clubroot


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clubroot,

disease of cabbages, turnips, radishes, and other plants belonging to the family Cruciferae (mustardmustard,
common name for the Cruciferae, a large family chiefly of herbs of north temperate regions. The easily distinguished flowers of the Cruciferae have four petals arranged diagonally ("cruciform") and alternating with the four sepals.
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 family). It is induced by a plasmodial slime moldslime mold
or slime fungus,
a heterotrophic organism once regarded as a fungus but later classified with the Protista. In a recent system of classification based on analysis of nucleic acid (genetic material) sequences, slime molds have been classified in a major group
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 that attacks the roots, causing, in the cabbage, undeveloped heads or a failure to head at all. Clubroot can be partially or in some cases completely controlled by the application of lime (if the soil is very acid), by rotation of crops, and by soil sterilization. The disease is also called finger-and-toe from the swollen shape it gives to roots. Plasmodial slime molds (phylum, or division, Myxomycota) are classified in the kingdom ProtistaProtista
or Protoctista
, in the five-kingdom system of classification, a kingdom comprising a variety of unicellular and some simple multinuclear and multicellular eukaryotic organisms.
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.

Clubroot

 

a disease attacking the roots of plants of the family Cruciferae, caused by the fungus Plasmodiophora brassicae. Most frequently it damages cabbage. Growths and swellings form on the roots; subsequently they decay and disappear. As a result, the root system develops weakly, and the plant becomes very stunted. The disease is widespread in the USSR and is most harmful in the nonchernozem zone. After the swellings decompose, the fungal spores get into the soil and grow into motile amoeboids that penetrate the roots of plants. After a complex process of development, the amoeboids form plasmodia, which decay and become spores when they reach maturity. The spores are dispersed by implements for tilling the soil, transplants, irrigation, earthworms, and soil insects. The disease develops best in a temperature of 18–24°C and a weak acid soil with 75–90 percent moisture content.

Countermeasures in hot beds and nurseries include the replacement of the contaminated soil or the disinfection of the soil by thermal or chemical treatment. Protective measures in open land include correct crop rotation, the use of hardy varieties, liming the soil, transplanting the seedlings at an early date, and weed eradication.

REFERENCES

Gerasimov, B. A., and E. A. Osnitskaia. Vrediteli i bolezni ovoshchnykh kul’tur, 4th ed. Moscow, 1961.
Zashchita ovoshchnykh kul’tur v zakrytom grunte ot vreditelei i boleznei. Moscow, 1969.

E. A. OSNITSKAIA

clubroot

[′kləb‚rüt]
(plant pathology)
A disease principally of crucifers, such as cabbage, caused by the slime mold Plasmodiophora brassicae in which roots become enlarged and deformed, leading to plant death.
References in periodicals archive ?
If you have clubroot-infested soil, lime it regularly to keep the soil above pH7, as clubroot prefers acid soil, improve drainage and start brassicas off in pots of compost, planting out when well established.
The fungus that causes clubroot - whose spores can survive in soil for 20 years and are easily spread on boots or tools - leaves a mass of swollen distorted roots on each plant.
One managed to beat clubroot by putting crushed mothballs at the bottom of each cabbage planting hole.
Finally this month, Mr Sykes from Huddersfield has followed up on my ideas about managing clubroot in your garden or on your allotment.
Crop rotation prevents a build(up of pests and diseases in the soil, such as clubroot in brassicas, eelworms in potatoes and tomatoes, and root rots in peas and beans.
To help keep wallflowers clubroot free, acid soils should be dressed with 4oz of ground limestone per sq yd.
The worst disease of all brassicas is clubroot, a airborne fungus that invades the root system, ca the roots to swell and become grotesquely defor The plants survive but fail to thrive, wilting i weather while the fungus, almost impossib eradicate totally, rests in the soil between crops.
If there is a problem with clubroot in your garden or allotment, treat them with a clubroot dip first.
Removing brassica weeds such as Shepherd's Purse and Wild Mustard helps to stop clubroot living on cultivated ground.
If you have had clubroot this year, and if you haven't spread lime for a couple of years, there is an almost cast iron case for spreading lime over the plot this year.
Other projects include a study to combat clubroot, a disease which ruins plants like turnips, brussels sprouts and oilseed rape and costs industry around pounds 30m a year in lost crops.
All green waste from an allotment should be composted, except where disease is present, eg clubroot on brassicas or blighted potato tops which should be binned or burned.