Plant Sanitation in Fruit Plantations. F. T. Brooks. 253 



PLANT SANITATION IN FRUIT 

 PLANTATIONS*. 



By F. T. Brooks, M.A. 



(Uni\ersity Lecturer in Botany, Camliridge.) 



The ideal variety of apple or plum for growth on a commercial 

 scale is one which crops heavily and regularly, is of good quality, 

 and is resistant to disease. Unfortunately it is as rare in the case 

 of fruit trees as in other cultivated plants, for all these desirable 

 qualities to be combined together. Many of the best market 

 varieties of apples and plums are subject to serious attacks of 

 fungoid or insect pests, and it often happens that the most 

 valuable commercial varieties are those which suffer most from 

 disease. Indeed, certain diseases, e.g. canker in apples and 

 silver-leaf in plums, may threaten the very extinction of some 

 varieties grown on a large scale, unless measures are taken to 

 control their ravages. Hence fruit growers must of necessity 

 spend considerable time and money in combating disease unless 

 they are prepared to see their plantations become derelict. 

 Whenever a crop is grown on a large scale and is forced to its 

 best efforts towards productivity, disease will frequently tend 

 to increase beyond the normal unless drastic measures are 

 taken to deal with it on its first appearance. If neglected, disease 

 becomes cumulative and in its latest stages often assumes the 

 character of an epidemic even though the particular malady is 

 not one of an essentially epidemic nature. 



Plant diseases, like human ailments, can be dealt with in 

 various ways. The best means of dealing with disease, if one 

 may so put it, is to avoid it altogether. With cultivated plants, 

 this desirable end can usually only be achieved by obtaining 

 varieties which are immune or very resistant to the most serious 

 pests, whether insect or fungoid. Thus in apples, ' Bramley's 

 Seedling ' is very resistant to canker, and in plums ' Pershore ' is 

 almost entirely immune from silver-leaf. With certain human 

 diseases, e.g. small-pox, an artificial immunity can be conferred 

 by vaccination, but similar methods of establishing immunity 

 in plants cannot yet be applied, chiefly because there is nothing 

 comparable in plants to the blood stream in man with all its 

 latent healing properties circulating rapidly through the body. 



* A paper read at the Eastern Counties Fruit Growers Conference, November 

 lyig. 



