Abstract

AIL-CATZIM, Carlos Enrique et al. Insecticidal and repellent effect of extracts of Pluchea sericea (Nutt.) on adults of Bemisia tabaci (Genn.). Rev. Chapingo Ser.Hortic [online]. 2015, vol.21, n.1, pp.33-41. ISSN 2007-4034.  https://doi.org/10.5154/r.rchsh.2014.09.038.

The use of repeated insecticide applications in agricultural crops to control Bemisia tabaci (Genn.) has resulted in resistance problems and environmental pollution. Inputs from plant species are an alternative to reduce this problem. Plants are a source of bioactive chemicals that can have insecticidal, repellent, attractant, anti-feeding or growth regulator effects. The aim of this study was to determine the insecticidal and repellent activity of ethanolic, acetonic and aqueous extracts of both leaves and stems of Pluchea sericea (Nutt.) on Bemisia tabaci (Genn.). The LC₅₀ of each of the extracts on adult whiteflies was estimated using bioassays with the residual film technique. Also, the repellent effect from the LC₅₀ of each extract was evaluated, and the repellency index (RI) was estimated. If RI = 1 the effect is neutral, if RI <1 the effect is repellent and if RI > 1 the effect is attractant. The leaf-ethanol, leaf-water and leaf-acetone extracts showed the lowest LC₅₀ values of 700, 1,190 and 1,250 ppm respectively, indicating high efficiency on B. tabaci, followed by the stem-water extract and lastly the stem-ethanol and stem-acetone extracts showed the least effectiveness. All extracts had repellent action, regardless of the solvent and plant organ at 24 and 48 h. However, water-based extracts may have greater potential for whitefly control in integrated pest management systems because they presented insecticidal and repellent effects, and the solvent is harmless and inexpensive.

Keywords : Cachanilla; whitefly; lethal concentration; repellency index; botanical extracts.

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