16 BULLETIN 1093, U. S. DEPARTMENT OF AGRICULTURE. 



on the right of Plate V, Figure 2, there will be noted sections of the 

 bog entirely out of the water. Flooding will not control an infesta- 

 tion in such cases. These must be controlled by spraying. 



CONTROL ON DRY BOGS. 



Gipsy moth infestations on dry bogs can be controlled only by 

 intelligent application of some arsenical poison, either in the wet or 

 dry form. It is probable that with more efficient apparatus for the 

 application of dry poison, it will be the most economical and satis- 

 factory way of applying poison to cranberry foliage. The leaf of 

 the cranberry vine being glabrous, it is very difficult to get poison 

 spray to adhere in sufficient quantities for satisfactory results un- 

 less the poison is applied in mist form. Great care should he 

 taken not to allow the mist to continue long enough in one section 

 to reach heyond the dew foint. If this should occur, the liquid will 

 run off , leaving only a very thin deposit of the poison on the leaves, 

 not enough to destroy the larvce present. 



Observations have shown that in case of an infestation on a dry 

 bog, resulting from egg masses deposited the previous season, it is 

 imperative that the application of poison should be made soon 

 after hatching is noted on the uplands, and also that it should be 

 applied in a mist form in order that the largest amount of poison 

 possible may settle on the terminal bud. It is important that the 

 bud be covered thoroughly in order that the larvae may get enough 

 poison to cause death before they can eat so far into the buds as to 

 cause injury. Six to eight pounds of arsenate of lead paste (or 

 one-half of this amount of dry lead) to 100 gallons of water should 

 effectually control gipsy moths in the first two larval stages if 

 properly applied. 



If during the first stage only light winds prevail, dispersion will 

 be minimized, and the central areas of medium or large sized bogs 

 may not become infested to such a degree that spraying will be 

 necessary over the whole area. Careful tests should be made by 

 the pan or net method to determine the degree of infestation along 

 the bog border nearest the infestation on the upland, should there 

 be any, and spraying operations governed accordingly. This applies 

 to wet bogs in case it is not desirable to control an infestation by 

 flooding. 



Should a bog be infested with the later larval stages of the gipsy 

 moth, from whatever cause, the only recourse is to spray with a 

 strong solution of arsenate of lead — using from 12 to 15 pounds 

 of lead paste to 100 gallons of water, and using the same care in 

 application as advised for the first larval stage. 



