Causal Agent:
Root-knot nematodes (Meloidogyne incognita)
| Characteristic Symptoms: | |
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Infected plants appear chlorotic, stunted, necrotic or wilted especially during periods of moisture stress and high temperatures. |
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Galls or knots are formed on the roots measuring 1-10mm in diameter or larger depending on the nematode species and gall location in the root system. |
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Severely infected root system are malformed with shortened and thickened individual roots suppressing root branching and growth. |
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Intensive galling reduces root efficiency resulting in permanent wilting, premature defoliation and plant death. |
| Conditions for Disease Development: | |
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J2s which are the infective stage of the root-knot nematode are most active at soil moisture levels of 40-60% of field capacity. |
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They are most abundant causing serious problems to their hosts in sandy soil with good drainage. |
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Plants stressed physically or by biological factors are more susceptible to attack and damage of nematodes. |
| Management and Control: | |
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Use resistant varieties, if available. |
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Crop rotation with non-hosts crops. |
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Grow crops that are antagonistic to nematodes like marigold to reduce population of plant parasitic nematodes. |
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Long fallow periods, deep plowing, solarisation are also effective in reducing nematode population. |
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Use of nematicides like fenamiphos, carbofuran, oxamyl and aldicarb. |
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