10 CALIFORNIA AGRICULTURAL EXTENstoN SErRvicE [CIRC 42 
Peach Blight, Coryneum beijerinckii Oud.—This has been a com- 
mon disease in the interior valleys of California but may be readily 
controlled. The fungus causing the trouble is active in the winter, 
attacking buds and twigs. In the spring the spores may infect new 
leaves and sometimes the fruit. Buds are infected, and later gum and 
dead areas appear in the twigs, frequently resulting in girdling and 
the loss of much fruiting wood. Red spots may also appear in the 
fruit when infected. Spraying with Bordeaux 5-56-50, or with liquid 
lime-sulfur, 6 gallons to 100 gallons of water, or its equivalent in dry 
lime-swdfur, in the fall between November 1 and December 15, will 
effectively control this disease. 
Peach Mildew, Sphaerotheca pannosa var. persicae (Wallr.) Lev. 
—Peach mildew is becoming more prevalent in certain districts. White 
powdery patches appear on young leaves, twigs and fruit. The fungus 
affects the epidermal tissues and checks their growth. The whitish 
patches on the fruit later turn brown and result in flattened areas. 
Definite control measures have not been determined but it is suggested 
that sulfur dust be applied in the early summer at the first indication 
of the disease in the district and that applieations be repeated if 
necessary. 
Peach Rust. Tranzschelic punctate (Pers.) Arth.—Peach rust has 
recently appeared, causing serious loss in certain districts of Califor 
nia. It attacks principally the mid-summer clingstone peaches but has 
also been found on other varieties. There are three places of infection, 
namely, new twigs, leaves and fruits. Spores infect the current 
season twigs in the fall. Bark pustules appear the following spring 
and give off spores to infect surrounding leaves and young fruits. 
Yellow angular spots appear in the leaves and dark pitted areas are 
formed on the fruit. Spraying with liquid lime-sulfur, 6 gallons to 
100 gallons water, or its equivalent in dry lime-sulfur, early in the 
fall (October 15-November 1) will control this disease. If the disease 
appears in the leaves in early summer the fruit infection may be 
prevented by spraying as soon as possible with liquid lime-sulfur 1 
gallon to 100 gallons of water. A stronger spray will be injurious to 
the foliage. 
Oak Root Fungus, Armillaria mellea (Vahl) Quel.—This is a root 
disease which spreads underground. Affected trees may fail gradually 
or die suddenly, at any season of the year. By removing the bark 
from near the crown of the tree the yellowish-white, fan-shaped 
mycelium of the fungus which is responsible for the wood decay may 
be observed. The disease spreads mainly by underground, slender,