ORCHARD SPRAYING EXPERIMENTS II. I9 



recommends. Again, arsenate of lead used at the rate of 2 

 lbs. to 50 gals, yielded double the percentage of russeted apples 

 when compared with the plot sprayed with 4 lbs. to 50 gals. 



A fair percent of the russeted apples in the several plots, with 

 the exception of plot F, were affected to a degree no greater 

 than is frequently found on unsprayed trees. We are here 

 again confronted with the question of physical and natural 

 causes vs. chemical ones in attempting a solution of this ques- 

 tion of russeting. This point will again be referred to. 



Lime-Sul'phur Plus Lead Arsenate Applied zvith the Gas 

 Sprayer.- If any conclusions might legitimately be drawn from 

 the results obtained this year it would appear that the effect 

 of carbonic acid gas upon the spray was, when the latter was 

 applied in fair weather, entirely negligible. Fortunately this is 

 not a critical question, as it seems that the gas sprayer for sev- 

 eral reasons is being increasingly supplanted by other power 

 machines. 



Sunscald. That the injury so designated was in reality a 

 scald produced by sunlight, there is no room for doubt. In the 

 first place, it was, with practically no exceptions, found only 

 on fruit upon the south and southern sides of the trees, and m 

 general only where such fruit because of its relation to adja- 

 cent foliage was directly exposed to the sun. (Fig 7). Second- 

 ly, the injury on such apples was always confined to the sur- 

 faces exposed to light at the hottest periods of the day. 



As previously stated, no lens action of intense sunlight 

 through drops of dew can, here account for any such injury, 

 owing as aforesaid to the absence of dew formation at this 

 period and to the great areas of the injured surfaces. 



Relation of Spraying to Heat. Did spraying during this 

 season bear any relation to the primary nature of the injury? 

 This question is readily 'disposed of. Fruit on trees that have 

 never been sprayed exhibited the characteristic burned surfaces. 

 Trees on Highmoor Farm that received only the first applica- 

 tion showed no injury to fruit until after the hot weather, when 

 typical sunscald was found. 



Did spraying affect the extent or degree of injury? This 

 seems to be a debatable point. In order to obtain the views of 



