1208 



MANUAL OF DETERMINATIVE BACTERIOLOGY 



Common name : Strawberry -stunt 

 virus. 



Host : ROSACEAE — Fragaria chiloen- 

 sis Duch. var. ananassa Bailey, culti- 

 vated strawberry. 



Geographical distribution : United 

 States (Oregon, Washington). 



Induced disease : In strawberry, little 

 if any reduction in chlorophyll, plants 

 erect but short ; leaves at first folded, 

 later open, dull in lustre, with papery 

 rattle when brushed by hand, leaflets 

 cupped or with margins turned down, 

 midveins tortuous; petioles I to § 

 normal length; fruits small, usually hard 

 and seedy; roots normal in appearance. 



Transmission : Bj^ strawberry -leaf 

 aphid, Capitophorus fragaefolii {APHI- 

 DIDAE). By grafting. Not by inocu- 

 lation of expressed juice. 



7. Nanus pruni H. {loc. cit., 128). 

 From New Latin Primus, generic name 

 of prune, from Latin prunus, plum tree. 



Common name: Prune -dwarf virus. 



Hosts: ROSACEAE— Prnnvs domes- 

 tica L., prune and plum; var. insititia 

 Bailey, the Damson plum, remains symp- 

 tomless. Experimentally, also Prunus 

 persica (L.) Batsch, peach. 



Insusceptible species: ROSACEAE — 

 Prunus avium L., cherry. 



Geographical distribution : United 

 States (New York); Canada (British 

 Columbia, Ontario). 



Induced disease: In prune, leaves 

 small, narrow, rugose, distorted, glazed. 

 Internodes short. Some branches escape 

 and appear normal. Blossoms numerous, 

 mature fruits few. Pistils aborted, pet- 

 als narrow and distorted. In Damson 

 and Bradshaw plums, no obvious mani- 

 festations of disease as a result of infec- 

 tion. 



Transmission : By budding and other 

 forms of grafting. Not demonstrated by 

 inoculation of expressed juice. No insect 

 vector is known. 



Literature: Berkeley, Canada, Domin. 

 Dept. Agr., Div. of Bot. and Plant Path., 

 Science Service, Publ. 679, 1941 ; Hilde- 

 brand, Phytopath., 32, 1942, 741-751; 

 Thomas and Hildebrand, Phytopath., 

 26, 1936, 1145-1148. 



8. Nanus sacchari H. {loc. cit., 129). 

 From New Latin Saccharum, generic 

 name of sugar cane, from Latin saccharum, 

 sugar. 



Common name : Sugar-cane sereh- 

 disease virus. 



Host : GRAMI NEAE—Saccharum offi- 

 cinarum L., sugar cane. 



Geographical distribution : Java, 

 Borneo, Sumatra, Moluccas, India, Mau- 

 ritius, Australia, Fiji, Formosa, Hawaii, 

 Ceylon. 



Induced disease : In sugar cane (Cheri- 

 bon variety), plant dwarfed, shoots 

 stunted, vascular bundles colored by the 

 presence of a red gum ; adventitious roots 

 from many or all nodes. 



Transmission : Not by inoculation of 

 expressed juice. No insect vector is 

 known . 



Thermal inactivation : In cuttings of 

 sugar cane, at 52° C in 30 minutes to 1 

 hour. Infected cane cuttings survive the 

 heat treatment required for cure through 

 inactivation of the causative virus. 



Literature : Houtman, Arch. Suikerind. 

 Nederland. -Indie, 33, 1925, 631-642; 

 Lyon, Bull. Exp. Sta. Hawaiian Sugar 

 Planters' Assoc, Bot. Ser., 3, 1921, 1-43; 

 Wilbrink, Arch. Suikerind. Nederland. - 

 Indie, 31, 1923, 1-15. 



Genus V. Rimocortius Milbrath and Zeller. 

 (Phytopath., 32, 1942, 430.) 



Viruses of the Rough-Bark Group, inducing diseases principally affecting bark, less 

 often wood, leaves, or fruit. Generic name from Latin rima, cleft or fissure, and 

 cortex, bark. 



The type species is Rimocortius kwanzani Milbrath and Zeller. 



