Does climate constrain the spread of Anthonomus santacruzi, a biological control agent of Solanum mauritianum, in South Africa?

This study aimed to test the hypothesis that climate, particularly low temperature and low relative humidity, restricts the survival and establishment of A. santacruzi in South Africa. The survival of A. santacruzi adults in relation to low temperatures and relative humidities was assessed in the laboratory. Climate analyses revealed that matches of < 50% were associated with failure to establish and that minimum temperature and relative humidity displayed the greatest discrepancies between South American collection and South African release sites. Thermal assessments on A. santacruzi adults calculated the CTmin and LT50 as 4.1 ± 0.2 °C (n=20) and –4.2 ± 0.3 °C (n=90) respectively. The LH50 of A. santacruzi adults was calculated as 46.9%. The establishment of A. santacruzi at only the warm and humid release sites in South Africa advocates for the consideration of low temperature and low humidity as factors impeding the agents’ establishment, particularly on the cooler and drier Highveld. Graphical abstract
Source: Biological Control - Category: Biology Source Type: research