A VIRUS LATENT IN TURNIPS

1956 ◽  
Vol 34 (1) ◽  
pp. 131-134 ◽  
Author(s):  
J. P. MacKinnon

Green peach aphids reared on turnip stecklings acquired a virus that was transmitted to plants of Physalis floridana Rydb. and P. pubescens L., hosts used in potato leaf roll studies. Symptoms on these hosts consisted of a yellowing of the veins of the leaves. Nicandra physalodes L., when infected, showed severe stunting and chlorosis. The virus was carried without symptoms on turnips and showed only slight stunting on several species of Brassica. It was not transmitted by mechanical inoculation and it does not appear to be similar to any of the viruses previously reported in turnips. The aphid Myzus persicae (Sulzer) acquired the virus during a seven-hour feeding period, and after a latent period of approximately 23 hr., transmitted the virus during a one-hour test-feeding period. Once infective, aphids remained so for several days.

1974 ◽  
Vol 40 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Masayoshi SUGAWARA ◽  
Makoto KOJIMA ◽  
Daiki MURAYAMA

2014 ◽  
Vol 94 (1) ◽  
pp. 1-7
Author(s):  
Almouner A.A. Yattara ◽  
Amadou K. Coulibaly ◽  
Frédéric Francis

Des études sur l’abondance et la diversité des pucerons ont été menées pendant trois campagnes agricoles au Mali. Sur la base de relevés de bacs jaunes installés dans des cultures de pomme de terre à Kati et à Sikasso, 2 525 pucerons ont été capturés et identifiés. Dix-neuf espèces de pucerons ont été recensées, dont deux qui ont été observéesin situsur la culture :Aphis gossypii(Glover) etMyzus persicae(Sulzer). La plupart de ces espèces sont des ravageurs de cultures et elles contribuent également à la transmission virale. Des échantillons foliaires prélevés dans des parcelles de pomme de terre dans les deux régions ont été testés par la technique ELISA pour la détection des deux principaux virus dommageables, soit lePotato VirusY (PVY) et lePotato Leaf Roll Virus(PLRV). Le taux de plantes virosées dans les deux localités pendant les trois années variait de 19,3 % à 21,8 % pour le PVY, alors qu’il était de 8,5 % à 9,3 % pour le PLRV. L’occurrence de ces maladies virales s’est révélée être très homogène d’une année à l’autre, avec des taux relativement importants. Cette étude est une première quantification dans cette région du Mali de l’importance des relations pucerons vecteurs–virus en culture de pomme de terre.


1965 ◽  
Vol 43 (5) ◽  
pp. 509-518 ◽  
Author(s):  
J. P. MacKinnon

Myzus persicae (Sulz.) transmitted a new virus to healthy Physalis floridana Rydb. from other P. floridana infected with a turnip latent virus complex. Symptoms were characterized by a chlorosis and sometimes cupping of only the lower leaves with slight stunting of plants. These symptoms could easily be mistaken for those incited by potato leaf roll virus but they were strikingly different from the yellow netting of plants infected with the turnip latent virus complex.In virus–vector studies with the new virus and M. persicae, an occasional aphid acquired the virus in 2 hours and 14% of infective insects transmitted it in 30 minutes. When acquisition and inoculation feedings were each increased to 48 hours, transmissions by single aphids of 70% and more were common. A few aphids transmitted the virus in a total transmission time of 30 hours, but most required 72 hours or longer to acquire, become infective, and transmit it.In comparative tests between the new virus and either potato leaf roll or the turnip latent complex, the new virus and potato leaf roll were recovered from plants 3 days after inoculation but the complex was not recovered for 14 days or longer. Of five aphid species tested, M. persicae was an efficient vector of all three viruses and the only species to transmit the new virus and the turnip latent complex. Plants infected with the new virus and showing symptoms were as easily infected with potato leaf roll as were comparable controls, but fewer of them became infected with the complex. The new virus and the complex were quite similar in host range, and susceptible plants were found in the Amaranthaceae, Chenopodiaceae, Cruciferae, and Solanaceae.The new virus is called mild chlorosis virus of P. floridana.


1964 ◽  
Vol 42 (9) ◽  
pp. 1159-1165 ◽  
Author(s):  
J. P. MacKinnon

Upper whole leaves from the same or different Physalis floridana Rydb. plants provided about equally good sources of potato leaf roll and turnip latent viruses for young nymphs of Myzus persicae (Sulz.). Half leaves infected with potato leaf roll virus varied as much as whole leaves, but half leaves infected with turnip latent virus differed the least of all sources tested. Newly detached leaves were better sources of potato leaf roll virus than those detached for 3 or 7 days, and leaves from plants that showed early symptoms of infection were better sources than those from plants that showed later symptoms. This was not true for sources of turnip latent virus.In serial transfer work that began with single nymphs, the number of plants infected with potato leaf roll virus increased as aphid time on the virus source increased, although a similar increase did not result with turnip latent virus. Some aphids differed by 5 days or more in the time they first transmitted either virus after leaving the source. No aphids lived for longer than 12 serial transfers or 13 days after leaving the virus source.


1971 ◽  
Vol 60 (3) ◽  
pp. 457-462 ◽  
Author(s):  
Umarany Kandiah ◽  
I. W. Selman

Experiments in a glasshouse have shown that the most favourable conditions for transmission of cabbage black ringspot virus by Myzus persicae (Sulz.) to turnip plants with two foliage leaves were as follows: an acquisition access period of five minutes; a test-feeding period of not less than two hours; the use of nine viruliferous aphids per test plant; the use of aphids from uncrowded colonies; the use of the third leaf from the base of an infected turnip (5-leaf stage) as virus source; and inoculation of the younget leaf of a test plant. Darkening plants for 24 or 48 h did not increase susceptibility to aphid inoculation, but increased it to mechanical inoculation in the summer. When the youngest leaf was inoculated, the age of the test plants (10-25 days after germination) did not influence transmission by aphid or mechanical inoculation.


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