174 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



shortest distance from lower Cape Cod or the mainland in these 

 directions is about 19 to 22 miles. Some of these larvse which were 

 borne onto the screen by northwest winds came from a source even 

 more distant, namely, 21 to 30 miles. A total of 8 larvse came from 

 the southeast during the two years — a distance of 9 to 12 miles or more 

 • — and 105 from infestations to the eastward of the screen in Province- 

 town. The data collected at this screen give new records on wind 

 dispersion of 20 to 25 miles or more and have great bearing on the 

 proper control measures to practice in preventing spread of the insect. 



The methods used to prevent spread of the gipsy moth by the 

 Bureau of Entomology in former years were to do as much work as 

 possible in the heavily infested area, consisting of roadside thinning^ 

 spraying and treating of egg clusters, so as to keep down such infes- 

 tations and prevent larvae being carried on vehicles and automobiles. 

 After 1912, when the theory of windspread of the newly-hatched larvae 

 was proved and accepted, the base of control measures was moved 

 adjacent to the border, especially the western, where there was greatest 

 danger of spread eventually to central and southern United States. A 

 strip of territory about 25 miles wide is carefully worked each year. 

 All old infestations are cared for in this area, and when new infesta- 

 tions are found, creosote is applied to all egg-clusters and in many cases 

 is followed by spraying. Tanglefoot bands are applied to trees, where 

 the infestation is at all heavy, to prevent the small larvse hatching 

 on or near the ground, ascending the trees and being blown long dis- 

 tances by the wind. 



Better results can be seen in preventing spread of the insect since the 

 latter course was taken, as the increased territory each year since 1912 

 has not been so great in proportion to that previously infested. 



Mr. C. W. Minott, of the Bureau of Entomology, conducted some 

 interesting investigations during May and June, 1916, with reference 

 to windspread of gipsy moth larvse on cranberry bogs. The woodlands 

 of the Cape Cod section of Massachusetts where cranberries are ex- 

 tensively grown, have become badly infested in some towns, and the 

 larvae have spread onto the bogs, thus causing trouble and alarm to the 

 growers. In many instances, vines on the bogs have been heavily fed 

 upon and even stripped of their foliage. The growers have met these 

 conditions by spraying and clearing around the borders to prevent, 

 as much as possible, the large larvse crawling in. 



Two bogs were selected for experiments on wind dispersion in Carver, 

 Mass., namely, Muddy Pond Bog, containing about one hundred acres 

 and Johns' Pond bog containing about forty-four acres (including 

 pond). Six screens made of cotton cloth tacked to a frame in two 

 sections, each being 3 by 10 feet, were set up horizontally near the vines 



