FAMILY CHLOROGENACEAE 



1149 



ibid., 24, 1934, 72-76; McCubbin, Penn- 

 sjdvania Dept. Agr., Gen. Bull. 382, 1924. 

 Strains : Numerous strains of peach- 

 yellows virus probably exist in nature. 

 One of these has been given a varietal 

 name, distinguishing it from the tj^pe 

 variety, vulgaris H. (loc. cit., 5) : 



3a. Chlorogenus ■persicae var. microper- 

 sica H. {loc. cit., 6). From Greek micros, 

 small, and New Latin Persica, former 

 generic name of peach. Common name : 

 Little-peach strain of peach-yellows virus. 

 Differing from the type variety by tend- 

 ency to cause a mild type of disease, 

 characterized by distortion of young 

 leaves, production of many short branches 

 on main trunk, later yellowing of mature 

 leaves, twiggy growth, shoots slightly 

 less erect than in typical peach yellows. 

 (Kunkel, Phytopath., 26, 1936, 201-219; 

 26, 1936, 809-830; 28, 1938, 491-497; 

 Manns, Trans. Peninsula Hort. Soc, 23, 

 1933, 17-19; 24, 1934, 72-76.) 



4. Chlorogenus solani H. {loc. cit., 7). 

 From New Latin Solanum, generic desig- 

 nation of potato. Synonym: Chloroph- 

 thora solani McKinney, Jour. Washington 

 Acad.Sci., 34,1944,151. 



Common names : Potato witches'-broom 

 virus, potato wilding or semi -wilding 

 virus. 



Hosts: SOL AN AC EAE— Solanum tu- 

 berosum L., potato. Experimentally, also 

 SOLA NACEAE — Lycopersicon esculen- 

 tum Mill., tomato ; Nicotiana tabacwn L., 

 tobacco; A'^. glutinosa L.; N. rusiica L. 

 APOCYNACEAE—Vinca rosea L., 

 periwinkle. CHENOPODIACEAE— 

 Beta vulgaris L., sugar beet. 



Geographical distribution : United 

 States (Montana, Washington), Russia. 



Induced disease: In potato, increas- 

 ingly pronounced flavescence in new 

 leaflets on one or more stems, production 

 of new dwarfed leaflets with marginal 

 flavescence on stems with unusually long 

 internodes and enlarged nodes, growth of 

 spindling axillary and basal branches. 



profuse blooming and fruiting, lack of 

 dormancy in tuber buds, formation of 

 many small underground tubers as well 

 as some aerial tubers ; plants grown from 

 diseased tubers form thread-like stems 

 and small simple leaves; infected plants 

 survive several seasons, with progressive 

 degeneration. In tomato, experimen- 

 tally, extreme leaf dwarfing, marginal 

 flavescence of leaves and abnormally 

 numerous axillary branches; stems be- 

 come hollow and die ; plants do not survive 

 long after infection. In tobacco, experi- 

 mentally, slender axillary branches with 

 dwarfed leaves, flowers on spindling pedi- 

 cels, numerous, small ; later leaves flaves- 

 cent or marginally flavescent. 



Transmission : By tuber-core grafts 

 with pre patent period of 29 to 114 days. 

 By stem grafts. By dodder, Cuscuta 

 campestris Yuncker {CONVOLVULA- 

 CEAE). Not by inoculation of ex- 

 pressed juice. Not by Macrosteles divi- 

 sus (Uhl.) {CICADELLIDAE). No 

 insect vector is known. Not through 

 seeds of diseased tomatoes. 



Thermal inactivation : at 42° C in 13 

 days, in tissues of Vinca rosea; at 36° C 

 in 6 days in small potato tubers. 



Literature : Hungerford and Dana, 

 Phytopath., I4, 1924, 372-383; Kunkel, in 

 Virus Diseases, Cornell Univ. Press, 

 Ithaca, N. Y., 1943, 63-82; Proc. Am. 

 Philosoph. Soc, 86, 1943, 470-475; Mc- 

 Larty, Scient. Agr., g, 1926, 395; Whipple, 

 Montana Agr. Exp. Sta., Bull. 130, 1919; 

 Young, Science, 66, 1927, 304-306; Am. 

 Jour. Bot., 16, 1929, 277-279; Young and 

 Morris, Jour. Agr. Res., 36, 1928, 835-854. 



5. Chlorogenus santali H. {loc. cit., 8). 

 From New Latin Santalum, generic desig- 

 nation of sandal. 



Common names : Sandal spike -disease 

 virus, sandal spike-rosette virus. 



Hosts: S AN TAL ACE AE— Santalum 

 album, L., sandal. Spike-like diseases 

 have been found also in RHAMNEAE— 

 Zizyphus oenopUa Mill., SAPINDA- 

 CEAE — Dodonaea viscosa Jacq., VER- 



