209 
difference between them and tlie untreated so far as rust was con¬ 
cerned. Where Bordeaux mixture, ammoniacal solution, ferrous ferro- 
cyanide, and cupric ferrocyanide were used the wheat was certainly 
much greener and more vigorous than in the untreated plats. In the 
miscellaneous treatments nothing appears to warrant the assumption 
that any of them prevented rust. 
In searching for the rust an interesting fact was brought out in con ¬ 
nection with the distribution and spread of the fungus. In every case 
the affected plants were found in spots scattered here and there in the 
plat. Frequently 25 or 30 plants growing together would be found 
badly rusted, while plants all around would be perfectly free from the 
disease. Again a single plant in a plat would be found showing per¬ 
haps only one affected leaf. Observations made upon these rust areas 
revealed the fact that they acted as centers of infection, the parasite 
spreading from them to adjoining plants and thence to other parts of 
the field. 
Examining the weather record for ten days preceding the discovery of 
rust, we find nothing to warrant the belief that the simultaneous appear¬ 
ance of the fungus the first week in May in widely separated spots was 
due to peculiar climatic conditions. The weather conditions at this 
time, so far as relates to temperature and rainfall, were not abnormal, 
as will be seen by consulting the table given below: 
Table 3. —Showing the daily mean temperature and daily precipitation at Garrett 
I*ark, Md., from April 20, ISO2, to May 20, 1S92. 
Date. 
Tempera¬ 
ture. 
Precipita¬ 
tion. 
Apr. 20 
40 
0. 85 
Apr. 2L 
44 
1.30 
Apr. 22 
52 
0. 80 
Apr. 20 
54 
Trace. 
Apr. 24 
55 
Apr. 25 
46 
Apr. 20 
49 
Apr. 27 
53 
Apr. 28 
02 
Apr. 29 
02 
0.40 
Apr. 30 
58 
May 1 
02 
May 2 
02 
Trace. 
May 3 
GO 
May 4 
00 
May 5 
75 
May 6 
05 
May 7 
02 
May 8 
45 
May 9 
01 
Trace. 
May 10 
50 
May 11 
04 
0. 09- 
May 12 
56 
May 13 
57 
Mav 14 
50 
0. 09 
May 15 
56 
Trace. 
May 1G 
59 
May 17 
05 
May 18 
50 
1.10 
May 19 
59 
May 20 
62 
Seventeenth treatment (May 16, 1892 ).—No critical notes were made 
on the experiment at this time. All plats were sprayed and dusted in 
the usual way, and from 50 to 100 specimens were collected from each. 
