56 MASS. EXPERIMENT STATION BULLETIN 427 



In the summer of 1932, further comparisons of fungicidal sprays were made 

 in the field. Six applications were made, the first on June 10 and the last on 

 August 8. The value of the treatments was determined by the counts of the 

 number of infections on the flowering stems gathered over the period from August 

 15 to September 13. The control of the disease was best with Bordeaux 4-4-50, 

 calcium arsenate 1 pound, and fish oil }/% pint; and plants receiving the Bordeaux 

 combinations appeared greener and relatively healthy throughout the season. 

 Plants from the plots sprayed with combined Bordeaux, calcium arsenate, and 

 fish oil were benched on August 10 after the last field application, and two addi- 

 tional applications were made on a portion of the benched plants. Yield records 

 were taken from October to May and comparisons were made with the yield of 

 plants never sprayed, either in the field or bench. The yield of flowers of the 

 plants sprayed in the field was twice that of the unsprayed plants, and no increase 

 over field spraying was shown by the plants sprayed twice more in the benches. 



In 1936, at Waltham and Lexington, comparisons were made between no 

 treatment and combined Bordeaux 4-4-50, calcium arsenate 1 pound, and fish 

 oil J^ pint. The Matchless and Boston Ward varieties were grown in both tests. 

 No perceptible injury from spraying was present. At Lexington there were 405 

 plants in each plot and the flowering stems were gathered for infection counts 

 from September 22 to October 9. At Waltham infection counts were made from 

 August 17 to September 1. Results of the two experiments were as follows: 



Number of Infections per 100 stems 

 Treatment Lexington Waltham 



Sprayed 5.1 9.8 



Unsprayed 255.6 155.0 



At Waltham, plants from the sprayed and unsprayed plots were benched on 

 July 7 and September 4. There was no significant improvement in the yield of 

 No. 1 carnations per plant from October 1936 to May 1937, inclusive, in favor 

 of spraying in the summer of 1936; but the contrasts in yield of flowers resulting 

 from early and late housing are especially significant. 



Treatment 



Sprayed 



Unsprayed 



In the summer of 1940, plots of the variety Nina Brener were sprayed periodi- 

 cally in the field, and 140 plants from each plot were planted in 48 square foot 

 benches in the greenhouse in July. An additional application was made after 

 the plants were established in the benches. The superior fungicidal efi"ect of 

 Bordeaux with calcium arsenate has been indicated, and a knowledge of the 

 effect of this combination upon the yield of cut flowers after the plants were 

 benched in the greenhouse was considered desirable. There was no blight among 

 the field plantings in 1940; nevertheless, a greater yield of flowers was obtained 

 from the plot sprayed with Bordeaux 5-5-50, calcium arsenate 1 pound, Penetrol 

 }/2 pint. Although not a significant difference, the results nevertheless revealed 

 the tolerance of the plants to the best fungicidal treatment for controlling blight. 

 There was no foliage injury from this treatment (Table 21). 



A similar experiment was conducted in 1941. The plants were sprayed four 

 times in the field, June 2, 12, 24, and July 3. On July 17, 140 plants from each 

 of the sprayed plots were benched in 48 square foot benches and sprayed further 

 on July 18 and August 5. Dow Potato Spray was included in the tests since 

 it represented a proprietary combined copper and calcium arsenate powder 

 which would appear to be more practical to use than combined homemade Bor- 

 deaux mixture and calcium arsenate. For the first and second application it 



