Toxicity and Combined Impact of Certain Insecticides and Jojoba Oil Against German Cockroach, Blattella germanica L.

The German cockroach, Blattella germanica, is a prominent housing urban pest that poses significant public health concerns due to its capacity to transmit various pathogens. This study investigated the toxicity of several insecticides emamectin benzoate, spinetoram, indoxacarb, thiocyclam hydrogen oxalate, and metaflumizone alone and in combination with jojoba oil at concentrations of 250, 500, and 1000 ppm. Based on the LC50s values of the tested insecticides for the adult of B. germanica, the most toxic insecticide was emamectin benzoate (0.414, 0.012 and 0.002 ppm), followed by spinetoram (2.96, 0.093 and 0.056 ppm), indoxacarb (4.88, 0.602 and 0.090 ppm), thiocyclam hydrogen oxalate (17.04, 0.769 and 0.182 ppm), metaflumizone (96.67, 21.22 and 2.042 ppm) and jojoba oil (350.64, 258.97 and 197.61 ppm) after 24, 48 and 72 hrs. post exposure, respectively. The incorporation of jojoba oil as a synergist significantly enhanced the toxicity, with pronounced effects observed at higher concentrations and extended exposure durations. Emamectin benzoate, spinetoram and indoxacarb showed marked improvements in efficacy when combined with jojoba oil. In contrast, thiocyclam hydrogen oxalate and metaflumizone remained the least effective compound, although slight enhancements were observed with jojoba supplementation. These findings suggest that jojoba oil may function as a valuable synergist, amplifying the insecticidal potency of conventional chemical agents. Its integration into pest management programs could improve control outcomes for B. germanica while potentially reducing the reliance on higher pesticide doses. Future research should focus on practical, application-oriented strategies to establish jojoba as a bioinsecticide and explore its combinations with other insecticides.