Causal Agent:
Fungus (Fusarium oxysporum f.sp. momordicae)
| Characteristic Symptoms: | |
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Affected plants show yellowing of leaf veins and wilting. |
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Vascular discoloration of infected stem and roots are important diagnostic symptoms. |
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One-sided wilt may also occur. |
| Conditions for Disease Development: | |
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The pathogen is soil-borne and is host-specific (i.e., infects only bittergourd). |
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The pathogen is disseminated primarily by movement of infested soil and plant debris.
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Infection occurs through the root, primarily in the area of elongation, and is aided by wounds created by insect/nematode feeding.
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The disease is most severe in light, sandy, slightly acidic soils (pH 5.0-6.0) with low to moderate soil moisture.
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Optimum soil temperature for disease development is at 20-27°C.
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The pathogen may be seed-borne.
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| Management and Control: | |
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Avoid planting in contaminated land or area with previous history of high FW incidence or do not plant bittergourd on the same area for a minimum of 5-7 years.
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Remove wilted plants including roots as soon as symptoms are observed to minimize spread of disease.
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Control root-knot nematode and root-feeding insects since they may help in disease establishment and spread.
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Use resistant/moderately resistant varieties, if available.
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Use resistant rootstock in grafted seedlings.
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Increase the soil pH by liming and reduce nitrogen level in the soil.
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Biofumigation of soil using chopped mustard leaves can help reduce inoculum level in the soil.
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| References: | |
| Compendium of Cucurbit Diseases (1996) by the American Phytopathological Society | |
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