avenues of research that would improve the ability to develop effective chemical repellents for specialty crops in Arizona.