130 THE BROWN-TAIL MOTH 



elaborate field experiments concerning the strength neces- 

 sary will be conducted this year. 



After the eggs have hatched in August the trees may also 

 often be sprayed to advantage so as to, prevent the work of 

 the young jjaterpillars and the consequent checking of the 

 fall growth of the tree, except in the case of trees in fruit. 



Spraying or sprinkling with kerosene emulsion or strong 

 soap solution will often destroy the caterpillars when they 

 swarm on fences and walks. 



Banding. — ^Uninfested trees may often be protected by 

 applying a band of some sticky substance over which the 

 caterpillars are unable to cross. This will not be effective 

 (1) if the branches of the trees interlock with those of an 

 infested tree; (2) if the trees stand so close together that 

 the small caterpillars can pass from one to the other while 

 suspended on their fine threads; (3) if the band either 

 'hardens or becomes covered with dust so that it does not 

 remain sticky; and (4) if the caterpillars are allowed to 

 become so numerous beneath the band that they form a 

 bridge over it with their threads and dead bodies. The 

 bands should therefore be frequently inspected and the 

 caterpillars below them removed or destroyed. If not de- 

 stroyed they will often leave the trees for shrubbery, where 

 it is more difficult to cope with them, and will transform 

 to moths. "Insect lime, raupenleim, tanglefoot, bodlime, 

 printer's ink, or even axle grease are among the materials 

 most used for banding. All may be dangerous to the tree 

 and should be removed after the caterpillar season has 

 passed." (Kirkland.) Possibly the most satisfactory and 

 safest substance is printer's ink applied as a band on heavy 

 building paper, beneath which is placed a band of cotton 

 next to the bark of the tree to prevent the ink from injur- 

 ing the tree and the ascent of the caterpillars in the crev- 

 ices of the bark beneath the paper. 



This banding will not, however, prevent reinfestation by 

 the winged moths, which fly to them and deposit their egg 

 clusters in July, so that it is not as efficient as in the case 

 of the gypsy moth, which does not spread by flight, and 

 which makes apparent the necessity of destroying the in- 

 sect in its immature stages as far as possible, so that the 

 winged moths may not spread, if its numbers are to be 

 reduced from year to year. 



Destroying Pupm. — Late in June and early July the 

 cocoons containing the pupse may be gathered, though it is 

 likely to be attended with severe inflammation of the skin 



