Abstract
ABSTRACT Samples collected from different plants (Potato, Carrot, Pear) from many sources shown signs of infection with bacteria. The isolated bacteria causing each disease were identified seven isolates of Erwinia carotovoa var. carotovora and five isolates belong to E.chrysanthemi that isolated of potato and fore isolates of E.c.c that isolated of carrot and fore isolates of E.amylovora isolated of Pear E.c.c. and E.ch caused black stem disease in potato and E.c.c. caused Rut Root for carrot and E.a. caused fire Blight.Chalcon used as a method for resisting these diseases and have shown that chalcon (acetophenon benzayl dehyde) better than chalcon (aceto phenon para methoxy benzayl dehyde) in resisting thes diseases except E.amylovora which have better result in chalcon (aceto phenon Paramethoxy benzayl dehyde) in 5% concentration.
