Seasonal Population Fluctuation of Empoasca spp. (Hemiptera: Cicadellidae) on Grapevine and Associated Environmental Factors

Abstract

Seasonal population fluctuation of Empoasca spp. (Hemiptera: Cicadellidae) on grapevine was investigated in relation to key environmental factors to understand pest dynamics and potential outbreak drivers. Field observations were conducted over multiple cropping seasons, and leafhopper populations were monitored at regular intervals using standardized sampling techniques. Data on temperature, relative humidity, rainfall, and host phenological stage were concurrently recorded to assess their influence on population trends. Results revealed distinct seasonal peaks of Empoasca spp., with maximum population density occurring during warm and moderately humid conditions coinciding with active vegetative growth of grapevine. Population decline was observed during cooler periods and heavy rainfall events, indicating strong environmental regulation of pest abundance. Correlation analysis showed a positive association between temperature and leafhopper density, while excessive rainfall exhibited a suppressive effect due to reduced survival and dispersal activity. Vine phenology also played a critical role, with young flushes of leaves supporting higher infestation levels compared to mature foliage. The study highlights the interactive effects of abiotic factors and host plant growth stages in shaping seasonal population dynamics of Empoasca spp. These findings provide essential insights for forecasting pest outbreaks and optimizing timing of control measures in grapevine production systems. Understanding environmental drivers of population fluctuation can support the development of integrated pest management strategies aimed at reducing leafhopper-induced damage and maintaining grapevine productivity.