Effect of temperature on the development and reproduction of olive psyllid Euphyllura olivina Costa (Hemiptera: Psyllidae)

Abstract

Euphyllura olivina Costa (Hemiptera: Psyllidae) threatens olive crops, necessitating an understanding of temperature's impact on its development and reproduction for effective management. To investigate these effects, laboratory-based experiments were conducted under constant temperatures ranging from 15 to 40 °C. The egg incubation period decreased significantly with rising temperatures, from 12.7 days at 15 °C to 3.2 days at 40 °C. The longest lifespans were observed at 25 °C, with females averaging 46.8 days and males 38.6 days. The highest egg-to-adult survival rates were at 20 °C, with 20.0% for females and 17.5% for males. Preadult survival rates exhibited notable variability, with the highest survivorship of 38.0% observed at 20 °C. The maximum average number of eggs produced per female peaked at 242.6 at 25 °C, while daily fecundity was highest at 32 °C, averaging 9.0 eggs per female per day. The population growth parameters showed their most favorable values at 25 and 32 °C, with r_m (0.033 and 0.050 d⁻¹, respectively) and R₀ (31.53 and 25.3 offspring per female, respectively) being highest at these temperatures. The predicted fecundity of next generation (G2) and the population trend index (I) reached their highest values at 25 °C (1576.9 and 7.9, respectively), indicating optimal growth conditions at this temperature. The temperature thresholds for the complete pre-adult stage were estimated at 5.2 °C for females and 5.4 °C for males, with thermal constants of 769.2°-days (DD) for females and 714.3 DD for males. These findings indicate that the most favorable temperature range for the population growth of this pest falls between 25 and 32 °C.