SUCCESSFUL REMEDIAL MEASURES 12J 



effective remedy against these caterpillars, especially in apple 

 orchards and on comparatively small shade trees. On larger 

 trees it is simply a question of reaching the foliage with the 

 spray. The chief drawback in the use of Paris green — the 

 commonest of these insecticides — is the danger of scorching 

 the foliage. In this respect the arsenate of lead is much safer, 

 as it does not injure the foliage at all. When Bulletin 64 was 

 published this substance was not upon the market, and conse- 

 quently had to be prepared by the user. It is now obtainable, 

 however, from Wm. H. Swift & Co., 75 Broad street, Boston, 

 Mass., who manufacture it in quantity, and offer it for sale 

 in wooden packages at from fifteen to eighteen cents per 

 pound. It is also for sale by the Bowker Chemical Com- 

 pany, 43 Chatham St., Boston, Mass. This is cheaper than 

 Paris green at the prices the latter has recently sold for. 

 The arsenate of lead is said to remain on the tree longer than 

 Paris green. It is a white powder and a deadly poison, so 

 that great care should be taken not to leave it around where 

 it might be mistaken for something else, or where it might be 

 reached by children or stock. Spraying with arsenical mix- 

 tures is most effective when it is done before the caterpillars 

 are one-fourth grown. It should certainly be done before they 

 are half grown. Later than this it is comparatively ineffec- 

 tive. 



Bandi7ig to prei'ent invasion. — In case of an un infested 

 apple orchard in the vicinity of an infested woodland, it will 

 be advisable to band the apple trees with cotton or raupenleim 

 before the caterpillars are half grown, to prevent invasion 

 from them. The same advice would hold in the case of other 

 uninfested trees in the vicinity of those infested. 



Banding the tree-trunks. — The remedial measure that has 

 been most generally employed is that of banding the trees 

 with some substance to prevent the ascent of the caterpillars. 

 It has already been pointed out that a large proportion of the 

 caterpillars drop off the trees from one cause or another, and 

 have in consequence to ascend the same or neighboring trees 

 in order to reach the leaves. The placing of some substance 

 around the trunk to prevent the upward progress of the insects 



