DISEASES OF THE APRICOT 223 



There are several troubles affecting the twigs, foliage and fruits 

 which are reduced by the following preventive treatment. For 

 bearing trees spray with heavy Bordeaux mixture (6-8-50) or lime 

 sulphur (1-12) between November 15 and December 15, to prevent 

 infection of the buds with the Coryneum (peach blight) fungus and 

 also to clean up, as far as possible, the spores of this fungus and 

 those of the brown rot (Monilia). During winter pruning remove 

 all dead twigs and small branches and as pink-color appears in 

 swelling bloom buds, spray with lime-sulphur (1-10) or with Bor- 

 deaux mixture when the blossoms are opening. 



For twig injury caused by frost and generally called "sour 

 sap," a heavy coating of whitewash applied about November 15 

 and renewed, if necessary, during the winter, is believed to be the 

 best preventive. 



There is prevalent in some districts a trouble called "black 

 heart" ; a pith disease which sometimes does great injury. No treat- 

 ment except that of pruning back to healthy wood has thus far 

 been proposed. Root knot is also a serious trouble of the apricot as 

 of several other trees. It will be considered in the chapter devoted 

 to disease of fruit trees. 



Until recently the apricot has been generally free from scale in- 

 sects, and it is not affected by those species which are worst on some 

 other fruit trees, but recently it has been seriously infested in some 

 cases with black and brown scales, which will be considered in a 

 later chapter. 



The ripe apricot is sometimes seriously assailed by the diabrotica, 

 a small green beetle, with twelve black spots upon its wing covers. 

 Driving the insects away with smoke smudges has been used to some 

 extent. Fortunately, the insect only occasionnally occurs in large 

 numbers. 



VARIETIES OF THE APRICOT 



Though nearly all standard varieties of the apricot have been 

 introduced and planted in this State, comparatively few are found 

 on the list of the orchard planters. Many local seedlings have been 

 brought to notice and propagated to some extent but finally aban- 

 doned, and the disposition is to restrict planting to a few old 

 varieties. 



At the conferences of the growers, canners and nurserymen in 

 1920 (which has been noted in Chapter XVI), the Blenheim, Royal 

 and Tilton were approved for commercial planting, Hemskirke and 

 Routier's Peach additional for home orchards and Moorpark for 

 drying (in locations where it does well). The canners recom- 

 mended that for the coast districts 100 per cent Blenheim be 

 planted, interior San Joaquin Valley 100 per cent TiJton, interior 

 Sacramento Valley 50 per cent Blenheim, 50 per cent Tilton. The 

 following are now commercially grown in California: 



* Royal. A French variety, for many years the leading California apricot 

 and now dividing first honors with the Blenheim. Of large size (when well 

 thinned out), free stone, fine color and flavor, good bearer, and fruit ripens 



