EXPERIMENTS IN THE CONTROL OF GRAPE ANTHRACNOSE. ( 



occasional diseased berries and cankered canes could be found. In 

 plat No. 6, which had been treated only one year, the diseased wood 

 and fruit* were especially abundant. 



Of the different mixtures used, the self-boiled lime-sulphur is 

 perhaps the least promising. It burned the foliage somewhat, and 

 there were more diseased fruit and wood in the plat sprayed with 

 this mixture than in that sprayed with Bordeaux mixture. 



The fungicides used in treating the dormant vines all seemed equal 

 in efficiency. For commercial purposes, however, the ease with 

 winch the mixture may be prepared must be taken into considera- 

 tion. From this point of view the concentrated lime-sulphur seems 

 to be best, as it is easily prepared and can be applied with any 

 good sprayer. The iron-sulphate and sulphuric-acid mixture is 

 somewhat more difficult to prepare, and any of the mixtures con- 

 taining sulphuric acid must be applied by hand unless a sprayer 

 especially adapted to withstand the corrosive action of the sulphuric 

 acid is devised. It would seem, therefore, that the lime-sulphur 

 solution will be most economical for dormant application. 



CONCLUSIONS. 



In conclusion, it may be said that anthracnose of the grape was 

 controlled in these experiments bj pruning out the diseased wood 

 and applying any one of four different treatments to the dormant 

 vines. The fungicides used successfully on the dormant vines were 

 two concentrations of the iron-sulphate and sulphuric-acid mixture, 

 a 4 per cent solution of sulphuric acid and a concentrated lime- 

 sulphur solution (1-10). A careful pruning out of the diseased 

 wood and treatment with summer sprays of 4-3-50 Bordeaux mix- 

 ture reduced the damage from disease to practically nothing. In 

 contrast to the results from the treatment the loss from disease on 

 the control plats in 1911 was 32.6 per cent and 12.2 per cent. In 

 1912 the loss on the control plat was 10 per cent of the fruit. In 

 addition to the diseased fruit, the young shoots and foliage in the 

 controls were considerably injured, while the treated plats were 

 practically undamaged. 



In combating anthracnose it would probably be advisable to com- 

 bine the treatment of the dormant vines with the use of the summer 

 spray, especially since black-rot or downy mildew of the grape is 

 usually present. The following treatment of anthracnose-infected 

 vineyards would then be recommended: 



(1) Prune out and burn all diseased wood; (2) spray the dormant 

 vines thoroughly with a concentrated lime-sulphur solution in the 

 proportion of 1 gallon of 32° Baume test lime-sulphur solution to 9 

 gallons of water; (3) spray the vineyard thoroughly five times, as in 



[Cir. 105] 



