Trogoderma granarium is a menacing pest of stored grain products. Phosphine is an effective insecticide against stored-product pests, but over time, the pest has developed resistance to phosphine due to its continuous use. The present study investigates phosphine resistance levels in insect pests across five districts of Punjab. The metabolic profile of resistant populations of the beetle was analyzed. The present investigation revealed that Layyah was the most resistant population to phosphine among all collections. Metabolic analysis showed that contents of glycogen, lipids, and trehalose reduced significantly whereas glucose, soluble proteins, and free amino acids increased remarkably in resistant populations. The insect used its energy reserves to satisfy the higher metabolic needs to cope with the stress caused by exposure to phosphine. It suggests that calculating the lethal dose of insecticide could overcome the infestation caused by the stored grain pests.

Keywords- insecticide, metabolic profile, phosphine resistance, Trogoderma granarium