Biological and lethal effects of some volatile plant oils, aloe aqueous extract and spinosad on cowpea beetle, Callosobruchus maculatus (F.)‎

Abstract EN

This study was carried out under constant conditions at 30±°C and 60± 5% RH on cowpea beetle, Callosobruchus maculatus (F.) treated with four volatile plant oils (clove, thyme, marjoram and rosemary), aloe aqueous extract and spinosad.

The obtained data are summarized as follows: The highest fecundity (63.67 eggs) was recorded in cowpea seeds treated with thyme oil at 0.5% and the lowest one (2.67 eggs) at 2.0% on rosemary oil, compared with (135.67 eggs) in the control.

The highest fertility (86.25%) was occurred at 1% of thyme oil, but the lowest one (zero%) was recorded in case of 2% marjoram oil as compared with control (68.38%).

There were no larval penetrations (zero) into seeds with all volatile oils at different concentrations except (7.73%) at 0.5% of thyme oil as compared with 11.19% in control.

Moreover, the highest fecundity (38.67 eggs) was recorded at 0.5% and decreased to (11.33 eggs) at 2%, the highest percentage of larval penetration (6.22 %) was recorded at 0.5% and decreased to 0.0% in the concentrations of 1.5% and 2%, compared with (11.19%) in control, when treated with aloe aqueous extract.

The percentage of eggs reduction was increased by increasing the concentrations used.

The highest percentage of reduction (94.25 %) was recorded at the concentration of 2%, while the lowest one (71.09%) was recorded at 0.5%.

The highest percentage of weight loss (3.39%) was recorded at 0.5% of clove oil, and the lowest percent (1.15%) was found at 2% of aloe aqueous extract.

The highest feeding deterrence index (FDI) was 36.83% as concerns aloe aqueous extract and the lowest one (19.65%) was recorded with clove oil.

Adult mortality percentage increased by increasing the concentration of the volatile plant oils used.

The highest percentage of mortality (72.22%) was recorded at 2% and 3% rosemary oil after 72 hr.

from treatment and 3% of both clove and thyme oils, while the lowest percent (2.78%) was recorded at 0.5% after 24 hr., of clove oil.

The highest percentage of mortality (52.78%) was recorded on cowpea seeds treated aloe aqueous extract at 3% after 72 hr., of treatment, while the lowest one (13.89%) was obtained at 0.5% after 48 hr.

The highest mortality of spinosad was 80.0% at 70 ppm after 72 hr., whereas the lowest percent (1.67%) was recorded at 40 and 50 ppm after 24 hr.

post-treatment, compared with 33.33% at 1 ppm after 24 hr.

exposure to malathion (1% powder) and the highest one of 100.00% which was recorded at 8 ppm after 72 hr., exposure period.