Abstract
Sunflower is a new emerging oilseed crop which can grown through-out the year. In West Bengal this crop mainly grow in rabi season which suffers many biotic stresses, out of which soil borne diseases are of great economic importance. A field study was conducted by AICRP on Sunflower, Nimpith Centre to identify the best management approaches to overcome the yield loss due to wilt of sunflower. It was observed that most of the fungal and bacterial antagonists tested were found effective against soil borne diseases in-vivo conditions. The isolates of fungal antagonists Trichoderma viride (Tv), and Trichoderma harzianum (Th) and one isolate of bacterial antagonist Pseudomonas fluorescens (Pf) were found very effective to control this seed borne disease when used as bio-agents. The above antagonists (bio-agents) with their combinations found highly effective against all the soil borne pathogens causing the sunflower wilt under in vivo conditions were used for seed, soil and seed+soil treatments to observe their effectiveness on seed germination, seedling emergence, early seedling growth and resistance of wilt incidence in sunflower cv. DRSH-1. Post studies further revealed that seed+seedling+soil application of the antagonists resulted in lesser wilt incidence compared to only seed or soil application of these antagonists resulting higher seed yield in farmer’s field. The lowest mortality of sunflower plants either in seedling stage or in mature stage also observed when the bio-inoculants were used in combination (T. harzianum+P. fluorescens (5.0g/lit 5.0g +5.0g/ kg of seed) and when the combination was used as seed inoculants and also used for spraying at the crown region before first and second irrigation. The data across of the years of study on demonstration fields, indicated that economic advantage in terms of the Benefit: Cost (B:C) ratio of the farmers under improved method of sunflower cultivation with seed treatments and application of bioinoculants results higher Benefit: Cost (B:C) ratio higher was recorded 1.41 (2014-15) and 1.45 (2015-16) which were much higher compared to conventional cultivation systems/ Farmer’s Practice, 1.06 (2014-15)-1.18 (2015-16). The conclusion of the present study is that T. viride, P. fluorescens and T. harzianum and their combinations have significant role on to effective management of sunflower wilt in West Bengal.
Highlights
In India, the sunflower is grown on about 7.0 million ha (2013-14) (Anonymous, 2016) and mostly grown in the states of Karnataka, Maharastra, Andhra Pradesh and Tamil Nadu with potential scope of growing in the non-traditional areas like West Bengal [1]
The results indicated that the growth of Trichoderma viride, Trichoderma harzianum, Pseudomonas fluorescens or their combination treated seedlings exhibited better result over the untreated ones for management of Sunflower wilt
The result of the three consecutive years of experiment i.e. in 2013-14, 2014-15 and 2015-16 it was revealed that all the bio-inoculants, either in single or in combination have significant contribution to reduction of sunflower wilt
Summary
In India, the sunflower is grown on about 7.0 million ha (2013-14) (Anonymous, 2016) and mostly grown in the states of Karnataka, Maharastra, Andhra Pradesh and Tamil Nadu with potential scope of growing in the non-traditional areas like West Bengal [1]. Management of stem rot of sunflower is a problem, since in the commercial hybrids and varieties resistance to this disease is not still available. There are very limited report regarding developing resistance source for effective management of the disease, [7]. In an effort to develop ecofriendly measures for the management of this disease, bioinoculants, such as different Trichoderma and Pseudomonas fluorescens species isolates were screened. Helienthii the causal agent of stem rot/wilt of sunflower. Trichoderma viride, Pseudomonas fluorescens and Trichoderma harzianum were used as bio-agents which is an eco-friendly and cost effective management of sunflower wilt. Trichoderma viride, Pseudomonas fluorescens and Trichoderma harzianum has been effectively used for preventing damping off disease of peanut caused by S. rolfsii and Rhizoctonia solani. Rolfsii; pv. helienthii to find out the most effective treatment(s) or bio-inoculant(s) (in single or in combination ) for the management of sunflower wilt and improvement in respect to yield and yield component and economics in sunflower and for their further evaluation to management of Sunflower wilt. (ii) To identify the superior treatment combination suitable for rabi season for minimizing the yield loss and to increasing in benefits to the sunflower growers in West Bengal
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