Severity of root rot (Rhizoctonia solani and Rhizoctonia bataticola) of cowpea (Vigna unguiculata L.) was reduced by 42.7 and 42.0%, respectively over control following the application of 10 μg/g Mn as manganese sulphate. Reduction in disease incidence was associated with increased levels of polyphenol oxidase (PPO), peroxidase (PO) and total phenols. PO activity was several times more as compared with PPO‐specific activity and increased markedly after infection either with R. solani or R. bataticola. Contrary to PPO and PO, the specific activity of catalase declined sharply. Infection also caused an increase in the content of reducing sugars, Cu, Zn and Mn but a decrease in o‐dihydric phenols, flavanols, total soluble sugars, non‐reducing sugars and Fe contents. It is suggested that Mn at the rate of 10 μg/g soil can be used to manage the root rot of cowpea.

Clusterbean seedlings growing in soil inoculated with Rhizoctonia were treated with either 5 or 10 ppm Cu 2+ and Mn 2+ . Soil was inoculated by pretreatment with 250 mg (wet weight) of Rhizoctonia inoculum. A similar set of plants was maintained in uninoculated soil. Root rot incidence of plants treated with Cu 2+ 5 ppm, Cu 2+ 10 ppm, Mn 2+ 5 ppm and Mn 2+ 10 ppm was 26.6, 30.5, 11.8 and 29.2% less than the inoculated control, respectively. Inoculation with Rhizoctonia reduced chlorophyll, non-structural carbohydrate and in vitro dry matter digestibility (IVDMD) content compared with uninoculated ones. Oxidative enzymes activities (polyphenol oxidase, peroxidase, phenylalanine ammonia lyase and tyrosine ammonia lyase), crude protein, phenolic content, structural components (acid detergent fibre, cellulose and lignin), silica, macronutrients and micronutrients increased in inoculated seedlings and this increase was further heightened by the Cu 2+ 10 ppm treatment compared with the Cu 2+ 5 ppm, Mn 2+ 5 ppm and Mn 2+ 10 ppm treatments in response to fungal invasion. It was concluded that the Cu 2+ 10 ppm treatment may be an effective soil nutrient to provide enhanced resistance of clusterbean plants to root rot (fungal) diseases.

Kevwords: Okra, wilt, seed treatment, fungicides Wilt disease of okra (Abelmoschus esculentus (L.) Moench) caused by Fusarium oxysporum f. vasinfectum (Atkinson) Snyder and Hanson is a serious problem in certain areas of India. It may occur both at seedling and adult plant stages (3). Plant mortality to the extent of 40% was recorded in some fields in surveys conducted during 1988-89 in Haryana State. Isolations from samples collected from these fields yielded I? oxysporum. Therefore, an experiment was

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