Diseases of fruit plantation medicinal and aromatic crops (2+1)

Panama wilt of Banana

The plants emerged from suckers growing out of diseased corms also wilt and die.
Causal organism: Fusarium oxysporum f.sp. cubens (E.F SMITH)
Panama wilt is one of the most devastating diseases of banana crop in the world being reported for the first time from Australia in 1874. In many countries banana trade was affected because of the wide spread occurrence of this disease.. It is a vascular pathogen and Rasthali, groups are susceptible.
Symptoms

• Fungal pathogen blocks the vascular system and causes wilting.
• Older leaves yellowing is the Initial symptom
• The infected plant shows yellowing of leaf blades, developing as a band along the margin spreading towards midrib
• The leaf wilts and the petiole buckles
• The leaf hangs between the pseudostem while the middle of lamina is still green.
• After four to six weeks, only the pseudostem remains, with dead leaves hanging round it. The cut stem smells like rotten fish
• Pseudostem splitting is common in Fusarium affected

Etiology
• Mycelium is septate, sporodochium is asexual fruiting body.
• Asexual spores are micro and macro conidia borne on sporodochium.
• Sexual fruiting body is the perithecium which produces ascospores in the ascus.
• Vegetative, resting structures are chlamydospores
Mode of spread and survival

Primary source of inoculum: The pathogen is both soil and water borne, spreads through infected suckers (rhizomes) and survives in soil as chlamydospores for long period.
• Primary spread occurs through infected rhizomes.
• Soil and water borne micro and macro conidia, serves as the secondary source of inoculum
Epidemiology
The disease is favoured by

• Soil temp of 28 -320c, Relative humidity-85-90%
• Acidic soil PH (5.5 to 6.0)
• Red loamy /sandy loam soil and presence of Susceptible host.
Management
• Always use healthy planting materials and collect planting material from disease free area.
• Rhizomes are treated with dung solution and smeared with Carbendazim powder.
• Use resistant varieties like Robusta and grand naine.
• Based on Soil PH apply lime@.100-150gm per plant. Select nematode free soil and follow drip irrigation.
• Chemicals- spray of carbendazim@1.0gm per lit (as soil drenching) or capsule (carbendazim) insertion to the base of the rhizome or injection of carbendazim @ 10g/lit. to the rhizome.
• Use of bio control agents-Pseudomonas fluorescens @ 60mg per capsule, each capsule applied near the corm or Trichoderma viride application to the soil along with FYM.