Seasonal Dynamics and Host-Genotype Associations of Hemipteran Pest Population in Sorghum Ecosystem under Çanakkale Field Conditions, Türkiye

Hemipteran insects represent an important component of the sorghum pest complex; however, information on the temporal dynamics and host-genotype associations of entire Hemipteran population in forage sorghum remains limited under Mediterranean conditions. This study investigated the taxonomic composition, dominance structure, seasonal dynamics, and host-genotype associations of Hemipteran pests in two sweet sorghum cultivars (M81-E and Topper-76) and two sorghum sudangrass hybrid (Nutrima and Nutri Honey) cultivars in 2020 and 2021 growing seasons in northwestern Türkiye. Field experiments were conducted in a split-plot design with four replications, and insect populations were monitored at approximately 10-day intervals from June to October using sweep netting, aspirator and beat sheet sampling methods. Fifteen Hemipteran taxa were recorded, and the reconstructed quantitative dataset comprised 1,673 individuals. Empoasca decipiens (Paoli) was the dominant species, accounting for 70.95% of total Hemiptera abundance, while aphids collectively represented 16.20%. Total Hemiptera abundance decreased from 1,126 individuals in 2020 to 547 in 2021, corresponding to a 51.4% reduction. Despite this decline, Shannon diversity increased from 0.920 to 1.383, Simpson diversity from 0.401 to 0.602, and Pielou's evenness from 0.399 to 0.577. Seasonal patterns also differed markedly between years, with populations concentrated mainly in September–October in 2020 but in June–July in 2021. Host-genotype associations were similarly year dependent: sorghum sudangrass hybrid cultivars supported higher abundance in 2020, whereas sweet sorghum cultivars supported higher abundance in 2021. These findings demonstrate substantial interannual restructuring of Hemipteran population and indicate that pooled multi-year abundance may obscure biologically relevant temporal variation in host associations. Phenology-based monitoring and multi-year cultivar evaluation should therefore be considered in integrated pest management strategies for Çanakkale forage-sorghum systems.