در شرايط آزمايشگاهي )CHILO SUPPRESSALIS WALK( جداشده از كرم ساقه خوار نواري برنج BEAUVERIA BASSIANA)BALS(VUILL اثر آفت كش هاي مصرفي درمزارع برنج بر روي جوانه زني اسپور و رشد شعاعي قارچ

Effect of common chemical pesticides on germination and mycelial Radial growth of Beauveria bassiana (Bals.) Vuill. isolated from rice stem borer,Chilo suppressalis (Walker) under laboratory conditions

Child suppressalis is a major pest in rice field of north of Iran. Beauveria bassiana was isolated from overwintering larvae during 1999-2000. B. bassiana is one of the biological control agents of this pest. The fungus activity was not observed at two months of agricultural season in the year. May be due to the chemical pesticides which are applied from time of planting to heading stage in rice field. The different concentrations of 0, 0.2, 1, 5, 25, 125 and 625 mg /kg from active ingredient of Benomil, Edifenphos,Tricyclazole (fungicides), Diazinon, Carbaryl (insecticides), Butacholor and Oxadiazone (herbicides) on the fungus were studied. The effectiveness of chemical pesticides were examined in factoriol test in Randomized Compeletely Design. Statistical analysis showed that all of pesticides had effects on B.bassiana. Among of chemical pesticides only Benomil reduced mycelial growth and spores germination in concentrations above 25 and 125 mg/kg, respectively. But others pesticides postponded growth of fungus. The results revealed that the fungicides had the most inhibition than other pesticides, also effectiveness herbicide of Butacholor and insecticide of Diazinon were more than others two herbicide and insecticide. Consequently, chemical pesticides that are applied in rice field are one of factors that to prevent B. bassiana activities.