72 The Spraying of Plants. 



and where the curculio, though abundant, is not so overwhelm- 

 ingly present as in a region almost exclusively devoted to fruit 

 production, it might be impracticable in the latter region ; sec- 

 ond, that the plum orchard was not sufficiently large to make a 

 test under the conditions of the commercial orchardist ; and third, 

 that the cherries upon which some of these experiments were 

 conducted ripened before the season of egg deposition of the 

 curculio was over. The force of these objections was fully 

 appreciated while the experiments were in progress, but the 

 work was done in the belief that results of value could be so 

 obtained, and with the expectation of giving the method a 

 thorough trial, from the standpoint of the commercial orchard- 

 ist, if the preliminary tests were sufficiently encouraging. 



" The present season [1890] a plum orchard of 900 bearing 

 trees in Ottawa County, Ohio, right in the heart of a great fruit- 

 growing region, was selected for the experiment. In the north 

 half of it the method of catching the curculios by jarring on a 

 sort of inverted umbrella mounted on wheels was employed, while 

 the south half was sprayed four times with pure Paris green 

 mixed w T ith water, in the proportion of 4 ounces to 50 gallons. 



" The first application was made May 8, just after the blos- 

 soms had fallen from the late-blooming varieties. There was a 

 heavy rain the same night, and it rained almost continuously 

 until May 15, when there was a short cessation. The second 

 spraying was done on that day. The third spraying was made 

 May 26, and the fourth and last, June 2. 



" On the jarred portion of the orchard a great many curculios 

 were caught, showing that they were present in numbers. A 

 careful examination of both parts of the orchard was made on 

 June 3. Between one and two per cent of the fruit on the 

 sprayed trees had been stung, while about three per cent of 

 plums on the jarred trees were injured. No damage to the 

 the trees was then perceptible. 



" Early in July the orchard was again examined. Some of 

 the sprayed trees showed that the foliage had been damaged by 

 the spraying, but the injury was not very serious. Not over three 

 per cent of sprayed fruit was stung at that time, while about 

 four per cent of that on the jarred trees were injured. But on 

 both the fruit was so thick that artificial thinning was neces- 

 sary to prevent overbearing. 



