STUDIES ON ROOT ROT OF OKRA (Abelmoschus esculentus L.) CAUSED BY Fusarium solani (Mart.) Sacc. AND ITS MANAGEMENT

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Okra (Abelmoschus esculentus L.) is an important vegetable crop, which was found to be suffering from root rot disease in moderate form in Visavadar taluka of Junagadh district, Gujarat state. (India) Isolation of diseased root portion on potato dextrose agar medium yielded a species of Fusarium. The Koch’s postulates were successfully proved by standard method. Based on morphological as well as pathogenicity test the fungus was identified as Fusarium solani. (Mart.) Sacc. F. solani was found to be external as well as internal seed borne in nature. Fungus was able to infect cotton, chilli, brinjal, bean and cowpea. Among the medias tested, Czapek’s medium was the best in either solid or liquid form for growth and sporulation of the fungus and hence was selected as the basal medium for further studies. Among the different systemic fungicides tested, carbendazim and propiconazole were found to be effective in inhibiting the radial growth as well as sporulation of the fungus and gave 95.75 and 87.59 percent inhibition, respectively. Among non systemic fungicides, thiram was most effective in inhibiting the growth (87.96 percent) as well as sporulation of the fungus followed by chlorothalonil (86.94 percent). While evaluating the various weedicides oxyfluorfen was observed effective in inhibiting the growth and sporulation and gave 77.25 percent inhibition. The minimum inhibition was observed in 2-4-D, (sodium salt) with an average of 31.25 percent. In the study of different nematicides the maximum growth and sporulation inhibition (68.95 percent) was observed in treatment of sebufos followed by dazomate with 44.10 percent. In evaluation of different insecticides prophanophose proved effective in reducing growth and sporulation and gave 94.35 percent inhibition, followed by monocrotophose and dicofol having 93.57 percent and 92.78 percent inhibition respectively. Cruiser was least effective (51.02 percent). In laboratory screening of bio-agents Trichoderma harzianum isolate I was observed to be a strong fungal antagonist by reducing the maximum growth (63.88 percent), followed by T. viride isolate I with (60.77 percent) growth reduction. Among the extract of various organic cakes used extract of mustard cake most significantly inhibited growth (49.26 percent), followed by extract of groundnut cake with 35.19 per cent inhibition In integrated disease control, soil application of mustard cake with carbendazim (0.1 %) and T. harzianum (20gm/pot) gave 83.33 per cent diseased control.