Clubroot disease devastates British brassica crops. Growers well know that once land is infested with the soil-borne microbe Plasmodiphora brassicae, clubroot persists for decades. This disease's symptoms of cancerous root galling are easily recognised. Infected crops lose vigour and the leaves show an unhealthy, dull green colour, wilting easily. Crop quality, sequencing and yield are lost. The microbe moves in soil moisture films from the long-lived, resting spores into host root hairs. There it penetrates, multiplies and moves deeper into the main roots. Host cells multiply chaotically as their hormone controls are lost. Another generation of resting spores forms in the galls and is discharged back into the soil. Tens of millions of spores are liberated from each gall.
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