TEMPERATURES 55 



The spread of this disease is favoured by damp condi- 

 tions. On its appearance, the affected part should be 

 cut away with a sharp knife and burnt. It is most 

 prevalent in autumn and early winter. The structures 

 should be kept as dry as is possible, consistent with the 

 maintenance of the plants in good health, using as little 

 water as possible, and admitting air freely except during 

 driving rains. A slight heat should be kept in the water- 

 pipes to prevent condensation, and, with judicious care, the 

 plants should soon grow out of this disease if they are 

 not too badly affected. Should the attack be very severe, 

 the best thing to do is to burn the plants and obtain a 

 clean stock, as the efforts to stamp out the disease will 

 cost more than the purchase of fresh plants. The chief 

 point to remember is that well-grown, vigorous plants 

 are better capable of resisting the attacks of all pests 

 than plants which exhibit a weakly condition through 

 mismanagement. 



Temperatures. If high temperatures are allowed, the 

 plants soon show ill effects in the weakened state of the 

 growth and foliage. In the winter months, assuming the 

 weather is mild, a night temperature of 45 is suitable, 

 and it may rise during the day by solar heat to 50 ; but 

 in spells of severe weather 5 less all round is necessary 

 to the health of the plants. When growth is apparent 

 in the spring, the temperature may be raised slightly ; but 

 later, in early summer, considerable difficulty will be found 

 in keeping the temperature as low as is desirable. 



Shading. At no time during the season must the plants 

 be placed out-of-doors, notwithstanding that this practice is 

 sometimes advocated. The chief reason for keeping them 



