CROPS, METHODS, MANAGEMENT 37 



is another subject which does not receive adequate atten- 

 tion in many commercial centres. There is too much of 

 the inclination to receive such evils with folded hands as 

 something inevitable or irremediable. Yet, both in the 

 direction of prevention and cure, great advance has been 

 made in recent years. It is true that success has not 

 attended all efforts, but the investigation of the life 

 history of some insects, or the minute forms of parasitic 

 fungi, is difficult and tedious, though that must precede 

 any systematic attempt at dealing with our enemies. 

 Again, some of those who have employed the substances 

 recommended have not exercised the promptness, discre- 

 tion, or caution that is needed, with the result that the 

 desired object has not been attained, or the plants have 

 been seriously injured. The knapsack sprayers and other 

 machines now in the market permit the work to be done 

 in an efficient and economical manner, while the majority 

 of the substances employed are obtainable at moderate 

 prices. Preparations of Paris Green, tobacco, quassia, 

 soft soap, and petroleum are those most largely used as 

 insecticides ; copper sulphate constituting the principal 

 basis of effective fungicides, though plenty of special 

 mixtures are sold that have proved well fitted for their 

 respective purposes. 



Cultivation under Glass 



The department of market gardening concerned with 

 the production of crops under glass is one of the most 

 astonishing developments of modern times. In such 

 centres as the Worthing district on the Sussex coast, 

 or north of London from Edmonton to Broxbourne, at 

 Swanley in Kent, as well as in many other localities, 

 a great acreage is under glass, and the produce in the 

 shape of fruits, plants, or flowers is enormous. To 

 deal with such a gigantic business, a special treatise 

 would be needed of considerable proportions ; here our 



