an investigation on effectiveness of some chemical and biological insecticides on diamondback moth, plutella xylostella l. (lep.: plutellidae)

diamondback  moth,  piute/la xylostella  l. is  a  major pest of cruciferous  crops worldwide.   it  out broke in cabbage   fields  of tehran province   in  1999 and   caused considerable   yield   losses.  seven treatments  including  biological   and chemical   pesticides   were used in   the field  test.  these   treatments were as follow:  consult  (ec i 0%) 0.4 kg/h & 0.5 kg/h, carbaryle  (wet able  powder  85%) 2.5  kg/h,  bth (iranian   product  as powder) i   kg/h & 2 kg/h, dipel~  (wet  able powder) 3  kg/h and  the control  in two factors  randomized  complete  block design  with split plot  combined  over times  in  four replicates.  the results  revealed  that  consult  0.4  kg/h, consult  0.5 kg/h, carbarylc  2.5 kg/h and  oipct®  3  kg/h  caused 79.09, 70.06,  70.01   and  65.77 percent larvae  mortality   respectively   and  were placed in  one  class  of duncan's multiple  range test. btll  i   and 2 kg/h  had  less  effect on  this pest,  and was placed  in  another class.  dipel  was also  more effective than  bti-1  on diamondback   moth larvae  in laboratory  bioassays.