Ra Ximhai (Sep 2012)
Use of natural enemies and biorational pest control of corne
Abstract
A general analysis of the potential use of natural enemies and biorational insecticides for control of main pests of corn in thestate of Sinaloa is presented. A discuss on their composition, dosage, toxicity and type of effect on beneficial organisms(natural enemies and pollinators) is too included. The work revealed that is possible implement the use of these natural enemies and products for the control of neonate larvae of Spodoptera frugiperda fall armyworm (J. E Smith) with Nomuraea rileyi (Farlow) (Samson); against thrips Frankliniella occidentalis (Pergande) using the nematodes Steinernema riobravis (Cabanillas and Poinar), S. feltiae (Filipjev) and Heterorhabditis bacteriophora (Poinar) at doses of 10,000 IJ (4x10 ~ IJ/m); against the corn silk fly Euxesta stigmatias (Loew) encouraging the natural parasitism of Spalangia sp., while for the cutworm Agrotis ipsilon (Hufnagel) can be with spinosad (soluble concentrate) at doses of 0.123 kg a. i, and to the corn earwormHelicoverpa zea (Boddie) using the analog of methoxyfenozide molting hormone (24%) at 144 mg of a. i/L. The biorational control agents that not affect significantly to the natural enemies were the nucleopoliedrosis virus SfMNPV and SeMNPV; N. rileyi and Isaria fumosorosea (Wize); Bacillus thuringiensis (Berlinier); the azadirachtin (neem) and parasitoids. In the case of products of chemical synthesis: Spinosad, oxymatrine and bifenthrin showed high rates of mortality in the control of corn pests, so these are considered as of high and moderate risk to Aphis mellifera (L.) bees, the methoxyfenozide presented relatively low toxicity to natural enemies. In general, biorational products have repellent effect on larvae and adults of these insects, inhibit feeding and induce molting, also causing deformities and impede the development and growth, too interfere with sexual intercourse and copulate, reducing the oviposition, as well as cause sterility of adults, so these may also constitute a risk to beneficial organisms. However, we concluded that these products are less toxic than chemical pesticides to nontarget organisms, which eventually will be used with less risk of environment contamination in the control of corn pest in theagricultural region of northern Sinaloa.
