Cephalosporium salvinae sp. nov. a pathogen of Salvinia rotundifolia willd

A new species ofCephalosporium is reported that is parasitic on the floating water fernSalvinia rotundifolia. In culture this fungus forms white, pulvinate colonies with a surface mat that may change to vinaceous-brown or violet with age. Small, ovate to spherical, hyaline conidia and spherical to elliptic chlamydospores are formed by this species. It represents a new member of theC. acremonium group. The pathogenic nature of the fungus has been confirmed.

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Zusammenfassung Eine neue Art vonCephalosporium ist beschrieben, die parasitisch an Wasserfarn,Salvinia rotundifolia, ist. In Kultur bildet dieser Pilz weiße, staubige Kolonien, die mit dem Alter braun oder violett werden. Diese Art bildet kleine ovale oder runde, hyaline Konidien und elliptische Chlamydosporen. Dieser Pilz ist ein neues Mitglied in derC. acremonium-Gruppe. Die pathogenetische Natur des Pilzes ist bestätigt worden.

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Based in part on a thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, Atlanta University.

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Published as Research Publication No. 25 Atlanta University Center Science Research Institute.     

Recherche d'enzymes intracellulaires chez les Kluyveromyces (van der Walt) (β galactosidase, β glucosidase, α glucosidase,tréhalase): Conséquences taxinomiques

23 strains of 19 species ofKluyveromyces are studied to verify if non assimilation of lactose, cellobiose or abutine, maltose, and trehalose depends on system of sugar transport or on absence of hydrolysing enzymatic system in cells. Results show that both phenomenons are present. Taxonomic consequences and phylogenetic implication of these cases are discussed.

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Collaboration technique: MmeBillon—Grand G.     

Zur Frage der Monogynie oder Polygynie beiMyrmecina graminicola (Latr.) (Hym., Form.)

Zusammenfassung Untersuchungen an 8 Kolonien vonMyrmecina graminicola ergaben, dass bei dieser Art neben monogynen auch echt polygyne Völker vorkommen. Im Gegensatz zu den Ergebnissen vonBaroni-Urbani (1968) ist daher eine funktionelle Monogynie beiMyrmecina nicht anzunehmen Ebenso kann eine obligatorische Monogynie ausgeschlossen werdent. Ob diese Art fakultative polygyn oder — wahrscheinlicher — regalmässig monogyn ist, kann noch nicht sicher entschieden werden.

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Summary By investigation on 8 colonies ofMyrmecina graminicola monogyny as well as real polygyny was proved in this species. Therefore contrary to the results ofBaroni-Urbani (1968) a functional monogyny ofMyrmecina cannot be supposed. An obligatory monogyny as well can be excluded. Whether this species is facultatively polygynous or—more likely—regularely monogynous, can't yet surely be decided.

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an der Immenburg 1, 53 Bonn, Rép. Féd. All.     

Spécificité des champignons pathogènes imparfaits [Hyphomycètes] pour les larves de coléoptères [Scarabaeidae etChrysomelidae]

Résumé L'étude de la spécificité des Hyphomycètes pathogènes de larves de Coléoptères a été effectuée avec diverses souches deBeauveria bassiana (Bals.) Vuill. B. tenella (Delacr.) Siem. Metarrhizium anisopliae (Metsch.) Sor. etNomuraea rileyi (Farl.) Sams. par contamination tégumentaire deCetonia aurata L.,Oryctes rhinoceros L.,Melolontha melolontha L. etLeptinotarsa decemlineata Say. Les essais ont été complétés par une contamination intrahémocoelienne dans le cas particulier des larves de Scarabeides. L'adaptation des pathotypes à leur h?te d'origine est confirmée chez les larves de Scarabeides et démontrée également après injection chezC. aurata etO. rhinoceros. Par contre, les larves de doryphore se révèlent sensibles à de nombreuses espèces et souches de champignons. Les résultats sont discutés par rapport aux travaux sur les relations h?teparasite en Phytopathologie et en Pathologie des Invertébrés.

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Summary Some strains ofBeauveria bassiana, B. tenella, Metarrhizium anisopliae andNomuraea rileyi were tested for specificity toCetonia aurata, Oryctes rhinoceros, Melolontha melolontha andLeptinotarsa decemlineata larvae. The contaminations were carried out by surface spray on larvae or by injection in the haemolymph with titrated spores suspensions. The experiments were conducted in blocks, each sequence of biossays was repeated 4 times. The results obtained were statistically interpreted after transformation of the mortality rates into angular values, which allowed the two-way analysis of variance and the comparison of the means by theDuncan & Staude's test. In the case of larvae ofL. decemlineata we have considered the time-mortality curves. By spraying it has been shown thatC. aurata, O. rhinoceros orM. melolontha larvae were susceptible only to the fungus strain isolated from insects of the same species. In the same conditions all twenty isolates were active on larvae ofL. decemlineata, but at a different degree. The host specialization of entomogenous Hyphomycetes strains cannot be considered as alone taxonomic criterion. According to epidemic works in plant infection it was appeared that host resistance of larvae ofScarabaeidae was vertical and that Colorado beetle larvae showed a horizontal susceptibility. After injection in the haemolymph ofC. aurata orO. rhinoceros larvae, the cryptogamic pathotypes were active only on their original host. The role of the defense reaction was discussed. Such investigations provided informations about the different modalities of the specificity of Hyphomycetes on insects.

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Avec la collaboration technique deP. H. Robert.     

Iscephalosporium acremonium capable of producing maduromycosis?

Summary A case of mycetoma apparently due toCephalosporium acremonium is described. The position ofCephalosporium spp. as agents of maduromycosis is briefly considered.     

Takakia im Himalaya

Summary A second species of the hitherto monotypic order Takakiales is described and figured en detail. This Himalayan species —T. ceratophylla (Mitt.)Gro. n. c. — is very similar to the type speciesT. lepidozioides from M-Japan and SW-Canada and also an orophyt.

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Herrn Dr. C. T.Rogerson, New York, möchte ich meinen herzlichen Dank für die Ausleihe des Originales vonLepidozia ceratophylla Mitt. auch hier aussprcehen.     

Sugli organi genitali maschili delle Rhinotermitidæ (isoptera)

Riassunto Si è studiato l'apparato genitale maschile di alcune caste e stadi diReticulitermes lucifugus e degli alati diPsammotermes assuanensis, Coptotermes sj?stedti, Schedorhinotermes javanicus, prestando particolare attenzione alla forma delle vescicole seminali, al loro contenuto, e all'attività del testicolo.

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Summary It has been studied the male genital apparate of some casts and stages ofReticulitermes lucifugus and of winged reproductives ofPsammotermes assuanensis, Coptotermes sj?stedti, Schedorhinotermes javanicus, with particular attention to the form of the seminal vescicles, to their contenute, and to the testicle's activity.

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Résumé Nous avons étudié la conformation des organes males de quelques castes et stades deReticulitermes lucifugus et des ailes dePsammotermes assuanensis, Coptotermes sj?stedti, Schedorhinotermes javanicus, en donnant une particulière attention à la forme des vésicules séminales, à leur contenu et à l'activité du testicule.

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Questa nota rappresenta l'ultimo dei nostri lavori che il prof. CarloJucci ha riveduto ed approvato per la stampa. A Lui la dedichiamo, grati per l'insegna mento datoci e per l'essempio costante di dedizione al lavoro.     

Zum Mechanismus der photodynamischen Inaktivierung von Saccharomyceszellen

Summary We have been shown that photodynamic damage in cells ofSaccharomyces caused by thiopyronine and also very probably by acridine yellow, thionine, trypaflavine, acridine orange, methylene blue and neutral red is due to aninterior effect where the dye enters the cell and attaches itself to important components of the cell — probably DNA or RNA — absorbing light energy and transfering this to these attached components.In the case of methyl green, malachite green and pyronine the low degree of inactivation caused by these dyes is explained by their poor ability to enter the cell and for lactoflavine (riboflavine) by its low light absorption. The relatively small photodynamic effect of brilliantcresyl blue is probably due to the low energy transfer from the dye to the attached component. We have further been able to show that for eosine this process ofinterior action is only a part of the explanation of this dye's action. The photodynamic effect of eosine is explained chiefly byexterior action. However theinterior effect of eosine can be increased by increasing the incubation time of the cells in eosine solution before exposing the cells to the light.

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FrauIngrid Pietsch danken wir für zuverlässige Assistenz bei der Durchführung der Versuche, der Deutschen Forschungsgemeinschaft für eine Sachbeihilfe.

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8. Mitteilung über photodynamische Wirkung von Farbstoffen.     

A comparison of some Ceratocystis species with sporothrix schenckii

Sympodulosporogenous states ofC. minor, C. montia, C. multiannulata, C. narcissi, C. nigrocarpa, C. perparvispora andC. pilifera were compared with typical and atypical strains ofS. schenckii from the aspects of some culture, morphological, serological characteristics, and mouse virulence. With a possible exception, all the former characteristics demonstrated among theCeratocystis species were either the same as, or varied in the same way as those observed amongS. schenckii strains. None of the former hydrolyzed starch, although all of the latter did. All species and strains cross reacted serologically in agglutination and Arthus-rype reactions, and produced similar gross pathological signs when injected with gastric mucin intraperitoneally into mice. Except for some variations in sizes and shapes of sympodulospores and of yeast-like budding forms observed in tissue smears and in cultures incubated at 37°C, theCeratocystis species were not significantly different from typical strains ofS. schenckii.

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Zusammenfassung Der sympodulosporogene Zustand vonC. minor, C. montia, C. multiannulata, C. narcissi, C. nigrocarpa, C. perparvispora undC. pilifera wurde mit typischen und atypischen Stämmen vonS. schenckii betreffs kultureller, morphologischer, serologischer Charakteristik und auf Virulenz für Mäuse untersucht. Mit einer möglichen Ausnahme waren alle Charakteristiken unter denCeratocystis-Arten dieselben oder sie wechselten wie diejenigen unter den Stämmen vonS. schenckii. Keine Stämme derCeratocystis hydrolysierten Stärke, während die Stämme vonS. schenckii getan haben. Alle die Arten und Stämme zeigten Kreuzreaktionen serologisch und in der Arthus-reaktion und zeigten dieselben groß-pathologischen Veränderungen nach intraperitonealen Injektionen mit Magenmuzin in der Maus. Außer etlicher Abwechslungen in Größe und Gestalt der Sympodulosporen und der hefe-ähnlichen Keimung, die in Gewebeausstrichen und in Kulturen bei 37°C beobachtet worden sind, waren dieCeratocystis-Arten nicht wesentlich unterschiedlich von typischen Stämmen vonS. schenckii.

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The author, Dr.R. W. Davidson (Colorado State University, Ft. Collins, Colorado), and Dr.F. Mariat (Institut Pasteur, Paris) have, in collaboration, identified the ascigerous state ofSporothrix schenckii strain G-118 isolated by the latter to beCeratocystis stenoceras (Robak)C. Moreau.     

Sur la spécifité deMetarrhizium anisopliae (Metsch.) sorokin

Résumé Le pouvoir pathogène de 8 souches deMetarrhizium anisopliae isolées de 7 Searabeides et du Doryphore a été comparé à l’égard de 9 espèces de ColéoptèresScarabaeidae: 5Dynastidae, 3Cetoniidae et 1Melolonthidae, par incorporation de différentes doses de conidiospores au milieu d’élevage des larves. Il a été ainsi montré que la plupart des Insectes étudiés sont sensibles seulement à la souche de Champignon isolée de la même espèce. Par contre lesOryctes sont sensibles à tous lesMetarrhizium provenant d’espèces appartenant au genreOrycles.

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Summary The pathogenicity of 8 strains ofMetarrhizium anisopliae has been investigated on 9 species of ColeopteraScarabaeidae (5Dynastidae, 3Cetoniidae and 1Melolonthidae), by incorporating different doses of conidiospores in the larval rearing medium. In this way, it has been shown that most of the insects studied However, species ofOryctes are susceptible to allMetarrhizium strains derived fromOryctes species. are susceptible only to the fungus strains isolated from insects of the same species.

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Nous remercions vivement MmeA. Deotte pour sa participation à ces essais et notamment la préparation des souches deMetarrhizium.     

Da ocorrência de Hanseniaspora valbyensis Kloecker em apêndice cecal humano e lesões epidérmicas

Summary This paper deals with the study of two strains ofHanseniaspora valbyensis Kloecker respectively isolated from human cecal appendix contents and from epidermal lesions in one case of dermatomycosis.

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Publicação no 183     

Cephalosporium madurae n. sp., cause of madura foot in India

Summary Madura foot incited by a new species ofCephalosporium is presented. Case history, clinical symptoms and morphological features of the new pathogen are discussed. Comparative studies with the previously reported species indicate that the species isolated is an undescribed one and the nameCephalosporium madurae is proposed for it. Dedicated to Professor Tibor Benedek,one of our greatest living Medical Mycologists, on the occasion of his 70th birthday.     

Une nouvelle espèce du genreHabrolepis [Hym. Chalcidoidea encyrtidae] parasite dePseudaonidia trilobitiformis [Homoptera diaspididae] en Nouvelle-Calédonie

Résumé Habrolepis neocaledonensis spec. nov., obtenue en Nouvelle-Calédonie dePseudaonidia trilobitiformis Green est décrite. Cette espèce vient se joindre à quatre autres espèces qui constitutent au sein du genre un groupe particulier. La question de l'homogénéité de ce groupe et de l'opportunité d'une redéfinition du genre est abordée.

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Summary Habrolepis neocaledonensis spec. nov., reared fromPscudaonidia trilobitiformis Green in New Caledonia, is described. It belongs to a group of the genusHabrolepis with 4 other species (H. aeruginosa, H. obscura, H. setigera, H. occidua). The homogeneity of this subdivision and the timeliness of a revision ofHabrolepis is discussed.

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Nous remercionsM. H. Compère spécialiste Emeritus de l'Université de Californie-Riverside pour l'enseignement qu'il nous a prodigué pendant notre séjour dans son laboratoire et le DrD. P. Annecke qui nous a procuré des specimens d'H. obscura et d'H. occidua.     

Coexistencia de „Madurella Mycetomi” y de „Madurella Grisea” en una Misma Observacion de Maduromicosis Podal Negra

Summary The author reports on the clinical and mycological studies of a case of black-grain maduromycosis in a woman from Santa Maria (Province of Catamarca, Argentine).Cultures of black grains in Sabouraud medium have developed colonies ofMadurella mycetomi and also ofMadurella grisea Mackinnon, Ferrada &Montemayor, 1949.The author questioned, which of the two species is the etiological agent in the present case and he concluded that the microscopic aspect of the black grain permits to suppose thatMadurella mycetomi is the agent in this case.

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En homenaje al Prof. Tibor Benedek.     

Beitrag zur Phytochemie der Hepaticae

Zusammenfassung In sauren methanolischen Extrakten aus gametophytischem Gewebe vonLophocolea bidentata (L.)Dum. undPlagiochila asplenioides (L.)Dum. konnte zum ersten Male Ellagsäure mit Hilfe dünnschichtchromatographischer Methoden identifiziert werden. Daneben fanden sich in den Extrakten noch einige andere bisher noch nicht identifizierte Phenole, darunter möglicherweise 8 Flavonoide.

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Summary Ellagic acid was detected in acidic methanol-extracts of gametophytic tissue ofLophocolea bidentata (L.)Dum. andPlagiochila asplenioides (L.)Dum. The identification was accomplished by thin-layer Chromatographic methods. Beside this compound some more still unidentified phenolics were found, among those probably 8 flavonoids.

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Herrn Prof. Dr. L.Brauner, mit den herzlichsten Wünschen zum 75. Geburtstag gewidmet.

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Herrn Prof. Dr. H.Jork von der Fachrichtung Pharmakognosie und Analytische Phytochemie sowie Fräulein S.Klein danken wir sehr für die Hilfe bei der Herstellung der UV-Spektren. Herrn grad. biol. et chem. S.Bartl danken wir für hilfreiche Diskussion.     

Facteurs de limitation des populations d'Aphis fabae dans l'ouest de la France III. Répartition et incidence des différentes espèces d'Entomophthora dans les populations

Résumé Plusieurs espèces d'Entomophthora participent à la régulation des populations d'Aphis fabae Scop. sur féverole dans l'Ouest de la France. Les r?les respectifs de chaque espèce ont été évalués en 1971 et de 1973 à 1975. Entomophthora fresenii Nowak. est l'espèce qui se dissémine le plus rapidement et le plus complètement dans les parcelles, et qui est la plus agressive au niveau des colonies. Ces deux caractères en font l'agent pathogène dominant d'A. fabae dans l'Ouest, 3 années d'observations sur 4.Entomophthora aphidis Hoffman, bien que présent tous les ans n'est le pathogène le plus efficace qu'en 1973.Entomophthora thaxteriana Petch etEntomophthora planchoniana Cornu n'apparaissent pas chaque année et, lorsqu'ils sont présents, n'interviennent que pour une faible part dans le développement des mycoses. Des facteurs inhérents à l'agent pathogène (spécificité, caractères du cycle) ainsi que des facteurs écologiques (climatiques) sont évoqués pour expliquer la prédominance d'E. fresenii.

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Summary Several species ofEntomophthora take part in the natural control ofAphis fabae Scop. on field beans (Vicia faba) in the West of France. The respective importance of each species was assessed in 1971 and from 1973 to 1975. Entomophthora fresenii Nowak. is the species that most completely and quickly spreads in the fields, and the most efficient in the colonies. For both reasonsE. fresenii is the main pathogen ofA. fabae in the West of France 3 years over 4. AlthoughEntomophthora aphidis Hoffman occurs every year, this species was the most efficient pathogen in 1973 only.Entomophthora thaxteriana Petch just occurred in 1974 and 1975 and, these years, its contribution in the total sum of infected aphids was low.Entomophthora planchoniana Cornu appeared in 1975 only, very late in the season, which makes its pathogenicity difficult to assess. Factors inherent to the pathogen (specificity ofE. fresenii, nature of its cycle, dependence of the aggregation of aphids) and ecological factors such as response to climate variations, may at least to a great extent explain the predominance ofE. fresenii. All these factors must be studied for a good understanding of this species.

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Les 2 premiers mémoires de cette étude ont été publiés dans Entomophaga respectivement parRobert et al. (18, 1973, 61–75) etRabasse & Robert (20, 1975, 49–63)     

Researches on the etiological agents of the american blastomycosis

Summary and conclusion We have been able to establish typical characteristics of the species, in artificial culture media, of the fungus causingPosadas-Wernicke's disease. Our work is base on the study of ten strains of the fungus and on their retrocultures — obtianed by inoculation of these strains in laboratory animals — in variosu culture media, among them cornmeal agar (Emmons media) which in our opinion is a medium indispensable for the differencing and for the classification of the fungus from other agents which produce syndromes of a like nature.A revision was made of the literature of the morphology of the causal agent ofPosadas-Wernicke's disease and an analysis of the predominant and characteristic fructification of the fungus. In attention to the above facts, we think that the fungus in question should be included in the genusAleurisma Link, 1809. Therefore, admitting the validity of this genus, we believe that the name of the etiological agent ofPosadas-Wernicke's disease should be changed toAleurisma immitis, the diagnosis being justified by the microscopic study inEmmons media and completed by the forms found in a medium rich in glycides. The diagnoses is the following: Aleurisma immitis. — In substratis pauperibus gignuntur hyphis mycelicis hyalinis, septatis, satis ramosis, ramulis in angulo pene recto; aleuriis abundantissimis, valde simplicibus, centralibus et regulariter seriatis, vel apicalibus, rarissime lateralibus, sessilibus, rare pedicellatis, rectangularibus, hyalinis, aliquoties in racemis et thyrsis dispositis. Spirae saepe videntur. In substratis carbohydratis plenis, chlamydosporis intercalaribus et apicalibus abundantibus; aleuriis et spiris nec numerosis aut typicis quam in pauperibus substratis.(so called Coccidioidomycosis)     

Classification des souches du groupeBacillus thuringiensis par la détermination de l'antigène flagellaire

Summary The serological study of 26 new strains ofBacillus thuringiensis (of which the biochemical features are also given) makes it possible to classify these strains into: 1^o Strains which are in concordance with the six serotypes previously described. 2^o Strains which have a new H antigen. Here, we describe two new serotypes: serotype 7 (aizawai), serotype 8 (morrisoni). On the other hand, the serological study of five new strains ofB. thuringiensis belonging to serotype 4 shows that the H₄ antigen must be divided into ?sub-factors?: ?4 a, 4b? to be found in the strains sotto, dendrolimus, T.84-A, L (Grig) and ?4 a, 4 c? to be found in the strains Pil 94, 1748 and Rhodesia. Table 6 gives the present statute of theB. thuringiensis strains' classification by the flagellar agglutination technic.

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Avec la collaboration technique deM. Lechevallier etT. Le Borgne. Nous remercions vivement les collègues qui ont bien voulu nous adresser des cultures et nous nous tenons à la disposition de tous ceux qui seraient intéresés par la détermination de l'antigène H de leurs souches. Nous remercions également notre collègueLe Minor pour ses précieux conseils.     

Les protéines des corps d'inclusion desBaculovirus

Résumé La comparaison des granules ou des protéines de granules desBaculovirus dePieris brassicae, Pygaera anastomosis, Hyphantria cunea, Carpocapsa pomonella, Mythimna unipuncta, Mamestra oleracea a été entreprise par les techniques d'électrophorèse, d'agglutination, d'immunofluorescence et de précipitation en gel. L'électrophorèse fait appara?tre l'étroite ressemblance qui existe entre les protéines des six sortes de corps d'inclusion. L'analyse immunochimique montre que chaque granule est bien distinct de tous les autres; elle peut servir de base à l'identification des divers virus.

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Summary The proteins ofBaculovirus capsules ofPieris brassicae, Pygaera anastomosis, Hyphantria cunea, Mamestra oleracea, Mythimna unipuncta andCarpocapsa pomonella are studied and compared. There is no significant difference in the composition of electrophoregrams of proteins extracted from capsules of six virus strains by means of a thioglycolate buffer, pH 10,5. Two chief zones (G and F bands) are identified in every one of these strains. Mobility of proteins (C proteins) contained in the G intermediate band is slightly identical, only C proteins ofPieris brassicae andPygaera anastomosis can be differentiated according to a slight difference between electrophoretic mobility. Agglutination and immunofluorescence techniques used for suspensions and smears of granules enable to recognize granules ofC. pomonella andM. unipuncta among the six types of granules. By the immunodiffusion technique, it is revealed that F antigens occurs in all strains and C antigens in five ones. In addition to these common antigens, there are specific antigens respectively named TPa, TPb, J, U, P antigens forP. anastomosis, P. brassicae, H. cunea, M. unipuncta andC. pomonella granules. Capsules taken in Hungary and France from larvae ofC. pomonella could not be differentiated by the techniques used. This work emphasizes both characters common to the group of viruses studied and differences sufficient for identifying every one of types studied.

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Avec la collaboration technique de LilianeCroizier.     

Étude du comportement de plusieurs souches deConidiobolus obscurus [ZygomycètesEntomophthoraceae] vis-a-vis des puceronsAcyrthosiphon pisum etSitobion avenae [Hom.: Aphididae]

Résumé Au sein de l'espèceConidiobolus obscurus (Hall & Dunn) Remaudière & Keller, les souches différant par leur comportement en culturein vitro présentent également des différences dans leur comportementin vivo. Les souches qui poussent rapidement, plissent le milieu et forment facilement des azygospores (type A) sont moins virulentes à l'égard deAcyrthosiphon pisum Harris et deSitobion avenae F. que les souches de type B, qui poussent plus lentement, plissent peu le milieu et ne produisent pas de spores de résistance. La durée d'incubation de la maladie chez les 2 espèces de pucerons est plus longue chez les individus infectés par une souche de type B que chez ceux infectés par une souche de type A. La formation d'azygospores à l'intérieur des pucerons morts de mycose placés à 2°C sur de la cellulose mouillée n'est observée que dans le cas des souches de type A. En dernier lieu le nombre de conidies émis par un cadavre lors de la sporulation est en moyenne plus élevé dans le cas des souches de type B que dans celui des souches de type A. Les 2 types de souches doivent être regardés comme des races biologiques au sein de l'espèceC. obscurus.

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Summary The 2 types of strain ofConidiobolus obscurus (Hall & Dunn) Remaudière & Keller which can be separated by differences in their growthin vitro, differed also in characteristics of their developmentin vivo. Strains which,in vitro, grow rapidly, fold the surface of agar media and readily produce azygospores (strains of type A), were less infective forAcyrthosiphon pisum Harris andSitobion avenae F. than strains of type B which grow more slowly, hardly fold the surface of agar media and fail to produce resting spores. However, the incubation period of the disease in both these aphid species was longer for type B than type A strains. Azygospores formed in aphids infected experimentally with type A strains but not in those infected with type B strains when the cadavers were placed on moist cellulose at 2°C. The mean number of conidia produced from aphids infected with strains of both types varied greatly but strains of type B produced more conidia per aphid than those of type A. The 2 types of strain should be considered as biological races within the speciesC. obscurus.

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Avec la collaboration technique de MesdamesM. Arnault etS. K. Best.