TEMPERATURE RELATIONS OF APPLE-ROT FUNGI 1 
By Charles Brooks, Pathologist, and J. S. Cooley, Assistant Pathologist, Fruit 
Disease Investigations , Bureau of Plant Industry, United States Department of Agri¬ 
culture 
INTRODUCTION 
The retarding effect of low temperatures on plant activities is a matter 
of general knowledge, and the principle has had a very general applica¬ 
tion in the storage of fruits. The better preservation of the fruit at low 
temperatures is due both to the slowing up of the activities of the fruit 
itself and to the checking of fungus and bacterial growth. This paper 
deals particularly with the latter phase of the storage problem. An 
effort has been made to carry on the investigations in a manner that 
would make the data of general physiological interest as well as of 
practical value in fruit storage. 
HISTORICAL REVIEW 
Eustace 2 made one of the first studies of the storage-rot problem 
in this country. Several varieties of apples {Mains sylvestris ) were 
inoculated with Alternaria sp., Glomerella rufomaculans (Berk.) Sp. 
and Von Schr., Sphaeropsis malomm Pk., Penicillium glaucum Lk., 
Sclerotinia fructigena (Pers.) Schrt., and Cephalothecium roseurn Cda.; 
and similar inoculations were made on agar petri plates. After two 
months at a temperature that varied from 30° to 33 0 E. and averaged 
32 0 Penicillium glaucum had made a good growth on both the agar 
and the apples and Alternaria sp. had made a slight growth on the 
apples. None of the other fungi had produced any growth, but all of 
them developed rapidly when removed to a temperature of 70°. In 
another experiment inoculated fruit and agar plates were placed in a 
storage room in which the temperature ranged from 35 0 to 56° and aver¬ 
aged 47 0 . All of the fungi made a good growth. At a temperature of 
48° to 69° the development of the fungi was still more rapid. 
Schneider-Orelli 3 made experiments with Gloeosporium herbarum Lk., 
Mucor piriformis Fisch., Penicillium glaucum , Botrytis cinerea Pers., 
Monilia fructigena Pers., Fusarium putrefaciens Osterw., Gloeosporium 
album Osterw., Gloeosporium fructigenum Berk., and Rhizopus nigricans 
Studies on Fruit Rots and Spots.—I. 
2 Eustace, H. J. Investigations on some fruit diseases. N. Y. State Agr. Exp. Sta. Bui. 297, p. 31-48, 
7 pi. 1908. 
3 Schneider-Orelli, Otto. Versuche fiber die Wachstumsbedingungen und Verbreitung der Faulnis- 
pilze des L-agerobstes. In Landw. Jahrb. Schweiz, Jahrg. 25, Heft 3, p. 225-246. 1911. Also in Centbl. 
Bakt. [etc.], Abt. 2, Bd. 32, No. 6/12, p. 161-169. 1912. 
- Zur Kenntnis des mitteleuropaischen und des nordamerikanischen Gloeosporium fructigenum. 
In Centbl. Bakt. [etc.], Abt. 2, Bd. 32, No. 13/19, p. 459-467. 1912. 
Journal of Agricultural Research, Vol. VTII, No. 4 
Washington, D. C. ' Jan. 22,1917 
Sx Key No. G—103 
( 139 ) 
