L58 GYPSY AND I',k< )W\-TAIL MOTHS. [Jan. 



BOSTOX, JULY, 1907. 



Spraying <>t' the Common and Public Garden. Exact data of a single 

 day's run of the .-praying mitlit used here were nut obtained. The local 

 superintendent. Mr. D. H. Sullivan, kept accurate records of the 

 total cost of >praying- the trees in these park spaces. The shade tree-. 

 numbering aliout J.Odir. ranged from 50 to 70 feet in height. About 

 J..")!)!) slii-ulis were also sprayed. The outfit was an S horse-power Olds 

 uasoline engine, with liOO-gallon tank, a single line of I 1 --inch hose and 

 a ' i-iiich nozzle. Arsenate of lead was used at the rate of 1"> pounds to 

 100 gallons of water. Xo division was made of the cost of spraying 

 shrubs and trees, but figured on the basis of trees alone, the expense 

 averaged 21 cents per tree. 



The data given on the preceding pages cover typical spray- 

 ing operations carried on under varying conditions in surface 

 treated and style of outfit. Their value lies in the fact that the 

 figures of cost were not obtained from estimates, Imt from the 

 a-tnal records made in the field, and include not only the time 

 ami material used, hut also the cost of delays incident to haul- 

 ing- water, breakdowns of machinery, and time spent in moving 

 out tits from place to place. The cases cited cover nearly all the 

 different problems the local superintendents are called on to 

 solve in spraying to destroy the gypsy and brown-tail moths. 



The only items not possible to figure accurately are tho-;- of 

 repairs, depreciation of outfit and interest on investment. The 

 latter might have been computed with a fair degree of accuracy, 

 but, since the spraying outfit question is yet in an experimental 

 stage, the items of repairs and depreciation for this year would 

 IK. t hold good for succeeding seasons. Already manufacturers 

 are perfecting notable improvements to he available for the \\"^ 

 trade. 



This careful study of actual field spraying operations shows 

 that, all things considered, best and cheapest results are ob- 

 tained by the use of high-power rigs throwing- a small solid- 

 -tnam -pray. While these outfits have their good point-, their 

 field of usefulness is limited by their weight, and depends 



largely oil flic proximity of - 1 roads and abundant water 3Up- 



ply I" the area- to be -prayed. It is not fea-ible a- a rule to use 

 the liig-|i-pre.--ure -,,lid >treaiu near houses, because of the di- 

 ..!., rations cau-ed by the spray, although in some cases ho' 



