48 
IOWA ACADEMY OF SCIENCE 
the style. An examination of scores of flowers showed that in the majority 
0 ^ cases they were infected, and in these cases, without exception, the points 
of infection were identical with the spots touched by the bees.” 
Fungi Spread 'by Other Animals. The spores of many fungi pass uninjured 
through the digestive tract of animals. It is probable that some of the spores 
of corn smut may pass the digestive tract of herbivorous animal uninjured, 
just as corn and other cereal grains often do. Corn smut is more resistant 
to heat than corn is; it is probable that the digestive juices will not entirely 
destroy the spores of corn smut. The spores of many fungi are accidentally 
carried by insects by attaching themselves to the body of insects, birds, or 
other animals. Birds like woodpeckers may convey many wood fungi by 
opening holes in trees; the same is true of boring insects. In a disease of 
cotton studied by one of us in 1889, it was shown that mice and other rodents 
scattered the sterile mycelium of the Oozonium. 
Fungi Scattered by Explosive Properties. Many fungi have explosive prop- 
erties but there are few of these among our cultivated crops. The Morchella, 
or Morel, forcibly ejects its spores ; so too, the cup-fungus, or Peziza, from which 
the spores are ejected; the Polyporus and various wood-fungi, and the Agaricus 
and other mushrooms, scatter their spores iir the same manner. 
Fungi Spread by Farm Tools. The pruning knife may be the cause of the 
spread of many diseases like pear blight. A knife used for cuttings when in 
contact with a contaminated soil may frequently contaminate many cuttings 
as in the Botrytis disease of the House Geranium. Farm implements used to 
cultivate the soil may spread many root diseases as shown by one of us in 
connection with the root-rot of cotton and other root diseases of the orchard 
and garden. The number of instances of such diseases might be multiplied. 
SOIL MOISTUEE AND FUNGUS DISEASE. 
Asparagus Rust. Regarding infection Prof Ralph E. Smith^^ makes inter- 
esting observations. After the statement that the marked freedom from rust 
of two seasons was due to unusual rainfall, he says; “In the dry seasons dnd 
upon the drier soils lack of moisture unquestionably reduced the vitality of 
the asparagus plants. Consequently they become more susceptible to disease 
and suffered in inverse proportion to the amount of soil moisture available.” 
The observations of Mr. Sirrine®^ led to the conclusion that the relation of 
atmospheric moisture in the form of dew or fog is the most important factor 
of this nature in the development of asparagus rust. 
Stone and Smith®® found a difference in the prevalence of the disease accord- 
ing to the moisture retaining properties of the soil, the trouble being worse 
upon the drier soils. 
Celery Root Rot. Mr. J. N. Hook®^ found that a serious root rot of celery 
in Ohio was caused by a species of rhizoctonia. The disease appeared in soils 
in which celery had been grown for several years and the diseased spots seemed 
to occur where the ground was lower or not well drained and the soil condi- 
tion seemed to be largely responsible for it. 
siBot. Gaz. 38:19-43. Bull. Cal. Agr. Exp. Sta. 165:51-58. 
32N. Y. Geneva Exp. Sta. Bull. 188. 
33Bull. Mass. Hatch Exp. Sta. 61. Ann. Repts. Mass. Hatch Exp. Sta. 12, 1.), 15. 
3^Cir. Ohio Agri. Exp. Sta. 72:6. 
