Evaluation of indigenous botanical insecticides against whitefly of sweetpotato

Among the many species of whitefly that attack plants, the most predominant is the greenhouse whitefly, Trialeurodes vaporium Westwood, and the SP whitefly, Bemisia tabaci. At the Northern Mindanao Integrated Agricultural Research Center (NOMIARC), whitefly became a major problem when potato was grown in the screenhouses since 2000. These insect pests hampered seed producton at NOMIARC because insecticides encouraged population build-up. With this scenario, Tatoy et al. (DA-NOMIARC) studied other alternative control measures against whitefly that were effective, environment-friendly, and had no adverse effects on health. These alternative control measures are the 13 botanical insecticides found in Region X such as tubli roots (Derris elliptica), wild sunflower (Tithonia diversifolia) leaves, madre de cacao or kakawate (Gliricidia sepium) leaves, makabuhay or panyawan (Tinospora crispa) vines, lagundi leaves, luyang dilaw or dulaw (Curcuma longa) rhizomes, neem (Azadiractha indica) seeds, tobacco (Nicotiana tabacum and N. rustica) leaves, eucalyptus leaves, hot pepper (Capsicum frutescens) leaves, adelfa leaves, and atis seeds.

Findings

• Early incidence of whitefly caused severe damage that reduced the yield of potato.
• Thirteen botanical insecticides found in Region X were evaluated against whitefly. Extracts of these plants sprayed at 5% concentration reduced the population of whitefly.
• Extracts of tobacco leaves, hot pepper leaves, rhizomes of dulaw, and roots of tubli had fast-acting effects both in the laboratory and screenhouse.
• Slow-acting poison was obtained from the extracts of neem leaves and seeds, madre de cacao leaves, vines of makabuhai, and wild sunflower leaves.
• ROI of treatment using neem leaf extracts was 39.2%, while that of makabuhay vines was 36.4% and tobacco leaves, 28.2%.

Source: PCARRD, 2004. Highlights 2003, Los Baños, Laguna.

http://pcarrd.dost.gov.ph/phil-organic/R&D%20pest%20management/ipm%20whitefly%20sweetpotato.htm