The comparative termicidal efficacies of 4 synergistic plant extract blends; A1:1:1, A3:1:1, A1:3:1 and A1:1:3 prepared from Olax subscorpioidea, Azadirachta indica and Cymbopogon citratus coated on chitosan nano particles, were assessed. The comparative mortalities and LD50 of the synergistic blends were determined at varied concentrations, using WHO susceptibility bioassays and probit analysis respectively. The results obtained show that all synergistic extract blends in the study possessed some level of termiticidal activity seeing as they achieved termite mortalities ranging between 25-100%. When graded with respect to mortality, the potency of the coated nanomaterials was in the order; A1:3:1 > A3:1:1 > A1:1:1> A1:1:3. The most potent synergistic blends were A1:3:1 and A3:1:1 as these produced termite mortalities as high as 96% and 100% respectively. Also, the termicidal efficacy of the synergistic blends appeared to be mostly attributable to the bioactive compounds in olax and neem rather than those from lemongrass. From the determined mortalities and LD50 of the coated nanomaterials, A1:3:1, was found to be the most potent of the plant based termiticide.
Keywords: Azadirachta indica, Chitosan nanoparticles, Cymbopogon citratus, Olax subscorpiodea, termicidal efficacy, termites
