Evaluation of the larvicidal efficiency of stem, roots and leaves of the weed, Parthenium hysterophorus (Family: Asteraceae) against Aedes aegypti L.

Objective: To assess the larvicidal potential of various extracts prepared from the stem, roots and\udleaves of Parthenium hysterophorus (P. hysterophorus) against 3rd and 4th instars of Aedes aegypti\ud(Ae. aegypti). Methods: The extracts from each part were prepared with four solvents; petroleum\udether, hexane, acetone and diethyl ether. Each part was dried, powdered and soaked in different\udsolvents, separately, for five days. The crude extracts thus formed were concentrated using rotary\udevaporator and stored as stock solution of 1 000 mg/L. Results: All the extracts prepared from the\udleaves were found ineffective against both the instars causing only 10%-40% mortality. Against\ud3rd instars, the hexane and petroleum ether extracts prepared from the stem of P. hysterophorus\udwere found effective exhibiting LC50 values of 379.76 and 438.57 mg/L, respectively. Likewise the\udhexane and petroleum ether extracts from the Parthenium roots resulted in LC50 values of 432.38\udand 562.50 mg/L, respectively, against 4th instars of Ae. aegypti revealing their larvicidal potential.\udIt was further found that the hexane extracts, whether from roots or stem, were 13-28% more\udeffective than the petroleum ether extracts. The qualitative phytochemical study of the effective\udextracts from the stems and roots showed the presence of alkaloids, saponins, terpenoids and\udflavonoids in different combinations. Conclusions: Our investigations demonstrated the potential\udof P. hysterophorus roots and stems against Ae. aegypti larvae and their benefits as new types of\udmosquito larvicides. Variety of types and levels of active constituents in each kind of extract may\udbe responsible for the variability in their potential against Ae. aegypti. Further research is needed\udto identify these components