849 Report ofr THE HORTICULTURAL DEPARTMENT OF THD 
experiment of this kind, since old infections cannot be cured and 
new ones are not rapidly formed. 
Another year’s observation confirms the recommendations 
made last year in regard to spraying with Bordeaux mixture, 
with good orchard sanitation, as a preventive of apple-tree 
canker. The presence of this disease in neglected orchards and 
its absence in orchards that have been well sprayed and well 
‘eared for in general, is strong evidence that with most varieties 
the disease may be easily controlled; but with some of the more 
susceptible kinds as the Esopus and the Twenty Ounce it is quite 
probable that the conditions known as sun-scald and sun-burn 
must be overcome before the canker fungus will be successfully 
combated. 
Another point of practical importance not mentioned in the 
former bulletin is the method that some orchardists have 
adopted for saving the larger diseased limbs. This is done by 
sawing the limb off just back of the diseased area and then 
inserting cions of the same variety. 
MACROPHOMA AND APPLE-TREE CANKER. 
In Bulletin 163, page 203, Macrophoma malorum (Berk.) Berl. 
et Vogl., is mentioned in connection with the body blight of the 
pear. This fungus is very common on both apple and pear trees 
and during the past season a number of cankered apple-tree 
limbs were found on which the injuries were evidently due to its 
attack. 
After repeated trials the fungus was finally induced to grow 
luxuriantly in test tuhe cultures where it fruited abundantly. 
The spores germinate readily in potato agar, but make very little 
growth. When transferred to sugar beet plugs they made bet- 
ter growth, but produced no spores. The method finally adopted . 
was to make plate cultures of the spores when they were located 
under the microscope, then transfer to sterilized bean stems in 
test tubes. 
