Insecticidal effects of Capsicum annuum on aquatic stages of Anopheles gambiae giles under laboratory conditions

Abstract

The developing trend of resistance in Anopheles gambiae toward synthetic mosquitocidal agents makes their management extremely difficult. A new approach in the fight against malaria vectors consist of using native plants with insecticidal value. Two varieties of Capsicum annuum the red and the yellow varieties were evaluated for their toxicities to An. gambiae. Ovicidal, larvicidal and pupal mortality effects of C. annuum fruit have been noted. The results showed that for 60 eggs, embryonic mortality was 100% when treated with the yellow variety of C. annuum. In addition, this variety was also detrimental to the embryonic development of An. gambiae. In contrast, at a concentration of 1 g L-1 of the red variety of C. annuum 19% of egg-hatched and 93% of total mortality rate from eggs to emergence. At a concentration of 0. 25 g L-1 of the red variety of C. annuum 44% of egg-hatched and 67% of total mortality rate from eggs to emergence. The embryonic development duration and first instars larvae development duration were longer (82 and 77 h, respectively) in media containing 1 g L-1 of C. annuum. The total mortality rate and the quantity of C. annuum in breeding media were highly conelated (r = 0.964; p<0.01). The number of males, females and the number of eggs laid per female were negatively conelated with the quantity of C. annuum in the breeding medium. This study shows that C. annuum fruits are significantly toxic on eggs, larval and pupal stages of An. gambiae. Future tests in the field will help determine if C. annuum may be effective for malaria control in tropical region. © 2007 Academic Journals.