46 BULLETIN 727, U. S. DEPARTMENT OF AGEICULTUBE. 



other bearing one lesion near the tip of a cotyledon, one lesion on the 

 first leaf, two on the second, and four on the third leaf. Unfor- 

 tunately, thinning had .again been completed. The next day 

 in another part of the field an infected plant was found which had 

 three lesions on the first leaf but none on the cotyledons. The 

 same day two other centers of two infected plants each were found 

 and the next day two more similar centers were found. In all of 

 these cases the lesions were fairly large, indicating that infection 

 had occurred perhaps two weeks previously. 



In the other four fields, similar original centers of apparently the 

 same age were found at about the same time. In field 2, the first 

 one found consisted of two adjacent plants, one with numerous 

 lesions on the first leaf. The first original center found in field 3 also 

 consisted of two diseased plants, of which one bore lesions on the 

 first leaf and on a cotyledon. In field 4 the first anthracnose center 

 was one very badly spotted plant, and in field 5 the first center noted 

 consisted of two diseased plants. Whether or not the originally 

 diseased plant was present in any of these cases is rendered question- 

 able because of the previous thinning operation. Just how the 

 fungus had passed the five weeks elapsing since the time of planting 

 the seed can not be answered at present. 



Near Albany, Ga., in a large watermelon field not previously 

 planted with this crop, careful search of about 1,000 hills revealed 

 only two single-hill centers of anthracnose. In each of three melon 

 fields near Monticello, Fla., one single plant center of anthracnose 

 was found. Single plant centers of anthracnose were found in one 

 field of cucumbers near Norfolk, Va. 



Under the fairly well controlled conditions among the Madison 

 fields in 1916, the simultaneous appearance of a few scattered centers 

 in each of the five experimental fields on land not previously sown 

 to this crop furnishes quite convincing evidence of disease intro- 

 duction with seed. But still more striking is the fact that anthrac- 

 nose appeared only in the five fields planted with seed from the same 

 source and not in the two private fields and numerous gardens also 

 under close observation (21). This correlates the occurrence of dis- 

 ease with seed from a particular source. 



ANTHRACNOSE IN SEED FIELDS. 



In view of the probability of seed carriage of the disease, as indi- 

 cated above, the next step was to ascertain what opportmiity there 

 was for the seed to become contaminated. First, was the disease 

 present in the seed fields ? 



A visit was made the first week in October, 1916, to a seed farm in 

 Ohio. The vines were dead at this time, but anthracnose was found 

 very prevalent on the fruits in certain fields. Since the seed fruits 



