Studies on blue mould rot of aonla (Emblica officinalis Goerth.) caused by Penicillium islandicum (Sopp.)
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Date
2017
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CCSHAU
Abstract
Aonla or Indian gooseberry (Emblica officinalis Goerth. Syn. Phyllanthus emblica L.) is one
of the most important indigenous fruit of Indian sub continent. The blue mould rot caused by
Penicillium islandicum adversly affects the fruit quality, quantity and ultimately reduces the marketable
value. In India, nearly 20 – 35 per cent of perishables are lost due to post harvest diseases. Keeping the
above facts in view, the present study was undertaken to survey orchards and terminal markets of Hisar
and Rewari districts of Haryana, screen different varieties, study the various biochemical and
epidemiological factors, and to develop suitable strategies through use of fungicides, chemicals,
bioagents and botanicals for management of blue mould rot of aonla. Fortnightly survey carried out
from November to January, 2015-16 revealed that blue mould rot incidence was higher in terminal
markets of Hisar and Rewari Distt as compared to orchards in the respective locations. Varietal
screening revealed that least blue mould rot intensity was found in Desi (2.67%) and Kanchan (3.33%)
while maximum rot was observed in Chakaiya (50.00%) and Banarsi (49.33%) aonla varieties. In
biochemical studies, it was observed that total soluble solids, total phenol, peroxidase and polyphenol
oxidase activity increased in diseased fruits in comparison to healthy fruits, while ascorbic acid and
acidity decreased over time in both healthy and diseased fruits. The epidemiological studies revealed
that the injury of the aonla fruits was found to be a pre-requisite for infection. A minimum number of
50 spores/ml was necessary for disease initiation whereas maximum blue mould rot incidence was
noted at 30ºC and 100 per cent relative humidity. Relative efficacy of five chemicals against blue
mould rot tested in vitro and in vivo at 0.2, 0.5 and 1.0 M concentrations revealed that boric acid at 1.0
M concentration was the best to inhibit growth in pre- and post-inoculation after five and ten days of
inoculation in both test conditions. In vitro and in vivo bio-efficacy studies involving ten plant extracts
at 5, 10 and 20 per cent concentration for the management of blue mould rot indicated that treatment
with neem leaf extract exhibited maximum mycelial growth inhibition (91.88%) at concentration of 20
per cent resulting in minimum pre- and post-treatment disease intensity of 7.31 and 8.13%,
respectively, after five days of inoculation. Similar trend was also recorded in pre and post treatment
after ten days of inoculation. Five bioagents were also studied for control of Penicillium islandicum by
dual culture technique. Significantly highest per cent growth inhibition of P. islandicum was noted in
Trichoderma harzianum (83.06%). T. harzianum with disease intensity 6.0 and 6.31 per cent was found
most efficient antagonist in reducing the blue mould rot with disease intensity of 34.48 and 39.75% in
pre- and post- inoculation, respectively, after five days of inoculation. Similar results were also
obtained in pre- and post-treatment after ten days of inoculation.
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