180 Report of the Botanist of thb 



APRICOT DISEASES. 



Collar Rot. — The most destructive apricot disease which we 

 have come across is a disease of the trunli which may be called 

 collar rot or dying at the collar. A large apricot orchard at 

 Sodus has been ruined by it. This orchard was planted in 1890 

 with apricots budded on apricot stocks. • In each subsequent 

 season some of the trees have died, and the others have made a 

 stunted growth. The dead trees were replaced by others budded 

 on Primus simani stocks. Many of these also died and then 

 trees on Primus niariana stocks were tried with no better re- 

 sults, and at the present time the orchard is practically worth- 

 less. 



We became acquainted with the orchard in 1899. In May of 

 that year we made a careful examination of the affected trees 

 and found the seat of the trouble located just below the surface 

 of the ground at the point where the bud was originally inserted, 

 which is called the union or collar. For a distance of three or 

 four inches above the union the bark was dead and brown en- 

 tirely around the trunk. On trees recently dead the injury 

 never extended below the union and often there w^as a sharp 

 line of demarcation between the living bark of the stock and the 

 dead bark of the trunk; but on trees which had been dead for 

 some time the bark of the stock also turned brown and it was 

 not so plain that the trouble had started at the union. 



As a rule, the affected trees wilt rather suddenly some time in 

 early summer after having put out their leaves in an apparently 

 normal manner. The trouble is not confined to any particular 

 part of the orchard; dead trees are intermingled with living ones. 

 Only a few of the trees have made a fair growth. The majority 

 of the living trees have gnarly, stunted branches bearing large 

 and prominent lenticels which make the bark very rough to the 

 touch. The lenticels somewhat resemble the Gytospora pycnidia 

 discussed below. 



We are unable to account satisfactorily for this apricot 

 trouble. Neither insects nor fungi seem to be the cause of it. 



