Wild Crucifer Research Articles

Bacterial Wilt of Walfflowers Caused by Xanthomonas campestns

SUMMARYBacterial wilt of wallflowers caused by Xanthomonas campestris is reported for the first time in the United Kingdom and a description is given of the disease symptoms. Isolates of X. campestris from wallflowers were pathogenic to seedlings of all wild and cultivated crucifers tested with the exception of Matthiola spp, (stocks). Four isolates of X. campestris from Brassica spp. and three other Xanthomonas spp. were not pathogenic either to wallflower or to stock seedlings. X. campestris isolates originating from cabbage were more virulent to cabbage seedlings than were isolates originating from wallflowers. X. campestris was isolated from wallflower seeds and from old wallflower debris.

Phenology and Microhabitat Selection of Some Flea Beetles (Coleoptera: Chrysomelidae) on Wild and Cultivated Crucifers in Central New York

AbstractThe flea beetle faunae associated with three cruciferous plants, Dentaria diphylla Michx., Barbarea vulgaris R.Br. and Brassica oleracea L. were investigated in the field near Ithaca, N.Y. The flea beetles were sampled regularly from these plants both in their natural habitats and in cultivated plots. The samples were taken either by visually counting the insects or with a D'Vac vacuum net. The behavior and microhabitat preferences of the beetles were determined by making quantitative observations and counting the individuals on vertical layers of the hosts and on host plants growing in different habitats. The flea beetle loads were calculated on the basis of dry weights of plants and flea beetles. Six flea beetle species were found on these three crucifers. On each plant species there was a dominant flea beetle species which constituted over 60 % of the total specimens collected. When the plants were grown in identical cultivated plots in an open field, the relative abundances of flea beetle species attacking them were greatly altered from the situation found in the natural habitats of the hosts. These results, together with the data on the seasonal abundances, behavior and microhabitat selection of the flea beetles, showed that the phenology and habitats of the plants greatly influence their utilization by different flea beetle species and partially determine the distinctiveness of the crucifer-beetle associations.

Lipaphis erysimi . [Distribution map

Abstract A new distribution map is provided for Lipaphis erysimi (Kalt.) ( Rhopalosiphum pseudobrassicae [Lipaphis erysimi] (Davis)) (Homopt., Aphididae) (Turnip Aphid (North America)). Hosts: Various cultivated and wild crucifers. Information is given on the geographical distribution in EUROPE, Austria, Belgium, Britain, Bulgaria, France, Denmark, Germany, Ireland, Netherlands, Norway, Poland, Sweden, Yugoslavia, ASIA, Ceylon, China, Cyprus, Formosa, India, Indonesia, Iran, Iraq, Israel, Japan, Korea, Malaya, Nepal, Pakistan, Pescadores Islands, Philippine Islands, Ryukyu Islands, Sabah, Singapore, South Arabian Protectorates, Thailand, Turkey, USSR, AFRICA, Cameroun, Egypt, Eritrea, Ethiopia, Kenya, Libya, Madagascar, Mauritius, Morocco, Nigeria, Republic of South Africa, Rhodesia, Sierra Leon, Sudan, Tanzania, Uganda, Zambia, AUSTRALASIA and PACIFIC ISLANDS, Australia, Fiji, Hawaii, Mariana Islands, New Zealand, Papua and New Guinea, Solomon Islands, NORTH AMERICA, Canada, Mexico, U.S.A., CENTRAL AMERICA and WEST INDIES, Costa Rica, Nicaragua, West Indies, SOUTH AMERICA, Argentina, British Guiana, Peru, Surinam, Venezuela.

A strain of tobacco mosaic virus isolated from a wild crucifer plant, Radicula sylvestris Druce

In this paper the authors described a virus which was isolated from a wild crucifer plant, Radicula sylvestris Druce and was identified as a strain of tobacco mosaic virus. This virus was named TMV-C.Radicula sylvestris infected with TMV-C showed no symptoms on the leaves. The plant may carry besides TMV-C, other viruses such as cucumber mosaic virus without showing any symptoms.TMV-C was isolated from about 9 per cent of the population of this plant.The virus was highly infectious to turnip and caused distinct mottling on the leaves, but very mild mottling on the leaves of cabbage.Vigna chinensis, Nicotiana glutinosa, N. tabacum var. white Burley, N. rustica, and N. sylvestris showed local necrotic lesions on the inoculated leaves followed by no systemic symptoms.Infected N. tabacum var. Samsun, N. acuminata, and N. debneyi showed necrotic lesions on the inoculated leaves followed by systemic mottling and necrosis. Infected N. alata showed necrotic lesions on the inoculated leaves followed by systemic mottling, and infected N. sanderae showed similar local lesions followed by systemic chlorotic spots. Zinnia plants showed vein clearing, mild mottling, and necrotic patches of the leaves by infection of the virus.N. tabacum var. Ambalema, Phaseolus vulgaris, Vicia fabae, maize, cucumber, and Raphanus sativus var. acantiformis were immune to the virus.TMV-C infection was interfered by the ordinary strain of tobacco mosaic virus in N. tabacum var. Samsun.This virus in the juice of the infected plant was not completely inactivated in ten minutes at 90°C, or by dilution up to 106.The infected sap stored at room temperature or at 4°C gave good infections for thirty days. Under an electronmicroscope, the virus particles show rod shape and about 300mμ long, and are quite alike those of the ordinary strain of tobacco mosaic virus.

Aphid transmission of severe-mosaic virus of annual stock

does not appear. First page follows. Introduction In the canyons of the Montara Mountains and the slopes along the Pacific Ocean, the mild-mosaic virus of annual stock (Matthiola incana var. annua) induces a conspicuous breaking in the color of the flower petals in all but white and yellow flowering types. The breaking renders these affected varieties unmarketable as cut flowers. A severe mosaic disease of annual stock with a striking color-breaking and conspicuous mottling and malformation of the leaves occurs in home gardens and in a nursery at San Pablo, Contra Costa County. The turnip or false cabbage aphid, Rhopalosiphum pseudobrassicae (Davis), breeds on annual stock under natural conditions; the cabbage aphid, Brevicoryne brassicae L., and green peach aphid, Myzus persicae (Sulzer), do not. Review of Literature A review of the literature on virus diseases of annual stock has been published by (Tompkins (1934), (1939)4 and (Severin and Tompkins (1948)). A paper by (Oliveira and Borges (1944)) appeared and was not reviewed in our last contribution. A number of cultivated and wild crucifers, tobacco and Nicotiana glutinosa were tested, by juice inoculation, with nine isolates of an annual-stock virus from Lisbon gardens. The symptoms induced by each of the isolates on the differential hosts were mosaic, rugosity, stunting, chlorosis, necrosis, blistering, and streak. Materials and Methods The virus causing severe mosaic of annual stock was obtained at San Pablo, Contra Costa County. Plants of the Fiery Blood Red variety of annual stock and the February variety of cauliflower grown from seeds were used in all experiments reported in this paper. All inoculated annual stock plants were held for observation after the flowering stage.