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EXPERIMENTS with Nursery Stock. 663 
Arrir Powpery Mitpew (Podosphera oxyacanthe [DC] Winter?) 
Seedling apples sometimes suffer quite severely from this dis- 
ease, which attacks their young shoot tips, often stunting the 
_ growth of the seedlings and preventing them from attaining 
_ a suitable size the first season. Compared with the injury caused 
by the apple thrips, however, that brought abour by the mildew 
is surely insignificant and, in New York State at least, hardly 
warrants any expensive measures in its prevention. The disease 
usually appears late in September, when the principal growth has 
been made, and seldom, if ever, spreads to vigorously growing 
_ budded stocks, even when these are in close proximity to dis- 
eased seedlings. The malady was not observed on bearing trees 
in the neighborhood of Geneva. 
The experiments in the prevention of this disease comprised in 
_ 1891 about 1,000 American stocks and the same number of French 
stocks, besides 500 seedlings. As stated in a previous publication,* 
_ the results of the first season’s treatment of the stocks was entirely 
negative and the treatments of seedlings which were made on 
May 21, June 3, 24, July 9, 24, and August 8, as well 
as the early treatments made on the first three dates 
- mentioned, failed entirely to prevent the appearance of 
: mildew the first week in September. Bordeaux mixture — 
and ammoniacal solution alone were used, the formule being 
those described on pp. 670, 671. This failure of the fungicides is 
considered by the author merely as additional testimony to the 
fact observed, that the mixtures were largely washed off before 
the disease appeared. On August 7 the French and Ameri- 
can stocks were budded with Twenty Ounce, Fameuse and Early 
Strawberry buds, as described in detail on p. 667, and in the season 
of 1892 the budded, and such of the stocks as were left unbudded, 
were treated with Bordeaux mixture and ammoniacal solution at 
dates the same as for all other stocks, viz.: May 27, June 16, 23, 
July 7, 21, and August 5. One-half the treated stocks were sprayed — 
_ five times on the first five dates mentioned, the other half were 
| Sprayed six times. | 
No powdery mildew appeared during the course of the season, 
and in October the results of the treatments were entirely nega- 



* Bull. No. 3,:1..¢., p. 60. 
