natural-products-in-plant-pest-management

198 D.B. Olufolajisolvents, particularly methanol, ethanol, acetone, hexane, petroleum ether,diethyl ether, chloroform or methyl chloride, have been used (Table 9.3)( Olufolaji, 2006; Ofuya, 2009).Mixed formulationsUsing herbal mixtures for crop protection is traditional with some farmers(Kitch et al., 1997). Efficacy of mixed formulations of medicinal plant powdersfor stored-grain protection has been subjected to empirical verification(Ogunwolu and Idowu, 1994; Dawodu and Ofuya, 2000; Emeasor et al., 2007).Overall pesticidal activity of each material was not mitigated by mixing thetwo against the test insects. However, synergistic or additive effects wouldbe desirable to enhance efficacy. Lale (2002) reported that mixing differentessential oils from plants, in some cases, provided much better control thansingle use (Table 9.3) (Ofuya, 2009; Olufolaji, 2006, 2008).Use of adjuvantsOfuya et al. (2007) have demonstrated the possibility of using organicflours from yam, cassava and plantain as diluents in the formulation ofinsecticidal dusts from buds of Eugenia aromatica and dry fruits of Piperguineense. Filtrates that are obtained in the preparation of aqueous neemextracts can be improved after dilution by adding brown sugar, whichimproves the adherence of the filtrate on leaves and other plant parts(Jackai, 1993).9.5 Attributes of the Botanicals Versus ConventionalSynthetic PesticidesThe botanicals have an array of good attributes over the synthetic pesticides,which is encouraging because the low technicality required for use hasenabled the developing world to achieve desirable advantages from theiruse. Ahmed and Stoll (1996) highlighted the various problems caused bysynthetic pesticides including toxicity to non-target organisms such as manand beneficial macro/microbes, pollution in the agro-ecosystem and developmentof resistance by the target organisms. However, the botanical pesticidespossess some special characteristics and may be used as betteralternatives in managing different agricultural pests:●●●The materials used for the production of the botanical pesticides areeasily available since they are usually weeds in the agro-ecosystem.Botanical pesticides are usually inherently less harmful than conventionalpesticides.Botanical pesticides generally affect only the target pest and closelyrelated organisms, in contrast to broad-spectrum conventionalpesticides that may affect organisms as different as birds, insects andmammals.