STUDIES ON THE MANAGEMENT OF FUNGAL FOLIAR DISEASES OF BLACKGRAM [VIGNA MUNGO (L.) HEPPER] IN GUNTUR DISTRICT OF ANDHRA PRADESH
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Date
2017
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Publisher
Acharya N.G. Ranga Agricultural University
Abstract
Investigations on “Studies on the management of fungal foliar diseases of
blackgram [Vigna mungo (L.) Hepper] in Guntur district of Andhra Pradesh” was
carried out in the Agricultural College Farm, Bapatla, Guntur district, Andhra
Pradesh during rabi, 2016-17.
A survey was conducted during rabi, 2016-17 in Guntur district of Andhra
Pradesh to record the occurrence and severity of fungal foliar diseases at 30-35,
40-45 and 50-55 DAS. Two mandals were selected based on the preceding year
blackgram cultivation statistics, in each mandal two villages and in each village two
fields were surveyed. There was no record of any fungal foliar disease at 30-35
DAS. At 45-50 DAS, overall mean PDI of Corynespora leaf spot (Corynespora
cassiicola) PDI was 31.89% and at 50-55 DAS it was 67.27%. The overall mean
PDI of Cercospora leaf spot (Cercospora canescens) at 40-45 DAS was 28.88% and
at 50-55 DAS it was 53.70%. The overall mean PDI of powdery mildew (Erysiphe
polygoni) at 40-45 DAS was 22.85% and 63.22% at 50-55 DAS.
During rabi, 2016-17, Corynespora leaf spot PDI of six genotypes viz., LBG
752 (r= -0.635), LBG 709 (r=-0.656), KU-15-6 (r= -0.637), LBG 20 (r= -0.640),
LBG 791 (r= -0. 648) and LBG 685 (r= -0.654) showed a significant negative
correlation with mean minimum temperature. Cercospora leaf spot PDI of three
genotypes viz., LBG 752 (r= -0.642), LBG 709 (r=-0.660) and T9 (r= -0.636)
showed a significant negative correlation with mean minimum temperature. Powdery
mildew PDI of six genotyes LBG 752 (r= -0.654), KU-15-3 (r=-0.655), LBG 709
(r=-0.664), KU-15-6 (r= -0.678), LBG 791 (r= -0.650) and PU 31 (r= -0.633)
showed significant negative correlation with minimum temperature. Regression
analysis for PDI of Corynespora leaf spot, Cercospora leaf spot and powdery mildew
revealed that maximum temperature and minimum temperature influenced the
development of the disease in all the genotypes.
Out of 16 genotypes (including check) evaluated for their reaction to fungal
foliar diseases, two genotypes T9 and LBG 645 were moderately resistant to
Corynespora leaf spot. The genotype LBG 645 was rated as moderately resistant to
Cercospora leaf spot. Ten genotypes viz., LBG 20, LBG 791, LBG 685, LBG 645,
LBG 787, PU31, LBG 790, KU-15-13, LBG 792 and T9 were categorized as
moderately resistant to powdery mildew.
Studies on the management of fugal foliar diseases with fungicides have
revealed that two sprays of Azoxystrobin 23 SC @ 0.05% has recorded significantly
lowest severity of Corynespora leaf spot (53.52%). Carbendazim 50 WP @ 0.05%
has significantly reduced the Cercospora leaf spot severity (33.75%). Trifloxystrobin
25% WG + Tebuconazole 50% WG @ 0.05% has absolutely controlled (0%) the
powdery mildew. Highest seed yield (9.33 q ha-1
), highest test weight (6.40 g),
highest B:C ratio (1.72), lowest per cent seed discolouration and per cent shrivelled
seed were recorded with Azoxystrobin 23 SC @ 0.05%.
Description
D5445
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