1909.] PUBLIC DOCUMENT — No. 73. r ' ^6f 



Yerj dry and possible to spray nearly every day during the 

 caterpillar season. In purchasing arsenate of lead, care should 

 be taken to buy from reliable dealers who are willing to guar- 

 antee their goods. 



The improvement in spraying apparatus has been very no- 

 ticeable, and better results have been obtained at a much less 

 cost than heretofore. It has been the experience of this office 

 that in woodland spraying it is necessary that the engine be 

 at least 7 horse power, and that the pump deliver not less than 

 35 gallons per minute at 225 pounds pressure, thus allowing 

 long lines of hose to be run from the machine, at the same 

 time maintaining sufficient pressure at the nozzle. In wood- 

 land spraying it is advisable to move the machine as little as 

 possible, and to keep it near the water supply. This may be 

 done by using plenty of hose, and it lessens the expense of 

 spraying. At the present time there are several good power 

 outfits on the market that are suitable for doing woodland, 

 street or orchard work. They vary in price from $700 to 

 $1,000, and a large area can be covered in a day by any one 

 of them. The average 7 to 10 horse power sprayer, under or- 

 dinary conditions, should cover at least 12 acres of woodland per 

 day. In purchasing these machines they should be looked over 

 very carefully, so that when delivery is made there will be no 

 disappointment in the machine ; and when starting the machine 

 in operation in the field a competent engineer should be se- 

 cured, who understands gasolene engines, as delays in the field, 

 with the gang of men ordinarily used on large machines, are 

 very expensive. Arrangements should be made when purchas- 

 ing a machine to have the necessary assistance in starting the 

 same. Great care should also be used in filling the tanks to 

 see that no foreign matter is pumped up from the brooks or 

 ponds, which may injure the pump. This may be avoided by 

 having a box made 18 inches square and 30 inches deep, to be 

 placed in the water supply. Bore holes in the box, and cover 

 them with wire gauze on both sides and bottom. Under or- 

 dinary conditions, this box will allow enough water to flow in 

 to supply the pump. Good judgment should be used in appor- 

 tioning the amount of arsenate of lead, because at times, espe- 

 cially in the early spring, 10 pounds to 100 gallons of water 

 will acet)mplish as good results as 15 pounds, and if the larger 



