FAMILY MARMORACEAE 



1207 



Fruit inferior in size, quality, and quan- 

 tity. Plants live only 2 or 3 years after 

 infection on the average. 



Strains: A strain of this virus is be- 

 lieved responsible for mild streak of black 

 raspberries, in which purple to violet, 

 greenish brown, or bluish streaks on canes 

 are narrowly linear or elliptical in form 

 and often very faint; when the bloom is 

 rubbed off, the lesions appear as though 

 watersoaked and discolored. Leaves are 

 slightly curled, their veins cleared. 

 Fruits are dry and dull in lustre, even 

 while still red, and of poor flavor when 

 ripe. 



Literature: Bennett, Michigan Agr. 

 Exp. Sta., Tech. Bull. 80, 1927; Wilcox 

 U. S. Dept. Agr., Dept. Circ. 227, 1923; 

 Woods and Haut, U. S. Dept. Agr., Plant 

 Dis. Rpt., ?4, 1940, 338-340. 



3. Nanus mirabilis H. {loc. cit., 126). 

 From Latin mirabilis, strange. 



Conamon name : Peach phony-disease 

 virus. 



Hosts : ROSACE AE — Primus persica 

 (L.) Batsch, peach. Experimentally, 

 also other Prunus species. 



Geographical distribution : United 

 States (Georgia, Alabama, Florida; 

 sparsely also in Mississippi, Tennessee, 

 South Carolina, Louisiana, Texas, Ar- 

 kansas, Missouri). 



Induced disease : In peach, tree 

 dwarfed, foliage abnormally green, fruit 

 small ; flecks in wood, especially in roots ; 

 sections of roots show characteristic well- 

 distributed purple spots after 3 to 5 min- 

 utes of treatment in 25 cc absolute methyl 

 alcohol acidulated by the addition of 1 

 to 5 drops of concentrated, chemically 

 pure hydrochloric acid. 



Transmission : By root grafting, except 

 by root-bark patch grafts, which are inef- 

 fective. Budding and grafting with parts 

 of stem fail to transmit this virus. 



Thermal inactivation : At 48° C in about 

 40 minutes in roots. 



Literature : Hutchins, Georgia State 

 Entomol. Bull., 78, 1933; Phytopath., 29, 

 1939, 12 (Abst.); Hutchins and Rue, 

 ibid., 29, 1939, 12 (Abst.). 



4. Nanus holodisci H. {loc. cit., 127). 

 From New Latin Holodiscus, generic 

 name of ocean spray. 



Common name: Ocean-spray witches'- 

 broom virus. 



Host: ROS ACE AE— Holodiscus dis- 

 color Max., ocean spray. 



Geographical distribution: United 

 States (Oregon and Washington). 



Induced disease : In ocean-spray, dis- 

 eased branches form clusters of thin wiry 

 shoots with abnormally short internodes 

 and crowded small leaves. Laterals num- 

 erous and more than normally branched. 

 Bronzy red color acquired early by af- 

 fected foliage. 



Transmission: By aphid. Aphis spir- 

 aeae Schout. (APHIDIDAE). By 

 grafting. Not demonstrated by inocula- 

 tion of expressed juice. 



Literature: Zeller, Phytopath., 21, 

 1931, 923-925. 



5. Nanus fragariae H. (Holmes, loc. 

 cit., 128; Blastogenus fragariae McKin- 

 ney, Jour. Washington Acad. Science, 34, 

 1944, 151.) From New Latin Fragaria, 

 generic name of strawberry. 



Common name: Strawberry witches '- 

 broom virus. 



Host : ROS ACE AE — Fragaria chiloen- 

 sis Duch. var. ananassa Bailey, culti- 

 vated strawberry. 



Geographical distribution : United 

 States (western Oregon). 



Induced disease : In strawberry, leaves 

 numerous, light in color, with spindly 

 petioles, margins of leaflets bent down, 

 runners shortened, plants dwarfed ; flower 

 stalks spindly and unfruitful; root sys- 

 tems normal and well developed. 



Transmission : By aphis, Myzus fragae- 

 folii Ckll. (APHIDIDAE). Not dem- 

 onstrated by inoculation of expressed 

 juice. 



Literature : Zeller, Phytopath., 17, 

 1927, 329-335. 



6. Nanus cupuliformans Zeller and 

 Weaver. (Phytopath., 31, 1941, 851.) 

 From diminutive of Latin cupa, tub, and 

 participal from Latin formare, to form. 



