54 MASS. EXPERIMENT STATION BULLETIN 427 



Field Experiments 



Thirteen fungicidal treatments were compared in the field in the 1929 experi- 

 ments on Jewel and Matchless carnations. Ten applications were made, the 

 first on June 21 and the last on September 29. Alternaria blight appeared early 

 in July but the disease did not become serious until September. A record of the 

 prevalence of the disease in the treated plots was made on July 20 prior to trans- 

 planting into the greenhouse benches. Calcium arsenate alone or in combina- 

 tion with lime sulfur caused injury which was subsequently followed by more 

 infection. Bordeaux with calcium arsenate was not injurious. A heavy infes- 

 tation of red spider mite developed on the plants treated with copper-lime dust, 

 and subsequently these plants also became badly infected with blight. Injury 

 from spraying and from the red spider mite clearly disposed the plants to more 

 disease. Unsprayed and uninjured plants showed an insignificant amount of 

 disease in 1929 up to July 30 (Table 20). The remaining plants in the plots in 

 the field continued to receive the fungicidal treatments, and the amount of disease 

 was determined by counting the infections on the cut flowers harvested from 

 September 14 to October 5, The best control was obtained with Bordeaux 

 mixture combined with calcium arsenate; with Bordeaux mixture and fish oil; 

 and with Bordeaux mixture plus calcium arsenate and fish oil. Control was 

 relatively poor with Bordeaux without the fish oil. The greatest amount of 



Table 20. Control of Alternaria Carnation Blight in the Field. 

 Jewel and Matchless Varieties. Waltham, 1929. 



Number of Infections 



Per Plant Per 100 Stems 



Fungicide' on 



July 30 Sept. 14- Oct. 28 



Oct. 5 



Dusts 



Sulfur 0.39 131 406 



Copper-Lime 20-80 0.69* 318 1,931 



Sprays 



Hammond's Copper Solution 1 gal. -50 gal 0.04 136 364 



Potassium Sulfide lMga].-50 gal..... 0.05 195 442 



Lime-Sulfur 1 gal.-50 gal 0.02 184 304 



Calcium Arsenate lJ^lb.-50 gal 1.66** 850 1,052 



Bordeaux 4-4-50 0.12 142 287 



Same, plus Fish Oil 3^ pt 0.01 53 167 



Bordeaux, Calcium Arsenate 0.00 • 63 162 



Same, plus Fish Oil J^ pt 0.02 54 129 



Lime-Sulfur, Calcium Arsenate 0.43*** 142 152 



Same, plus Fish Oil K pt - - -- 0.72*** 164 197 



No Treatment 0.04 519 1,056 



'Fish Oil was added to improve wetting. 



* Heavy infestation of red spider mite. 

 ** Severe injury; fungus secondary. 

 *** Injury prevalent; fungus secondary. 



