Biochemical response in phosphine resistant and susceptible adult beetles of Trogoderma granarium to the sublethal dose
Different pesticides and fumigation are used for stored grain pests because they are causing huge damage to stored grains world especially in tropical regions. In the present study, effect of phosphine is being evaluated on Khapra bettle (Trogoderma granarium) which is a very serious pest in stored grain godowns of Pakistan. For this purpose, the LC50 of phosphine against adults of two different strains of T. granarium collected from different cities of Punjab like Lahore and Faqeerwali were determined by FAO method. On the basis of LC50 Lahore strain was considered as resistant strain whereas Faqeerwali strain as susceptible strain. Resistant and susceptible adults of these two strains of T. granarium were exposed to sub-lethal dose (LC30) for 20 hours to evaluate different enzymes such as AcP, AkP, amylase, ChE, trehalase, ALAT, ASAT, ICDH, LDH and metabolites viz., glucose, glycogen, free amino acids, protein and total lipids. In susceptible populations all enzymes activities were enhanced after treatment with phosphine except for ASAT and ChE while resistant beetles significantly raised (with respect to their controls) the activities of AcP, Akp and amylase. Phosphine treatment on resistant adult beetles caused depletion of glycogen and trehalose and glucose contents increased by 54%. Total lipids, protein and FAA increased in both populations. Carbohydrates increased in phophine the induction of the major enzymes under the present experimental condition.