Potential of kaffir lime (Citrus hystrix) leaf extract as biopesticide in improving pre and post-harvest quality of chili (Capsicum annuum)

Purpose: Chilli production in Malaysia is declining due to production problems such as pest and diseases which cause plants to become stunted, unhealthy, and damaged. To overcome this problem, most farmers prefer using chemical fertilizers and pesticides due to their fast reaction and effectiveness. In long term, application of these chemicals input may lead to an environmental damage and human health problems. To conserve our nature, the use of natural input in agriculture is highly recommended.

Research Method: This study was conducted to identify the potential of plant extract, namely kaffir lime in increasing the plant productivity and reducing the severity of pests for chilli trees. The study was performed by spraying the chilli trees with 25, 50, and 75% (v/v) kaffir lime extracts. Controls consisted of plants without any treatment as negative control and plants applied with a commercial chemical pesticide as positive control.

Findings: Results indicated that there were significant differences (p<0.05) between treatments with respect to all parameters including pre-harvest (plant height and pest severity) and postharvest (fresh weight and number of chilli pods) parameters except for the stem and crown diameter, soluble solid concentration, fruit firmness and colour measurement of chilli. The results found that chilli plants sprayed with 25% kaffir lime extract had the lowest pest infestation. Moreover, application of the 25% kaffir lime extract had produced the heaviest weight of chilli fruits and the highest number of chilli pods compared to other treatments including the positive control (chemical pesticide). Therefore, it was concluded that 25% kaffir lime extract produced healthier chilli plants, higher yield and better quality of chilli.

Originality/ Value: Limited number of studies are available on eff ectiveness of kaffir lime-based insecticides. Therefore, this study was conducted as an effort towards understanding the versatility of kaffir lime leaves extraction as an alternative pesticide on chilli plants’ pre- and postharvest performance.