Rao et.al.
economic choice presently no such resistant varieties
Field evaluation of effective fungicides against
are available in India (Shashikanth et al. , 2007).
purple blotch of onion
Management of disease using fungicides is efficient
The experiment was laid out in randomized block
strategy; however indiscriminate use of fungicides
design with 13 fungicide treatments and untreated
leading to development of resistance in pathogen
control with 4 replications. The general agricultural
population demands new molecules to combat the
practices being followed for onion were adopted for
disease. Hence, the present study was undertaken
all the experimental plots. FYM (30 t/ha) and NPK
to determine the field efficacy of fungicides for the
(Urea: 65 kg, single Super phosphate: 366 kg, murate
management of purple blotch disease of onion.
of Potash: 46.5 kg) were added to all the plots. Onion
Materials and Methods
seeds @ 3g/plot (cv. Arka Niketan) were directly
sown in 15cm wide rows in a plot measuring 1.5 sq.
The study was conducted during kharif in two
mt. Forty days after sowing; thinning of seedlings
consecutive years of 2012 and 2013 at Indian Institute
was carried out to maintain a spacing of 10cm
of Horticultural Research, Hessaraghatta, Bangalore.
between plants and 15 cm between rows. The field
was kept free from weeds by frequent hand weeding
Fungicides
during the early stages of the crop. A total volume
A total of 13 fungicides including 5 non-systemic
of 500 litres spray solution was used per hectare.
fungicides, 4 systemic fungicides and 4 combination
The first foliar application was carried out as soon as
products were evaluated against purple blotch
the symptom of the disease was noticed in the field.
disease of onion. Fungicides evaluated and their
Observations on disease scoring were recorded one
concentrations tested are listed in Table 1.
day prior to each foliar application. A total of three
foliar applications were given at ten days intervals.
Table 1. List of fungicides evaluated
Chemical Name
Commercial Name
Concentration / litre
A
Non Systemic Fungicides
1
Captan 50% WP
Captaf
2.5g
2
Chlorothalonil 75% WP
Kavach
2.5g
3
Copper oxy chloride 50% WP
Blitox
2.5g
4
Mancozeb 70% WP
Dithane M-45
2.5g
5
Propineb 70 WP
Antracol
2.5g
B
Systemic fungicides
6
Difenconozole 25% EC
Score
1.0ml
7
Triademorph 80% EC
Calixin
0.75g
8
Hexaconozole 5% SC
Contaf
0.75ml
9
Propiconozole 25% EC
Tilt
1.0ml
C
Combination products
Pyraclostrobin 6.7% + Dimethomorph
10
Cabrio team
2.5g
12% WG
11
Pyraclostrobin 5% + Metiram 55% WG
Cabrio top
2.5g
12
Cymoxanil 8% + Mancozeb 64% WP
Curzate M8
2.5g
13
Metalaxyl-M 4% + Mancozeb 64% WP
Ridomil MZ
2.0g
90