Abstract:
– Methanol leaf extracts of two
Ethiopian traditional medicinal plants viz., Lomisar
[vernacular name (local native language, Amharic);
Cymbopogon citratus (DC) Stapf. (Poaceae)] and
Bisana [vernacular name (local native language,
Amharic); Croton macrostachyus Del. (Euphorbiaceae)] were screened for larvicidal activity
against late third instar larvae of Anopheles arabiensis Patton, a potent malaria vector in Ethiopia.
The larval mortality was observed 24 h of post
treatment. Both plant extracts demonstrated varying degrees of larvicidal activity against Anopheles
arabiensis. Cymbopogon citratus extract has exhibited potent larvicidal activity than Croton
macrostachyus at lower concentrations. The LC50
and LC90 values of Cymbopogon citratus were
74.02 and 158.20 ppm, respectively. From this data,
a chi-square value 2.760 is significant at the P<0.05
level. While, the LC50 and LC90 values of Croton
macrostachyus were 89.25 and 224.98 ppm, respectively and the chi-square value 1.035 is significant
at the P<0.05 level. The present investigation establishes that these plant extracts could serve as potent mosquito larvicidal agents against Anopheles
arabiensis. However, their mode of actions and larvicidal efficiency under the field conditions should
be scrutinized and determined in the near future.
