APRICOT DISEASES 
APRICOT DISEASES 
Brown Rot 
Sclerotinia fructigena 
A decay of the fruit while still on the 
tree, occurring some seasons in moist 
localities. The young growth as well as 
the fruit is also sometimes affected, the 
new shoots wilting and dying back from 
the attacks of this fungus. This is the 
most serious obstacle to stone fruit pro- 
duction in the Eastern states, but does 
not find sufficient moisture for its devel- 
opment in the arid West, except on early 
varieties in occasional seasons of late 
rains in the moister localities. 
Spraying with self-boiled lime-sulphur 
just as the fruit is setting and again with 
the same following subsequent rains is 
recommended for trial. 
Rate E. SMITH, 
Berkeley, Cal. 
Bad Blight 
Characterized by a dying of the buds 
during the early winter and caused very 
largely by the fungus responsible for 
Peach Blight. 
Similar trouble is caused more or less 
by “Sour Sap” conditions. 
See Biicur under Peach. 
Fruit Drop 
The fruit falls to the ground while still 
very small. Partly due to weather condi- 
tions and partly to lack of cross pollina- 
tion, which can be secured by mixing 
varieties in planting. Seasonal conditions 
such as heavy rains at blossoming time 
or frosts may have this effect. The 
cherry, almond, peach and pear are af- 
fected in the same way. 
The drop may not occur until the fruit 
reaches some size. 
See general article on SETTING AND 
Dropping or Frcirs under Fruits. 
Fruit Spor. See Blight under Peach. 
GumMMosis. See Cherry. 
Scab 
Cladosporium carpophilum 
Same as Peach Scab, which see. 
Blossom Rot 
Sclerotinia 
The young fruit decays while still very 
small and enclosed by the calyx or outer 
cup of the blossom. The trouble occurs 
549 
when wet rainy weather prevails during 
the time of fruit setting. It commences 
in a rotting of the calyx cup, which is 
dead and susceptible to decay by sapro- 
phytic fungi, which decay spreads to the 
young fruit. It is caused by various 
fungi, of which perhaps a species of Scle- 
rotinia, apparently S. livertiana, is most 
common, causing a decay of the young 
fruit on the tree. When such fruit is 
picked and placed in moist chamber it 
develops an abundant cottony mold in 
which black sclerotia soon forms. This 
appears to be the same fungus causing 
the cottony mold or white rot of the 
lemon storage. Botrytis vulgaris is also 
common in this trouble. Same treatment 
as brown rot. 
Spraying for shot hole fungus might 
also be of some benefit in this trouble. 
Shot Hole and Fruit Spot 
Coryneum beijerinckit 
This fungus is the same as that caus- 
ing the peach blight and produces in the 
apricot a spotting of the fruit, shot hole 
effect in the leaves and killing of the 
buds. 
Spray with Bordeaux mixture during 
November and again in spring just as 
the buds open. 
See Blight under Peach. 
Sour Sap and Seasonal Effects 
The apricot is particularly sensitive to 
sour sap and other seasonal effects. It is 
a tree having a free flow of sap, quick 
to respond to stimulating influences and 
one having the characteristic of all the 
stone fruits of forming an abundance of 
gum when injured in any manner. On 
this account, if any active movement from 
the roots is started early in the season by 
warm weather or an abundance of moist- 
ure and this activity be checked again by 
less stimulating weather conditions, 
trouble is very apt to follow. The sap 
becomes stagnant in the tissues, full of 
sugars and other easily fermentable sub- 
stances, gum begins to form, sunburn 
may also occur and very often severe in- 
jury takes place in the tissues of the sap 
wood and cambium layer. 
RaLtpuH BH. SMITH, 
Berkeley, Cal. 
