Effect of <i>theretra alecto</i> L. (Lepidoptera) on Photosynthesis in Grapevines

The present study evaluates the impact of the Levant hawk moth (Theretra alecto Linnaeus) larvae on the photosynthetic efficiency of grapevines in vineyards of the Samarkand, Fergana and Andijan regions, Uzbekistan. Larval feeding significantly reduced the net photosynthetic rate by an average of 35%, particularly during the L4 and L5 developmental stages. This decline was closely associated with decreased stomatal conductance and transpiration rate, leading to reduced physiological functioning of the plants. Laboratory observations revealed an average egg hatching rate of 80.1% and larval survival increasing from 52.1% at L1 to 97.0% at L5. The Canonical Correspondence Analysis identified the L4 stage as the most damaging period. Temperature and humidity were found to influence larval development, with optimal growth conditions ranging from 24°C-27°C and 40-45% RH. These findings highlight the need for early monitoring and stage-specific pest control strategies to mitigate the economic damage caused by T. alecto in vineyards.