Antimicrobial and insecticidal activities of Solanum torvum Sw. (Solanaceae) and Smilax zeylanica L. (Liliaceae) on Cryptolestes pusillus (Schon.) (Coleoptera: Cucujidae)

Abstract

The bioactivity and insecticidal activities of different parts of two plants, viz. leaf, stem, root and inflorescence of Solanum torvum and leaf, stem and root of Smilax zeylanica were assayed against gram positive and gram-negative pathogenic bacteria, fungi, brine shrimps and the insect, red flat grain beetle, Cryptolestes pusillus were investigated. Toxicidal activity of the chloroform and methanolic extracts of leaf, stem, root and inflorescence of S. torvum and leaf, stem and root of S. zeylanica on some microbes (Gram-positive bacteria: Bacillus cereus, Bacillus megaterium, Bacillus subtilis, Staphylcoccus aureus, Sarcina lutea, Streptococcus-���� haemolyticus and Gram negative bacteria: Salmonella typhi, Shigella dysenteriae, Shigella shiga, Shigella sonnei, Shigella boydii, Escherichia coli, Klebsiella species (K.sp.), Pseudomonas aeruginosa, Proteus sp.; and fungi: Aspergillus fumigatus, Aspergillus niger, Aspergillus flavus, Vasin factum, Candida albicans, Mucor sp., Fusarium oxysporum and Colletotrichum falcatum) were determined. The bioactivity of the extracts on the brine shrimp, Artemia was also observed. In addition, the toxicity of the extracts on the beetle, C. pusillus was· determined. Methanolic extracts of root of S. torvum and S. zeylanica exhibited higher toxicity on the microbes, brine shrimp and the beetle. All the extracts of the test plants showed toxic effects on the microbes tested by inhibiting their growth. The findings of the investigation elucidated that the Methanolic extract of two test plants possessed strong residual toxic effects on C. pusillus that may have promising potential in controlling storage pest management programmes.