Efficacy of bioagents and fungicides against Phytophthora nicotianae infecting Crossandra

Phytophthora nicotianae causing a polycyclic soil borne disease infects a wide range of host plants belonging to different families all over the world. The foot and root rot disease of crossandra is a major setback for its cultivation in the country, wherever the crop is grown, causes huge loss to flower industry. Due to soil borne nature of the disease, management is a challenging process. Therefore, the bio-efficacy of the fungicides and bio-agents against Phytophthora nicotianae causing the root rot disease of crossandra was studeed. Ten different novel fungicides and bio-agents were screened against root rot disease under in-vitro condition. Of these, most of the systemic fungicides were found to completely inhibit radial growth of the fungal mycelium, whereas in case of bioagents, Trichoderma harzianum (84.19%) and Streptomyces viridobrunneus (81.44) was found to be most effective in reducing the mycelial growth inhibition of Phytophthora nicotianae.