Ecofriendly Management of Fungal Foliar Diseases of Groundnut (Arachis hypogaea L.)
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Date
2018-06
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University of Agricultural Sciences, Dharwad
Abstract
Groundnut is an important oilseed and food crop of India. An experiment was
conducted in the Bioresource farm, IOF, UAS, Dharwad during kharif 2017 to know the
relationship of weather factors with fungal foliar disease development and to manage
them organically.
The results from survey indicated that, the severity of early leaf spot (ELS), late
leaf spot (LLS) and rust ranged from 20.00 to 42.22 PDI, 17.78 to 66.66 PDI and 17.78
to 60.88 PDI respectively. Maximum severity of fungal foliar diseases was recorded in
Dharwad and minimum in Bagalkote district.
Epidemiology studies revealed that early sowing on 22nd June 2018 escaped the
rust infection while late sowing on 25th July 2018 escaped leaf spot infection. Spore
load was highest during 38th standard meteorological week (SMW) for ELS and 40th
SMW for LLS and rust. The correlation studies of PDI with weather parameters
indicated a significant positive correlation with cumulative rainfall (CRF) and
cumulative number of rainy days (CRD), irrespective of the dates of sowing. Regression
studies indicated that fungal foliar disease development was significantly positively
affected by CRD. In vitro spore germination studies revealed that all the botanicals evaluated
(Adhatoda vasica, Azadirachta indica, Pongamia pinnata) were more effective at five per cent concentration against fungal foliar diseases. In vivo studies revealed that, minimum disease severity was recorded in
consortia of bioagents (Trichoderma harzianum – Pseudomonas fluorescens – Bacillus
subtilis) treated plots which was on par with wettable sulphur. All the plant growth and
yield parameters were positively influenced in all the treatments when compared to the
untreated control. The highest yield (41.51 q/ha), highest net returns (Rs. 1,21,712) and
B:C ratio (3.75) was recorded in the consortia of bioagents treated plots.