ANTHRACNOSE OF CUCURBITS. 51 
ATTEMPTS TO PROVE THE PRESENCE OF THE FUNGUS ON THE SEED. 
With all of the observational evidence pointing so strongly toward 
seed carriage of the fungus, repeated efforts were made during the 
spring of 1917 to isolate the organism from commercial seed or in 
other ways to prove its presence. 
Besides numerous samples of seed collected at the Ohio farm 
at different stages in the cleaning process, a generous supply of 1916 
seed was later secured from that farm. This seed, as well as some 
of that used in 1916, was tested in a variety of ways in an attempt 
to detect the presence of the anthracnose fungus. The following 
methods were employed: 
(1) Seeds were placed in agar plates. 
(2) Seeds were planted in Petri dishes on sterile filter paper moistened with water 
or a nutrient solution. 
(3) Seeds were planted in large damp chambers on moistened filter paper. 
(4) Seeds were planted in sterile sand in damp chambers. 
(5) Seeds were planted in sterile soil in flats in the greenhouse. 
In the first three methods the fungus might be detected by its 
saprophytic growth on the substratum or by its parasitic develop- 
ment on the seedling. In the last two methods the latter possibility 
was relied upon. The results of these tests are summarized in 
Table V. 
TaBLeE V.—Summary of laboratory tests of cucumber and muskmelon seeds to prove the 
presence of the anthracnose fungus. 
Seed used. Time 
Date. Method. in 
Source. Number. days. 
_ 1916. 
INWRS As} |) MON ea OM as Bik SO A (1) 11 dilution plates in 2 per cent dextrose 8 
Le agar from wash water. 
1917 
TSO Goel IO) cKO WO Bia A oe AY ie Sir 15 | 5ineach of3 plates, 2 per cent dextrose agar - 8 
5 | Muskmelon seed, 1915. .....--- AGA See ClO) Saas reais SA ce Udeiaar as Baees eae 8 
5 | Ohio (fruit tissue adhering). . . 24 | 6 in each of 3 plates, 2 per cent dextrose 17 
solution in filter paper. 
ESS UOali Coys SPB ie ie Berks Sey Re rie ete Soll Spiones ia lees Oe Doe adage soko seaascscos 17 
5 eae (fruit tissue adhering). - . 30 | 6 seeds in each plate; filter paper plus water. 17 
26 nT Ose rere eel ULI ae Mey Ne Sh 2 200 | Wash water on cucumber plants........... 14 
26 Ohio (fruit tissue adhering)... 33 | In arops of water on cucumber foliage; 2 (2) 
ants. 
Mare eet | OO eins ore OR ena 1, 200 12'sterilized sand flats, in greenhouse... .... 14 
U2 ae aee GO ee ae SR ea 150 | Damp chamber, wet filter paper.....-...-. 18 
12 ee collected in October, IO osse CLO eae rere ge erie here ee se cules aL 18 
mallow eee Bae OHSS ES Ei eee 200 | Sterile sand, in damp chamber.......... 23 
LA eee GONE een aero ieee 48 | 2 per cent dextrose solution, in filter paper. 16 
P83 | ON OUKG) Aes Se aT a Sheers Ain a cea GHNWie UWL Cer paDel= ene. enercs a aser ae aCe ar 16 
WDB liane O10 ae RUE Eee re aan e 12 | Prune decoction, in filter paper............ 16 
ZO ROM cle Ol ome me sees ae pane 6 | 2 per cent dextrose solution, in filter paper. . 15 
23 d GF RAVWAC (Gs fall Ge Tap tos can Teepe pee ee a ce SU 15 
12 | Prune decoction, in filter paper..-......... 15 
100 | Wet filter paper, in damp chamber......... lve 
LOON PEA: LOS a Sse Ra i Pata etapa acto Bret iota ns 16 
LOOW Steril eisanadhaimytl aie eee see ee 16 
NGO |ssses (OA rie Aina aman ern ern Gh catia Saale aery 16 
ATOOR eee COR eee eee claret ton ae 16 
AQORP Sterile loamy iatilats ses) soe ene ne 16 
60 | Sterile sand, in damp chamber............. 14 
4, 069 
1 Two pounds. Failure, 
