THE CULTUEE OF GEEEN CEOPS. 83 



planting any of those green crops in spring and early 

 summer make the soil firm, and before setting out 

 the plants puddle their roots in a thick mixture of 

 soil, soot, and water, with a liberal amount of fine 

 sulphur powder stirred in. Another preventive 

 measure is to spread on the surface of the ground, 

 particularly round the plants, soil or sand mixed 

 with paraffin, carbolic, or creosote, or spent carbide 

 of calcium used alone. These things must be applied 

 immediately after planting. A device that has been 

 fairly successful is to place round each plant a tarred 

 felt disc at the time of planting. The discs are about 

 3 inches in diameter and have a slit from edge to 

 centre to allow of their being placed round the stems ; 

 a number of short slits at the centre accommodate 

 the stems and allow for growth. Where these are 

 used, the planting is perhaps best done without drills 

 and the discs pressed down close to the soil. 



Club Root (Plasmodiophora brassicce). This dis- 

 ease, known also as Finger and Toe, and Anbury, 

 attacks all plants belonging to the cabbage family, 

 turnips, radishes, etc., and often proves very destruc- 

 tive. It is caused by a minute organism, the spores 

 of which are able to live in the soil for a number of 

 years in a dormant condition, ready to attack any 

 crop of this family that may be sown or planted there. 

 The disease is very infectious, and though it cannot 

 spread through the air, it may soon be distributed in 

 the various soil operations and in farmyard manure 

 unless care is taken to restrict it. Affected plants 

 show distorted, malformed roots which, in a severe 

 attack, are rendered useless. The swollen portions 

 decay later in the season and liberate large numbers 



