ROYAL BOTANIC GARDENS, KEW. 
BULLETIN 
OF 
MISCELLANEOUS INFORMATION, 
Nos. 172-174. ] APRIL—JUNE. (1901. 
I.—PLANT DISEASES.—II. LEAF-CURL. 
(Hxroascus deformans, Fuckel.) 
(With Plate.) 
This well-known disease is at times very destructive to peach 
oliage; less frequently almond and apricot leaves are also 
1 
. 
thus enabling the spores to be diffused by wind, rain, insects, &€. 
ungest shoots are also swollen and distorted by the 
hen once attacked a tree rarely recovers unless prompt pre- 
ventive measures are taken, but becomes more diseased as time 
goes on, owing to the spread of the mycelium present in the 
tissues. 
The parasite does not develop every season, at least not to an 
appreciable extent, even on trees that are known to contain 
mycelium in their tissues. It is least abundant during those 
years when the foliage reaches the fully developed condition 
without a check, whereas it is most abundant when the young 
leaves are checked in their growth by a sudden chill, and the 
more so if this chill follows damp warm weather, On the other 
hand, when evidence of the growth of the fungus has been un- 
mistakable, its further course has been completely arrested by a 
sudden increase in temperature. 
9893—1375—9/1901 Wté4 D&S 29 
r 
