PR ne NOMS. iON eam 
bowie >, 
Ay 
but with our present limited knowledge of its habits it is impossible 
Wa i ie 
AGRIOULTURE. 
4 a 
HS Ape “4 
Sie 
350 REPORT OF THE COMMISSIONER OF 
The germ tubes continue to increase in length without furt. 
change for about twenty hours, when there appear upon the free en 
slight swellings, which gradually enlarge and become more or les: 
globular and dark colored. When full grown these bodies are about — 
8 in diameter, and soon after attaining this size they germinateina 
manner similar to that of the original spore. a 
The tubes from these secondary spores continue growing and ulti- 
mately develop the same kind of bodies from which they were de-— 
rived, and this process continues as long as moisture and heat are — 
furnished (Fig. 4). | 
On the 18th of November, 1887, sporestaken from adiseased apple 
were sown in several places upon the cut surface of ahealthy Wine- 
sap. Spores were also sown at the same time upon the uninjured 
surface of the same specimen. Six dayslater the brown spots where — 
the spores were sown upon the cut surface were one-half an inch in 
diameter, while no effect whatever was produced where the sowings 
were made upon the uninjured surface. These experiments were 
repeated a number of times, but in no case did we-succeed in infect- 
ing the apple where the spores were sown upon the uninjured sur- 
ace. * 
Infection was readily secured by inserting a knife blade firstina 
diseased apple and then in a healthy one. About eight days after 
the spores are sown the little black pustules usually appear, show- 
ing that reproductive bodies have again been formed. 5 
There is frequently found at the base of the spore-bearing threads 
a rather thick and dark walled cavity (Fig. 2), which, as seen na 
cross-section, shows a clear zone completely filled with minute, col- 
orless, oblong bodies borne upon slender, transparent basidia or 
stalks that spring from the surrounding walls. 7 
These sacs or conceptacles are called pycnidia, a name determined 
by their contents. What may be their rdle in the economy of the 
fungus is a matter of question. It is probable, however, that they 
aid in some way in the propagation of the fungus. The spore- 
bearing threads first described, spring directly from the walls of the 
pycnidia, and it is probable that they live through the winter in the 
decaying fruit, as we have found them in abundance in January, and | 
at this date they developed a great number of spores when placed in 
a warm, moist atmosphere. : 
From the foregoing account of the disease and its cause, it willbe 
readily understood that we have a dangerous foe to contend with, - 
to suggest means of combating it. 
4,—TuE Rust or BEETS. 
Uromyces betce, Pers. 
(Plate IIL.) 
(a) GENERAL OBSERVATIONS. . 
This disease is not a new one to other countries, and the life his- 
tory of the parasite causing it was followed through by Kihn as 
early as 1869, while the summer form was described as Uredo betce 
by Persoon, and the winter stage as Uromyces betce by Tulasne 
earlier than this. The discovery of the scidio-stage is due to Kihn 
