1921.] " Damping Off " and "Foot Rot " of Tomatoes. 653 



CONTROL OF "DAMPING OFF" AND 

 ''FOOT ROT" OF TOMATOES. 



W. F. Bewley, D.Sc, 

 Mycologist, Experimental and Research Station, Cheshunt, Herts. 



In a previous issue of this Journal (October, 1920) attention 

 was drawn to the important disease known as " Damping off " 

 and "Foot Rot " of tomatoes. The relation of its intensity to 

 different cultural conditions was indicated and it was shown 

 that it could be controlled by sterilising the soil, seeaboxes and 

 pots by means of heat or formaldehyde. 



Many growers, however, do not find it convenient to adopt such 

 methods, but rather desire some remedy which may be effectively 

 employed to check the spread of the disease should it appear. As 

 the result of continued investigation such a remedy has been 

 found, which for convenience has been named " Cheshunt 

 Compound." 



Preparation of the Cheshunt Compound." — The compound 

 contains '2 oz. of Copper Sulphate and 11 oz. of Ammonium 

 Carbonate. Powdered copper sulphate and ammonium carbonate 

 should be obtained, reduced to a fine state by crushing oat any 

 lumps that may be present and then thoroughly mixed in the 

 proportions given. Larger quantities may be prepared, so long 

 as the proportions remain the sarae. The mixture may be stored 

 in the dry state in an air-tight receptacle, but if left exposed to 

 the air it gradually loses ammonia and becomes less potent. 



Mixing the Solution. — The dry mixture should be stored for 

 24 hours in a* tightly corked glass or stone jar before using. The 

 solution is then prepared by dissolving 1 oz. of the dry mixture in 

 a little hot water and making up to 2 gallons with water. The 

 solution must not be put into vessels of iron, tin or zinc, as- it 

 would corrode them and lose its strength, and only just as much 

 as is required for immediate use should be prepared. 



Method of Use. — Plants which are already attacked receive 

 no benefit from the solution but eventually die, unless the 

 healthy tops are cut off above the diseased part and tie ted as 

 cuttings. It is possible, however, to kill the infective organ^'sms 

 by watering infested soil with the solution, after which immediate 

 planting may follow without in any way harming the plant. It 

 is possible, also, to treat infected soil with plants in situ. 

 The solution effectively destro^^s the disease organisms and at 

 the same time increases the vigour of the plant. When the soil 



