Effet de l'exposition aux rayons γ sur la réaction hémocytaire multicellulaire des larves deMamestra brassicae [Lep.: Noctuidae]

Résumé L'exposition des larves deMamestra brassicae L. à une irradiation γ de 7 000 rad, provoque l'affaiblissement de la réaction de défense multicellulaire de l'insecte h?te vis-à-vis d'Aspergillus flavus Link. Le processus hémocytaire donne naissance à des granulomes à enveloppe plus réduite et moins bien organisée que chez les animaux non traités, dont le champignon s'échappe précocement. La mort très rapide desMamestra irradiées et infectées est bien due essentiellement à l'action de l'agent pathogène. Cependant des bactérioses se manifestent de manière limitée. Ces résultats présentent une signification importante pour les méthodes de lutte contre les insectes faisant appel aux rayonnements.

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Summary Exposure ofMamestra brassicae L. larvae to a γ ray dose of 7 000 rad, causes the weakening of the multicellular defence reaction of the host toAspergillus flavus Link. The hemocytic process give rise to granulomes not so voluminous and well-organized as in the non treated animals, and the fungus escape early from these structures. The death of the infected and irradiatedMamestra larvae, which occurs quickly, is essentially due to the action of the pathogen. However a few bacterial infections are also observed. These results are of great significance for the methods of control of insect pests using radiations.

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Les auteurs remercient MmeN. Bres et MmeJ. Cavalier pour leur aide technique.     

The possible role of entomophagous insects in the genetic control of the codling moth,with special reference toTrichogramma

The release of sterilized codling moth enriches the animal community of the orchard. This enrichment leads to new situations also for the entomophagous species and may provide special possibilities in the use of entomophaga. Codling moth control by the sterility principle may provide certain entomophagous species with an extra food source, namely, the released moth and, possibly more important, the sterile eggs laid by these moths. This extra food may be detrimental to the sterility control because of certain predators of the adult codling moths (e.g.Vespula maculata L., other predatory insects and entomophagous birds). On the other hand, the extra food source may be advantageous. For example, sterilized moths, at the rate of release currently used in control programs, should deposit up to 5 to 10 million eggs per hectare per season. These eggs may produce 2,5 to 5 million adultTrichogramma parasites, assuming 2Trichogramma per egg and 75 % parasite mortality. Both inviable eggs of sterilized moths and gamma sterilized eggs proved to be reasonably satisfactory food for the larvae ofTrichogramma evanescens Westw. This parasite also attacked and developed in normal eggs ofAdoxophyes reticulana.Hbn. These results suggest that release of limited numbers ofTrichogramma parasites could be combined with release of sterile codling moths to provide improved control of this pest and to aid in the biological suppression of other injurious tortricids.

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Résumé Lors de l'emploi des males stériles dans la lutte contre les insectes, la population du verger est enrichie par le lacher de Carpocapses. Les prédateurs peuvent diminuer le nombre des adultes lachés, mais les œufs stériles pondus par ces derniers sont aptes à enrichir la population de Trichogrammes, comme nous l'avons montré par nos expériences en laboratoire. Cette population peut être un complément à l'utilisation des males stériles dans la lutte contre le Carpocapse. Elle peut surtout être efficace dans la lutte biologique contre d'autres Tortricides.

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This paper was read at the 3rd meeting of the IOBC working group on genetic control of Codling Moth andAdoxophyes at Montfavet, France, November 24–26, 1971.     

L'utilisation d'une maladie a virus comme méthode de lutte biologique contrePieris brassicae L.

Summary A virus disease of the ?granulosis? type was encountered by us in laboratoryreared caterpillars ofPieris brassicae L. This disease was first seen byPaillot (1924–25) and the virus was recently described byVago, Lépine andCroissant (1955). Extraction of the granules was made in the laboratory and a series of tests was designed to know the possibility of inducing the disease in healthy caterpillars (no attempt was made to determine the median lethal dose). After a first series of successful laboratory experiments an application was made in the field. (in La Crau — Var). Caterpillars of the last three instars were treated (in the beginning of December 1955) with a suspension prepared by grinding dead cabbageworms. A portable automatic compressed air sprayer was used and a non germicide wetting agent was added. Typical signs of the disease appeared three weeks after treatment and death of the caterpillars occured within a period of ten days. In laboratory tests, when treated caterpillars matured to adults, the butterflies laid fertile eggs but a high percentage of first instar larvae died of the disease. The success of the field tests is encouraging to continue the study of a possible use of virus diseases as means of Biological Control of pests.

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I.N.R.A., Laboratoire de biocénotique et de lutte biologique de La Minière.     

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.     

Les protéines des corps d'inclusion desBaculovirus III. Étude comparée de la granulose dePieris brassicae et de la polyédrose deBombyx mori

Résumé L'étude des protéines des granules dePieris brassicae L. et des polyèdres nucléaires deBombyx mori L. par les techniques de filtration sur gel, d'électrophorèse et d'immunodiffusion révèle de nombreuses ressemblances. La comparaison des protéines des corps d'inclusion engendrés par lesBaculovirus des Lépidoptères contribue à montrer l'homogénéité de ce groupe.

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Summary It is generally admitted that the viruses of nuclear polyhedroses and granuloses of Lepidoptera form two distinct groups serologically. A comparative study of proteins of nuclear polyhedral bodies ofBombyx mori and of granules ofPieris brassicae was carried by using techniques of gel filtration, electrophoresis and immunodiffusion. The characteristics of proteins of granules studied by gel chromatography and electrophoresis are closely related to those of proteins of polyhedral bodies. In immunodiffusion, the extraction of proteins of polyhedral inclusion bodies by the carbonate reveals a common antigen (C antigen) which is recognized by homologue serums and anti-protein heterologue serums of inclusion bodies of seven otherBaculovirus. The extraction by the thioglycolate reveals, in addition to C antigens, specific antigens: T antigen for the granulosis ofPieris brassicae and B antigens for the nuclear polyhedrosis ofBombyx mori. The comparison of proteins of inclusion bodies generated by granulosis and nuclear polyhedrosis viruses contributes to show the homogeneity of the LepidopterBaculovirus group.

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Avec la collaboration technique de LilianeCroizier.     

Observations sur la biologie et le comportement cleptoparasite d'Eurytoma waachtli [Chalc.: Eurytomidae], parasite dePissodes validirostris [Col.: Curculionidae] dans les cones de pin sylvestre a Fontainebleau

Résumé Des observations ont été effectuées sur la morphologie des stades préimaginaux et le cycle de développement d'Eurytoma waachtli Mayr., qui se développe en ectoparasite sur les larves de 4^e stade du curculionidePissodes validirostris Gyll. dans les c?nes de pin sylvestre. On a constaté que le chalcidien n'attaque les larves dePissodes que si celles-ci sont préalablement parasitées et paralysées par des ichneumonides du genreScambus. E. waachtli détruit d'abord la larve deScambus puis se développe sur la larve du Coléoptère. Un tel comportement peut être qualifié de cleptoparasite. Le développement d'E.waachtli, en général monovoltin, est étroitement lié à la fois à celui dePissodes et à celui deScambus sp. En limitant le nombre de parasites primaires,E. waachtli joue un r?le favorable à l'accroissement des populations dePissodes validirostris.

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Summary Observations have been carried out on the morphology of the pre-imaginal stages and the life cycle ofEurytoma waachtli Mayr., which occurs as ectoparasite on 4th instar larvae of the weevilPissodes validirostris Gyll. in cones of Scotch pines. It has been established that the attack by this chalcidid ofPissodes larvae occurs only when they have been previously parasitized and paralysed by ichneumonids of the genusScambus. First,E. waachtli kills the larva ofScambus, then feeds on the weevil larva. Such a behaviour may be called “cleptoparasitism”. The development ofE. waachtli generally monovoltine, is strongly related both to the development ofPissodes and ofScambus sp. By limiting the number of primary parasites,E. waachtli is playing a part in the increase ofP. validirostris population levels.

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Avec la collaboration technique deJ.-P. Raimbault.     

Hibernation d'Apanteles chilonis [Hym.: Braconidae] sous le climat méditerranéen

Résumé L'introduction d'Apanteles chilonis Mun. en France a été tentée pour lutter contreChilo suppressalis Wlk. La multiplication du parasito?de est décrite. Des essais ont été menés au laboratoire sur la résistance des stades endoparasites aux températures basses (2, 5, 10 et 15°C). L'hibernation a été suivie entre 1975 et 1978 dans un insectarium extérieur. Le développement hivernal aboutit à l'achèvement de la vie endoparasite dès les mois de mars et avril. La mortalité est très forte à ce moment en raison de températures insuffisamment élevées pour la nymphose. La synchronisation des cycles du parasito?de et de l'h?te étant aléatoire, des recherches ont été entreprises sur la présence d'h?tes intermédiaires dans le milieu naturel. NiSesamia nonagrioides niOstrinia nubilalis ne conviennent, par contre la bioécologie deChilo phragmitellus présente des éléments favorables.

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Summary Apanteles chilonis is a Japanese endoparasitoid ofChilo suppressalis (Lep.: Pyralidae) An attempt has recently been made to introduce it into France to control the same pest in rice fields. The means of breeding the parasite in fairly large numbers is described. The parasite can develop in the field in summer, but in winter its life cycle is more likely to be affected by adverse conditions. The resistance of its 3 larval instars to temperatures ranging from 2 to 15°C. was tested in the laboratory. Mortality estimation for a gregarious endoparasitoid is discussed. Two different check lots ofC. suppressalis larvae were necessary, 1 of which was parasitized. Mortality was then calculated usingAbott's formula. The 2nd instar ofA. chilonis was the most resistant; its mortality after 30 days at 5°C being 44%, compared with 60% for the 1st instar and 77% for the 3rd. From 1975 to 1978, parasitized larvae ofC. suppressalis were wintered under near-natural conditions in an outdoor insectary. Periodic dissection of these larvae showed that the development ofA. chilonis progressed slowly from egg to the 2nd larval stage and faster after this. Although at low temperatures eggs were killed, 1st instar larvae were found during the coldest months, December to February. Second and 3 rd instars occurred from March to April and the adults from late April to late May. Mortality of the parasitized host was high, exceeding 80% and occurring late in winter or in early spring rather than in the coldest months. Only a few adultA. chilonis were formed; at best, 123 adults emerged from 120 hosts during spring 1978. Some of the host population emerges in spring, which should allow the parasite to breed on its progeny. However, rice cannot be sown until the end of April in southern France, because of the climate andC. suppressalis larvae have no suitable food available until June. Unless the adult parasites, therefore, can find the few scattered, still-diapausing, larvae of the host in which to oviposit, they will die without laying eggs. Synchronisation of the parasite attack with the development ofC. suppressalis is therefore doubtful. The possibility of the parasite adopting a transient host within the same environment asC. suppressalis has been investigated and is discussed. An other speciesChilo, C. phragmitellus,Hüb. occurs in reeds. Its larvae are appropriate hosts forA. chilonis and reach a suitable stage in spring. It has not yet been found to be parasitized byA. chilonis under natural conditions, though adultA. chilonis have been recovered from a reed community in the immediate vicinity of a rice field. Common species likeOstrinia nubilalis L., the European corn borer, orSesamia nonagrio?des Lefb. (Noctuidae), are unsuitable hosts. It might be rewarding to test other strains ofA. chilonis from elsewhere in Japan.

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Avec la collaboration technique deH. Magnin etA. Radisson.     

Biological control ofDiatraea saccharalis [Lep.: Pyralidae] in Florida by periodic releases ofLixophaga diatraeae [Dipt.: Tachinidae]

Lixophaga diatraeae (Townsend) parasitized 20 to 78% ofDiatraea saccharalis (F) larval populations within 3 weeks after release. The flies (4 to 6 days old) did not migrate from the release area, but the progeny dispersed as much as 3 km into adjacent untreated areas within 5 generations. Progeny dispersal, apparently during the prelarviposition period, resulted in 100% parasitization ofD. saccharalis larvae in some plots. In 2 of the 3 tests, the host population decreased after the releases. Percentage damaged internodes increased with distance from the release site.

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Résumé Des lachers de la mouche parasite, appelée vulgairement mouche de Cuba, dans les champs de anne, en Floride, ont limité les populations du foreur de la canne. La tachinaire a parasité 20 à 78% des foreurs. En outre, la descendance des parasites a été retrouvée à plus de 3 km des points de lacher. Les dégats aux cannes à sucre furent moindres dans les champs où les lachers ont été effectués que dans les champs voisins.

     

Parasites,predators and other arthropods associated withMusca domestica and other flies breeding in bovine manure

The species of flies breeding in bovine manure, their parasites and predators as well as other associated arthropods in 3 localities in and near Bangalore are recoreded. The flies areMusca domestica L.,Musca pattoni Austen,Stomoxys calcitrans L.,Physiphora aenea F.,Physiphora demandata F.,Sargus metallinus F.,Sepsis thoracica R.-D.,Sepsis nitens Wiedemann,Sphaerocera scabricula Hal, andLeptocera (Coproica) hirtula Rondani. Four species of hymenopterous pupal parasites of these flies have been obtained:Spalangia cameroni Perkins from pupae ofM. domestica, M. pattoni, S. calcitrans, P. aenea andP. demandata; Spalangia endius Walker from pupae ofM. domestica, M. pattoni andS. calcitrans; Spalangia nigroaenea Curtis from pupae ofM. domestica andS. calcitrans; andDirhinus trichiophthalmus Masi from pupae ofSargus metallinus F. Percentage parasitism of fly puparia in field samples was noted. Four species ofHister andAleochara puberula Klug feeding on various immature stages ofM. domestica, 2 species of scarabaeid beetles, 2 species of ants and a pseudoscorpion were also found in the manure. The importance of biotic regulatory factors in the control of flies is discussed.

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Résumé Dans 3 localités de Bangalore ou proches de cette ville, on a inventorié les espèces de mouches vivant dans le fumier de vache, leurs parasites et prédateurs ainsi que d'autres arthropodes associés. Les mouches récoltées sont:Musca domestica L.,Musca pattoni Austen,Stomoxys calcitrans L.,Physiphora aenea F.,Physiphora demandata F.,Sargus metallinus F.,Sepsis thoracica R-D.,Sepsis nitens Wiedemann,Sphaerocera scabricula Hal. etLeptocera (Coproica) hirtula Rondani. Quatre espèces d'hyménoptères parasites des pupes ont été obtenues de ces mouches:Spalangia cameroni Perkins deM. domestica, M. pattoni, S. calcitrans, P. aenea etP. demandata: Spalangia endius Walker deM. domestica, M. pattoni etS. calcitrans, P. aenea etP. demandata; Spalangia endius Walker trans; etDirhinus trichiophthalmus Masi deSargus metallinus F. On a noté le taux de parasitisme des nymphes dans les conditions naturelles. Quatre espèces deHister etAleochara puberula Klug s'attaquant aux divers stades non imaginaux deM. domestica, 2 espèces de scarabeides, 2 espèces de fourmis et un pseudoscorpion ont été également trouvés dans le fumier. L'importance de ces facteurs biotiques dans la régulation des populations de mouches est discutée.

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Paper presented at the seminar on utilization of farm wastes for rural industrial growth, National Dairy Research Institute, Bangalore, 31 st December, 1975.

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This paper is published with the permission of the Director-General, Indian Council of Medical Research, New Delhi     

Über morphologische folgen der parasitierung von Euscelis-männchen (Homoptera auchenorrhyncha) mit dryiniden-larven

Summary At the end of July 1959 in a field population (from Taucha near Leipzig) all males of the leafhoppers Euscelis plebejus Fall. and E. distin, guendus Kbm. parasitized by Dryinid larvae (Gonatopus sepsoides Westwood) had a significantly larger Aedoeagus than the not infested ones. With E. plebejus the infested males were larger on the whole too. This finding is in contrast with the more or less strong reduction of the outer genitalia normally produced by entomophagous parasites in Homoptera. A thorough discussion of this discrepancy by all available observations on the bionomical and morphological effects of Dryinid infestation leads in connection with ecomorphological statements on the relation between generative and vegetative development in leafhoppers to the conception, that the infestation by Dryinids only then causes a reduction of the host genitalia, if it happens very early (Aphelopinae). If the parasitization occurred in already older host larvae, the transformation of metabolism caused by check of the gonads only effects a delayed development and by this an increase of growth. By this the male host at least, reaching the adult stage at all, shows a general enlargement of size, only faint indeed—due to the relatively short parasitization timend surely to be proved only with eurymorph species as E. plebejus or with organs positively allometrical growing as the Aedoeagus of the Euscelis species. Along with this the size of the latter is demonstrated to be modificable in the second line by parasitic infestation.

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Herrn Professor Dr. Arno Wetzel zum 70. Geburtstage gewidmet.     

Prédateurs et parasites d'Aphytis [Hym., Aphelinidae]

Summary Very few predators and parasites ofAphytis have been recorded. Among predators, only Coccinellids preying on Diaspine scale insects have been mentioned as damaging to the preimaginal stages ofAphytis on occasion, and a single case of a mitePyemotidae has been known to have destroyed the pupae. As to the parasites known, they are accidental and rare. There are cases where only the male lives as a parasite onAphytis, the female developing normally as a primary parasite onAphytis hosts. Two species harmful toAphytis have been found in Lebanon:Pyemotes herfsi Oudemans (Acarina, Pyemotidae) andApterencyrtus adeli n. sp. (Hymenoptera, Encyrtidae). P. herfsi is a polyphagous predator, and its increase in number might constitute a threat to theAphytis in the field and the insectary.A. adeli is the only example known so far of a true hyperparasite whose males and females develop onAphytis. It has been found abundantly on larvae ofAphytis mytilaspidis as well as on many other hosts.

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Extrait d'une thèse de Doctorat de troisième cycle (biologie animale) soutenue à la Faculté des Sciences de l'Université de Paris le 2 avril 1968.     

Abwehrreaktionen vonMalacosoma neustria gegen Tachinenlarven bei gleichzeitigem Auftreten einer Kernpolyedrose

Summary Two types of larvae ofMalacosoma neustria (L.) different in their behaviour as well as in their activity, produce also layers of hemocytes of different thickness after parasitization by the tachinidMericia ampelus wilk. A nuclear polyhedrosis that occurred simultaneously killed both larval types at different speed. The possibility is discussed that the quality of the hemocyte reaction to parasitization depends not only directly on the larval type, but also indirectly through the polyhedrosis.

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Durchgeführt mit Unterstützung der Deutschen Forschungsgemeinschaft.

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Herrn WOR Dr. J. M.Franz danke ich für wertvolle Anregungen und jederzeitige Unterstützung der Arbeit.     

L'élevage massif artificiel deCeratitis capitata Wied.

Summary A method of artificial mass-breeding ofCeratitis capitata has been developped after the results obtained byFinney andChristenson. The breeding of the larvae is obtained on a medium made of powdered atomised carrot and brewer's yeast, the development of molds and bacteria being inhibited by benzo?c and hydrochloric acids. Nearly 80 per cent of the eggs give adult flies. An original method for obtaining the eggs in an artificial egg-laying apparatus is described. The development of the insect is completed in 21 days at the temperature of 26°C. A daily production of 20 000 flies or more is easily obtained, at very low cost, by the work of a single person.

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Travail réalisé avec la collaboration technique de MlleM. Barthes.

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Station de Zoologie agricole du Centre de recherches agronomiques du Sud-Est.     

Susceptibility of gypsy moth larvae toLymantria spp. nuclear-and cytoplasmic-polyhedrosis viruses

SevenLymantria spp. viruses from widely separated sources were used in a screening test for virulence. Laboratory data show thatLymantria dispar L. cytoplasmic-polyhedrosis virus of Japan, and the nuclear-polyhedrosis virus of Connecticut (U.S.A.) are more virulent than other five viruses when tested on the larvae of the gypsy moth. The nuclear-and cytoplasmic-polyhedrosis viruses ofLymantria fumida Btl. were also infectious forL. dispar larvae.

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Résumé On a comparé au laboratoire la virulence de 7 souches différentes de virus des polyédroses nucléaire et cytoplasmique isolées deLymantria spp. Les essais effectués par contamination de la nourriture montrent que les chenilles deLymantria dispar L. sont sensibles à tous les virus employés. Les données permettent d’établir que la souche américaine de virus de la polyédrose nucléaire et la souche japonaise de virus cytoplasmique deL. dispar sont les plus virulentes.

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Presented at the 1st meeting of the “Working Group onLymantria dispar, O. I. L. B.”, Tempio Pausania, Italy, October 16–17, 1969.     

Biological studies ofPteroptrix smithi [Hymenoptera: Aphelinidae]

The developmental history, longevity and fecundity ofPteroptrix smithi (Compere) are described and discussed. Both sexes develop as primary parasites ofChrysomphalus aonidum (L.). Developmental duration at 26°C averages 25 days and the average fecundity at this temperature is 26.5 eggs for unmated and 21.4 eggs for mated females. Under laboratory conditions 50–80% of the eggs are laid during the first few days of adult life. Longevity of females ranges from a maximum of 44 days at 20°C to a minimum of 15 days at 32°C. Male longevity does not differ significantly.

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Résumé Les deux sexes sont parasites primaires de la CochenilleChrysomphalus aonidum L. La durée du développement à 26°C est en moyenne de 25 jours et la fécondité moyenne à cette température est de 26,5 œufs chez les femelles vierges et 21,4 œufs chez les femelles accouplées. Au laboratoire 50 à 80% des œufs sont déposés au cours des tout premiers jours de la vie imaginale. La longévíté des femelles varie de 44 jours à 20°C à 15 jours à 32°C, celle des males n'est pas significativement différente.

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Dedicated to Prof.H. Mendelssohn on the occasion of his 60th birthday.     

Role écologique deDigitalis purpurea dans la limitation naturelle des populations du puceron strié de la pomme de terreAulacorthum solani parAphidius urticae dans l'ouest de la France

Résumé En Bretagne les cultures de pommes de terre sont colonisées parAulacorthum solani,kltb,Macrosiphum euphorbiae thomas etMyzus persicae sulz. Lorsque le vol de contamination initiale par A.solani etM. persicae est de grande amplitude, le vol de dissémination est virtuellement absent, et inversement. Nous montrons que ceci est d? au très fort parasitisme qui affecte les populations dès leur installation sur les pommes de terre. En ce qui concerneA. solani, attaqué en particulier parAphidius urticae Hal. le r?le de la digitale en tant que producteur de pucerons et de parasites est mis en évidence. Le synchronisme entre la production de pucerons ailés et de parasites varie selon les biotopes et à ce titre la température para?t avoir une action prédominante.

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Summary In western France, the potato crops are regularly invaded byA. solani kltb,Myzus persicae sulz. andMacrosiphum euphorbiae thomas. Whenever the primary infestation by winged aphids is low, then the dissemination flight is relatively important and conversely (fig. 1). The reason is that aphidiids exert a good control as soon as aphid populations are building up. These parasites may be carried as eggs or young larvae in the alate aphids ofA. solani (table 1) and asD. purpurea constitutes one of its main winter host (A. solani is anholocyclic), the impcrtance of this plant was investigated as regards to aphid, parasite and hyperparasite production.Aphidius urticae hal-was the only parasite recorded so far with five hyperparasite species. On potato plants, too,A. urticae seems specifically concerned withA. solani otherwise attacked byAphidius picipes nees andAphidius ervi hal. It was shown some discrepancies between different biotopes as regards to the rate of parasitism at the same time (table 2) and attention is stressed on apparent differences between parasitization of apterous and winged instars (table 3), the importance of which is discussed regarding to the amount of winged invaders the foxglove may produce by the time the potato plants are shooting. Temperature appears to exert an important r?le in this respect.

     

PHYSIOLOGISCHE WECHSELBEZIEHUNGEN ZWISCHEN PIERIS BRASSICAE UND DEM ENDOPARASITEN APANTELES GLOMERATUS. DER EINFLUß DER PARASITIERUNG AUF WACHSTUM UND KÖRPERGEWICHT DES WIRTES1

Zusammenfassung Der Parasitismus von Apanteles glomeratus (L.) bewirkt bei den Larven seines Wirtes, Pieris brassicae. L., eine Blockierung des Gewebewachstums und der Reservestoffspeicherung, sobald sich die Parasitenlarven zum 2. Stadium gehäutet haben. Das Ausmaß der durch diese Blockierung bedingten Wachstumshemmung der Wirtsraupe ist von der Anzahl der in ihr vorhandenen Parasitenlarven unabhängig; es scheint jedoch vom Häutungstermin derselben bestimmt zu werden. Gemessen am durchschnittlichen Trockengewicht erwachsener Pieris-Raupen beträgt der Hemmungseffekt zwischen 60% und 80%. Die Stoffwechselkapazität der Wirtsraupen wird trotz der Blockierung nicht eingeschränkt, sondern steht den Entwicklungsbedürfnissen der Parasitenlarven zur Verfügung, wobei der Grad ihrer Inanspruchnahme von der Individuenzahl der Parasitenlarven abhängt.

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Summary Apanteles glomeratus and Pieris brassicae served as models to investigate the parasitic effect on growth and body weight of the host. Three kinds of host larvae were used in the experiments: Aunparasitized larvae, B-larvae being parasitized on the first day after hatching from the egg, and C-larvae parasitized on the sixth day after hatching. Parasitism by A. glomeratus blocks the growth of the host body independently of the number of parasite larvae living in a host, when the dry weight of the host tissues has reached about 20% (in B-larvae) or 40% (in C-larvae) of the final dry weight of the unparasitized host larva. This blocking occurs on the first and about the third day of the host's fifth instar, respectively. Further growth of the host-parasite-system comes from the development of the parasite larvae only, and depends on the number of them present in the host body. In this way slightly parasitized Pieris-larvae remain abnormally small, whereas heavily parasitized ones grow up to a final body weight higher than unparasitized larvae. This effect is apparent in the maximum and the final live weight as well as in the final dry weight of the total system.The blocking effect seems to be induced by the parasite's second-instar larvae, because growth of the host tissues ceases immediately after the moulting of the parasites. At this moment the host larva seems to loose most of its metabolic autonomy and becomes governed by the parasite larvae. The blocking effect, the physiological mechanism of which is not yet understood, is absolute. It preserves about 80% of the host's spatial and nutritional capacity for the development of the parasite larvae. This reserve of space and metabolic potency is completely exhausted only when the number of parasites exceeds 60 or 80 per host larva in B- and C-larvae, respectively; smaller parasite numbers use only a part of this reserve.It is concluded that the Apanteles larvae, being unable to feed on or to destroy solid host tissues, prevent their synthesis by a blocking effect, thereby eliminating the competition of the host body for nutrients absorbed by the host's gut. Because of the varying number of parasite larvae in the range of 1 to 160 the expected nutritional requirement of the parasite larvae present is uncertain in their early stages of development. Preserving about 80% of the host's physiological capacity independently of the number of the moulting parasite larvae, A. glomeratus guarantees conditions sufficient for the development of even an extraordinarily numerous progeny.

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Gefördert durch die Deutsche Forschungsgemeinschaft     

Le complexe des ennemis naturels des Aphides du Pêcher dans la moyenne vallée du Rhone

Résumé Dans le cadre d’une recherche écologique sur les Aphides du Pêcher soutenue par le Comité Lutte Biologique de la DGRST, en vue d’explorer les modalités d’application à cette culture du concept de la Lutte intégrée, une première étude a présenté l’analyse de la dynamique des populations des pucerons les plus nuisibles et montré l’importance de certains ennemis naturels (Leclant & Remaudière, 1970). L’objet du présent article est de dégager les principaux éléments du complexe biologique intervenant dans la régulation des populations et de préciser les rapports existant entre quelques-uns d’entre eux. Les recherches ont été accomplies de 1968 à 1970 dans plusieurs vergers vergers de Pêcher de la région de Valence (Dr?me) et plus particulièrement au domaine de Gotheron (Saint-Marcel-lès-Valence).

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Summary Samples consisting of about 20 infested twigs of 6 to 8 leaves have been collected periodically and kept alive during a period of 10 days. At this time, most of the predators have achieved their growth and the parasites have mummified their hosts; then they are isolated until hatching. Syrphids play a predominant role in the regulation of the aphid population.Epistrophe balteata andSyrphus vitripennis are the most frequent of the six species obtained. 35% of the Syrphids is destroyed by parasites; however their action at the highth of the orchards is not affected because their number appears to depend on the immigrants. Spiders have a significative impact at the end of the winter when fundatrix larvae hatch. Coccinellids (Col.), Chamaemyiids (Dipt.) and other predators and parasites are not very important factors of regulation. Aphids parasitized by fungi (Entomophthora aphidis andplanchoniana) are found more or less frequently according to the climatic conditions of the year. An epizootic situation occurred in June 1968 which determined a quicker decline of the populations ofMyzus persicae. Cultural practices affect the relative importance of the various natural enemies: in orchards with high weeds the action of Coccinellids may be preponderant.

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Communication présentée à la 2^e réunion du groupe de travail PBI ?Biological Control of Aphids?, Paris, 16–18 septembre 1970.     

Field observations on impact of egg parasiteTelenomus remus [Hym.: Scelionidae] on tobacco caterpillar,Spodoptera litura [Lep.: Noctuidae] in tobacco nurseries in Andhra Pradesh,India

The tobacco caterpillar,Spodoptera litura F. is a major pest in the tobacco nurseries causing damage by defoliation. Inundative releases were carried out with 650,000 parasites from 1st July, 1974 to 30th November, 1976. This paper reports the effectiveness from 1976 to 1979 of the parasite in reducing the population of tobacco caterpillar.Telenomus remus Nixon was found significantly effective in reducing the pest population at the peak of infestation in the site of release as compared to control nurseries where no parasites were released. However, the difference inSpodoptera population between the site of release and control was minimal during the last 1979 nursery season which suggests the necessity of inundative releases ofT. remus after every 2 years for effectively checking the population ofS. litura in tobacco nurseries.

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Résumé La noctuelle du tabac,Spodoptera litura F. est un ravageur très important des pépinières de tabac du fait de ses défoliations. On a procédé à des lachers inondatifs de 650.000 parasites du 1^er juillet 1874 au 30 novembre 1976. Cette note indique l'action du parasite entre 1976 et 1979 dans la réduction des populations de chenilles du tabac. On a constaté queTelenomus remus Nixon a une activité significative dans la réduction des populations du ravageur au moment du maximum d'infestation dans le lieu de lacher par rapport aux pépinières témoins sans introduction de parasites. Cependant la différence des niveaux de population entre le lieu de lacher et le terrain a été minimum lors de la dernière période de plantation en pépinière en 1979, ce qui suggère la nécessité d'effectuer tous les 2 ans des lachers inondatifs deT. remus pour lutter efficacement contreSpodoptera dans les pépinières de tabac.

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Paper presented at the 4th Tobacco Symposium held at Rajahmundry-533 105, India, 19–22 Jan. 1981.     

Élevage en nouvelle-calédonie deMicrophthalma Europaea Egg. [Diptera,Tachinidae] Sur L'hote de SubstitutionProtaetia Fusca Hrbt. [Coleoptera,Scarabaeidae, Cetoniinae]

Résumé La TachinaireMicrophthalma europaea Egg., parasite de larves deScarabaeidae en Afrique du Nord [Hurpin & Fresneau, 1964] a été multipliée à Nouméa (Nouvelle-Calédonie) sur un nouvel h?te de substitutionProtaetia fusca Hrbt. (Cetoniinae). Cet h?te nouveau permet maińtenant un élevage massif du parasite en Nouvelle-Calédonie, avant sa libération éventuelle à l'?le Wallis contre les larves d'Oryctes rhinoceros L., unDynastinae ravageur du cocotier.

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Summary The Tachinid fly,Microphthalma europaea Egg., parasite onScarabaeidae larvae in North Africa (Hurpin & Fresneau, 1964) was multiplied in Noumea (New Caledonia) on a new alternative hostProtaetia fusca Hrbt. (Cetoniinae). The contingent introduction of this parasite fly to Wallis island against larvae ofOryctes rhinoceros L. (Dynastinae), the coconut rhinoceros beetle, so could be now more easy from New Caledonia.

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Nous remercions le DrP. Jourdeuhil, Directeur de la Station de Lutte Biologique d'Antibes (France), d'avoir bien voulu lire notre manuscrit et nous apporter ses conseils les plus judicieux.