Abstract
Isolation from orange trees infected with branch wilt showed the presences of Hendersonula toruloidea Nattras as potential pathogen , Seven fungicides were used in vitro in the following concentration 50,100,150mg/L Al the fungicides caused significant inhibition growth of mycelium .According to bioassay technique of H.toruoloidea culture filtrate which includes young shoot cutting and shortage in calculate water leakage. It was clear that culture filtrate caused shoot cutting wilt after one and totally dried after three days and this culture filtrate also caused water leakage in orange shoot cutting .Host range of H.toruoloidea include the following citrus species Lemon(C.limon)limetta (C.limetta)SourOrange (C.sinensis),Grapefrute(C.paradisi)&Mandarin (C.deliciose).
