Biological control and integrated control of cabbagae yellows

Abstract

Biological control and integrated control were tested for cabbage yellows caused by Fusarium oxysporum f. sp. conglutinans in a heavily infested field.
A single treatment of the suspensions of 3 mixed antagonists of Streptomyces sppor charcoal compost fixed with the antagonists, Bacillus subtilis and two isolates of Actinomycets slightly suppressed the disease incidence in the heavily infested field.
In order to protect plant from infested soil, a physical method of seedlings in small bags or long bags of woven polyester cloth ("root-proof" sheet) permeable to water and nutrients and placed into the planting holes was used. It suppressed the disease incidence drastically, especially when treated with biological control.
Cropping a resistant variety in the previous cultivation also suppressed the disease incidence in the next susceptible variety cultivated.
The population density of the pathogen in these cases was lowest inside of the "root-proof" bags, so the disease incidence did not appear to cause severe damage. While, antagonists treatments decreased the population density of the pathogen, the suppression of disease incidence did not appear to be so remarkable.
At the final check of disease incidence, I checked if plant roots were restricted inside the "root-proof" bags or not. In most cases, secondary roots grew out of the bags. However, they did not appear severely damaged.
These phenomena suggest the severity of disease was determined by the period of pathogen infection.