Susceptibility of Black Fig Fly Silba adipata (Diptera: Lonchaeidae) Adults to Spinosad, Abamectin and Emamectin Benzoate by Ingestion

ABSTRACT Fig ( Ficus carica L.) production is increasingly constrained by the black fig fly, Silba adipata McAlpine (Diptera: Lonchaeidae), an invasive frugivorous pest that causes premature fruit abscission and significant economic losses. Amongst the poorly studied control strategies, toxic bait formulations represent a promising alternative within integrated pest management ( IPM ) programmes, particularly given the documented requirement for protein feeding by adult females. This study provides the first evaluation of the oral toxicity of three biorational insecticides, spinosad, abamectin and emamectin benzoate, against adult S. adipata . Median lethal concentrations ( LC 50 ) and median lethal times were estimated under laboratory conditions. Spinosad and emamectin benzoate exhibited high oral toxicity, with LC 50 values ranging from 3.9 to 5.0 mg L −1 , and were significantly more toxic than abamectin ( LC 50 = 33 mg L −1 ). Sex‐specific differences in susceptibility were observed, although these differences could not be fully explained by body weight. When sex differences were not considered, mean lethal times were similar amongst insecticides, ranging from 4 to 8 h. A significantly higher proportion of adults consumed the sugar–abamectin bait compared with the other insecticides in one experiment but not in the other. Considering both toxicity and speed of kill, spinosad and emamectin benzoate appear to be the most suitable candidates for toxic bait development against S. adipata, although the partial attraction of S. adipata adults to abamectin‐based baits warrants further investigation. This study establishes baseline toxicological information for this species and provides a scientific foundation for the development of sustainable attract‐and‐kill strategies targeting this poorly studied invasive pest. Future studies should focus on improving bait formulations to enhance attraction and toxic persistence under field conditions.