INFLUENCE OF SOIL TEMPERATURE AND MOISTURE ON 
INFECTION OF YOUNG WHEAT PLANTS BY OPHIOBO- 
LUS GRAMINIS 1 
By H. H. McKinney, Pathologist , and R. J. Da vis, formerly Field Assistant , 
Office of Cereal Investigations, Bureau of Plant Industry, United States Depart¬ 
ment of Agriculture. 2 
INTRODUCTION 
There are many statements in the literature regarding the influence 
of weather and soil drainage on the occurrence of the take-all and 
foot-rot diseases of wheat. In most cases, however, these reports 
have been based on rather casual observations which, in many 
instances, have been made on the foot **ots in general rather than on 
take-all, the specific foot rot caused by OpMobotus graminis. Doubt¬ 
less the lack of agreement among certain workers as to the influence 
of temperature and moisture on the take-all disease is due largely 
to the fact that they have been dealing not with one disease, but 
with several which are very similar in appearance but caused by 
different parasites. 
Gaillot (6) 3 states that in France wheat foot rot is favored by 
mild, moist weather, whereas Reuther (13) states that in Germany 
the foot disease was favored in 1913 by vernal frosts. In neither of 
these reports is it clear which foot rot is referred to, but it appears that 
these workers have in mind the foot rots as a whole. According to 
Lindau (10, p. 256) wet soil favors infection by Ophiobolus graminis, 
and directly in line with this Dombrovski (5) states that the proper 
drainage of the soil reduces losses due to this parasite. 
McAlpine (11) states that opinions are most conflicting in connec¬ 
tion with the occurrence of take-all in Australia. He states that 
some observers claim it to be more prevalent during wet seasons, while 
others say that dry seasons favor the disease. His own observations 
indicate that the disease occurs under all climatic conditions. Robin¬ 
son (14), also working in Australia, states that a dry summer followed 
by a wet winter affords the most favorable conditions for the develop¬ 
ment of the disease. Sutton (16), working in western Australia, and 
Waters (17), working in New Zealand, claim that wet soil conditions 
favor take-all, whereas Hori (7), working in Japan, thinks the disease 
is less prevalent on poorly drained soils. In this connection, however, 
it should be pointed out that Hori’s observations included a large 
number of cases of take-all on barley. It is entirely possible that the 
disease on this host may not react the same as on the wheat plant 
when placed under similar soil conditions. 
In this country take-all has been observed for so short a time that 
little definite information is at hand concerning its development in 
the field under different temperature and moisture conditions. 
Kirby (9), working in New York, states that his observations indicate 
little or no difference in the amount of infection occurring on high 
1 Received for publication Dec. 19, 1924; issued January. 1925. 
2 These investigations were carried on in cooperation with the Wisconsin Agricultural Experiment 
Station. 
8 Reference is made by number (italics) to “Literature cited,” p. 840. 
Journal of Agricultural Research, 
Washington, D. C. 
74333-261-3 
Vol. XXXI, No. 9 
Nov. 1, 1925 
Key No. G-504 
(827) 
