Biology of Bactrocera dorsalis (DIPTERA: TEPHRITIDAE): implications on population dynamics and pest management

Fruit production is one of the fastest growing sectors in Botswana. As one of the agricultural sectors, fruit production is very crucial as it contributes immensely towards income generation and employment opportunities, especially for vulnerable rural livelihoods. Despite all the benefits, one of the biggest hurdles in the fruit production industry is disease and insect pests. Chief among these insect pests is the Bactrocera dorsalis (Hendel) (Diptera: Tephritidae). Bactrocera dorsalis is a worldwide economic insect pest of fruit and vegetables that has spread its geographical range to many African countries including Botswana. It was first detected in Botswana in 2010 in the Chobe district. However its spread and establishment around the country following its first detection is largely unknown. Furthermore despite this pest being of economic importance and a biosecurity threat, its response to prevailing Botswana microclimates and global change remained unknown. My study therefore investigated (i) presence and (ii) seasonal population dynamics of B. dorsalis in Botswana. Furthermore I investigated the thermal tolerance of B. dorsalis by measuring its different thermal low and high temperature activity traits vis a vis Critical thermal limits (CTLs), Lethal temperature assays (LTAs), and Supercooling points (SCPs), in order to understand how temperature largely impact this specie’s activity and thus population dynamics, abundance and consequently invasive potential. My seasonal monitoring results indicate that B. dorsalis is now established in the Chobe district, (its first area of detection) as shown by its continued presence all year round and high average monthly trap catches (