Articles
Effect of curing methods on Botrytis neck rot disease of onions in the Canadian prairies
Article number
1398_23
Pages
171 – 178
Language
English
Abstract
Onion neck rot caused by the fungus Botrytis allii Munn. is one of the most damaging storage diseases resulting in significant yield losses for the Canadian prairie growers.
This disease is latent; onion plants remain symptomless in the field with bulbs typically showing symptoms 1-2 months after harvest in the storage.
The infection can occur anytime during the lifecycle of a plant, but the most common time of infection is during harvesting.
Until now, it was unknown which curing method is most effective for reducing neck rot incidence under the short-season temperate growing conditions of the Canadian prairies.
We performed a three-year field study to compare methods of curing onion bulbs naturally (in the field) and artificially for maintaining bulb quality in long-term storage.
The amplified DNA fragment of onion leaves collected before bulb lifting, subjected to a polymerase chain reaction (PCR) using Botrytis specific primer pair BA2f/BA1r, revealed that more than 80% of plant samples collected were positive for B. allii infection.
However, the percentage of diseased bulbs after 6 months of cold storage varied significantly with the method of curing.
Our results revealed that the artificial curing method significantly (P<0.05) reduced neck rot disease (13.86%) and maintained bulb quality in storage as compared to curing bulbs naturally (21.68% bulbs with neck rot) under open field conditions.
Out of 11 onion cultivars tested, the red cultivars resulted in a higher number of diseased bulbs as compared to yellow and white cultivars among both curing methods.
The results presented here provide information to vegetable growers on the best curing methods to achieve high bulb quality and minimize post-harvest losses due to neck rot disease.
This disease is latent; onion plants remain symptomless in the field with bulbs typically showing symptoms 1-2 months after harvest in the storage.
The infection can occur anytime during the lifecycle of a plant, but the most common time of infection is during harvesting.
Until now, it was unknown which curing method is most effective for reducing neck rot incidence under the short-season temperate growing conditions of the Canadian prairies.
We performed a three-year field study to compare methods of curing onion bulbs naturally (in the field) and artificially for maintaining bulb quality in long-term storage.
The amplified DNA fragment of onion leaves collected before bulb lifting, subjected to a polymerase chain reaction (PCR) using Botrytis specific primer pair BA2f/BA1r, revealed that more than 80% of plant samples collected were positive for B. allii infection.
However, the percentage of diseased bulbs after 6 months of cold storage varied significantly with the method of curing.
Our results revealed that the artificial curing method significantly (P<0.05) reduced neck rot disease (13.86%) and maintained bulb quality in storage as compared to curing bulbs naturally (21.68% bulbs with neck rot) under open field conditions.
Out of 11 onion cultivars tested, the red cultivars resulted in a higher number of diseased bulbs as compared to yellow and white cultivars among both curing methods.
The results presented here provide information to vegetable growers on the best curing methods to achieve high bulb quality and minimize post-harvest losses due to neck rot disease.
Publication
Authors
P. Singh, S. Rao
Keywords
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