INSECT PESTS 231 



the trunks of the trees after October 1, and must be 

 kept fresh and soft whenever the nights are warm, up 

 to May 1. If the ground is frozen all winter the bands 

 need have no care until spring, when the frost is 

 out and the nights are warm, when they will be 

 crawling, and the tar or ink must be soft at these 

 times so as to catch them. If the trees are young it 

 is best to put a band of paper about the trunk, upon 

 which to apply the tar, to prevent injury to the 

 bark, but on old trees which have a thick bark no 

 harm will be done. If the band is used care must 

 be taken that there are no openings under it that 

 the insects can crawl under, for it takes but a few 

 individuals to lay eggs enough to destroy much of the 

 foliage on a tree of good size. Another effectual remedy 

 is to encircle the tree with a tin or zinc trough, in which 

 is placed some cheap non-drying oil. The chief objec- 

 tion to this method is the cost of the troughs and the 

 care required to keep them filled with oil and to keep 

 them from being filled with the insects as they crawl 

 into the oil. The remedy which is now most in use is 

 to leave the trees until the larvae begin to hatch, and 

 then spray with Paris green in water, quarter of a pound 

 to fifty gallons, or with the bordeaux mixture, half a 

 pound to fifty gallons. The first application should be 

 made just before the flowers open and the second when 

 the petals have fallen. This remedy has the advantage 

 that constant attention need not be given during the 

 winter, that this and many other insects are killed at one 

 or two sprayings, and the bordeaux will prevent the apple 

 scab fungus from injuring the foliage. Thus two objects 

 are gained by one spraying. 



The Apple Aphis or Plant Louse (Aphis mali) — 

 The aphides, of which this is only one of a great number 

 of species, are green, brown or black insects very small 

 in size^ that suck the juices of the tender shoots and 



