Radhakrishnan, N VNayana, KKAU2017-08-312017-08-312015http://krishikosh.egranth.ac.in/handle/1/5810030128Banana (Musa spp.), being the fourth most important food after rice, wheat and maize products, it tolls up as a major fruit crop of India. Among the various diseases of this crop, Sigatoka leaf spot disease is a serious factor limiting the productivity of the same. It causes losses by reducing the functional leaf surface of plant, which results in small bananas that fail to ripen and may fall. Hence a field study entitled “Integrated management of Sigatoka leaf spot disease of banana caused by Mycosphaerella musicola R. Leach ex J.L. Mulder” was conducted at Coconut Research Station, Balaramapuram with an objective to study the effect of Pseudomonas fluorescens, the secondary nutrient magnesium, the micronutrients, zinc and boron and new generation fungicides on growth, incidence of Sigatoka leaf spot disease and yield of banana as intercrop in coconut gardens. The parameters studied were grouped into four main categories namely disease factors, weather factors, biochemical or physiological responses and growth and yield characteristics. Studies were conducted to assess the effect of treatments on disease intensity and incidence revealed that, there was a reduction in disease factors during all months with respect to treatments in contrast with the control plots. In both the case of disease incidence and disease intensity all the treatments were significantly superior over control. With respect to the disease incidence studies, it is clear that fungicide alone or combination treatments of the same along with Micronol or Mg + Zn + B is highly effective to lower the disease incidence. Disease intensity studies indicated that, foliar spray of new generation systemic fungicides such as tebuconazole, propiconazole or the contact fungicide copper hydroxide gave better disease suppression of yellow Sigatoka disease. The pathophysiological studies of chlorophyll content revealed that there was an increase in chlorophyll content in all the treatments. Mainly the combination treatments of fungicides with Mg + Zn + B and Bio control agent (PGPR mix II). There was an increase in magnesium content, boron content and zinc content in all combination treatments when compared to the alone treatments and from the untreated plants. But in case of protein content analysis, there was a decrease in total protein content in treated plants, mainly in the plants treated with systemic fungicides. The activity of defense related phenol and OD - phenol study exhibited that, there was an increased phenol content in treated plots. Effect of treatments on plant height and plant girth indicated that all treatments resulted in higher height and girth observed in control at harvest stage. Study of the other growth parameters like number of leaves and number of functional leaves also resulted in the same conclusion that a 1.5 to 2 fold per cent increase in number of functional leaves at harvest stage where as 0.5 fold per cent increase in number of leaves in all the treated plants when compared to the absolute control. The study of yield per plant revealed that, 0.5 to 1 fold per cent increase in bunch weight. The other yield parameter studies revealed that the total number of hands, fingers per bunch and number of suckers were more than in untreated plots whereas, the number of days took for bunch emergence and bunch maturity was comparatively lower in case of treatment with maximum bunch yield, T5, Mg + Zn + B plus tebuconazole @ 0.1%. The maximum number of days took for bunch emergence and bunch maturity was in absolute control. Hence the results of integrated management for banana Sigatoka disease with respect to disease management, yield attributing characteristics were effective in the field trial that conducted. The economic analysis also revealed that the best inorganic treatment is application of Mg + Zn + B plus tebuconazole (0.1%) which recorded the highest yield, net income and benefit cost ratio which is followed by Mg + Zn + B plus PGPR (20 g l-1) under organic treatments. For the integrated management of banana Sigatoka leaf spot disease (caused by M. musicola R. Leach ex J.L. Mulder) in humid tropical southern zone of Kerala, the best treatment was found to be; Mg (2 g l-1) + Zn (3 g l-1) +B (2 g l-1 ) plus tebuconazole (0.1%) with aspect of maximum disease suppression, disease intensity reduction and highest yield.ennullThesis