The effect of two Egyptian isolated bacteria Bacillus thuringiensis HD-120 and B.t HD- 187 were tested Under laboratory, semi field and field conditions. Under laboratory conditions the LC50s obtained 105 and 91 Ug/ ml after treated with Bacillus thuringiensis HD-120 and HD-187 respectively. The potency of the two bacterial strains recorded, 18438.09 and 21274.72IU/ mg respectively. When the tomato plant treated with both HD-120 and HD- 187 B. t, HD-120 and HD-187 the LC50 obtained 133 and 101 Ug/ml The potency of the two bacterial strains recorded, 22736.824 and 29940.594 IU/ mg respectively. Data the fields show that the weight of tomatoes significantly increased to 19.99±12.7 and 13.93±13.1ton/feddan when treated with B.t HD-120 and HD-187 respectively in El- Sharkia and El- Dakahlia as compared to 17.11±10.6 and 8.92±18.6 ton/feddan in the control. When the tomatoes treated with the isolate B.t, HD-187 the weight of tomatoes recorded 18.18±10.6 and 12.57±16.6 ton/feddan in the two corresponding areas.
