New Approaches in Controlling Red Spider Mite Tetranychus urticae Koch on Tomato Plants with Reference to Genetic Mutations Associated with Pesticides

Abstract

Tomato Solanum lycopersicum L. (Family: Solanaceae) is considered one of the most important vegetable crops. Egypt is the fifth greatest producer of tomatoes in the world,531,115 Fa. of the crop grown annually, and an average productivity of 8105260 tons (FAO2013). Tomato production for fresh consumption is the most important source of income for small producers in several region of country. However, this vegetable crop is often severally damaged by many phytophagous pests (insects and mites). In Egypt, the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is become one of the most important pests on many greenhouse and filed vegetable corps, especially Solanaceae and Cucurbitaceae which can build to high population densities and cause serious damage to tomato plants. The two-spotted spider mite T. urticae is highly polyphagous and has been recorded to feed from over 1100 plant species, among them tomato (Dermauw et al. 2012).The application of synthetic acaricides are the most widely methods used for controlling T. urticae. One of the major problems in the control of T. urticae is their ability to rapidly develop resistance to many important acaricides after only a few applications because of the frequent use of pesticide, (Van Pottelberge et al. 2008). Several groups of insecticides have been used to control T. urticae, such as organophosphates (OPs) and carbamates, targeting acetylcholinesterase, pyrethroids and avermectins, targeting the voltage-gated sodium channel and glutamate-gated chloride channels, etoxazole and bifenazate targeting chitin synthase 1 and cytochrome b, respectively. (Helle 1962 and Van Leeuwen et al. 2009). Many resistance mutations associated with target site of pesticides include, G119S,A201S, T280A, G328A and F331W in acetylcholinesterase gene (ace); L1024V, A1215D,F1538I in the voltage-gated sodium channel gene (VGSC); G314D and G326E in glutamategated chloride channel genes (GluCls); G126S, I136T, S141F, D161G, P262T in the cytochrome b (cytb) and I1017F in the chitin synthase 1 gene (CHS1), (Van Leeuwen et al.2008, Tsagkarakou et al. 2009, Van Nieuwenhuyse et al. 2009, Khajehali et al. 2010, Kwon et al. 2010a, b and c, Dermauw et al. 2012, Van Leeuwen et al. 2012 and Ilias et al. 2014).To reduce these problems, it is necessary to minimize the chemical control. Synthetic pesticides have been used less frequently, consumption rates dropped 61% by (FAO 2001),but the market share remains high. In contrast, the consumption of botanical and biological products had increased 69% by (FAO 2001). In recent years, the use of plant-derived chemical compounds has increased, reaching 7.6% of the world market (FAO 2001 and Yu 2008).Induced response in plants is one of the important components of pest control in agriculture, and has been exploited for regulation of pest herbivore population, (Howe and Jander 2008, Sharma et al. 2009 and Agrawal 2011). Direct defenses are mediated by plantcharacteristics that affect the herbivore’s biology such as mechanical protection on the surface of the plants (e.g., hairs, trichomes, thorns, spines, and thicker leaves) or production of toxic chemicals such as terpenoids, alkaloids, anthocyanins, phenols, and quinones) that either kill or retard the development of the herbivores, (Hanley et al. 2007). Indirect defenses against insects are mediated by the release of a blend of volatiles that specifically attract natural enemies of the herbivores, (Arimura et al. 2009).Induced resistance could be exploited as an important tool for the pest management to minimize the use insecticides in pest control (War et al. 2012). Plants respond to herbivory through various morphological, biochemicals, and molecular mechanisms to counter/offset the effects of herbivore attack (War et al. 2012). Most of the plant defense responses against insects are activated by signal transduction pathways mediated by Jasmonic acid, Salicylic acid, and ethylene (Gill et al. 2010 and Shivaji et al. 2010). A broad spectrum of defensive responses are induced by jasmonates that include antioxidative enzymes, proteinase inhibitors (PIs), volatile organic compounds (VOCs), alkaloid production, trichome formation, and secretion of extra floral nectar (EFN) plays an important role as plant indirect defence (Mao et al. 2007, Dickens 2006 and Pauwels et al. 2009). Most studies on conservation biological control of T. urticae focus on predators (Fejt and Jarosik 2000, Heikal and Fawzy 2003, Heikal et al. 2003, El-Saiedy et al. 2008, Sarwar et al. 2011 and Afifi et al. 2013a). These predators are frequently responsible for maintaining spider mite populations below damaging levels and play an important role in their natural control (Croft and Luh 2004). The compatibility of two entomopathogenic fungi, Beauveria bassiana and Paecilomyces fumosoroseus, in combination with plant extracts, garlic-pepper,along with the predatory mites. Phytoseiulus persimilis and Neoseiulus californicus were evaluated by (Numa-Vergel et al. 2011). It provided safe environment resulted in reduction in pesticides application for about 60% for tomatoes and 70% for cucumbers, (Granges and Leger 1998).This study covered the following points in a trial to reach an integrated control for red spider mite, T. urticae on tomato plants by means of decreasing the effects of genetic mutations associated with the frequent use of synthetic pesticides.