FAMILY MARMORACEAE 



1211 



2c. Rimocortius psorosis var. alveatum 

 Fawcett and Bitancourt. (Phytopath., 

 33, 1943, 854.) From Latin alveatus, hol- 

 lowed out like a trough. Causing blind- 

 pocket psorosis, characterized by trough- 

 like pockets in bark and wood or bj^ erup- 

 tive lesions. 



3. Rimocortius pyri (Holmes) cotnb. 

 nov. {Marmor pyri Holmes, Handb. 

 Phytopath. Viruses, 1939, 76.) From 

 New Latin Pyrus, generic name of pear, 

 from Latin pirus, pear tree. 



Common name : Pear stony -pit virus. 



Host : ROSACE AE — Pyrus communis 

 L., pear. 



Geographical distribution: United 

 States (Oregon, Washington, Califor- 

 nia). 



Induced disease : In pear, fruit deeply 

 pitted and deformed; bark cracked and 

 resembling oak bark; veinlet chlorosis of 

 some leaves, failure of lateral buds to 

 grow, reduction of foliage. Bartlett and 

 Comice varieties of pear appear to be 

 tolerant, producing sound fruit from 

 infected trees. 



Transmission: By budding. Xot by 

 inoculation of expressed juice. No insect 

 vector is known. 



Literature: Kienholz, Phytopath., 29, 

 1939, 260-267; 30, 1940, 787 (Abst.). 



Genus VI. Adelonosus Brierley and Smith. 



(Phytopath., 3^, 1944, 551.) 



Viruses capable of multiplying in living plants but producing no recognizable symp* 

 toms in these except on interaction with distinct viruses with which they form com- 

 plexes. Transmitted by aphids, by sap, or by both means. Generic name from Greek 

 adelos, invisible, and nosos, disease. Only one species is recognized thus far; this is 

 the type species. Adelonosus lilii Brierley and Smith. 



1. Adelonosus lilii Brierley and Smith. 

 (Phytopath., 34, 1944, 551.) From Latin 

 lilium, lily. 



Common name : Lily-symptomless 

 virus. 



Host : LILI ACE AE— Lilium longi- 

 florum Thunb., Easter lily. 



Insusceptible species: All other tested 

 lilies and many related plants in the same 

 and other families (for list, see Phyto- 

 path., 34, 1944,549). 



Geographical distribution : United 

 States, Japan; probably coextensive with 

 commercial culture of Easter lily. 



Induced disease : In Easter lily, no 

 obvious manifestation of disease when 

 this virus is present alone ; when together 

 with cucumber-mosaic virus, however, 

 the lily-sj^mptomless virus is a deter- 

 mining factor in the production of ne- 



crotic-fleck disease; the lily-symptomless 

 virus is so widely distributed in sup- 

 posedly healthy stocks of the Easter lily 

 that cucumber-mosaic virus formerly 

 was thought to be the sole determining 

 factor in necrotic flecking, now recognized 

 to be caused by the virus complex lily- 

 symptomless virus (Adelonosus lilii) plus 

 cucumber-mosaic virus (Marmor cucii- 

 meris); the complex acts independently 

 of the presence or absence of lily latent - 

 mosaic virus (Marmor inite), which is 

 often present with the essential members 

 of the complex in flecked Easter lilies. 



Transmission : By inoculation of ex- 

 pressed juice, with some difficulty. By 

 aphid. Aphis gossypii Glov., cotton 

 aphid (APHIDIDAE); preinfective 

 period after obtaining virus, 4 to 6 days. 



