Studies on Fungal Foliar and Fruit Diseases of Pomegranate (Punica granatum L.)
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Date
2016-08
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University of Agricultural Science, Dharwad
Abstract
The leaf/fruit spot of pomegranate caused by various organisms such as Colletotrichum gloeosporioides, Alternaria alternata, Sphaceloma punicae, Cercospora punicae, Drechslera sp. and Phomopsis sp., take a heavy toll on the crop. Major pomegranate growing districts of Karnataka were surveyed for the prevalence of fungal diseases. Survey revealed that anthracnose and Cercospora disease severity was highest in Gadag and Belagavi districts respectively in mrig bahar. Scab disease severity was highest in Koppal district during ambia bahar. By standard tissue isolation, microscopic observation and by Koch postulates, the pathogens viz., C. gloeosporioides, C. punicae and Pestalotiopsis algarionsis were proved.
Morphological and cultural characters of 30 isolates of C. gloeosporioides were studied. Majority of the isolates produced white mycelia, regular margin, coarse texture with fluffy growth and white to grey pigmentation. The isolates were identified as Colletotrichum sp. by sequencing the amplified ITS rDNA region, and analyzed in NCBI BLAST program.
An attempt was made to study the effect of weather parameters on progress of anthracnose. During ambia bahar of 2015 and hasta bahar of 2015-16 RH was significantly positively correlated with disease.
Variety Ganesh showed resistant to C. gloeosporioides as accumulation of defence enzymes like PPO (0.074 absorbance/min/g), PAL (0.028) and Peroxidase (0.029) were high in it.
In vivo experiment over two locations revealed that captan 2 g/lit followed by vitavax power 1g/lit followed by Iprobenphos 1 g/lit followed by cabriotop 2 g/l followed by captan 2 g/l followed by vitavax power 1 g/l followed by Iprobenphos 1 g/lit followed by cabriotop 2 g/lit of water at 15 days interval gave per cent anthracnose disease reduction of 6.80 and also increase in fruit yield (11.87 kg/tree).