INSECTS AND DISEASES AFFECTING PLANTS. 207 



CHAPTER LIV. 

 INSECTS AND DISEASES AFFECTING PLANTS. 



There is no subject referred to in this volume, that I 

 feel so incompetent to discuss as that of insects. Not 

 that our experience with the pests has not been ample 

 enough, but all the knowledge obtained from that expe- 

 rience leaves us at times utterly helpless to prevent their 

 ravages, particularly on plants grown out of doors. Un- 

 der glass, we may say that they are entirely under control, 

 and I have always considered that no better evidence of 

 the incompetency or negligence of the person in charge 

 of the greenhouse could be had, than to see the plants 

 covered with insects. 



The most annoying of all insects of the flower garden, 

 is the 



Rose Slug, Selandria rosce, a light green, translucent 

 little fellow, varying from one-sixteenth of an inch to 

 nearly an inch in length. There are evidently two species 

 or varieties, one of which confines its ravages to the lower 

 side of the leaf; the other eats it entire. The first is by 

 far the most destructive here. In a few days after the 

 plants are attacked they appear as if they had been 

 burned. 



The best remedy we have found, is a preventive one, 

 which, in fact, ought to be used against all insect life. 

 Before the leaves of the roses appear, just as soon as the 

 buds begin to develop, apply Whale-oil Soap, in the pro- 

 portion of one pound to ten gallons of water; this, 

 steadily applied for ten days, with a syringe or garden 

 engine, has, in my experience, entirely prevented the at- 

 tacks of the insect. But once let it get a foothold and it 

 can hardly be driven off by this application, unless it bo 

 made strong enough to injure the foliage, making the 



