Induction of Systemic Acquired Resistance in Mulberry against Leaf Spot (Phloeospora maculans) Disease and its Biochemical Effect in Leaves
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Date
2014
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Publisher
SKUAST Kashmir
Abstract
Investigations on “Induction of Systemic Acquired Resistance in Mulberry against Leaf Spot (Phloeospora maculans) Disease and its Biochemical Effect in Leaves” were carried out during 2011-2012. Fungus causing leaf spot was isolated from infected leaves on potato dextrose agar medium. It was observed that culture was very slow to grow and sporulated only under high humidity conditions at high temperature (25-35oC). The optimal temperature for fungal growth was ascertained 25±1oC. The pathogenicity of the fungus was proved by following Koch’s Postulates. The typical diseased spots were developed on potted plants within 10-14 days. In green house, seven SAR chemicals along with fungicide carbendazim at three different concentrations were evaluated against the leaf spot. All the tested SAR chemicals reduced the incidence and intensity significantly at all the concentrations, but least incidence and intensity was observed at higher concentrations of all the tested chemicals except calcium chloride @ 15 mg/ml, where phytotoxity was observed. Disease incidence ranged from 12.59 to 51.97 per cent at 45 days after sprouting and 13.21 to 64.78 per cent at 70 days after sprouting. Disease intensity ranged from 10.48 to 42.30 per cent at 45 days after sprouting and 12.70 to 51.52 per cent at 70 days after sprouting. Minimum disease incidence and intensity with maximum per cent disease control was observed in BABA @ 2.0 mg/ml was proved most effective SAR chemical having minimum incidence 12.59 to13.21 per cent and intensity 10.48 to 12.70 per cent with highest disease control 75.22 to 75.33 per cent both at 45 and 70 days after sprouting respectively fallowed by carbendazim @ 0.5mg/ml with disease control 71.58 to73.03 per cent. Similar results were obtained from field also. Disease incidence ranged from 10.47 to 34.04 per cent at 45 days after sprouting and 13.05 to 51.32 per cent at 70 days after sprouting. Disease intensity ranged from 7.05 to 28.03 per cent at 45 days after sprouting and 9.29 to 36.99 per cent at 70 days after sprouting. Minimum disease incidence and intensity with maximum per cent disease control was observed in BABA (2.0 mg/ml) fallowed by carbendazim (0.5 mg/ml), INA (2.0 mg/ml) and salicylic acid (1.5 mg/ml). Among all elicitors tested, β-Amino butyric acid induced greater systemic resistance in mulberry. Biochemical parameters viz., crude proteins, total carbohydrates, chlorophyll-a, chlorophyll-b and total chlorophyll, moisture and ash content decreased in infected leaves, where as all these parameters increased in SAR treated and healthy leaves in comparison to diseased leaves. In case of diseased leaves the phenols shows substantial increase as compared to healthy leaves and SAR treated leaves. Nitrogen, phosphorus and potassium content also decreased in diseased leaves as compared to SAR treated and healthy leaves.
Description
PhD of SKUAST Kashmir
Keywords
Sericulture, Biochemical, Mulberry, Leaf spot