natural-products-in-plant-pest-management

Antimicrobials to Prevent Biodeterioration of Grains 95exhibited antifungal activity against tested strains (Stojanovicet al., 2005).Organic solvent leaf extracts of two Moroccan Cistus L. species Cistusvillosus L. and Cistus monspeliensis L. (Cistaceae) used in traditional medicinewere tested for their antifungal properties against A. fumigatus. The extractsdiffered in their antifungal activities. C. villosus extracts exhibited higheractivity than C. monspeliensis (Bouamama et al., 2006).Antifungal activity of Trapa natans L. fruit rind, extracted in different solventswith increasing polarity was observed and 1,4-dioxan, chloroform,acetone, dimethylformamide, ethanol, and water did not reveal any activityagainst A. niger (Parekh and Chanda, 2007).4.3 In Vitro Evaluation of the Active Components for AntifungalActivity against Important Biodeterioration-causing FungiPlants possess unlimited ability to produce secondary metabolites and morethan 12,000 of them have been isolated, which is probably less than 10% ofthe total. Useful antimicrobial phytochemicals are phenolics and poly phenols,quinones, flavones, flavonoids and flavanols, tannins, coumarins, terpenoidsand essential oils, alkaloids, and lectins and polypeptides. Cowan(1999) has critically reviewed the antimicrobials of plant origin and has listedthe plants with antimicrobial activity.Many secondary metabolites have been identified and many more areyet to be discovered. There is growing evidence that most of these compoundsare involved in the interaction of plants with other species, primarilyin the defence of the plant from plant pests. Secondary compounds representa large reservoir of chemical structures with biological activity (Duke, 1990).This resource is largely untapped for use as pesticides.Considering the advantages of organic pesticides over synthetic pesticides,nowadays, attempts are made by many workers to screen plants forantimicrobial activity, isolate and characterize the bioactive compounds fromdifferent parts. Such attempts to isolate antimicrobials of plant origin andtest their efficacy against different storage fungi to prevent biodeteriorationof grains are, however, very few.The high terpene hydrocarbon content in the oils of chamomile, lavender,eucalyptus, and geranium are responsible for their antifungal activity againstA. niger and Aspergillus ochraceous (Lis-Balchin et al., 1998). Antimicrobialcompounds, such as 3-0-methylveracevine, 3-0-[3-(2,2,2,-trifluoroethoxy)]-5-(methoxybenzoyl) veracevine 3-0-(3,5-diiodobenzoyl) veracevine, 3-0-(3-thienoyl) veracevine, isolated from the seeds of Schoenocaulon officinaleshowed highly significant antifungal activity against A. flavus and A. niger(Oros and Ujvary, 1999).Mathekga et al. (2000) isolated an acylated form of a phloroglucinol fromHelichrysum caespititium. The structural elucidation revealed that the compoundwas 2-methyl-4-2’-4’(6’-trihydroxy-3’-(2-methylpropanoylphenyl)-2-0-enylacetate). This compound completely inhibited the mycelial growth