522 Journal of Agricultural Research Vol. III, No. 6 
The map (fig. 3) shows the location of the coppice growth and other 
chestnut trees than those used in the test, with the position of the 
exposure stations. The character of the diseased coppice growth is 
shown in Plate LXV, fig. 1, which shows a view taken from Station V. 
The older forest, which was the source of the ascospores for the traps 
exposed at Station VI, is shown in Plate LXV, fig. 2. The period from - 
August 30 to November 11, 1913, was covered by the tests presented in 
Table XVII. ; 
The time and amount of rainfall, and in some cases the wind direction, 
are necessary in interpreting the results. Table XVIII gives the rainfall 
for the time covered by the water spore-trap tests. 
TaBLE XVIII.—Rainfall record for period covered by the water spore-trap tests in 
1913 at West Chester, Pa. 
Date of rain. Rainfall. Date of rain. Rainfall. Date of rain. Rainfall. 
Inches. Inches. Inches. 
Aug. 29 and 30 1.10 || Sept. 21 and 22 0. 83 || Oct. 20........ 0. 08 
Sept. 7and 8 -37 BO... sees 02 Ly rs 
12 and 13 -095 || Oct. 1......... I. 12 2 Beccaveniinsis 1. 44 
17 and 18 .26 Bie ie vitae eure .12 BO wiesnvecesare 
18 and 19 . 68 1B sleet . 06 || Nov. 8 and 9.. 1.00 
1g and 20 . 09 1S eee +73 
2oand 21 43 LO¥ eves saws . 86 
Tests Nos. 1, 2, and 3 were started in the field after the rain of August 
29 and 30, late in the day, and the traps were taken to the laboratory 
for analysis before the next rain. Judging from the results obtained 
from our exposure plates, no ascospores should have been present, and 
our failure to get any colonies of the chestnut-blight fungus in the test 
cultures suggests that during that period there was no wind dissemina- 
tion of either pycnospores or ascospores. There was a small amount of 
rain during the period that traps 4 and 5 were exposed, but the analyses 
were not made until two and three days later. Considering the fact that 
ascospores germinate at once in water, the failure to get any colonies of 
the Endothia parasitica in these tests is not surprising and again points 
to the absence of pycnospores. Traps 6, 7, and 8 were removed from 
the field a few hours after the heavy rain of September 18 and 19, and 
the analyses gave a large number of colonies of the chestnut-blight 
fungus. It appears probable that the spores were caught during the 
few hours following ‘the rain, since the cultures indicated the origin of 
the colonies from ascopores only (5). It should be noted from Tables 
XVII and XVIII that traps 9 to 12 were removed from the field just 
following periods of rain. The wind was blowing from the infected trees 
toward trap 10 only, and this was the only one in the series which yielded 
the blight fungus. Traps 13 to 16 were removed from the field shortly 
after the rainy period of October 24 to 26, and all yielded positive results, 
trap 16, located 389 feet from the nearest chestnut tree, giving 431 spores. 
The length of time after the rain when the tests were made and the 
direction of the: wind are the possible explanation for the negative re- 
sults for traps 17 to 19. Unfortunately no traps were exposed during 
the rainy periods of October 1 to 3 and October 11. 
It is probable that the figures recorded for tests Nos. 6 to 8 and 13 to 16 
represent the number of spores blown into the traps during the few hours 
