NOTES' ON FACTORS IN FUNGUS DISEASES OP PLANTS, WITH RECORDS 
OP OCCURRENCES OP PLANT DISEASES AT AMES FOR 
A PERIOD OP TWENTY-FIVE YEARS. 
BY L. H. PAMMEL AND CHAELOTTE M. KING. 
STATEMENT OF THE PROBLEM. 
Literature. 
Nature of Disease. 
Two Kinds of Disease. 
Factors of Environment in Plant Disease. 
The Plant an Organism Responsive 
to Outside Conditions. 
Influence of Soil and Air in Plant 
Disease. * 
Influence of Soil and Moisture. 
Influence of Lig-lit. 
Influence of Acclimatization. 
Fungi as the Cause of Disease. 
Two Kinds of Parasitic Fungi. 
How Fungi are Spread. 
Wind an Agent of Infection. 
Water an Agent of Infection. 
Carrying of Fungi by- insects. 
Other Animals as Means of In- 
fection. 
Fungi Scattered by Explosive 
Properties. 
Fungi Scattered by Farm Tools. 
Soil Moisture and Fungus Diseases. 
Asparagus Rust. 
Celery-root Rot. 
Grain Rust. 
Weather and Fungus Diseases. 
Exoasceae, 
Rust. 
Peronosporeae. 
Monilia Disease. 
Apple Scab. 
Some Epidemics of Fungus Diseases. 
Mildews. 
Rusts. 
Downy Mildews. 
Apple Blight. 
Clasterosporium, 
Immunity and Disease — resistant varie- 
ties, 
Acclimatization. 
Some resistant varieties. 
Immunity from one disease on ac- 
count of the presence of an- 
other. 
Susceptibility of transplanted plants. 
Immunity through fertilizers. 
Immunity by presence of toxin. 
Biologic Species. 
It is important in a study of plant diseases to understand the causes of 
wide-spread epidemics; notes on the prevalence of diseases, and their seasonal 
and geographical distribution, are an aid to this knowledge. 
LITEEATUEE ON THE SUBJECT OE PLANT DISEASES. 
Some Iowa Puhlications. In 1882 was begun by L. H. Pammel a series of 
notes on fungi common in Iowa, especially in the vicinity of Ames. These 
notes have been presented in various publications as follows: 
The Asparagus Rust in Iowa. Bull. la. Agr. Exp. Sta. 53 : 60-67. 
Bacteriosis of Rutabaga. Bull. la. Agr. Exp. Sta. 27:130-134. 
Corn Molds and disease. Bull. la. Agr. Exp. Sta. 54 :250. 
Corn Smut. Proc. la. Acad. Sci. i:95-96. 
Diseases of ‘plants at Ames, 1894. Proc. la. Acad. Sci. 2:201-208. 1894. 
Experiments with fungicides. Bull. la. Agr. Exp. Sta. 16 :316-329. 
Fungus diseases of grasses. Bull. la. Geol. Survey. 1:185-292. 
Fungus diseases of grasses. Bull. la. Agr. Exp. Sta. 54:250-344. 
Fungus diseases of plants and their remedies. Rept. la. Hort. Soc. 3 :440-444. 
The most important factor in the development of rust. Agr. Sci. 8:287^291. 
New Fungus diseases in Iowa. Jour. Mycology 7:95-103. 
Notes on some fungi common during the season of 1892 at Ames, Iowa, Agr. Sci. 
7:20-27. 
Potato-rot and its prevention. Bull la. Agr. Exp. Sta. 27:120-130. 
The potatO-rot fungus. Press Bull. la. Agr. Exp. Sta. July, 1903. 
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