454 Report or THE HoRTICULTURIST OF THE 
tial preventive, because when the rot attacks one of a cluster of 
fruits it usually spreads till every fruit in the cluster is diseased. 
When the fruits do not touch each other the disease is less 
destructive. 
LEAF SPOT. 
(Cylindrosporium padi Karst.) 
This disease is discussed under leaf spot of the cherry. See 
page 421. In general it is more liable to produce the shot hole 
appearance on plum foliage than on cherry foliage. 
Treatment.—As a result of extended experiments it can be 
stated that the plum leaf spot may be controlled by thorough 
treatment with Bordeaux mixture, 1-to-11 formula. In some 
seasons two treatments are most economical, but under conditions 
favorable to the disease at least three should be given.*® If but 
two treatments be made give the first about ten days after the 
blossoms fall, but not later than June 1; make the second treat- 
ment about three weeks later. The disease may be better con- 
trolled by three treatments and usually three treatments will be 
most profitable. Make the third from three to four weeks after 
the second. 
YELLOWS. 
The Japanese plums are subject to a disease which has the 
appearance of peach yellows. It occurs on trees which have been 
worked on plum roots as well as on those which are on peach 
roots. No remedy is known. 
The treatment recommended is the same as that which is recom- 
mended for peach yellows — dig out and burn the diseased trees. 
PLUM INSECTS. 
PLUM CURCULIO. 
(Conotrachelus nenuphar Herbst.) 
Description.— The adult is a small, peculiar, gray beetle. It 
passes the winter under the bark of trees, or under rubbish, and 

48 Beach, 8. A. Sixteenth Ann. Rept. this Station, 1897: 211. 
