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Subject: Entomology × Author: Harpreet Kaur Cheema × End date: 2013 × Start date: 2011 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    EVALUATION OF INSECTICIDE RESISTANCE PROFILE IN Spodoptera litura (FABRICIUS) POPULATIONS THROUGH BIOLOGICAL, BIOCHEMICAL AND MOLECULAR DIAGNOSIS
    (PAU Ludhiana, 2013) Harpreet Kaur Cheema; B. K., KANG
    Evaluation of insecticide resistance profile in Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) populations was done through biological, biochemical and molecular diagnosis. Population from Sangrur was found to be the least susceptible for most of the insecticides, except for chlorpyriphos, chlorantraniliprole and novaluron which were least toxic to population from Bathinda, and pyridalyl which was least toxic to population from Ludhiana. Population from Hoshiarpur was found to be the most susceptible for all insecticides except acephate and pyridalyl to which Bathinda population was most susceptible. Thiodicarb among the conventional group of insecticides and chlorantraniliprole among the newer insecticides were found to be the most toxic against all the test populations. The synergistic effect of TPP (6.16- fold), PBO (3.72- fold) and DEM (1.73- fold) in the least susceptible population suggested the involvement of esterases and mixed function oxidases in providing resistance to various insecticides. Synergistic effect of PBO (6.21- fold) on the fenvalerate- selected population followed by TPP (5.74- fold) and DEM (1.89- fold) indicated the possible role of mixed function oxidases, esterases and to some extent glutathione S- transferases in imparting resistance to pyrethroids in S. litura. Multiple detoxification enzymes and AChE insensitivity were found to be involved in imparting resistance in S. litura towards various insecticides. Selection with fenvalerate increased the activities of MFOs, esterases and GST by 1.84, 1.73 and 1.3 times in S. litura proving their role in pyrethroid-mediated resistance. Activities of MFO, esterases and insensitivity of AChE can be used as biochemical tools for monitoring insecticide resistance in S. litura. RAPD markers established the presence of inter and intra population variations that might be related to insecticide resistance. Alignment between COI sequences of fenvalerate- selected (SGR-Sel) and susceptible types (SGR) identified existence of a single base/ nucleotide polymorphism at position 421 represented by substitution of T in SGR-Sel with C in SGR type. Based on this polymorphism, COI based specific primers were developed, tested and validated for differentiating amongst these S. litura types.