FUNGAL DISEASE (Pre & Post - Harvest): CROWN ROT

CROWN ROT

Symptoms:

It is the most serious post harvest problem, especially where dehandling and boxing of fruit is not carried out in modern and centralized air-conditioned plants.

• A number of fungi are associated with crown disorder viz.   Colletotrichum musae (C.musae), Fusarium spp, Vetricullium theobromae (V.theobromae) and Botryodipiodia theobromae (B.theobromae).
• Blackening of the crown tissue occurs initially at the cut surfaces, but the rot may spread into the crown during transportation.
• Rotting is most noticeable if transit time exceeds 7 days and high incidence of disease may cause premature ripening of the fruits.

Control:

Dip or spray the harvested hands with 0.05% Bavistin.

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Posted in: 49. Fungal disease - Crown Rot

FUNGAL DISEASE (Pre & Post Harvest): CIGAR END ROT

CIGAR END ROT

Symptoms: 

Two fungi are associated with this disease viz. verticillium theobromae (V.theobromae) & Trachyspaera fructigena (T.fructigena). The fungus attacks at the flowering stage and its incidence is spotted during rainy season. Spray of Bavistin @ 1 gm/lt or Kavach (Chlorothalonil) @ 1gm / lt of water on the bunches is recommended.:

•   As the fruit develops, the infection spreads slowly along with the fruit growth  causing blackening of the skin. 

•   Tip of the infected fingers later gets covered with a powdery mass of spores resembling grey ash end of a cigar. 

Control: 

• Removal the untransformed flowers after the finger emergence. 
• Spray the bunches with Bavistin @ 1 gm/lt or Kavach (Chlorothalonil) @ 1gm / lt of water once in 15 days and later on cover the bunches with polythene sleeve. 

 

 

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Posted in: 48. Fungal disease - Cigar end rot

FUNGAL DISEASE (Pre & Post - Harvest): ANTHRACNOSE

ANTHRACNOSE

Symptoms: 

It is a serious pre and post harvest disease caused by Colletotrichum musae.

• Infection starts at the distal end of the young harvested fruits as minute black spots, spreading slowly to the whole fruit which eventually turns black and shriveled. It spreads to the other hands through the stalk affecting the    whole bunch. 
•  On ripening fruits, the symptoms appear as sunken  brownish lesions which get covered  by salmon colored    fungal sporulation. Lesions expand faster and coalesce giving a black appearance to the fingers.

Control:
Spray bunches twice with 0.25% Indofil M-45 or 0.25% Kavach at 15 days interval.

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Posted in: 47. Fungal disease - Anthracnose

FUNGAL DISEASE (Foliar) : PANAMA WILT.

PANAMA WILT (OR) FUSARIUM WILT 

Symptoms:

 Panama wilt is caused by Fusarium oxysporum f.sp. cubense. Both external and internal symptoms are present in the affected plant.

• Symptoms commence as yellowing of older leaves and progresses to youngest leaf. 
• The affected leaves collapse gradually at the petiole and hang around the Pseudostem. 
• At advanced stages of the disease development, splitting of the Pseudostem occurs coinciding with the collapse of crown.

Wilt is a vascular disease and attacks the conducting tissues. A transverse section of the Pseudostem/leaf base/rhizome exhibits presence of wilt fungus in the form of purplish or brownish-black discoloration of the vascular bundles that disrupts the translocation of nutrients leading to collapse of foliage and cessation of the growth of the crown.

Control: 

• Provide good drainage in field wherever water stagnation occurs. 
• Bimonthly drenching and weekly spray with 0.1% Bavistin for 2-3 weeks on and around the infected plants. 
• Uproot severely infected plants and burn them. Liming of the infected soil at the site of uprooted plants, helps in reducing the survival of fungus.

Click this link for: 

A highly successful method for effective control of Panama Wilt (or) Fusarium wilt in Banana plants.

     

 Regards,

A.Vishnu Sankar

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Posted in: 43. Fungal disease - Panama or Fusarium Wilt

FUNGAL DISEASE (Foliar) : CORDANA LEAF SPOT.

CORDANA LEAF SPOT 

This disease is caused by Cordana musae. (C.musae).

Symptoms: 

1. The fungus produces individual brown lesions which are upto several centimeters in length with a dark margin and surrounded by a chlorotic halo. 
2. The lesions enlarge in size, coalesce, and produce necrotic areas. Ultimately, the leaves turn brown and dry out. 

Control Measures:

Spray 0.25% Kavach or 0.25% Indofil M-45 or 0.1% Tilt at 15 days interval.

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Posted in: 46. Fungal disease - Cordana Leaf Spot

FUNGAL DISEASE (Foliar) : YELLOW SIGATOKA (Sigatoka Leaf Spot)

YELLOW SIGATOKA (Sigatoka Leaf Spot):

Symptoms:

In India, it is caused by Cercospora musae (C.musae), the asexual form of Mycosphaerella fijiensis.

• Symptoms start as tiny, yellow broken streaks followed by the development of brown spindle shape lesions in the streaked areas with a yellowish halo.
• Slowly lesions darken and become elliptical brown spots with a grayish centre demarcated by a well defined brown or black border.
•  These lesions coalesce and enlarge causing death of leaf blade.
• This results in reduced photosynthetic area and eventually reduced harvestable yield coupled with accelerated fruit maturity and immature ripening.

 Control Measures:

• Keep the orchard clean, remove the diseased leaves and burn outside the plantation. 
• Make proper drainage of water to avoid water logging. 
• Contact fungicide Mancozeb(2.5gm / lt) or Calixin (2ml/lt) with Teepol (Sticking agent ) must be sprayed during initial symptoms. 
• During severe infection Bavistin @ 2gm / lt or 0.1% Tilt can also be used and repeat at 15 days interval. 
• Increment in Potassium in the fertilizer dose and 6 feet X 6 feet spacing in plantation minimizes the infestation.

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Posted in: 45. Fungal disease - Sigatoka Leaf Spot (Yellow Sigatoka)