April, '15] 



SCOTT: ARSENATE OF LIME 



195 



During 1913, in the Rockfish Valley Orchard, at Avon, Va., 50 

 Winesap and Yellow Newtown apple trees were sprayed four times 

 with arsenate of lime follo^dng the usual schedule, and the remainder 

 of the orchard was sprayed ^dth arsenate of lead. With both poisons, 

 lime-sulphur solution was used as a fungicide in all the apphcations 

 except the last, in which Bordeaux mixture was used. 



The trees were examined from time to time during the season and 

 no difference could be observed between the two kinds of poison, 

 either in their effect on the fruit and foliage or in the control of the 

 codling moth and other insects. No injury was produced and the 

 codling moth was controlled equally well in both cases. 



During 1914 a similar experiment on a larger scale was conducted 

 in the same orchard. About 200 Winesap apple trees were sprayed 

 wdth arsenate of lime and a like number with arsenate of lead and 5 

 trees were left as checks. As a fungicide lime-sulphur solution was 

 used with the arsenicals and the trees were sprayed (1) after the blos- 

 som buds separated, shomng pink, (2) as soon as the petals fell, (3) 

 three w*eeks later and (4) about nine weeks after the petals fell (the 

 first week in July). 



Although no actual counts were made it was estimated at picking 

 time that about 60 per cent of the fruit from the unsprayed trees 

 was infested vdih the "bodling moth. The fruit from the adjacent 

 trees of the sprayed plots was reasonably free from this insect and no 

 difference could be noted in the efficiency of the two kinds of poison. 

 At the opposite end of the orchard from the check trees, however, 

 the codling moth was not so well controlled and the superintendent 

 was of the opinion that the arsenate of lead had given slightly better 

 results than the arsenate of lime. 



In a similar experiment conducted in an apple orchard near Han- 

 cock, Md., the powdered form of arsenate of lime was used and here 

 again this poison proved to be the equivalent of arsenate of lead. 



During the past spraying season (1914) several apple growers co- 

 operated with the writer in testing this material and, as shown by 

 the follomng reports, uniformly good results were obtained. 



■Mr. Fred Johnson, a member of this association and formerly an 

 assistant in the United States Bureau of Entomology, used 50 pounds 

 of arsenate of lime in his orchard at Westfield, N. Y., and in a letter 

 to. the writer dated September 28, 1914, he made the following state- 

 ment in regard to the results: 



I would say that we used this preparation (barium-sulphur crystals) together with 

 the arsenate of Hme on three rows of Baldwin trees in one of our orchards at the 

 strength you recommended. AU the rest of the orchard was sprayed with home- 

 prepared hme-sulphur and arsenate of lead. This season the whole orchard is as 

 entirely free from scab and codling moth as I could wish, so you may judge that the 



