468 
Journal o f Agricultural Research 
Vol. XXX, No. 5 
and other references cited below). 
The above account indicates that the 
rot of pears and apples caused by a 
Phytophthora is rather widely dis¬ 
tributed in the United States. It is 
granted of course that the apples 
from Washington and Idaho are not 
known positively to have become 
infected with Phytophthora in the 
State where they originated. Never¬ 
theless, in the absence of proof to 
the contrary, it is fair to assume that 
they did become infected there. 
It is noteworthy that during this 
investigation Phytophthora rot was 
found in one lot, the storage lot of 
Rome Beauty apples from Idaho, 
approximately four months after the 
usual time for harvesting the variety 
named. Most of those who have 
studied this disease have found it 
either in fruit in the orchard or in 
fruit which had been taken from 
the orchard only a few days before. 
(Bubak (2), Clinton ( 2 ), Giissow (4), 
Hesler (14), Marchal ( 7 ) , Schoevers (12), 
Unamuno (13), Whetzel and Rosen¬ 
baum {15), and Wormald (16).) The 
apples in which Lafferty and Pethy- 
bridge (6) found the rot had been picked 
on October 14 and were sent to them on 
November 20. The authors make the 
statement (6, p. 29) that it is not known 
whether infection occurred prior to 
gathering or in storage. Osterwalder 
(8, p. 44-0) reports that he did not see 
the fungus at any time on stored apples. 
From the context the natural inference 
is that he is referring to the rot. 
What was thought to be Phytophthora 
cactorum was also reported in 1922 from 
Pennsylvania on growing apple fruits by 
Thurston (14)- 
SUMMARY 
There has been found on the Chicago 
market in pears and apples from 
Michigan and in apples from Wash¬ 
ington and Idaho a rot from which a 
species of Phytophthora has been 
isolated. 
This Phytophthora when inoculated 
into healthy pears and apples re¬ 
produced the diseases and was easily 
recovered from the affected tissues. 
Evidence is presented which in¬ 
dicates that the Phytophthora isolated 
from pears and apples is similar to 
and probably identical with P. cacto¬ 
rum. 
The observations of Lafferty and 
Pethybridge (6) are confirmed, that 
the apple and pear Phytophthora 
produces “sphaero-conidia” and both 
paragynous and amphigynous anther- 
idia. 
LITERATURE CITED 
(1) Beach, W. S. 
1922. THE CROWN ROT OF RHUBARB CAUSER BY 
PHYTOPHTHORA CACTORUM. Pa. Agr. Exp. 
Sta. Bui. 174, 28 p., illus. 
(2) Bubak, F. 
1910. DIE PHYTOPHTHORAFAULE DER BIRNEN IN 
bohmen. Ztschr. Pflanzenkrank. 20: 256-261, 
illus. 
(3) Clinton, G. P. 
1920. new or unusual plant injuries and 
DISEASES FOUND IN CONNECTICUT, 1916-1919. 
Conn. Agr. Exp. Sta. Bui. 222: 397-482, 
illus. 
(4) Gflssow, H. T. 
1920. PHYTOPHTHORA CACTORUM (LEB. ET COHN) 
schroeter. Phytopathology 10: 50. 
(5) Haskell, R. J., and Wood, J. I. 
1922. DISEASES OF FRUIT AND NUT CROPS IN THE 
united states in 1921 . U. S. Dept. Agr., Bur. 
Plant Indus., Plant Disease Surv. Bui. Suppl. 
20, 138 p., illus. [Mimeographed]. 
(6) Lafferty, H. A., and Pethybridge, G. II. 
1922. ON A PHYTOPHTHORA PARASITIC ON APPLES 
WHICH HAS BOTH AMPHIGYNOUS AND PARA¬ 
GYNOUS ANTHERIDIA; AND ON ALLIED SPECIES 
WHICH SHOW THE SAME PHENOMENON. Sci. 
Proc. Roy. Dublin Soc. 17: 29-43, illus. 
(7) Marchal, E. 
1908. SUR UNE MALADIE NOUVELLE DU POIRIER. 
Bul. Soc. Roy. Bot. Belg. 45: 343-344. 
(8) Osterwalder, A. 
1905. DIE PHYTOPHTHORAFAULE BEIM KERNOBST. 
CentbL Bakt. (II) 15: 435-440. 
(9) Pethybridge, G. H. 
1913. ON THE ROTTING OF POTATO TUBERS BY 
A NEW SPECIES OF PHYTOPHTHORA, HAVING 
A METHOD OF SEXUAL REPRODUCTION NOT 
hitherto described. Sci. Proc. Roy. Dub - 
lin Soc. 13: 529-565, illus. 
(10) Rose, D. H. 
1924. LEATHER ROT OF STRAWBERRIES. Jour. 
Agr. Research 28: 357-376, illus. 
(11) Rosenbaum, J. 
1917. STUDIES OF THE GENUS PHYTOPHTHORA. 
Jour. Agr. Research 8: 233-276, illus. 
(12) Schoevers, T. A. C. 
1915. HET PHYTOPHTHORA-ROT DER PITVRUCHTEN . 
Tijdschr. Plantenziekten 21: 153-159. 
(13) Unamuno, L. M. 
1911. LOS ESTRAGOS DE LA PHYTOPHTHORA CAC¬ 
TORUM en las peras y ciruelas. (Abstract) 
Ztschr. Pflanzenkrank. 21: 379. 
(14) UNITED STATES DEPARTMENT OF AGRICUL¬ 
TURE, BUREAU OF PLANT INDUSTRY, PLANT 
DISEASE SURVEY: 
1918. APPLE. PHYTOPHTHORA ROT CAUSED BY 
PHYTOPHTHORA CACTORUM. U. S. Dept- Agr., 
Bur. Plant Indus., 2:168-190. [Mimeographed.] 
1922. Adams, J. F. diseases of fruit and 
NUT CROPS IN THE UNITED STATES IN 1922, U. S. 
Dept. Agr., Bur. Plant Indus., Suppl. 28: 392, 
illus. 
(15) Whetzel, II. H., and Rosenbaum, J. 
1916. the phytophthora rot of apples. Phy¬ 
topathology 6: 89-90. 
(16) Wormald, II. 
1920. A PHYTOPHTHORA ROT OF PEARS AND AP¬ 
PLES. Ann. Appl. Biol. (1919/20) 6:89-100), 
illus. 
