كليدواژه :
Nuclear polyhedrosis virus , Beet armyworm , virus production , كشاورزي , ويروس چندوجهي هسته اي , برگخوار چغندرقند , توليد ويروس , وزن لارو , larval weight
چكيده لاتين :
Although commercial formulations of nuclear polyhedrosis virus (NPV) to control beet armyworm larvae had been available for a long time, however, itʹs production remains limited to in vivo culture. Due to this limitation, optimizations of variables that will maximize virus yield are necessary. Three of these variables are larval weight, initial inoculum and food source. The larvae were separated into different instars based on measurements of head capsule widths. The bioassay with different weight groups and doses of 104,105,106 and 10ʹ PlB/ml of virus revealed that the 4th instar larvae reared on sugar beet leaf and treated with 106 P1B/ml fulfill the most appropriate conditions of virus production. To determine the effect of food source on virus yield, sugar beet leaf and semiartifrciai diet were used. The applied inoculum for 1st, 2nd, 3rd, 4th, and 5th instar larvae were (5,10,15), (20,25,30), (40,50,60), (70,80,90) and (100,110,120) PlB/mm2 of food surface respectively. Maximum mortality rate of infected larvae occurred at the prolonged period of latent time and this condition was suitable enough for maximum virus yield. A degree of maturation resistance was found to exist in the 6th instar larvae. The larvae which reared on sugar beet leaf, produced ca. ten-fold more viruses than the corresponding larvae that fed on the diet.
