228 THE FRUIT GROWER'S Gi'WE. 



invade the cells, certain destruction in some instances following the penetration; but 

 the diseases caused by fungi present many peculiarities according to the species of 

 parasite or of host. Sometimes the tree or plant attacked is simply enfeebled, doubtless 

 robbed of nourishment. Infested parts, in other cases, take an abnormal shape or size. 

 These modifications of growth are often as injurious as the abstraction of nutriment. 

 Stems or branches are swollen and knotted, leaves curled and distorted, fruit made 

 unsightly or worthless. There is no room for doubt that fungi are the principal agents 

 in inducing ferment-changes and decay, and that when they occur in great numbers 

 their effects may prove of serious consequence to the fruit grower and consumer. 



Much information of practical value on fighting these invisible foes has been attained 

 by successful investigators of the maladies. No one method of prevention or cure can 

 be made general, but something can be offered for special cases. Incorporating material 

 in the soil, being directly useful to the plant, may prevent or reduce the ravages of 

 fungi in giving that special condition and quality of growth resistive of the germs. Pow- 

 dered substances may destroy such fungi as creep over the surface, but are practically 

 innocuous in the case of those that pursue their destructive work beneath the bark. 

 Much in the way of prevention is effected by selecting varieties for culture which are not 

 subject to injury by fungus ; indeed, careful discrimination leads to useful results in 

 the selection of disease-resisting varieties. The least vigorous growths are not always 

 most liable to disease, the plethoric often suffering most, as in the case of trees grown 

 on land which is too rich. There are, however, some conditions more favourable than 

 others for the development of the parasite, and these it is the business of cultivators to 

 find out by studying the growth, soil, and methods of cultivation. Washing the stems 

 and larger branches of fruit trees with alkaline solutions makes the bark smooth, more 

 elastic, less liable to crack or be pierced by insects, and a more certain barrier to fungi. 

 Knowing how, where, and when to assail fungoid enemies is important. Strike the 

 fungus spore in spring and summer, when protruding its germinal tube, with a sulphide 

 or a sulphate, and it is prevented penetrating and burrowing in the tissues of the 

 intended host, Something, however, can be done in winter. Destruction of dead leaves, 

 affected fruits, prunings, and all refuse by burning is helpful; and vigilance in 

 picking off any diseased leaves, twigs, or fruits the following season, and burning them, 

 does much towards freeing fruit trees from fungus depredations, whilst limiting the 

 extent of infested areas. 



The foregoing remarks on fungi are based on the researches of Professor T. J. 



