Temperature-dependent development and population growth of the invasive pest Cassida vittata vill. In sugar beet crops

Abstract

The sugar beet flea beetle, Cassida vittata Vill. is an invasive pest that significantly damages sugar beet crops in Morocco by affecting the leaves. To gain a deeper understanding of how temperature influences the development and reproduction of C. vittata and to facilitate its population management, laboratory-based experiments were conducted. Individuals were subjected to a range of constant temperatures spanning from 15 °C to 36 °C. The most extended lifespans for both adult females and males were recorded at 30 °C, with respective longevities of 62.8 and 62.5 days. The highest likelihood of eggs maturing into the adult stage occurred at 25 °C, with survival rates of 39.0% for females and 37.5% for males. Preadult survival rates displayed significant variability with temperature, with the highest survivorship observed at 25 °C (76.5%). The maximum average number of offspring produced per female reached 225.1 eggs at 25 °C. Daily reproduction, maximum total fecundity, and maximum daily fecundity were also notably higher at 25 °C. The population growth parameters exhibited their most favorable values at 25 °C, with r (0.0933 d−1), and R0 (87.15 offspring per female) being highest at this temperature. The temperature thresholds for the complete pre-adult stage (1st instar larva to adult) were estimated to be 9.4 °C for females and 9.0 °C for males. The thermal constants from the 1st instar larva to the adult stage were calculated to be 526.3 and 476.2 DD, respectively. These findings indicate that the most favorable temperature range for the population growth of this invasive pest falls between 25 °C and 30 °C.