54 BULLETIN 727, U. S. DEPARTMENT OF AGRICULTURE. 
the usual number of rows, twice the ordinary quantity, or about 2 
pounds of seed, was planted in each field. This allowed a test of 
about 70,000 seeds per field. 
TaBLE VII.—Effect of seed disinfection upon the occurrence of anthracnose in cucumber 
fields at Madison, Wis., in 1917. 
: Results. 
oe of Area. Subdivision. Seed treatment. 
On Aug. 13. On Sept. 8. 
One-quarter | West half...) 2 per cent formalde- | No anthracnose.) Noanthracnose. 
McKenna... acre. \ hyde,! 10 minutes. 
ae ts dos-=-- | asthalfes. 4 perscentetormalde=s|-pes “douse: Do. 
hyde,! 5 minutes. 
Pie doe=eee- West halfessiOlsspericentiCuSO7 10) bass -dors sees Do. 
Brittenbach - | minutes. 
cr key do.-2.+. 2) Kast half-._<|l-perecent*€uSO«g 5))|-----do_ eeee_ =: Do. 
minutes. 
sese do... .--..| North half*:| Hot-water,52° C.,,10' |S 2doress sates Do. 
Tobacco... .- minutes. 
eae does | south half 1915seedeuntreatedmer|assen0 One ae Do. 
TSomy ees One-halfacre=s|-e sass ase 1916 seed, untreated... .| 1 plant diseased..| 2 centers of an- 
thracnose. 
1 40 per cent solution. 
Until August 1 careful inspection of all of these fields was made 
twice each week. A special effort was made to detect an original 
diseased plant in the Isom field before the thinning and the elimina- 
tion of the interplanted rows, but no success was attained. Unfortu- 
nately, the first Sainnenoe: did not appear until a month after its 
normal date of appearance, and a complication is afforded by the 
earlier appearance of anthracnose in field 1 as a result of overwinter- 
ing in the soil. While the Isom field was a considerable distance from 
field 1, there is a possibility, even though very shght, of the introduc- 
tion of the disease by insects, pickers, or cultural operations. Since, 
however, the other fields were equally exposed to this type of infec- 
tion, it is significant that anthracnose appeared only in the field 
planted with 1916 untreated seed. This is taken as a rather convinc- 
ing indication but not conclusive proof of disease introduction with 
the seed. 
Assuming that anthracnose was present in the 1915 seed, its failure 
to appear in the south half of the tobacco field has some significance. 
It suggests that possibly the fungus does not survive the eighteen 
months’ desiccation. 
For the more extensive field, tests arrangements were rad with a 
pickling company whereby all ‘of the seed distributed to its erowers 
in one district was to be previously treated, while in a neighboring dis- 
trict similar seed, untreated, was to be used. This trial was made 
in triplicate, one trial in each of the three States of Indiana, Wiscon- | 
sin, and Michigan. Both Ohio seed and Iowa seed were thus tested; 
the former in Indiana and Wisconsin, the latter in Michigan. For 
the disinfection of all of this seed the treatment of proved effec- 
