426 STATE HORTICULTURAL SOCIETY. 



Powdery mildew. — The fungus causing this disease succumbs readily to 

 treatment with any of the copper compounds.* Where the disease exists 

 alone we would recommend the use of the ammoniacal copper carbonate 

 solution. In regions where the mildew is common the vines should be 

 carefully watched, and at the first sign of the trouble, applications should 

 begin and be repeated at intervals of 12 or 15 days. Excepting on the 

 Pacific coast there are comparatively few regions where this disease exists 

 alone, and of course where it is associated with any of the other maladies 

 mentioned in this paper one treatment will answer for all. 



Black rot — Four general methods of treating this disease are now prac- 

 ticed by us, as follows: 



1. In spring, after the vines have been pruned and before the buds 

 begin to swell, spray the wood with the simple solution of copper sulphate. 

 About the time the leaves are one third grown apply the Bordeaux mixture. 

 Repeat the latter treatment when the vines are in full bloom and thereafter 

 at intervals of 10 or 12 days until the fruit begins to ripen. 



2. Omit the spraying with the simple solution, but for the rest follow 

 the rules laid down in No. 1. 



3. Treat exactly the same as No. 2, except use the ammoniacal solution 

 instead of the Bordeaux mixture. 



4. For the two first treatments apply the Bordeaux mixture the same 

 as in No. 2, then for the rest of the season use only the ammoniacal copper 

 carbonate solution. 



In regard to these various methods it may be said that No. 1 is objec- 

 tionable on account of the additional cost of the treatment with the simple 

 solution. In the majority of cases it is doubtful if these early applications 

 do any real good; still in an old vineyard which has never been treated, it 

 may prove beneficial by destroying many of the dormant spores. Method 

 2 is probably the most reliable of all, as it has stood the test of several 

 seasons and has never failed us, no matter how favorable the weather is for 

 black rot and other diseases. It is more expensive than either No. 3 or 

 No. 4, moreover the mixture by spotting the fruit may render it unfit for 

 market. The plan outlined under No. 3 last season gave fully as good 

 results as any of the others. It possesses the advantage of being cheap 

 and requires no special apparatus to carry it out. The last method, or No. 

 4, has no particular advantages over the others unless it be that it allows 

 the use of the Bordeaux mixture at a critical period without danger of 

 spotting the fruit. All things considered we should advocate for an ordin- 

 ary season either No. 3 or No. 4, but if heavy rains are frequent we would 

 recommend that the Bordeaux mixture alone be used. 



Anihracnose. — This disease rarely occurs alone. As a rule it is found 

 associated either with black rot or mildew, and when this is the case no 

 additional treatment can, in the present condition of our knowledge, be 

 recommended. For anthracose alone the only remedy that has given any 

 beneficial results is the Bordeaux mixture, applied in the same manner as 

 recommended for black rot. 



General treatment. — In many parts of the country it is a common thing 

 to find downy mildew, black rot, and anthracnose all working together. In 

 such cases the question has arisen as to whether we could not devise some 

 general treatment which would hold all of these maladies in check. Experi- 



*This does not refer to Vinifera stock. 



