17 



plants: Therefore the substance known as arsenate of lead, which 

 admits of much stronger proportions without damage to foliage, was 

 introduced and has since been extensively used, not only against, the 

 well grown gipsy moth larvae, but against other leaf -eating insects. 



But against the larger larva? other measures may be used to advantage. 

 It has been pointed out that it is the habit of the larvae to descend upon 

 the trunk of the tree in the early morning and to hide under any pro- 

 tection until nightfall. Therefore, if a strip of burlap or other coarse, 

 cheap cloth is tied about an infested tree trunk by the middle, in such 

 a mariner that the flaps hang down (see fig. 7), the caterpillars, as soon 

 as they have reached this stage, will gather 

 for the day under the cloth and ean be 

 destroyed by crushing or cutting. The 

 burlap should be examined daily, and may 

 be employed from the latter half of May 

 to the first or middle of August as late 

 as the latter date, for the reason that many 

 caterpillars transform to pupse under the 

 burlap and many egg masses are also laid 

 under it. As Kirkland has well expressed 

 it, " It should be borne in mind that the 

 cloth band is in no sense a tree protector; 

 nor is it a trap. Its function is simply to 

 give the shelter which the caterpillars 

 seek by day. Serving as it does as a 

 hiding place for various insects, it is better off the tree than on unless 

 it can be attended to and kept clean. At the end of the caterpillar 

 season all burlaps should be removed and burned. To insure best 

 results on high trees, such as street elms, burlaps should be placed 

 around some of the larger limbs, as well as around the trunk, as many 

 caterpillars will seek shelter up in the tree rather than descend to the 

 ground. The most effective results in using the burlap are obtained 

 where cavities, crevices, etc., in the trees have been first filled with 

 cement or covered with zinc and all loose bark removed. If these 

 hiding places are destroyed nearly all the caterpillars will seek the 

 burlap at some time during the season." 



One of the most effective methods of destruction consists in killing 

 the eggs. The egg masses are often conspicuous and accessible and 

 may be destroyed by applying creosote mixtures by a small swab or 

 paint brush. This mixture may be bought at agricultural warehouses 

 and seed stores at from 50 cents to $1 a gallon. Every egg mass thus 

 treated means the destruction of 500 potential caterpillars. The egg 

 clusters should be creosoted early in the autumn if possible, since they 

 are likely to be broken and the eggs scattered on the ground by the 

 rubbing of animals against the trees, or by the breaking open of the 



FIG. 7. Manner of applying burlap 

 bands: a, band as originally tied; b, 

 band with upper half turned down. 

 Greatly reduced (after Forbush). 



275 



