摘要:

AbstractPathogenecity and race classification of some isolates ofV. dahliaefrom resistant tomato in MoroccoIn Morocco, the cv. H 204, resistant toVerticillium dahliaerace 1 is widely used under plastic tunnels. Use of this cultivar controlled the disease for many years but recently a high incidence ofVerticilliumon this hybird was obsereved.V. dahliaewas isolated from 90 % of the wilted plants.The other 10 % were infected byF. oxysporum f. sp.lycopersicialone (7 %) or in association withV dabliae(3 %). The inoculation of theVerticilliumsusceptible cv. Vemone and of the race 1 resistant cv. H 204 by 120 isolates obtained from the resistant hybird, showed that (69 %) of the isolates are race 1 and 31 % are race 2. There are different virulence levels ofV. dahliaerace 2 both on the susceptible cv. Vemone and on the race 1 resistant cv. H 204. Race 2 on the average was less virulenton the susceptible than on the resistant cultivar.

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00721.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractPhyllody and apostasis of cassava plants were frequently observed during recent disease surveys in the Cauca Valley of Colombia. Many valuable cassava clones have been affected rendering them unsuitable for hybridization. Light and electron microscopic observations have revealed the presence of mycoplasma‐like organisms in the diseased phloem tissues. The causal agent is sensitive to tetracycline and streptomycin at 1000 ppm a. i., but not to penicilli

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00722.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractOf the 91 tested cucurbit seed samples from thirteen countries nine from four countries were found to be infected withDidymella bryoniae. The pathogen is located on and in the seed coat including the perisperm and in the tissue of the cotyledons. Primary seedling infection occurred on the radicle, hypoctyl and cotyledons. Infection of the radicle generally caused pre‐emergence tot while infection on the hypocotyl and cotyledons developed furthere inoculum for infection of the first true leaves and the stem. Experimentally, all the isolates ofD. bryoniaecould infect cucumber (Cucumis sativus), oriental melon (Cucumis melo var. makuwa), pumpkin (Cucurbita pepo) and watermelon (Citrullus vulgaris) at different growth stages; the susceptibility of cucumber and pumpkin was markedly influenced by previailing humid conditions.The blotter method was found more suitable for detection of seed‐borne infection than the agar plate met

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00723.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractHistological reactions of wheat resistant or sensitive against infection ofPseudocercosporella herpotrichoidesThe microscopic observations reveal important histological differences between the sensitive or resistant varieties. The disease rapidly affect the whole of the first three leafsheath tissues in the “Étoile de Choisy” variety; in the “Roazon” variety, it only affects the first two sheaths. The inter‐ or intracellular mycelia can be observed both under the form of filaments more or less dilated or under the form of dense segments in the sensitive variety. However in the resistant variety, only short segments can be observed. The tissues of those two varieties are gradually destroyed when they are in contact withP. herpotrichoideshyphae, whereas the hyphae remain undamaged. In “Etoile de Choisy” the hyphae develop in great quantity whereas in “Roazon”, the development remains limited. In the varietyAe. ventricosano. 11, which is very resistant, the parasite rarely penetrates into the more external cell layers of the first leaf sheath,‘those invaded host cells are destroyed by the mycelium but, at the same time, the mycelian hyphae degenerate and dilate. Thus, theAe. ventricosano. 11 tissues seem to be the seat of a strong f

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00724.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractSensitiveness of seedlings of Triticinae against the pathogenic agens ofPseudocercosporella herpotrichoides(Fron) DeightonThe study of the sensitiveness of 16 varieties or lines of Triticinae against two races ofPseudocercosporella herpotrichoidesshows that, whatever the strain used, the importance of the attacks is much less serious on seedlings ofAe. ventricosano. 11,Ae. squarrosano. 15,Ae. squarrosano. 33 and Roazon, Roazon was the least sensitive among theTriticum. It is obvious thatAe. ventricosais the most resistant one in all varieties or lines used.

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00725.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractCucumber green mottle mosaic virus may spread in bottlegourd under field conditions through soil contaminated with infected plant debris followed by contact. No seed transmission was noticed in bottlegourd (Lagenaria siceraria) or vegetable marrow (Cucurbita pepo) although pollen grains and cotyledons from infected bottlegourd flowers or seeds, respectively, contained negliginle amounts of virus. Cucumber leaf beerles (Raphidopalpa fevicollis) are probable vectors since their regurgitated fluid and excretes contained infective virus particles. No vector fungi were found in the soil around infected bottlegourd plants.

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00726.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe virus causing mosaic of muskmelon in the Punjab is transmitted through seed, sap and aphids but not through beetle, whitefly, fungi or contact. It systemically infectedNicotiana tabacum(var. “White Burley” and CTRI‐Special),N. glutinosa, N. rusticaandCapsicum annuumbesides various cucurbit hosts when inoculated mechanically. The virus gave positive reaction with the antiserum of cucumber mosaic virus and the particles are spherical in shape. The virus has been identified as a distinct strain of cucumber mosaic virus and is designated as muskmelon strain of cucumber mosaic virus (CMV

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00727.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe extent of contamination of wheat seedlots by brome mosaic virus (BMV), and the possible transmission of the virus through seed, were investigated by radial immunodiffusion (RID), enzyme linked immunosorbent assay (ELISA), and enzyme‐assisted immunoelectroblotting (IEB) tests. BMV was purified from seed washings, and from plants grown from contaminated seed. All three serological tests proved of value in detecting contaminated seeds, while ELISA and IEB were especially useful in detecting virus in infected plants grown from such seed.Rhopalosiphum padiaphids were shown to increase the incidence of BMV infectLon in seedling batches containing a few seed‐infected plants. The implications of these findings for wheat breeding schemes are discus

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00728.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractCytological changes occurring after infection byAbutilonMosaic Virus (AbMV) have been investigated in the host plantsAbutilon sellovianumRgl.,Malva parvifloraL.,Malva silvestrisL., andSida micranthaSchr. Two types of virus‐like inclusions were found in different tissues: particles of 16–18 nm in diameter and elongated filaments with 6–8 nm in diameter. The particles are detectable in the nuclei (Abutilon sellovianum, Malvaspec.) and cytoplasm (Malvaspec.) of cells in the bundle area, and the filaments accumulate in the nuclei (Sida micrantha) and the plastids (Malvaspec.) of leaf mesophyll

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00729.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractAt the apices of growing hyphae ofPhytophthora megaspermaf. sp.glycinea(Pmg) distinctly more fluorescein‐isothiocyanate labelled Concanavalin A was bound than else‐where in the mycelium. In combination with some other analytical evidence this observation conclusively indicates that the α‐mannan in the cell wall of the fungus is predominantly concentrated or exposed at the hyphal tips. The possible relevance of this fact to the host‐pathogene interaction between Pmg and soybean is d

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00730.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY