1,721,105 research outputs found
Functional relationships between Collembola and plant pathogenic fungi of agricultural soils
No full textThe interactions between the collembolan Mesaphorura krausbaueri and four soilborne plant pathogenic fungi all living in the same layer of agricultural soil were studied under laboratory conditions. Mycelia of Gaeumannomyces graminis var. tritici, Fusarium culmorum and Rhizoctonia cerealis were palatable to Collembola and were a food source adequate for reproduction. Hyphae of Bipolaris sorokiniana were toxic and repellent for M. krausbaueri, but its conidia were eaten and proved to be a sufficient diet for reproduction. The four fungi fed had a different impact on the life processes of M. krausbaueri. Depending on the species of fungus, the animals produced significantly different numbers of eggs and had different life spans. In particular, animals fed with G. graminis var. tritici showed early maturation, early burst in egg production, early loss of fertility and early death. The different nutritional values of the four fungi pathogen for cereals might have a different influence on the life strategy of Collembola in the field. Thus, since these fungi usually coexist in agricultural soils, though in different percentages, this influence might also affect the capacity of different fungi to attack the plant and thus modulate the appearance of disease
Cariologia e sistematica di Lernaea cyprinacea L. (Crustacea, Copepoda).
No full textVengono riferiti i primi risultati sulla cariologia di Lernaea cyprinacea L..Tutti gli esemplari sono stati raccolti in Italia (Umbria, Emilia Romagna, Lombardia) ed erano parassiti di varie specie di Teleostei. L'analisi cariologica ha evidenziato per tutti gli esemplari 2n= 16
Soil-borne plant pathogenic fungi in relation to some collembolan species under laboratory conditions
No full textInteractions between springtails (Onychiurus armatus, O. tuberculatus, Folsomia candida) and plant pathogenic fungi (Gaeumannomyces graminis var. tritici, Fusarium culmorum, Bipolaris sorokiniana and Rhizoctonia cerealis) living in the same soil layer were investigated under laboratory conditions. The fungi are responsible for the foot and root disease complex of winter cereals and can cause serious reduction in yield. Since these species coexist in agricultural soils, feeding preference tests were performed in such a way that the springtails were allowed to interact simultaneously with all the tested fungi. O. armatus, O. tuberculatus and F. candida fed on the mycelia of G. graminis var. tritici, F. culmorum and R. cerealis: in the first hours of the trials individuals of all springtail species distributed themselves among the colonies, though moving from one to the other. Subsequently F. culmorum mycelium became the preferred food of all species tested; however, the other two fungi continued to be consumed. Mycelia of G. graminis var. tritici, F. culmorum and R. cerealis were shown to be an adequate food source for reproduction of Folsomia candida. Bipolaris sorokiniana mycelium had both repellent and lethal effects on F. candida and O, armatus is, whereas this fungus was lethal, although not repellent. for O. tuberculatus. Long-term experiments on T. candida indicate that conidia of B. sorokiniana were eaten and proved to be a sufficient diet for reproduction
Evoluzione del cariotipo negli animali del suolo: i miriapodi Pauropodi.
No full textVengono presentati i primi dati sulla cariologia dei Pauropodi al momento praticamente nulli. Si riferiscono i dati preliminari dell'analisi cariotipica di tre diverse specie. Allopauropus (A.) brevisetus, Allopauropus (A.) danicus e pauropus huxley
Ricerche sui Collemboli XXVIII. Su di una nuova specie endogea di Schaefferia.
No full textViene descritta la nuova specie Schaefferia scossirolii. La specie è caratterizzata dalla presenza di 3+3 occhi e 6+6 setole sui Denti. Gli esemplari sono stati ottenuti da campioni di terreno di un campo coltivato localizzato nei dintorni di Caserta
Interactions between Collembola and soil-borne cereal pathogen fungi
No full textLaboratory studies on the interactions between some species of Collembola and the most important pathogenic fungi of the foot and root of cereals were performed. Onychiurus armatus and Onychiurus tuberculatus actively grazed on the hyphae of Gaeumannomyces graminis var. tritici, Fusarium culmorum and Rhizoctonia sp. They did not have a higly specific feeding preference; they fed on the mycelium of all the three fungi even when present contemporaneously.Experiments carried out utilising another cereal pathogenic fungus, Bipolaris sorokiniana, indicate that its hyphae were repellent and produced one or more non-volatile metabolites that were lethal at least for some species of Collembola. Our investigations suggest that B. sorokiniana did not produce the toxic metabolite or metabolites throughout its entire life cycle. The substance(s) is/are produced when only hyphae are present, whereas we observed that Onychiurus pseudogranulosus actively fed on conidia that the forms only later
Effects of Collembola on plant-pathogenic fungus interactions in simple experimental systems
No full textTake-all and brown foot rot, caused respectively by Gaeumannomyces graminis var. tritici and Fusarium culmorum, are two important components of the foot and root fungal disease complex of winter cereals world-wide. These fungi persist in soil and in crop debris in the same layer of agricultural soil as Collembola, a well represented taxon of soil animals. Previous in vitro tests showed that these fungi grown on agarised medium were readily consumed by springtails. In a simplified experimental system with wheat plants and the pathogenic fungi grown on millet and wheat kernels, the severity of disease was significantly reduced by collembolan feeding activity
Karyotypes and habitat interrelations among soil Arthropoda: Collembola and Protura
No full textIn five species of Onychiurus (Collembola Onychiuridae) the diploid chromosome number is higher in animals of narrower width. In three species of Acerentomon (Protura, Acerentomidae) the number of the chromosome arms (FN), not the chromosme number, is inversely correlated to the length of the foretarsus and consequently to the narrowness of the passages they can frequent
Analisi cariologica di tre specie di Onichiuridi (Collembola, Insecta)
No full textL'analisi cariologica di tre specie di collemboli onichiuridi, tutti appartenenti allo stesso genere Onychiurus (Protaphorura) ha messo in evidenza l'alto numero di cromosomi del corredo diploide di queste specie, con 2n= 16 in O. quadriocellatus e 2n= 18 in O. armatus e O. glebatus. Questi numeri sono i più alti finora accertati nei collemboli
Chromosome studies in Protura Eosentomoidea
No full textKaryological investigations on specimens diagnosed as Eosentomon transitorium, collected in different sites, was carried out
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