DISEASES AND INSECT ENEMIES. 28 1 



cultural enemies vanquished, but they are often maae the 

 means of a richer and a fuller success. 



In a valuable paper read before the New Jersey State 

 Horticultural Society, and recently published in the " Ameri- 

 can Entomologist," Mr. A. S. Fuller makes the following 

 useful suggestions : — 



" Insects and diseases are frequently so closely united, or so 

 dependent upon each other, that the naturaHst often finds it 

 difficult to determine to which the fruit grower should attribute 

 his losses. Some species of insects attack only diseased or 

 dead plants ; others only the living and healthy. If a plant 

 shows signs of failing, we are inclined to speak of it as being 

 diseased, whether the failure is caused by a lack of some ele- 

 ment in the soil, attacks of parasitic fungi, or noxious insects. 

 The loss is t.he same in the end, whether from one or all of these 

 enemies combined. 



" There are two practical methods of combating insect ene- 

 mies and diseases of plants ; one is to so carefully cultivate and 

 stimulate the growth of the plants that they may possess the 

 power of resisting attack ; the other is to make war directly up- 

 on them by artificial means. Of course, the first method is 

 most applicable or practicable against the more minute species, 

 such as the plant-lice, rust, smut, and mildew. I do not recom- 

 mend forcing plants to extremes, in order to enable them to re- 

 sist their enemies, as this might work an irreparable injury ;' 

 but the condition to be aimed at should be a healthy, vigorous 

 growth ; for anything beyond this is more the sign of weakness 

 than strength. 



" The half-starved, overworked and uncared-for horse is sure, 

 sooner or later, to become the prey of various kinds of internal 

 and external parasites, which are thrown off, or successfully 

 resisted in their attacks, by the healthy, vigorous, and well-fed 

 animal ; and the same principle holds good all through the ani- 

 mal and vegetable kingdoms, — whether the subject be a man, 

 horse, sturdy oak, or delicate strawberry plant. Not that all 

 diseases are due to loss of vigor through starvation and neglect; 

 but that a large number of them are is well known." 



