PHYTOPHTHORA DRECHSLERI براي مبارزه بيولوژيكي عامل بوته ميري طالبي STREPTOMYCES ارزيابي استرين هاي

Evaluation of Streptomyces Strains as Biocontrol Agents for Cantaloup Wilt, (Phytophthora drechsleri)

Thirteen strains of Streptomyces were evaluated as a potential biological agent for control of cantaloup root rot that caused by P. drechsleri. Eight strains of Streptomyces were obtained from soil surrounding the roots of cucurbit plants in Varamin area and five strains were obtained from soil surrounding roots of capsicum in glasshouse. Dual culture and cellophane overlay technique were used for in vitro assay. In dual culture and cellophane overlay techniques, all strains of Streptomyces inhibited the growth of P. drechsleri. The inhibition rate varied among strains of Streptomyces and ranged from 33.01% to 93.07% in dual culture and from 36.18% to 100% in the cellophane overlay method. Adding a mixture of 13 Streptomyces strains (5 g) prepared in 1 kg wheat bran to soil infested with mixture of six P. drechsleri isolates increased seedling survival by 43.07% (P < 0.05). Also seed treatment with 7.3 x 10ʹ cfu per seed increased plant stand by 50.21% (P < 0.01). Average population of Streptomyces in potting mix decreased at a uniform rate.