THIRTY-SEVENTH ANNUAL REPORT. 27 



canvass of the state undertaken that fall showed about 70 per cent of the 

 men who had sprayed, while they had controlled scabs, had injured their 

 fruit, some so greatly that they refused to spray with Bordeaux mixture; 

 they preferred to run the risk of injury from apple scab and other fungi 

 rather than to use the Bordeaux mixture. We began the next year a set 

 of experiments to determine whether or not this mixture could be used 

 without injury, and under what conditions the injury did most damage. 

 Before that, however, I undertook a complete survey of the whole subject. 

 I wrote to several hundred apple growers in New York asking to have their 

 experience. I wrote to the horticulturists in every experiment station in 

 the United States ; I corresponded with men near the coast of Europe where 

 apples are grown ; I wrote to the Japanese ; I wrote to New Zeeland, and every- 

 where where Bordeaux mixture has ever been used, asking for the experience 

 in the use of this mixture. I thought by thus taking a broad survey of the 

 subject 1 might obtain some clews as to what the conditions at least were 

 under which trees suffered most; and from this survey I did obtain clews, 

 starting points which were invaluable in j^lanning the experiments which 

 we undertook last year. 



Before I go further, I suppose I may as well briefly describe this injury 

 that occurs to apples, not mentioning that which occurs to other fruits, 

 for it is the apple we are most concerned with; there may be some here who 

 have not observed it. On the fruit of the apple it first manifests itself early 

 in the season as small black dots, sometimes brownish dots, on the sprayed 

 surface of the fruit; that is, part of the fruit that you see is most sprayed; 

 as the season goes on, these spots multiply; when the fruits are half-grown 

 the spots begin to coalesce and run together; the cells of the epidermis of 

 the apple split and the fruit becomes badly russeted, and sometimes much 

 malformed and greatly reduced in size, and the general appearance of the 

 badly injured specimens is that of a cracked-open Flemish Beauty pear 

 that we so often see when badly affected with the scab that attacks the pear 

 and the apple. The fruit is not only reduced in size and malformed, and 

 thus injured in appearance, but its keeping quaUty is seriously injured. 

 We found from actual experiments in both cellar and storage work that the 

 breaking open of the epidermis by the spray allows the escape of the moisture 

 from the apple, so the fruit becomes mealy, and germs of decay set in the 

 injured fruit; it does not keep nearly as long as the sound fruit. On the 

 foliage yellow spots appear, brownish spots, very dark yellow, almost brown 

 at first. These eventually become almost black and the whole leaf turns 

 yellow, and much of the foliage drops in severe cases, so that often in a well 

 sprayed orchard a quarter and even half of the foliage lies on the ground. 

 Of course this means the fruit does not attain its full size and the crop is thus 

 crippled, and the tree growth so weakened that buds fail to set for the succeed- 

 ing crop, so that very material injury is caused to the tree as well as to the 

 current fruit crop by this injury. The blossoms are sometimes badly in- 

 jured if spraying is done — and it never should be done of course — while 

 trees are in blossom, and often the blossoms drop so that no fruit sets what- 

 ever. 



There are several other agencies that cause similar injuries. For instance, 

 the frost; a heavy frost soon after apples set, which causes the r-usseting of 

 the fruit. This frost injury is very similar to the Bordeaux injury. So 

 also the work of the blister mite, a small mite which gets under the epidermis 

 of the apple or into the epidermis, and causes an injury similar to the Bor- 

 deaux injury. So, too, one or two fungi at certain periods of the growth 



