1196 



MANUAL OF DETERMINATIVE BACTERIOLOGY 



canes remain short and become rosetted. 



Transmission: By aphids, principally 

 Amphorophora rubi Kalt., but also A. 

 rubicola Oestl. and A. sensoriaia Mason 

 (APHIDIDAE). Not by inoculation 

 of expressed juice. 



Literature: Bennett, Michigan Agr. 

 Exp. Sta., Techn. Bull. 80, 1927; 125, 

 1932; Cooley, New York Agr. Exp. Sta. 

 (Geneva), Bull. 675, 1936; Harris, .Jour. 

 Pom. and Hort. Science, 11, 1933, 237-255 ; 

 17, 1940, 318-343; Rankin, New York 

 Agr. Exp. Sta., Geneva, Bull. 543, 1927; 

 New York Agr. Exp. Sta., Geneva, Tech. 

 Bull. 175, 1931. 



51. Marmor persicae H. (Holmes, loc. 

 cit., 81 ; Flavimacula persicae McKinncy, 

 Jour. Washington Acad. Science, 34, 1944, 

 149.) From New Latin Persica, former 

 generic name of peach. 



Common name : Peach-mosaic virus. 



Hosts: ROSACEAE—Prunus persica 

 (L.) Batsch, peach and nectarine, all 

 tested varieties. Experimentally, also 

 P. armeniaca L., apricot; P. communis 

 Fritsch, almond; P. domestica L., plum 

 and prune. 



Insusceptible species : Attempts to in- 

 fect sweet and sour cherries have thus 

 far failed. 



Geographical distribution : United 

 States (Colorado, California, Utah, Ok- 

 lahoma, Texas, New Mexico, Arizona). 



Induced disease : In peach, short inter- 

 nodes in spring growth, sometimes break- 

 ing in flower pattern, chlorotic mottling 

 and distortion of foliage early in season, 

 masking of leaf symptoms or excision of 

 affected areas of leaf lamina in midsum- 

 mer; fruit small, irregular in shape, un- 

 salable. Some peach varieties are less 

 damaged than others, but all are thought 

 to be equally susceptible to infection, and 

 equally important as reservoirs of virus 

 when infected. In almond, experimen- 

 tally, symptomless infections ; symptoms 

 appear in some apricot and plum varieties 

 when experimentally infected, not in 

 others. 



Transmission : By budding and other 



methods of grafting. Not by inoculation 

 of expressed juice. Not through soil. 

 No insect vector is known. Not through 

 pollen or seed from diseased plants. 



Thermal inactivation : Not demon- 

 strated; virus not inactivated by tem- 

 peratures effective in inactivating peach- 

 3'ellows virus. 



Literature : Bodine, Colorado Agr. Exp. 

 Sta., Bull. 421, 1936; Bodine and Durrell, 

 Phytopath., 31, 1941, 322-333; Cation, 

 ibid., 2A, 1934, 1380-1.381; Christoff, 

 Phytopath. Ztschr., 11, 1938, 360-422; 

 Cochran, California Cultivator, 87, 1940, 

 164-165; Cochran and Hutchins, Phyto- 

 path., 28, 1938, 890-892; Hutchins, Sci- 

 ence, 76, 1932, 123; Hutchins et al., U. 

 S. Dept. Agr., Circ. 427, 1937, 48 pp.; 

 Kunkel, Am. Jour. Bot., 23, 1936, 683- 

 686; Phytopath., 28, 1938, 491-497; 

 Thomas and Rawlins, Hilgardia, 12, 1939, 

 623-644; Valleau, Kentucky Agr. Exp. 

 Sta., Bull. 327, 1932, 89-103. 



52. Marmor astri H. {loc. cit., 83). 

 Fi'om Latin astruin, star. 



Common name : Peach asteroid-spot 

 virus. 



Host : ROSACE AE — Pruniis persica 

 (L.) Batsch, peach. 



Geographical distribution : California. 



Induced disease : In peach, discrete 

 chlorotic lesions spreading along veins, 

 forming star-like spots ; developing leaves 

 normal in appearance, becoming affected 

 as they mature. Some chlorophyll re- 

 tained in lesions as leaves turn yellow. 

 Affected leaves shed early. 



Transmission: By grafting. Not by in- 

 oculation of expressed juice. No insect 

 vector is known. 



Literature : Cochran and Smith, Phyto- 

 path., 28, 1938, 278-281. 



53. Marmor rubiginosum Reeves. 



(Phytopath., 30, 1940, 789.) From Latin 

 rubiginosus, rusty. 



Conunon name : Cherry rusty-mottle 

 virus. 



Host : ROSACE AE — Primus avium L., 

 sweet cherry. 



