BASIC COPPER SULFATE AS A FUNGICIDE i:}7 



Drain reported that with both dusts there was a small amount of russet on 



Mcintosh apples but no foliage injury. A few scab spots were detected on trees 



receiving the dilute mixture. Bartlett pears showed neither scab nor injury. In 



addition Drain stated that the dust distributed well, and appeared to have good 



adhesiveness. 



Grapes 



Experiments were conducted in the College vineyard, under the supervision of 

 O. C. Roberts, to determine the relative effectiveness of spray and dust applica- 

 tions of basic copper sulfate (lots 5 and 2) and of Bordeaux 4-4-50 in disease 

 control and foliage injury on grapes. Two concentrations of sprays and two of 

 dusts with lead arsenate in all cases were employed as with apples. Crude 

 saponin 25 gms.-50 was used in the first three spray applications and raw linseed 

 oil 1 pt.-50 in the fourth. Crude saponin 1 pound in 100 was incorporated in the 

 first three dust applications and omitted in the fourth. The variety Worden was 

 used in the tests. The vines, located in a portion of the vineyard where condi- 

 tions were relatively uniform, were divided into 6 groups fplots), of 3 rows each, 

 with approximately 9 vines to a row. Five plots received dilute and concentrated 

 sprays, dilute and concentrated dusts, and Bordeaux, respectiveh\ The sixth 

 served as a check. The details of the treatments were as follows: 



Copper Number of Amount of 



Fungicide Content Applications Material 



Per cent 



Dilute spray 0.06 4 35.5 Gals. 



Concentrated spray 0.19 4 37.0 Gals. 



Dilute dust 2.50 4 8.0 Lbs. 



Concentrated dust 5.00 4 7.5 Lbs. 



Bordeaux 0.24 4 35.5 Gals. 



Check 0.00 0.0 



Spray and dust treatments of basic sulfate were applied when the first leaves 

 were about to appear (May 14), when the shoots were about 12 inches long (June 

 11), when the grapes were about the size of peas (July 18), and when the grapes 

 were from K to ^ grown (August 11). The weather conditions at the time of 

 application were as follows; 



May 14 — clear, no wind, 53° Fahr. 



June 11 — partly cloudy, light breeze, 70° Fahr. 



July 18 — clear, light southerly breeze, high humidity, 65° Fahr. 



August 11 — partly cloudy, no wind, 65° Fahr. 



The Bordeaux was applied on May 14, June 10, July 12 and August 11. The 

 sprays were applied under 75 to 100 pounds pressure with a double action, Deming 

 barrel hand pump equipped with two lines of hose to which were attached rods and 

 disc nozzles. The dusts were applied with an American Beauty hand duster. 

 The adhesiveness of the spray was considered poor, partly due, it is believed, to 

 the similarity in color of the spray residue and foliage, while that of the dusts was 

 highly commended. 



The concentrated spray and dust caused considerable injury to the foliage, the 

 dilute spray a little and the dilute dust practically none. The leaves remained 

 green 10 to 14 days longer than with Bordeaux and complete defohation was 

 delayed fully as many days. The Bordeaux was the most injurious of all treat- 

 ments and the "burned" condition of the foliage was decidedly apparent. This 

 may have been due to carbonating of the lime. The rainfall during the summer 

 was comparatively high and the temperature low. Some mildew was detected on 

 the check rows during the latter part of August and the first of September, but no 

 black-rot was observed on any vines. There was not sufficient disease present 



