Plantation Crops

Leaf rust in coffee and its management

• It is an oriental leaf disease. It is considered as one of the seven classic diseases of the world since,

  1) It ruined the economy of Sri Lanka rendering it bankrupt and

  2) It changed the social habit of people from coffee drinking to tea drinking.

• Cause : Hemelea vastatrix
• There are 39 physiological races of Hemelea vastatrix arer reported of which 23 occur in India. 1868: Leaf rust disease first time observed in Sri Lanka 1869: Observed in India.
• Arabica coffee is more susceptible than robusta and excelsa. Season of occurrence : Throughout the year. Peak period : August to November

Symptoms of coffee leaf rust disease
Defoliation: Initially small pale yellow spots appear on the lower leaf surface ---- turn ---- orange yellow (Due to powdery mass consisting of uredospores) on the entire surface of leaves due to coalescence of spots -- finally necrotic spots and defoliation.
Barren & dead twig: During favourable year for disease spread the damage is so devastating that, only barren and dead twigs could be seen devoid of cropping branches for the succeeding year.
Crop loss: Crop loss due to this disease may go up as high as 70 per cent.

Management or control measures for leaf rust

1) Replacement with resistant material/tolerant material: Replace the susceptible material in the plantation.

2) Chemical control: Bordeaux mixture @ 0.50 per cent concentration.
Alternative fungicides: Systemic, curative and eradicant fungicides can also be used Viz.,

a) Plantvax ( Oxycarboxin) 20 EC @0.03 per cent a.i (1.50 ml per litre of water)

b) Bayleton 25 WP @0.02 % a.i ( 0.80 g per liter of water)

Spray schedule

i) Pre blossom – February – March

ii) Pre monsoon – May – June

iii) Post monsoon – September – October