Larvicidal and IGR activity of extract of Tanzanian plants against malaria vector mosquitoes.
OBJECTIVE
This paper reports the larvicidal activity of seventeen Tanzanian plant species against the malaria vector, Anopheles gambiae s.s. Giles larvae. Some of the plants are used traditionally as sources of insecticidal materials.


METHODS
The crude extracts from the leaves, stem and root barks of the investigated plants were obtained by solvent extraction and then bio-assayed following WHO protocols showed LC50 values 10 to 400 ppm after 24 h exposure. The structures were determined on interpretation of spectroscopic data.


RESULTS
The most active extracts were those from the stem and root barks of Annona squamosa, Uvaria faulknerae, U. kirkii and Uvariodendron pycnophyllum, all of which had LC50 values between 10 and 100 ppm. Long-term exposure beyond 24 h also showed more susceptibility of the larvae to the extracts. Larvae deformities by forming tail-like structures were observed for the methanol extracts of Tessmannia martiniana var pauloi.


CONCLUSIONS
The results suggest that the investigated plant extracts are promising as larvicides against An. gambiae s.s. Giles mosquitoes and could be useful leads in the search for new and biodegradable plant derived larvicide products.
Kihampa
Charles
C
Department of Environmental Science and Management, Ardhi University, Dar es Salaam.
Joseph
Cosam C
CC
Nkunya
Mayunga H H
MH
Magesa
Stephen M
SM
Hassanali
Ahmed
A
Heydenreich
Matthias
M
Kleinpeter
Erich
E
D000818:Animals; D031041:Annona / Q000737:chemistry; D029061:Annonaceae / Q000737:chemistry* / Q000145:classification; D000852:Anopheles / Q000187:drug effects* / Q000254:growth & development; D007887:Fabaceae / Q000737:chemistry*; D007303:Insect Vectors / Q000187:drug effects* / Q000254:growth & development; D007306:Insecticides / Q000494:pharmacology*; D007605:Juvenile Hormones / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects; D008288:Malaria / Q000635:transmission; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D013636:Tanzania; D031046:Uvaria / Q000737:chemistry / Q000145:classification
D007306:Insecticides; D007605:Juvenile Hormones; D010936:Plant Extracts