= 
New YorK AGRICULTURAL EXPERIMENT STATION. (ae 
approximate the conditions at the outside and at the interior of 
commercial packages of seed held in storage. 
SOURCE AND PATHOGENICITY OF CULTURE. 
The culture of P. campestris which was used in this test was 
isolated in March, 1902, from a Long Island seed cabbage which 
had already passed the winter in the trenches. 
To be certain that neither its exposure to low temperatures 
during the winter nor its subsequent long cultivation in the 
_laboratory had destroyed its pathogenicity it was inoculated with 
proper precautions into two young healthy cabbage plants in 
the greenhouse, April 6, 1903. Ten days later the first signs of 
black rot were showing and within a few days both plants 
developed unmistakable evidence of this disease. The check plants 
remained healthy. 
EXAMINATION OF THE SEED. 
Tubes containing 5 seeds each were examined at intervals of 
about a month. One to two ce. of sterile water was added to each 
tube and allowed to stand over night. On the following morning 
the water and seeds were distributed among three lactose agar 
plates. From these plates the resulting colonies were removed 
and studied. 
A detailed statement of the dates and results of the various 
examinations is given in the accompanying table. 
TaBLy [EXAMINATION OF TUBES CONTAINING ARTIFICIALLY 
INFECTED CABBAGE SEED. 
| 
| Tusres CONTAINING 
TuBEs EXAMINED. P. campestris. 
DATE. Interval. 
| | 
| Not | Not 
| Paraffined. paraffined. | Paraflined. paraffined. 
; Months. No. | No. No. No. 
A aia!! AIDS ae ots B16 ofa eRe oe Or COD Dine Reread ek tae nt aD Aol eee eicreeeac a rnieie aee 
MIDIS #2 Sh, Siocate ether niahs 1 | 3 3 2 2 
Ugh ees ah ce erteteie wisn 2 3 4) 1 2 
PAUSE RRO sis cccnvos¢ 3 1 1 0 | 0 
September 4.......... 4 | 3 3 1 | 1 
October Bee 5G jaws 5 | 3 3 2 | 3 
November 7.......... 6 | 3 3 3 | 3 
December oe athe 7 | 3 3 } 2 2 
January 14., bey) earl 84 | 1 1 | 0 0 
MANUAL: O85 oie eae, ae 9 1 1 0 0 
February 26.....5..:.06 10 3 3 2 3 
AS aia 7 RO eee 11 2 2 1 if 
PLLA GeaLee EN foie eieser -$ stays! aaa oye 26 26 14 | 17 
*Experiment started. 
