Efficacy of Mixture of Pesticides on the Mortality and Energy Reserves of a Stored Grain Pest Trogoderma granarium Everts
Efficacy of Mixture of Pesticides on the Mortality and Energy Reserves of a Stored Grain Pest Trogoderma granarium Everts
Tanzeela Riaz1, Farah Rauf Shakoori2,*, Hareem Mansoor1, Sana Khan1 and Mushtaq A. Saleem1
ABSTRACT
Trogoderma granarium has become one of the most destructive insect pests of many amylaceous stored products. Its control has become difficult due to the emergence of resistance against almost all the known insecticides and fumigants. The development of resistance can be delayed by using binary combinations of insecticides. Keeping in view the importance of synergism as well as the concerns about environmental hazards and emergence of resistance against these insecticides, the current project was designed to figure out the lethal concentration (LC50) of emamectin, abamectin and spinosad alone and in various conbinations such as abamectin:emamectin (1:1, 2:1, 3:1, 1:2 and 1:3) and abamectin:spinosad (1:1, 2:1, 3:1, 1:2 and 1:3) against two larval instars (4th and 6th) of MBDIN and Lahore populations of T. granarium. The LC50 of abamectin, emamectin and spinosad for 4th larval instars of Lahore population was 172, 185 and 196 ppm, respectively while LC50 of these insecticides against 4th larval instar of MBDIN population was 186, 192 and 198 ppm, respectively. Similarly, the LC50 of abamectin, emamectin and spinosad for 6th larval instars of Lahore population was 165, 180 and 174 ppm respectively, while LC50 of these insecticides against 6th larval instar of MBDIN population was 169, 184 and 179 ppm respectively. The abamectin was the most effective than emamectin and spinosad. Based on relative toxic unit, the 3:1 mixture of abamectin:emamectin showed higher toxicity among all the tested mixtures. The toxic effect of LC20 of this 3:1 mixture on soluble and total proteins, total lipids, glucose, glycogen, free amino acid and trehalose contents was also recorded. The results indicated that contents of glycogen, trehalose, total lipids, free amino acids, soluble proteins and total proteins were significantly deceased in both larval instars except the free amino acids that increased in 4th larval instar of both populations. The glucose contents increased in both larval instars of exposed groups of both populations with reference to unexposed group of the respective population. It is concluded that the mixtures of insecticides were more effective than the administration of insecticides alone to control T. granarium.
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December 2019
Vol. 51, Iss. 6, Pages 1999-2399
