摘要:

In vitroevaluation of the antagonistic properties ofTrichodermaspp. againstPyrenochaeta lycopersiciandPhomopsis sclerotioideswas carried out, using two different methods: the cellophane‐agar plate method and the duaí culture method. With these methods, the direct interaction between pathogen and antagonist was demonstrated, showing very remarkable differences between the different isolates. Growth inhibition ranging from 20 to 100% was found. Proliferation in non‐sterilized soil was investigated for the isolates showing the most interesting antagonistic properties. A Belgian isolate ofTrichoderma hamatumwas found to be able to proliferate very well in soil and to maintain a high population density during the whole experimental pe

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1988.tb00340.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Three experimental trials were carried out in Northern Italy during 1985 and 1986 in order to control grey mould of grapevine (Botrytis cinerea) by using isolates ofTrichodermaspp. resistant to several fungicides commonly sprayed against grapevine pathogens, alone or in alternation with benzimidazoles or dicarboximides, in vineyards where fungicide‐resistant strains ofB. cinereaare frequent. The antagonists alone partially controlled the pathogen on cv. Moscato ďAsti. In one case, the integration of chemical and biological control measures showed slightly better results than for the fungicide alone (for benomyl but not for vinclozolin), but further trials are needed to investigate the full potential for using fungicide‐resistantTrichodermain alternation with fungicides.Trichodermaspp. performed very poorly on cv. Bar

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1988.tb00341.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Three strains ofFusarium oxysporumwere tested for their antagonism toFusarium oxysporumf.sp.dianthi,two from alluvial soils of the Durance valley (Provence, FR) known to be suppressive toF.o.f. sp.melonis(strains 47 and 20 of Alabouvette) and a third from carnation growing medium, in which it spontaneously appeared (TF3). Strains 47 and 20 were introduced into perlite before planting carnations and found to have variable efficacy against fusarium wilt, according to the formulation of the inoculum. With a talc preparation, these strains gave only 15% witted plants, compared with 49% in the control. With a bran‐perlite inoculum, only strain TF3 gave better results than the control. Repeated introduction of TF3 through the season increased the incidence of disease, whereas a single treatment before planting in perlite was effective whatever the formulation (humid bran‐perlite, bran‐perlite powder, talc, liquid). However, the antagonistic activity of TF3 was not sufficient to control the disease in a naturally infested

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1988.tb00342.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

The microbial control ofAlliumwhite rot (Sclerotium cepivorum) has shown promise experimentally but has yet to be used in commerce.Alliumcrops are grown from dry or fluiddrilled seed at a range of seed rates, from bare root and module‐grown transplants and from sets and cloves. The period of susceptibility to infection may be prolonged or short in cool and hot climates, respectively. Primary infection of theAlliumhost results from the growth of hyphae from germinating sclerotia to the roots; secondary infection results from hyphal growth between plants. Sclerotial populations in the soil are often low, hence sclerotia are widely dispersed and therefore inaccessible to microbial control. New sclerotia form on host stem tissue, rarely on roots, rendering them accessible to microbial control. Hyphal parasites may therefore be effective at reducing primary and secondary infection and the formation of new sclerotia. Parasites of sclerotia may restrict the survival of new sclerotia and hence reduce primary infection in future, but not the current season's crops. The opportunities and problems that the variety of growing techniques and conditions ofAlliumcrops present for microbial control of white rot will be reviewe

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1988.tb00343.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

De nombreux travaux montrent que certaines souches de rhizobactéries appartenant au groupePseudomonas fluorescens‐putidaont un effet positif sur la croissance des plantes et sur leur protection vis‐à‐vis des agents pathogènies du sol. Si tous les modes ďaction de ces bactéries telluriques sont encore loin ďêtre compris, on observe cependant une corrélation constante entre ľintensité de la production de pigments fluorescents (sidérophores), la capacitéà produire un antagonismein vitroet la stimulation de la croissance des plantes. Le principe de la bactérisation est ďintroduire une population bénéfique dans un milieu et de ľy maintenir ou de lui faire atteindre un niveau suffisant afin ďobtenir finalement les effets voulus. Il a done été nécessaire de suivre la dynamique des populations introduites dans plusieurs types de milieux de plus en plus complexes: culturesin vitro, substrats artificiels et substrats naturels. Ceci a permis ďobtenir de précieux renseignements sur ľévolution des populations en conditions contrôlées de température et ďHR. Les résultats obtenus montrent que: (1) la bactérisation est ďautant plus efficace qélle est réalisée précocement dans un milieu biologiquement simple. Aussi ľenrobage microbiologique des sentences et des boutures ainsi que le bactérisation de plantulesin vitropeuvent donner de bons résultats. Corrélative‐ment, le maintien des populations dans un biotope est ďautant plus difficile à réussir que celui‐ci est biologiquement complexe; (2) le biotope doit offrir à la population introduite la possibilité de se maintenir, ďy trouver des éléments assimilables et de éy multiplier activement. Ceci est malheureusement pas le cas pour certains substrats artificiels et naturels dans lesquels le maintien de la population est encore problématique et nécessite des ‘rappels’ de bactérisation; (3) les caractères intrinséques de la souche sélectionnée en vue de la bactérisation sont déterminants; (4) il est nécessaire de maintenir une quantité minimale de cellules bactériennes au niveau du systéme racinaire pour obtenir un effet sur ľamélioration de la croissance de la plante. Le seuil minimal de biostimulation se situe fréquemment aux environs de 104bacteries par cm de racine (betterave sucrière, laitue, pelargonium, chrysanthème). Mais le seuil de biosatur

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1988.tb00344.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Conidia, chlamydospores and mycelia ofConiothyrium minitans, Gliocladium roseum, Trichoderma harzianumandT. viridewere obtained from liquid or solid culture and formulated within alginate pellets. Quantitative assessment of these pellets over a 12‐week period showed a decrease in the number of colony‐forming units (cfu) from about 107to 103‐104g‐1air‐dried pellets. Qualitatively, growth was assessed by direct plating the alginate pellets on rich (potato dextrose agar, PDA) and poor (water agar, WA) substrates. Rate of growth (mm day‐1) from individual pellets was decreased by water potential in the range ‐0.25 to‐2.8 MPa, with growth significantly less on WA than PDA for all species exceptG. roseum.All species grew from 95 to 100% of direct‐plated pellets on PDA over the water‐potential range tested. However, on WA, interaction between water stress (‐2.8 MPa) and lack of nutrients resulted in a reduction, with less than 30% of pellets of some formulations showing growth. In contrast to the quantitative results, there was little change in the growth rate of test species from pellets over a 12‐week period, particularly on PDA. Growth from pellets could not be conclusively demonstrated in unsterile soil. The shelf‐life and viability of alginate pe

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1988.tb00345.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

DeuxPseudomonasdu groupefluorescens‐putida,à forte activité inhibitrice vis‐à‐vis de bactéries phytopathogènes, ont été confrontéà une gamme de 23 pathovars dePseudomonas syringae.lis ont confirmé leur activité antagoniste sur ces derniers germes. Deux essais réalisés dans des conditions normales de culture de plein champ ont démontré la potentialité de ces antagonistes comme moyen de lutte contre la moucheture bactérienne, due àP. syringaepv.tomato.Des travaux complémentaires ont montré que ľactivité antagoniste des deux germes inhibiteurs n'est pas semblable, ľun des deux agissant essentiellement par la production ďun sidérophore. Le mécanisme ďaction du

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1988.tb00346.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Light‐colouredSphagnum fuscumpeat is the substrate most widely used in glasshouses in Finland. A number ofStreptomycesstrains which are strongly antagonistic against a number of soil and seed‐borne fungal pathogens, bothin vitroandin vivo, have been isolated from light‐coloured peat. Seed dusting withStreptomycesprevented or reduced damping‐off and foot‐rot disease caused byAlternaria brassicicolaandRhizoctonia solanion crucifers. Seed treatment slightly increased yields of cereals in fields experiments. Spraying the substrate with a suspension ofStreptomycesreduced root diseases on cucumbers caused byPythium, and in many cases successfully prevented fusarium wilt of carnations. A dry powder preparation has been made from theStreptomycesisolates, and applied at a dose of 5‐10 g kg‐1in seed dusting, and 0.1‐10 g 100 m‐2when spraying the substrate. The microbe was most effective in peat soil, although good results have also been obtained in fine sa

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1988.tb00347.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Crown gall disease of cultivated plants, caused byAgrobacterium tumefaciens,constitutes a serious problem for the fruit tree, rose and grapevine nurseries in Greece. All three biotypes ofA. tumefaciensexist in Greece. Biotypes 1 and 2 have a wide host range being responsible for the disease on fruit trees and roses while biotype 3 isolates have a narrow host range infecting grapevine only. All Greek isolates of biotype 1 and all but 3 isolates of biotype 2 were sensitive to biological control with the antagonistic bacteriumA. radiobacterstrain K84, but the biotype 3 isolates were insensitive to biocontrol. Experiments on the effectiveness of the method in artificial infections of seedlings as well as in naturally infested soils showed that the method is effective and can be applied without any risk of development of forms insensitive to biocontrol. The use of a lyophilized preparation of K84 with skim milk as suspending medium is recommended. The lyophilized antagonistic bacterium retains its activity and the final concentration (106cfu ml‐) is adequate to protect treated plants from crown gal

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1988.tb00348.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

The vegetative compatibility of four hypovirulent isolates ofCryphonectria parasiticawas checked with 35 virulent isolates obtained from chestnut samples collected in many regions of Italy. Artificial inoculation tests confirmed the effectiveness of a mixture prepared with hypovirulent isolates. This was packed in squeezing tubes, to simplify the biological control of chestnut blight in practice.

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1988.tb00349.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY