ANTHRACNOSE OF CUCURBITS. 831 
conditions is not clear; unless the rains of July 12, 16, and 19 served 
to render conspicuous the incipient centers already existent. 
We have then, on August 1, 20 centers in field 1 and 13 in field 2, 
none of -which were showing much secondary infection. The further 
observation of anthracnose occurrence in fields 3, 4, and 5 was inter- 
AMY 
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AYOGUS7- SLPOTLITELSO 
Fic. 12.—Diagram showing the weather conditions at Madison, Wis., during the summer of 1916. The 
curverepresents the daily mean temperatures; the dotted line, the approximate optimum for the fungus; 
the black columns, the rainfall. 
fered with by the removal of plants in connection with a mosaic con- 
trol experiment. The data presented above, as well as results that 
were obtained later on these fields, are summarized in Table III. 
Taste III.—Anthracnose in fields at Madison, Wis., in 1916. 
Progress of disease. 
: : Date 
Field. ae Number Number Number 
: Date. of Date. of Date. of 
centers. centers. centers. 
INO nS etnrak a ceteris ho Kil iyele July 19 | July 27 15 | Aug. 3 20} Aug. 15 46 
TNO} a aie eg ey A July 2On Ie sadoe-s: 5} Aug. 1 13 | Aug. 14 30 
INOS Sen rece emt eat are ied July 21 | July 21 1} July 26 5 | Aug. 11 12 
Doha Cis a ees ie hes cease OOO ae July 22 | July 22 1 ee ea eh aba Aug. 18 6 
IN| Os OSes a ee a ME lat OHeiex ac6lO sade Ps iat ks alee a eT ee A dorses 10 
INO sel Qe Oe a GERI Ca oa a hae Aug. 24 | Aug. 24 1 EY faeces a Aug. 30 2 
The slowness of spread of the disease up to the first week in August 
may be in part explained by the extremely hot, dry weather of July, » 
with no heavy rains after July 20. Reference to the weather chart 
will show that the daily mean temperatures during the latter part of 
July were well above the optimum (75° F.) for this fungus. Edger- 
