Management of Purple Blotch Complex of Onion in Indian Punjab

Amarjit Singh,Ajmer Singh Dhatt,Ritesh Kumar Yadav,Sandeep Jain

doi:10.3126/ijasbt.v5i4.18632

Amarjit Singh, Ajmer Singh Dhatt + Show 2 more

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https://doi.org/10.3126/ijasbt.v5i4.18632

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Abstract

Six systemic fungicides viz., Kitazin 48 EC (iprobenfos), Tilt 25 EC (propiconazole), Folicur 25 EC (tebuconazole), Score 25 EC (difenoconazole), Amistar Top 325 SC (azoxystrobin 18.2% + difenoconazole 11.4%) and Nativo 75 WG (trifloxystrobin 25% + tebuconazole 50%), and two non-systemic fungicides viz., Indofil M-45 75 WP (mancozeb) and Kocide 77 WP (copper hydroxide), were evaluated under in vitro and field conditions for their efficacy to manage purple blotch complex of onion caused by Alternaria porri and Stemphylium vesicarium. Field efficacy of the fungicides at different concentrations were determined in controlling the purple blotch complex of onion under artificial epiphytotic conditions on bulb and seed crop (cultivar PRO-6) during the Rabi season 2014-2015 and 2015-2016, respectively. The triazole fungicides, tebuconazole and difenoconazole proved superior in inhibiting growth of A. porri and S. vesicarium under in vitro conditions, respectively. Further, foliar sprays (3 for bulb crop and 4 for seed crop) of tebuconazole 25 EC (Folicur) @ 0.1 per cent at fortnightly interval most effectively managed purple blotch complex of onion under field conditions with highest Benefit: Cost ratio (8.75:1 and 88.7:1) in bulb and seed crop, respectively. Seed-to-seed method of onion seed production recorded significantly lower disease severity and higher seed yield than that of bulb-to-seed method under natural epiphytotic conditions. The present findings can be instrumental in devising strategy for the integrated management of A. porri, S. vesicarium singly as well as in complex, serious limiting biotic factors in onion production. Int. J. Appl. Sci. Biotechnol. Vol 5(4): 554-565

Highlights

Onion (Allium cepa L., 2n=16), a bulbous, biennial herb is the most important and one of the five most important fresh market vegetables worldwide (Cramer, 2000)
Typical diseased spot on the leaves were selected and cut into bits of about 1 to 1.5 mm with the help of sterilized scalpel, washed with sterilized distilled water and disinfected with 0.1 percent mercuric chloride (HgCl2) solution for 30 to 60 seconds. These disinfected bits were immediately rinsed in double sterilized distilled water repeatedly to remove the traces of mercuric chloride and toweled on sterilized filter paper, prior to their being aseptically transferred to Petri plates containing 20 ml of autoclaved potato dextrose agar (PDA) in a laminar flow and incubated at 25±1oC in BOD incubator for 10 days
The resulting fungal culture was purified by hyphal tip technique in PDA slant both for A. porri and S. vesicarium

Summary

Introduction

Onion (Allium cepa L., 2n=16), a bulbous, biennial herb is the most important and one of the five most important fresh market vegetables worldwide (Cramer, 2000). In-Vivo Evaluation of Different Fungicides against Onion Purple Blotch Complex in Bulb and Seed Crop Field efficacy of six systemic fungicides viz., Kitazin 48 EC (iprobenfos), Tilt 25 EC (propiconazole), Folicur 25 EC (tebuconazole), Score 25 EC (difenoconazole) @ 0.1 per cent, Amistar Top 325 SC (azoxystrobin 18.2% + difenoconazole 11.4%) and Nativo 75 WG (trifloxystrobin 25% + tebuconazole 50%) each @ 0.05 per cent, and two non-systemic fungicides viz., Indofil M-45 75 WP (mancozeb) @ 0.3 per cent and Kocide 77 WP (copper hydroxide) @ 0.25 per cent, were determined in controlling where,

Results

Conclusion