256 MANUAL OF FRUIT DISEASES 
time. However, the majority die in winter. Occasionally 
longitudinally ribbed excrescences develop on the trunk or arm 
of diseased vines. These outgrowths are not fleshy, nor are 
they hard, and they should not be confused with crown-gall 
(see page 253) and outgrowths following winter-injury.  In- 
ternal symptoms are characterized by a dry heart-rot of the 
trunks in affected por- 
tions. 
In June or early July 
the leaves show a peculiar 
yellowing, dwarfing and 
curling. Later, the dis- 
coloration disappears, al- 
though the other abnor- 
malities persist. Such 
vines, while apparently 
on the road to recovery, 
are found to be dead or 
are considerably weakened 
the following year. The 
vines may die during the 
summer and as a result 
the leaves wilt. Many 
vines freeze to death as a 
result of a weak growth 
the previous season. 
On the green shoots, petioles, peduncles and leaf-veins small 
reddish brown or black spots are produced (Fig. 68). These 
may be deep, in which case V-shaped slits are noticeable; or 
they are more superficial, and are so numerous as to coat the 
affected part for some distance. When these lesions are older, 
they show either as reddish elevations or as a longitudinal 
cracking. 
Berries affected with the dead-arm disease exhibit a rotting 
Fic. 68. — Dead-arm on grape-canes. 
