Thermal Requirements and Population Growth Parameters of Dysaphis plantaginea (Hemiptera: Aphididae) on Apple

Abstract

Thermal requirements and population growth parameters of Dysaphis plantaginea (Hemiptera: Aphididae) on apple were investigated to understand its developmental biology and population dynamics under varying temperature regimes. Laboratory experiments were conducted at different constant temperatures using apple seedlings, and developmental duration, survival rate, fecundity, and longevity were recorded across life stages. Results indicated that temperature significantly influenced the biological performance of D. plantaginea, with moderate temperatures supporting optimal development, higher survival, and increased reproductive output. At lower temperatures, developmental time was prolonged and fecundity reduced, while higher temperatures beyond the optimum negatively affected survival and adult longevity. Thermal requirements analysis revealed clear thresholds for development, with a defined lower developmental limit and degree-day accumulation requirement for completion of the life cycle. Population growth parameters, including intrinsic rate of increase, net reproductive rate, and finite rate of increase, were highest at optimal temperature conditions, indicating rapid population buildup potential in apple orchards. Life table analysis showed that survival probability decreased progressively with age, while reproductive output was concentrated in early adult stages. The study highlights the strong influence of temperature on the population ecology of D. plantaginea and its potential for rapid outbreaks under favorable climatic conditions. These findings provide essential baseline information for predicting pest phenology and improving temperature-based forecasting models for integrated pest management in apple production systems.