Abstract:
The growing concerns over the environmental and health impacts of synthetic pesticides
have led to a search for natural alternatives in pest and pathogen management. This
study evaluates the antimicrobial and insecticidal properties of selected plant extracts
Vitex negundo, Psidium guajava, Syzygium cumini, Moringa oleifera, and Lantana
camara—against common pathogens and Carpophilus beetle. The antimicrobial
activity was tested against Bacillus spp., Escherichia coli, Aspergillus spp., and
Trichoderma spp. using the paper disc diffusion method, while insecticidal effects were
evaluated against Carpophilus spp. using a contact toxicity bioassay. Results showed
significant antimicrobial activity, with Vitex negundo and Psidium guajava exhibiting
inhibition values of 2.4 cm and 1.6 cm, respectively, compared to a standard control of
2.6 cm against Bacillus spp. Lantana camara and Syzygium cumini showed inhibition
values of 2.3 cm and 2.1 cm, respectively, compared to a standard control of 2.5 cm
against Escherichia coli. Syzygium cumini exhibited strong antifungal effects with a 2.1
cm inhibition zone compared to a standard of 2.4 cm against Aspergillus spp. while
Vitex negundo showed a 1.3 cm inhibition zone compared to 1.4 cm for Trichoderma
spp. Insecticidal assays revealed that Syzygium cumini and Lantana camara were
particularly effective, significantly reducing beetle survival rates. Statistical analysis
confirmed the significance of plant species and extract concentration on both
antimicrobial and insecticidal activities (p < 0.05). These findings suggest that these
plant extracts have potential as sustainable alternatives to synthetic pesticides, though
further research is needed to explore practical field applications.
