September, 1921 SCIENTIFIC AGRICULTURE 13 



black spot has ahva.ys been pre valient. out that the quantity of the copper ap- 



The coraniereial Bordeaux dust used in i)lied was less than that applied in the 



these experiments was diluted to con- Bordeaux si)ray. This was due to the 



tain the same copper and arsenic equi- under estimation of the spreading- i)ower 



valent as the C(){)per-arsenic dust. of the dust, in makino- up the Formula. 



The insect injuries, as will be seen. It is interesting to note also that in t/iis 



were insignificant on all plots, but t;ie orchard the russetting of fruit was neg- 



differences in scab were remarkable. The ligible. 



figui-es in the foregoins: table uive a verv n^ i i *> u .li i. w • , • 



■ 1 4^ -J £ ..r 1 ' ^ 1 ■ table 2 shows the results obtained in 



niadeciuate idea of the scab control on moA u +u - -, ■ 



., ^ . 1 i-\ ^r- 1 IJ'JU. Here the copper and arsenic con- 



tlie treated areas. On the unspraved area +,,,^. „ j i,- i 



^. ,, ,, ,, , ' • ,, tent wa.s made higher, 

 practically all the apples were scabbv. 



Moreover each apple contained a great ^''^^^ ^"'^ fungicidal value of the cop- 

 number of scab spcts and manv were crack- Pei"-arsenie dust can be still further in- 

 ed, and the apples were dwarfed in size. ^Teased by raising the copper content of 

 On the treated areas the apples ^dl'ich l;'"; ,^"!'* is shown from the results of 

 were scabbed usuallv contained onlv one ^^^^^^ '^- ^^^^ ^^'^^^^^^ a^'^^-^ i" t'n^ ex- 

 or two scab spots "and those " generallv Periment were all dusted with sulphur 

 j^jj^j^ll ^ lead arsenate dust on the third applica- 

 The 90-10 sulphur dust gave the liest ^^^'^^' t'^^, o^^^^^" ^^'^'''^ applications consist- 

 control, bnt this plot was slightly favored. "^- «* ^^^^ copper-ar.senic dust, 

 being on somewhat /ligher ground and In the S. B. Chute orchard the apples 

 consisting of a trifle smaller and more from the various plots Avere picked sep- 

 open trees. The 3-1 copper-arsenic dust arately and turned in to the packing 

 gave very good control indeed, considering warehouse. Table 4 shows the pack out 

 the severity of the infection. And in as obtained from the foreman, expressed 

 this connection it is worth while pointing in percentages. 



Table 2. Results from S. B. Chute's Orchard, 1920. 



Xo. of Cod. Green 



^Material apples Russ- Bud- ling fruit Tussock 



counted Scab ' etted moth motlh worm moth 



p.c. p.c. p.c. p.c. p.c. p.c. 



Uusprayed 4,000 72.-1: 0.8 2.8 0.1 3.8 OA 



Sprayed as per 



Nova Scotia Sprav 



Calendar ". . . 4,000 29.7 3.9 3.4 0.02 1.9 0.8 



Dusted with 

 31/^-114 copper 



arsenic dust 4,000 24.2 8.0 5.8 0.06 1.8 0.1 



Dusted with 90-10 



sulphur-lead 



arsenic dust 5,000 40.0 2.8 5.7 0.04 l..s 0.1 



Table 4. 



Xo. 1 No. 2 No. 3 Domestic Culls 



p.c. p.c. p.c. p.c. p.c. 



Unsprayed 19.2 9.5 32.2 36.2 2.7 



Nova Scotia Spray Calendar . . 48.5 16.6 18.0 14.7 1.8 



DiLsted with 31/2-114 



copper-arsenic dust 57.5 12.3 12.3 16.5 1.3 



Dusted with sulphur-lead 



arsenate dust 34.0 17.5 16.2 29.5 • 2.7 



