This is in continuation to my previous
post on Diseases of apple: White root rot Management. In today’s post we are
going to discuss about the Premature Leaf Fall.
Description: Pre
mature defoliation in all apple-growing states of Himachal Pradesh, Jammu and
Kashmir, Uttarakhand and North- east in recent years. The disease is caused by
fungus, Marssonina coronaria and
Alternaria mali resulting in mid-season pre mature defoliation. Its affects
all the commercial cultivars grown in India. Disease appears both on leaves and fruit. Dark
brown patches having pin head fruiting structures, develop on upper surface of
leaves varies from 5-10 mm diameter typical blotch symptoms. Various small and
large blotches depending on the climatic conditions after the initiation of
disease coalesce to form large dark brown blotches and the surrounding areas
turn yellow. The yellowing advances towards petiole end, developing abscission
layer and induce mid season defoliation. It reduces the fruit size and delays
ripening. The fruits are poorly coloured and lack flavour. Irregular necrotic
blotches on mature leaves characterize the disease. The blotches develop
suddenly and increase rapidly during June-July (high humidity and high temperature)
and cause yellowing and defoliation. The mid-season defoliation may be
responsible for poor growth and development of fruiting buds and result into
low productivity in ensuing year. Infection of the fruit appears in the
harvested fruits and dark brown depressed spots are most common on ‘Golden
Delicious’.
In coming post we shall be discussing
about the disease cycle of premature leaf fall.
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