STUDIES ON POST HARVEST DISEASES OF APPLE AND THEIR MANAGEMENT
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Date
2018-03
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UHF,NAUNI
Abstract
ABSTRACT
The present study was conducted to assess yearly losses due to biotic spoilage of apples and to develop methods
of post harvest management of apple fungal decays including cultural, physical, biological and chemical ones; and their
integration to evolve a workable, eco friendly control strategy to increase shelf life of apple fruits. In different fruit markets
surveyed in Himachal Pradesh, total losses due to apple decay varied from 7.80 to 21.93 per cent. Fourteen different types
of post harvest fungal pathogens were found associated with rotting of apple fruits in Himachal Pradesh. Blue mould rot due
to P. expansum was found to be the foremost cause of post harvest rot of apple with a mean per cent incidence of 4.73 and
9.19 in Shimla and Solan districts, respectively. The susceptibility of Scarlet Spur was found to be highest followed by
Golden Delicious with mean per cent rotting of 63.40 and 63.07 per cent, respectively. Tydeman’s Early Worcester was
found to be most tolerant to all the rot causing fungi. Minimum fruit rotting of Starking Delicious apples was observed in
fruits picked at 106 DAFB (12.81%) and also those picked during early morning hours (16.34%). Precooling treatment with
HIWC (ice water and calcium chloride) for 30 min was found most effective with 82.26 per cent control of fungal decay.
Treating apples in water at 48˚C for 3 min was highly effective in controlling various fungal rots under study with control of
70.79 per cent. UV exposure of 15 min was highly effective (65.04%) in controlling various fungal rots under study. Neem
oil (1%) as skin coating provided complete control of all the fungal decays under study. The next effective skin coatings
were eucalyptus, cinnamon and clove oil at 1 per cent concentration with 99.21, 98.70 and 97.93 per cent disease control,
respectively. Impregnation of fruit trays with Botanical Formulation 2 (BF2) at 10 per cent concentration provided 97.67
per cent control of all the test fungi. Cow urine was most effective in providing 79.21 per cent growth inhibition of test
fungi under study. Overall maximum growth inhibition of all the test fungi (71.97%) was recorded with T. hamatum
followed by the yeast isolate (66.63%), B. subtilis (64.98%) and T. harzianum (62.43%). Sodium ortho-phenylphenate
(SOPP) at 1 per cent concentration was most effective in checking the fungal decay under study. Under in vitro conditions,
mancozeb (0.1%) was the most effective fungicide providing 84.83 per cent growth inhibition. The efficacy of mancozeb as
dip treatment at 0.1 per cent concentration was again judged to be significantly superior followed by 0.05 per cent
carbendazim with per cent control of 95.97 and 92.35 per cent. Preharvest spray of mancozeb (0.3%) was highly effective in
checking all the test fungi under different type of storage for 6 months. 1-methyl cyclopropene (MCP) fumigation of apple
fruits immediately after harvesting was most effective in checking the test fungi under study providing 89.60 per cent
control. In integration experiment, minimum rot incidence and per cent fruit rotting were observed in fruits treated with
combination T7 i.e. Mancozeb preharvest spray (0.3%) + HIWC + Bacillus subtilis + Neem oil (1%) + BF-2 impregnated
trays followed by T6 and T8. CA storage was highly effective in checking fungal rotting of Starking Delicious apples
followed by refrigerated storage and air-cooled storage. Among different treatments, maximum mean firmness (14.17
lbs/sq.inch), minimum TSS (9.24 ˚Brix), minimum total sugar content (7.66%), maximum total phenol content (694.59
mg/Kg) and maximum titratable acidity (0.26%) was recorded in fruits treated with combination T7. Minimum mancozeb
residues (4.86 mg/Kg) were reported in fruits stored in ambient conditions of Shimla, followed by air-cooled storage (5.40
mg/Kg), CA storage (7.13 mg/Kg) and refrigerated storage (7.14 mg/Kg) after 45 days. Irrespective of different types of
storage conditions, maximum residues (10.10 mg/Kg) were recovered on the initial day (0th day) of storage whereas,
minimum (2.69 mg/Kg) at 45th day of storage with half life of 24 days.
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