Rhizoglyphus tritici

The present study was conducted to evaluate the susceptibility of Rhizoglyphus tritici against the comparative potential of ether extracts from Azadirachta indica, Eucalyptus sp., Citrullus colocynthis, Allium sativum, Nicotiana tabacum, Curcuma longa, Nerium indicum, Syzygium aromaticum, Ocimum tenuiflorum and Cassia fistula. The whole trial was executed under laboratory conditions with five concentrations from T1-T5 (0.5%, 1%, 2%, 4% and 8%), and four exposure periods (7, 14, 21 and 28 days). The percentage inhibition of mite population was both time-dependent and concentration-dependent. All the plant extracts exhibited significant acaricidal potential for adult mite as compared to control. The significant population inhibition percentage trend was observed of C. longa 91%, 95.54%, 94.97% and 97.46% and S. aromaticum 88.06%, 92.17%, 95.27% and 96.67% followed by C. fistula 92.03%, 93.27%, 93.22% and 92.07% while least population inhibition percentage was observed of N. tabacum 84.70%, 85..08%, 90.70% and 93.14% after 7, 14, 21 and 28 days. The median lethal concentrations were also calculated for all extracts, and it was observed that S. aromaticum was highly toxic to mites at lowest concentration 0.128, 0.028, 0.006 and 0.005 followed by C. longa 0.071, 0.036, 0.027 and 0.016 while least toxicity was observed in C. colocynthis 0.047, 0.030, 0.009 and 0.009 against R. tritici, and lethal concentration (LC50) decreased with an increasing time of exposure of the R. tritici to the ether extract. It was concluded that acaricidal potential of plants is directly proportional to time exposure and during first and second week C. fistula and S. aromaticum followed C. longa but suddenly after two weeks acaricidal potential of S. aromaticum was boost up and it was concluded that C. fistula, S. aromaticum and C. longa proved to be more effective gainst stored grain mites as compared to the others plant extracts. Perhaps, this new study will provide the basis for further investigation in order to develop new and safer acaricides in field conditions.