[Evaluation of efficacy of ripe and unripe fruit oil extracts of Melia azedarach against Rhipicephalus (Boophilus) microplus (Acari: ixodidae)]

Abstract

Hexanic extracts gotten of the fruits of cinamomo (Melia azedarach) were tested on engorged females and larvae of Rhipicephalus (Boophilus) microplus. Four extracts were produced: one of unripe fruits and three of ripe fruits, being one with the fruits immediately processed, another one with fruits stored for five months and one tested after storage of the extract for 2 (two) years at 4 degrees C. The tests were made in triplicate, in 0.25% - 0.0156% dilutions. The effectiveness of extracts was evaluated through the comparison of the Reproduction Estimate of the groups "controlled and treated" for females, of mortality for the larvae, and of the calculation of the DL50 and the relative power for larvae and females. The extract of unripe fruits presented the effectiveness varying the 3.6% - 100% for females, and of ripe fruits it varied of 5.2% - 99.7%. The two extracts caused a mortality of 100% of the larvae in the highest concentrations. The extract of stored fruits presented effectiveness of 14% - 83% on females, while the extract stored in refrigerator presented effectiveness of 8.4% 100% and both did not present larvicidal effect. The results demonstrate a superiority of the unripe extract, with a minor DL50 and superior power 1.497 times to the extract of ripe fruits.