Effects of cypermethrin, deltamethrin and nimbicidine on population of <i>tribolium castaneum</i> (Herbst)

Abstract

Context: Pyrethroid insecticides and plant products can control the population of stored products insect pest Tribolium castaneum (Herbst).  

Objective: To determine the influence of cypermethrin, deltamethrin and nimbicidine individually and combinedly on the population of T. castaneum.  

Materials and Methods: One hundred T. castaneum adults (1:1) aged 10-20 days old were introduced into a beaker containing 100 g of either fresh or treated flour and kept in an incubator (30 ± 0.5ºC). After 4 months the total number of adults were assessed. Pupae and fourth to sixth instar larvae were also counted.  

Results: The population of T. castaneum was significantly (P<0.01) reduced by cypermethrin, deltamethrin and nimbicidine alone and their combinations over a period of 4 months than control. Among chemicals, cypermethrin alone at 2 ppm was the most effective in reducing the total population (PRC 63.44), followed by 5 ppm dose of deltamethrin (PRC 55.81) and 24 ppm dose of nimbicidine (54.39). In case of adult population the maximum reduction was in 24 ppm of nimbicidine (PRC 76.17). However, the combined dose of cypermethrin, deltamethrin and nimbicidine significantly (P<0.01) reduced the pupal and adult population. The lowest larval population was found in the treatment of cypermethrin (2 ppm) (PRC 61.51) followed by the deltamethrin (5 ppm) (PRC 51.17).  

Conclusion: In cypermethrin and deltamethrin the reduction of population was probably due to mortality of different life stages of T. castaneum but in case of nimbicidine it was most probably due to its growth regulatory activity.  

Keywords: Cypermethrin; Deltamethrin; Nimbicidine; Population; Tribolium.

DOI: http://dx.doi.org/10.3329/jbs.v18i0.8780

JBS 2010; 18(0): 84-87