Tetranychus urticae Koch is a major mite pest in various crops both in the United States and worldwide. T. urticae incurs significant economic loss to Florida crops, including specialty crops such as strawberries, Fragaria x ananassa Duchesne. Recent studies have shown that the manipulation of ultraviolet radiation has applications in pest management. This study attempts to test the efficacy of ultraviolet C spectrum (UVC) in suppressing the hatchability of T. urticae eggs using an autonomous robot developed to apply UVC in open-field strawberries. Tetranychus urticae eggs were collected after adult females were given 24 hours to lay eggs and then placed on 2 cm leaf discs. The eggs were then placed on the mid-canopy of strawberry plants and exposed to 0 J/m2 (control), 200 J/m2, or 350 J/m2, followed by a minimum of four hours of darkness. An analysis of variance (ANOVA) was conducted to determine statistical difference in egg hatchability. Results showed UVC had a significant impact on the hatchability of T. urticae eggs. In control plots of ‘Florida Brilliance’ and ‘Florida Radiance’, the percent egg hatchability was 57 and 26 times higher compared to plots receiving 350 J/m2, respectively. In control plots of ‘Florida Brilliance’ and ‘Florida Radiance’, the percent egg hatchability was 20 and 3 times higher compared to plots receiving 200 J/m2, respectively. This project demonstrates that UVC application can be a potent tool when developing integrated pest management strategies that target T. urticae egg control.
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