132 TWENTY-FIFTH ANNIVERSARY REPORT. 
CHRYSANTHEMUM. 
The common Septoria leaf spot of chrysanthemums being preva- 
lent among plants in the Station greenhouse in the fall of 1891, an 
experiment on its control by spraying was undertaken. Three fun- 
gicides were tested — potassium sulphide, ammoniacal solution of 
topper carbonate and bordeaux mixture. Bordeaux gave results 
sufficiently good to warrant the recommendation of its use combined 
with the careful removal of diseased leaves. 
CLEMATIS. 
Stem rot, or the decay of clematis plants at the surface of the 
soil, has long been known as a destructive disease and a puzzle to 
plant pathologists. In 1884 the Station botanist made an attempt 
to learn the cause of this disease.®° A fungus belonging to the 
genus Phoma was found growing in the decayed roots of diseased 
plants, and it was suspected of being the cause of the trouble; but 
positive proof of this was lacking. Up to the present time the 
cause of the clematis disease has not been definitely determined. 
CORN. 
While New York is not one of the so-called corn States, corn is, 
nevertheless, a very important crop here. Fortunately, it is subject 
to but few diseases, smut being the most important. In some sea- 
sons truck farmers on Long Island suffer considerable loss from a 
wilt disease of sweet corn. Affected plants wilt and dry up without 
apparent cause. This may occur at any stage of growth, but most 
commonly about the time of tasseling. The disease is most de- 
structive to early dwarf varieties. The most characteristic symp- 
tom of the disease is the appearance of conspicuous yellow streaks 
within the lower portion of the stem. 
An investigation of this disease was made by the Station in 1896 
and 1897.8 Strange to say, it was found to be an undescribed 
disease and the organism causing it unknown to science. It soon 
became evident that the cause of the trouble is a yellow bacterium 
which multiplies to enormous numbers in the water-conducting 
vessels of the stem, clogging them and thereby hindering the ascent 
of water from the roots to the leaves. The bacteria-laden vessels 
appear as yellow streaks in the white pith of the corn stalk. 
© Rpt. 11:557-560 (1892). 
* Rpt. 3:383-385 (1884). 
* Bul. 130 (1897); same in Rpt. 16:401-416. 
