Fumigant toxicity of volatile synthetic compounds and natural oils against red flour beetle Tribolium castaneum (Herbst) (Coleopetera: Tenebrionidae)

Two synthetic volatile compounds (benzaldehyde and propionic acid) and two volatile oils (camphor and eucalyptus) were screened individually and in combinations against different life stages of Tribolium castaneum. Benzaldehyde–propionic acid combination recorded the maximum larvicidal (LC50= 78.03 µl/l) and adulticidal (LC50 = 30.60 µl/l air) activities and this treatment was also effective in reducing the oviposition, egg hatchability and adult emergence of T. castaneum. Among the individual treatments benzaldehyde was found to be more toxic to adults (LC50= 34.07 µl/l) and larvae (94.15 µl/l). The individual treatments of camphor and eucalyptus oils were less effective, but combinations of benzaldehyde–camphor oil were found to be effective. Benzaldehyde–propionic acid combination recorded 99.3% adult mortality inside a 1 m^3 wooden cage after 15 days and this mixture can be used as a fumigant in store houses.