Mosquito larvicidal activity of aqueous extracts of long pepper (Piper retrofractum vahl) from Thailand.
Aqueous extracts of nine medicinal plants were bioassayed against larvae of Culex quinquefasciatus Say and Aedes aegypt (L.). Among these plants, the long pepper, Piper retrofractum Vahl (Piperaceae), showed the highest level of activity against mosquito larvae. To gain more information on larvicidal activity of P. retrofractum, fresh fruits of this plant were extracted in water and the extracts made into powder and bioassayed against 3rd and 4th instar larvae of Cx. quinquefasciatus and Ae. aegypti in the laboratory. Extracts of unripe (001/3) and ripe (002/3 and 001/4) fruits showed different levels of activity against Cx. quinquefasciatus larvae. Extracts 001/3 and 002/3 were equi-toxic to a Bacillus sphaericus resistant and susceptible strains, both from Thailand. The ripe fruit extract 002/3 was somewhat more active against Ae. aegypti than Cx. quinquefasciatus. Another ripe fruit extract (001/4) was much more toxic to both mosquito species. Diluted solutions of the solid extract (002/3) in distilled water lost their larvicidal activity upon aging. Loss of activity at 25 degrees C was greater than that stored at 4 degrees C, and greater in water than in acetone solution.
Chansang
Uruyakorn
U
Division of Medical Entomology, National Institute ofHealth, Department of Medical Sciences, Ministry of Public Health, 88/7 Tiwanon Road, Nonthaburi 11000, Thailand.
Zahiri
Nayer S
NS
Bansiddhi
Jaree
J
Boonruad
Thidarat
T
Thongsrirak
Pratom
P
Mingmuang
Jiranuch
J
Benjapong
Nipa
N
Mulla
Mir S
MS
D000330:Aedes / Q000187:drug effects / Q000254:growth & development; D000818:Animals; D003465:Culex / Q000187:drug effects / Q000254:growth & development; D009033:Culicidae / Q000187:drug effects* / Q000254:growth & development; D004305:Dose-Response Relationship, Drug; D007303:Insect Vectors / Q000187:drug effects / Q000254:growth & development; D007306:Insecticides / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D009032:Mosquito Control / Q000379:methods*; D010572:Pest Control, Biological; D031701:Piper / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology*; D013785:Thailand
D007306:Insecticides; D010936:Plant Extracts