Potentiality of Adenanthera pavonina (L.) (Leguminosae) and Dinarmus basalis (Rond.) (Pteromalidae) against Callosobruchus chinensis L. (Bruchidae)

Abstract

The petroleum ether, acetone, chloroform and methanol extracts of the leaves, seed and stem wood of Adenanthera pavonina (L.) were tested against Callosobruchus chinensis L. adults through residual film assay at doses of 2831, 2477, 2123, 1769 and 1415 μg/cm2 on the surface of the Petri dishes, where the test insects were released to observe mortality or any sort of behavioral changes due to the action of the extracts compared to the controls. The seed extract was found to offer the highest mortality of the beetles than leaves and stems after 12h, 24h and 48 h of exposure respectively. According to the intensity of activity observed through mortality of the adult beetles the potentiality of the petroleum ether, acetone, chloroform and methanol extracts could be arranged in a descending order of chloroform > acetone > methanol petroleum ether extracts. In comparison to all other biological assays repellent activity of the A. pavonine extracts have been detected for seed, leaves and stem wood of petroleum ether, acetone, chloroform and methanol extracts respectively. All the test extracts offered repellency at 0.01% level of significance (P<0.001) except the stem (acetone) extract which was found 0.1% level of significance (P<0.01). According to the intensity of repellency the result could be arranged in a descending order: leaf (pet. ether extract) >leaf (chloroform extract) seed (methanol extract > stem wood (acetone) extract and in all the cases significant differences were noticed. The brine shrimp lethality effect of the above mentioned extracts also found promising and the seed extract was found to offer the highest mortality of the nauplii after 30 min, 24h and 48h of exposures respectively. According to the intensity of the activity it could be arranged in the following order: seed > leaf stem wood extract. The anitbacterial activity of A. pavonina extractives collected in petroleum ether, acetone, chloroform and methanol of leaves, seed and stem wood tested against 15 bacteria (6 Gram-positive bacteria, S. aureus, B. cereus, B. megaterium, B. Subtilis, S. lutea, S. –β-haemolyticus and 9 Gram-negative bacteria, S. typhi, S. dysenteriae, S. shiga, S. sonnei, S. boydii, E. coli, Klebsiella sp., P. aeruginosa, Proteus sp.) at concentrations of 50 and 200μg/disc along with a standard antibiotic, Ciprofloxacin 30μg/disc. The in vitro screening for antimicrobial activity was carried out by using disc diffusion and micro broth dilution techniques. All the extracts showed significant inhibitory activity over the bacteria. The maximum diameter zone of inhibition 22 mm was recorded to chloroform fraction of the seed extract of A. pavonia. The susceptibility order of extracts were seed>leaf>stem. The antifungal activity of the A. pavonina extractives collected on the above chemical solvents were tested against seven pathogenic fungi (F. vasinfectum, A. fumigatus, A. niger, A. flavus, Mucor sp., C. albicans, P. notatum) at concentrations of 50 and 200μg/disc along with a standard Nystatin (50μg/disc). Chloroform fraction of leaf extract showed higher activity 19 mm zone of inhibition than stem>seed as well as the fractions of chloroform>petroleum ether. Among all the chloroform, methanol, petroleum ether and acetone extracts of the leaves, seed and stem wood of A. pavonina, only chloroform extracts of the seed and the stem wood were subjected to evaluate the minimum inhibition zones just depending on the intensity of activity. The MIC values of the chloroform extract of the seed was 256µg/ml against B. cereus; 128 µg/ml against S.-β-haemolyticus, S. dysenteriae and 64 µg/ml against Klebsiella sp. The MIC values of the chloroform extract of stem wood were 128 µg/ml against S.-β-haemolyticus; 64 µg/ml against B. megaterium, S. sonnei and 32 µg/ml against S. typhi. Methanol and chloroform extracts of A. pavonina is toxic and repellent to C. chinensis. This study found that extracts of A. pavonia was not toxic to, and did not reduce the offspring of Dinarmus basalis (Rond.), a larval-pupal parasitoid of C. chinensis. Plant extracts was also not repellent to D. basalis. In malathion, the higher percentage of suppression was 76.05% at 16 mg/cm2 at the introduction level of 2 pairs but 34–52% suppression occurred at 8–4 mg/cm2 at the introduction levels of 4, 8 and 12 pairs whereas 83.00% suppression was recorded at the introduction levels of 2 pairs at 2 mg/cm2 in case of chloroform treated seeds of green gram. The highest parasitism 23.70% occurred at the introduction levels 12 pairs at 8 mg/cm2 but lowest 8.30% at the introduction levels of 2 pairs at 16 mg/cm2 in case of malathion The combinations of methanol and chloroform extracts of A. pavonia and parasitoid reduced populations of C. chinensis. The overall assessment of toxicity of A. pavonina extracts individually and combinedly with parasitoid, D. basalis are very much promising and their efficacy on stored grain pests might have future to be used as a control agent or tool. It may open its possibility as a control agent for the insect pests as well.