WALNUT 



growth the first year, many of them not more than 6 

 inches. After this the growth is rapid. The trees are 

 tied to stakes with strips of cloth, since they are very 

 tender when growing, and the swaying of the tree by 

 the wind quickly causes any other tie to cut through 

 the bark. Walnut trees are pruned very little. At first 

 small limbs are allowed to start about 

 the trunk, but later these are pi-uned ott' 

 to a height of 4 feet. Some of the longer 

 growths are shortened back while the 

 trees are young; and after they are older 

 the low limbs which bend down in the way 

 of cultivating are removed. 



The Santa Barbara Softshell begins to 

 bear the third year from planting, but 



WALNUT 



1961 



tricts in southern California, viz., Prseparturiens, May- 

 ette, Chabcrte, Parisienne, Franquette, etc. These va- 

 rieties are hardier in resistance of frost and leaf-burn 

 from summer heat. They are largely root-grafted upon 

 the seedlings of the California Black Walnut in the nur- 

 sery and are also being top-grafted upon old native trees. 

 E. J. WiCK.sON. 



^mm 



bear as young, and they are not regular 

 bearers. 



Walnut orchards in California receive 

 thorough tillage. Th.v arc h. avily irri- 

 gated in winter, aiul |ii.i«,.,l ;,li,,ut 8 in. 

 deep in the sprin;;. .\ftir tins tlii-y are 

 irrigated and cultivarr.l until thr mits be- 

 gin to fall, -about the 1st of .September. 

 Late irrigation fills out the nuts and 

 causes the hull to open readily. Heavy 

 fogs are also desirable during harvesting. 

 The nuts are shaken rtciwn and picked up. 

 They are then si.ria.l in trays iil)Out 5 

 in. deep until dry. wlirn tiny an' hh-aehed 

 and shipped to'iiiaik.t. Walnuts were 

 formerly bleached wiiii funn-s of sulfur, 

 but this was found injurious to the nut. 

 They are now usually dipped in a solution 

 of chloride of lime (chlorinated lime) and 

 sal-soda, to which a sufficient amount of 

 sulfuric acid has been added to set free the chlorine. 



The majority of Walnut-growers are organized into 

 local associations. Representatives of these associa- 

 tions form the executive committee of the Southern 

 California Walnut-Growers' Association. This execu- 

 tive committee provides the form of contract which 

 the local associations may enter into with brokers, 

 and fixes the price. The local associations are man- 

 aged in several ways. In some the growers bleach 

 their own crop, while in 



this work at its own packing 



erv few 



271J. The California Wild Walnut - Jugl 



WalnutHa. 111,1-1- rliicf among the more serious 

 diseases of ./' i the United States is a bac- 



terial blight 1 : , i aiH-h and leaf of that tree. 



This blight mn iia- h- l i • ai.st development along the 

 Pacific coast, t-s|.c>.iull> m tn-ange and Los Angeles 

 counties, California. The germ which causes this dis- 

 ease is a newly described species of Pseudomonas (P. 

 jiu/Iandis). Different effects of the disease are shown 

 in' Fig. 2714. 



The organism "f Walnut bac.teriosis winters in the 

 fallen nuts, in tlir di^i a-. .1 tissues of affected branches, 

 and especially in tin I'lih ravity of the latter. New in- 

 fections occur as s.ion as s|uiiig growth begins, taking 

 place near the growing point of branches, in the open- 

 ing leaves, and upon the young and tender nuts. The 

 finer lateral veins of the leaves and the adjoining par- 

 enchyma are destroyed, and the midrib is often af- 

 fected. The injury resulting from infection of the branch 

 will larHvlv dp|irnd on the tenderness of the latter at 

 tin- time and point of infection. If the tissue is tender 

 a canker-likf spiif will be eaten through to the pith, or 

 till' iMiijit' i-nil of till' shoot may be destroyed. If the nut 

 is intii.i ,liii, iiiall, its complete destruction usually 

 foil" ' I i\o action of the germ involving hull, 



sliill I II ! Nuts infected early in the season 



nio-il. ■ lil \. I . 'I -mail, while later infections frequently 



that 



those making 

 ad of the micro 

 is generally ( 



best French varieties a 

 rejection of the varieties popu- 

 ) the chief commercial i" 



slower and hardier growth. The sp 

 organism through infected branches is generally only 

 local — it rarely extends more than a few inches from 

 the point of infection. A marked blackening of the in- 

 jured parts results from the rapid oxidation of the tan- 

 nic acid they contain, though this is not distinctive 

 of injury from this disease. Fseuclonwiias jnqlandis 

 is actively motile; hence fogs, rain or dew aid in its 

 spread and increase the number of infections. The 

 water of irrigation may carry the germ for miles. 

 The destruction of the tissues of the Walnut is effected 



