Diseases of Fruit Plantation Medicinal and Aromatic Crops

Wilt disease

Causal organism: Fusarium spp.
Symptoms

• External: Yellowing, upward drooping of older leaves and leaf epinasty.
• Internal: Brownish black coloration and blocking of vascular bundles.
Etiology

• Mycelia septate, intercellular and produce intracellular haustoria.
• Asexual spores: micro and macro conidia borne in sporodochium.
• Sexual spores: ascospores
• Primary source of inoculum: Chlamydospore
• Secondary source of inoculum: micro and macro conidia.
• Spread: through irrigation water and soil.
Epidemiology

• Disease is favoured by a temperature of 28-30⁰c, sandy soil with acidic pH of 5.5-6.5 and optimum soil moisture.
Life cycle

• Perithecium is a sexual fruiting body bearing ascus, which produce ascospore when mature.These ascospores are blown by air and land on the host as a chance.
• It enters the host through natural openings and start the infection process.
• The host shows wilt symptoms & produces micro and macro conidia which again land on the hosts as the asexual life cycle continues.
• If conditions become adverse like high / low temperature, high / low relative humidity then it starts sexual life cycle.
• Plasmogamy, hook formation, crozier formation, karyogamy, meosis, mitosis takes place & produces lot of ascospores as observed in sexual life cycle.
Management

• Deep summer ploughing.
• Soil sterilization
• Uprooting & burning of infected plant.
• Neutralize the soil PH
• Mixing of recommended doses of N: P: K in the fields.
• Crop rotation to be followed.
• Use of Carbendazim solution (0.1%) for soil drenching
• Soil application of Trichoderma viridae, the bio control agent.