DISEASES OF BRASSICAS

Evening Star, Issue 20666, 13 December 1930, Page 28

DISEASES OF BRASSICAS

The most serious disease which attacks tho cabbage family is that known as club root (Plasmodiophora Brassicae). It is a slimo fungus, and is variously called “ finger and too ” (in turnips), “ anbury,” and “ club.” It is increased by means of spores which enter tho roots, forming rough, gnarled masses, or “ clubs ” (says the ‘ Gardeners’ Chronicle,’ London). The affected plants make but little headway, as all the nutriment prepared by ,the few expanded leaves is used up in the growth of the swollen roots. Although the plants make . adventitious roots when tho natural ones aro destroyed, these. soon become infected, and on pulling up a diseased plant a mere blunt, woody stem is often all that is found. This disease is more troublesome in light, sandy soils than in heavy, clay land. There are several ways of combating the disease. First, the crop should have a complete change of ground; second, apply limo at the late of 21b to tho square yard; third, plant only strong seedlings free from tho disease. The soil should bo firm to encourage hard growth, and when high enough the plants should be moulded up to encourage the formation of stem roots, which will be of great service should tho lower roots become infested with the disease. Experiments in controlling club root with mercuric chloride have been carried out satisfactorily over a number of years at the Staffordshire Farm Institute. The method employed is to sterilise the seed bed by watering it with a solution of one ounce of mercuric chloride in six gallons of water, and ten days after germination tho seedlings should be watered with a solution of ono ounce in ton gallons of water, tho watering being repeated seven days later. Before planting tho seedlings should be dipped for. ono minute in mercuric chloride solution of ono ounce in ten gallons of water, or proportionately less if desired.