Showing papers in "Biocontrol in 1972"
TL;DR: A sequence of actions is suggested for establishing a quality control program that elucidates the behavioral status of laboratory-reared strains and the possibility of the evolution of new pest species.
Abstract: The present situation and objectives of mass rearing insects are reviewed under the aspect of behavior. The highest degree of “typical” behavior is required in those species that have to compete with their natural counterparts in the field. Selection pressure and conditioning during the process of mass rearing might alter the behavior of the organisms produced under artificial conditions and cause failures of field-releases. Problems that warrant more considerations are displacement failure to reach natural counterparts and the possibility of the evolution of new pest species. A sequence of actions is suggested for establishing a quality control program that elucidates the behavioral status of laboratory-reared strains.
141 citations
TL;DR: It is suggested that some widely held concepts of biological control should be discarded to enable the rigorous application of genetic strategies for pest control.
Abstract: Selection and maintenance of insect stocks for biological control programmes depend on the objective and the scope of propagation. Propagation for inoculative releases with the objective of colonization must ensure that the source colony contains a sufficient amount of genetic diversity. The implications of the origin and the size of the source colony are discussed. During propagation genetic decay can result from, among other processes, the founder effect, inbreeding or the selection of laboratory «ecotypes». Standardized strains of insect parasites and predators are recommended for mass production programmes for inundative releases. In addition to laboratory-construted strains for genetic controls, hybrid strains showing superior fitness, new pathotypes, and strains carrying genetic markers, may be useful for biological control. Some inferences are drawn from population genetic theory and applied to insectary rearing programmes. It is suggested that some widely held concepts of biological control should be discarded to enable the rigorous application of genetic strategies for pest control.
96 citations
TL;DR: Genetically markedNasonia vitripennis females that oviposited second or third on aSarcophaga bullata pupa produced fewer progeny than those that were the first to oviposit on the host.
Abstract: Genetically markedNasonia vitripennis females that oviposited second or third on aSarcophaga bullata pupa produced fewer progeny than those that were the first to oviposit on the host. The proportion of males in these progeny was also significantly increased (p.<0.001). Implications of these results on the evolution of hymenopterous parasites are discussed.
72 citations
TL;DR: Two species of female parasitoids were found to discriminate between superpara sitized and nonparasitized hosts and the source of the host marking pheromone was found to be the alkaline (Dufour’s) gland in both species.
Abstract: Two species of female parasitoids,Cardiochiles nigriceps andMicropletis cro ceipes (Hymenoptera: Braconidae) were found to discriminate between superpara sitized and nonparasitized hosts. The source of the host marking pheromone was found to be the alkaline (Dufour’s) gland in both species.
61 citations
TL;DR: Study of factors relating to the pathogenic microorganism showed the importance of the fungus strain used B. bassiana, as a species, but the virulence of different biotypes towards a particular host is very variable.
Abstract: L’etude des facteurs lies au germe entomopathogene montre l’importance du choix de la souche du Champignon et de l’inoculum. Le biotype le plus virulent estB. bassiana no 18, son optimum thermique se situe a 25°C et il est confirme que la mortalite des larves est fonction de la dose de spores utilisee. De plus, le terme du processus infectieux peut etre retarde ou avance, la mortalite differee etant d’autant plus importante que l’inoculum est plus reduit. Les facteurs lies a l’hote ont ete consideres par rapport a la sensibilite des differents stades du developpement et par rapport au role de la mue dans le rejet des teguments. Apres contamination des 4 stades larvaires deL. decemlineata il n’y a pas de difference de niveau de mortalite totale, par contre, l’examen de la mortalite differee met en evidence une resistance croissante a la mycose au cours du developpement larvaire. Plus les larves sont proches de la mue au moment du traitement, plus la mortalite differee est importante et, a partir d’un certain seuil, variable avec la dose de spores, le niveau de mortalite cumulee baisse. Une attention particuliere a ete portee a la temperature, dont depend la duree du developpement larvaire du Doryphore. Les meilleures conditions d’infection sont realisees a 20°C en raison de l’allongement correlatif de la duree de l’intermue, bien que l’optimum thermique de l’Insecte et du Champignon se situe a 25°C. Le role de la temperature sur l’infection apparait beaucoup plus important que celui de l’humidite.
59 citations
TL;DR: It has been shown that most of the insects studied However, species of Oryctes are susceptible to allMetarrhizium strains derived fromOrycte species are susceptible only to the fungus strains isolated from insects of the same species.
Abstract: Le pouvoir pathogene de 8 souches deMetarrhizium anisopliae isolees de 7 Searabeides et du Doryphore a ete compare a l’egard de 9 especes de ColeopteresScarabaeidae: 5Dynastidae, 3Cetoniidae et 1Melolonthidae, par incorporation de differentes doses de conidiospores au milieu d’elevage des larves. Il a ete ainsi montre que la plupart des Insectes etudies sont sensibles seulement a la souche de Champignon isolee de la meme espece. Par contre lesOryctes sont sensibles a tous lesMetarrhizium provenant d’especes appartenant au genreOrycles.
41 citations
TL;DR: Aspects of the microhabitat distributions of the gypsy moth, Porthetria dispar (L.) (Lepidoptera: Lymantriidae), and some of its parasitoids were investigated in the field by means of sticky panels and Gypsy moth egg masses exposed at different heights in trees.
Abstract: Aspects of the microhabitat distributions of the gypsy moth,Porthetria dispar (L.) (Lepidoptera: Lymantriidae), and some of its parasitoids were investigated in the field by means of sticky panels and gypsy moth egg masses exposed at different heights in trees, by egg masses exposed within forested and cleared areas, and by gypsy moth pupal collections from different heights in trees.Ooencyrtus kuwanai (Howard)(Hymenoptera: Encyrtidae), Apanteles melanoscelusRatzeburg (Hymenoptera: Braconidae), and gypsy moths were caught most frequently on stickly panels placed in upper portions of trees. In contrast,Apanteles laevicepsAshmead, a parasitoid of cutworms, was most often caught near the forest floor.O. kuwanai attacked equally egg masses exposed at different heights in trees, but parasitized those in a clearing less often than those within the forest prosper.Brachymeria intermedia (Nees) (Hymenoptera: Chalcididae) emerged mostly from pupae collected near the tops of trees and not at all from those collected below 5 m. The results are discussed as they relate to field sampling procedures, behavioral activities of gypsy moth and parasitoid adults, and integrated control possibilities for the gypsy moth.
32 citations
TL;DR: It is concluded that, apart from phenological effects on the insects and host plant, the two primary Parasitoids have considerable impact in controlling numbers of their host, T. erytreae, and that the secondary parasitoidA.
Abstract: Associated with the citrus psylla,Trioza erytreae (Del Guercio), in Salisbury, Rhodesia, are two primary parasitoids and 13 secondary and tertiary hyperparasitoids. One of the primary parasitoidsTetrastichus? radiatus remains external to the psyllid host whereas the other primary,Psyllaephagus pulvinatus, is an internal parasitoid. The major secondary hyperparasitoidAphidencyrtus cassatus, which was recorded in large numbers, attacks both primary parasitoids. Accounts are given of the biology of the two primary parasitoids and ofA. cassatus. The other hyperparasites in the complex are numerically unimportant and summaries of their biology are contained in a table. A diagram is given to illustrate the interrelationships of the parasitoids in the citrus psylla complex. It is concluded that, apart from phenological effects on the insects and host plant, the two primary parasitoids have considerable impact in controlling numbers of their host,T. erytreae, and that the secondary parasitoidA. cassatus through its attacks on the primary parasitoids is also of major importance in determining population levels achieved by the citrus psylla. Some characteristics of the parasitoids in the complex are discussed which might explain the high population levels of citrus psylla achieved in the Salisbury area. Several research avenues exist which would clarify the feasibility of biological control procedures againstT. erytreae.
29 citations
TL;DR: A new species ofTrichogrammatoidea, which has been reared from eggs ofHeliothis armigera onPolianthes tuberosa and from those of an unidentified Lepidopteron onCajanus cajan, was successfully bred and did not show any perceptible preference for any of these hosts.
Abstract: A new species ofTrichogrammatoidea which is being described byH. Nagaraja asT. armigera, has been reared from eggs ofHeliothis armigera onPolianthes tuberosa and from those of an unidentified Lepidopteron onCajanus cajan. In the laboratory the parasite was successfully bred onCorcyra cephalonica, Achaea janata, Gnorimoschema operculella andPlutella xylostella; it did not show any perceptible preference for any of these hosts. It also parasitised eggs ofSpodoptera litura, but although development proceeded to the adult stage, adults failed to emerge, suggesting unsuitability of this host.
24 citations
TL;DR: Methods are proposed as a contribution towards the formalization of an approach to the selection and introduction of entomophagous insects to assist in selecting the best species for introduction into an area with a known species composition and distribution.
Abstract: Methods are proposed as a contribution towards the formalization of an approach to the selection and introduction of entomophagous insects. Once the critical resources necessary for the reproduction and survival of a predator or parasitoid have been identified, sites are arranged to sample these insects in different grades of the same critical factor. These grades of a resource may be ranked, and organized on gradients, or unranked, but in both cases the range of samples represents a resource set. The entomophagous insect distributions on these sets are analyzed and quantified by formulae that show the breadth of a species distribution, the similarity between distributions, and the interaction species will experience on each of the resource sets. These calculations can assist in selecting the best species for introduction into an area with a known species composition and distribution.
22 citations
TL;DR: The reproductive relations and the probability of hybridization between an arrhenotokous and a thelyTokous form of A. mytilaspidis were investigated so as to determine the significance of thelytoky in biosystematic studies and its value as a taxonomic character.
Abstract: The reproductive relations and the probability of hybridization between an arrhenotokous and a thelytokous form ofA. mytilaspidis were investigated so as to determine the significance of thelytoky in biosystematic studies and its value as a taxonomic character. Gene markers were utilized to detect and follow the various phases of the introgressive process between the arrhenotokous and thelytokous forms. The two forms show only a partiel sexual isolation, the major barrier is prezygotic, arrhenotokous males are much less efficient in recognizing the thelytokous female and copulating with them. A thelytokous female, once inseminated, will utilize the sperm as efficiently as the arrhenotokous female. Viable and fertile hybrids are produced and when conditions are favorable and a suitable host is present the introgressive process will result in a hybrid swarm. The hybrids acquire traits carried by both ancestral stocks.
TL;DR: Suggestions are made for the continuation of both short-and long-term procedures to be adopted in biological control work and examples cited of the value of both approaches.
Abstract: There has recently been some discussion as to the most effective methods of carrying out biological control investigations — the need for detailed ecological investigations, life-table studies, population studies, etc.
TL;DR: An account of the Indian species of the genusEretmocerusHaldeman is given and three new species (E. indicus, E. mashhoodi and E. gunturiensis) are reported for the first time from India.
Abstract: An account of the Indian species of the genusEretmocerus
Haldeman is given. Three new species (E. indicus sp. n.,E. mashhoodi sp. n.,E. gunturiensis sp. n.) are described. Three species (E. haldemani
Howard,E. mundus
Mercet,E. corni
Haldeman) are reported for the first time from India. A revised key to the known species of the genus is also given.
TL;DR: In this paper, biological and morphological characters of the thelytokous and arrhenotokous forms of A. mytilaspidis and their hybrids were investigated.
Abstract: Biological and morphological characters of the thelytokous and arrhenotokous forms ofA. mytilaspidis and their hybrids were investigated. Some biological differences between the thelytokous and arrhenotokous forms were found. The former is adapted to warmer condition and will parasitizeHemiberlesia lataniae as well asDiaspis echinocacti, while the latter will not parasitizeH. lataniae. The overall fecundity of the thelytokous form is lower than that of the arrhenotokous form, whereas the “effective fecundity”, female progeny per female parent, is higher in the thelytokous form. Apart from the no. of setae in the wings delta, there are no distinguishing morphological characters between the arrhenotokous and thelytokous forms.
TL;DR: An account of the Indian species of the genusAphelinusDalman is given and two new species (A. kashmiriensis sp. n., A. desantisi sp.n.) are described.
Abstract: An account of the Indian species of the genusAphelinus
Dalman is given Two new species (A. kashmiriensis sp. n.,A. desantisi sp.n.) are described. Four species (A. nikolskajae
Jasnosh,A. flavipes (Foerster),A. abdominalis (Dalman),A. asychis
Walker) are reported for the first time from India. A key for the separation of the Indian species ofAphelinus is presented.
TL;DR: Determinism and dynamic aspects of the parasite migration are discussed; also the influence of the age of host egg on the developmental success ofP.
Abstract: Le moment, le lieu et le mode de penetration d'un parasite ovo-larvaire dans son hote embryonnaire sont reperes par des techniques histologiques. Dans le travail ici presente, la ponte du parasite s'effectue dans des œufs-hotes âges de 15 a 30 minutes. Les principales etapes de l'embryogenese du Lepidoptere parasite sont decrites afin de montrer comment s'effectue la penetration de l'Hymenoptere dans son hote. Le determinisme et la dynamique des deplacements de la larve parasite sont discutes.
TL;DR: The use of reducing agents improves the classical process of solubilization of inclusion bodies and should make it possible to establish an accurate differential diagnosis.
Abstract: L’etude immunochimique des corps d’inclusion formes par lesBaculovirus de Lepidopteres est entreprise en vue de differencier ces viroses. Le travail relate decrit l’influence de differents solutes sur l’extraction des proteines des granules de la granulose dePieris brassicae. L’interet de l’emploi d’agents reducteurs tels que l’acide thioglycolique ou le mercaptoethanol pour la solubilisation des granules est mis en evidence.
TL;DR: Intra- and interspecific competition for food in larvae ofSyrphus ribesii andS.
Abstract: Intra- and interspecific competition for food (Myzus persicae) in larvae ofSyrphus ribesii andS. corollae were investigated in the laboratory at 20°, 16 hrs light. A competing unit consisted originally of six newly hatched larvae, trhee of each species or six of one species.S. ribesii had a low larval survival (about 35–40%) and a prolonged larval period (about 16–17 days) under both intra- and interspecific conditions, although food consumption was greater when mixed withS. corollae. InS. corollae, larval survival was significantly smaller when mixed withS. ribesii than under intraspecific conditions (25.0% and 73.1%). Larval period was somewhat increased in the mixed series.
TL;DR: It appears that a good regulation of the populations of C. horni may occur, due to the high percentage and persistence of the parasitism, and exposure of naturally or artificially lowered populations of aphids to constant parasitism seems far better for the prevention of outbreaks.
Abstract: Le puceronCapitophorus horni peut causer de graves prejudices aux cultures d’artichauts dans l’Ouest de la France. La presente note fait l’inventaire des parasites (Aphidiides et Entomophthorales) de cet aphide et precise leur role dans la regulation de ses populations.
TL;DR: The endoparasitic larvae of two pupal parasites, Pimpla turionellae L. andPimpla flavicowisThs, move inside the host pupa (Galleria mellonella L.) in a characteristic manner during their development.
Abstract: Die endoparasitischen Larven der beiden nahe verwandten PuppenparasitenartenPimpla turionellae undPimpla flavicoxis legen wahrend ihrer Larvenentwicklung in der Wirtspuppe eine charakteristische Wanderung zuruck. Unabhangig von der Lage des Parasiteneies in der Puppe wandert die Junglarve sofort nach dem Verlassen des Eies zum Kopfende der Puppe und zerstort dort das Gehirn und die umliegenden Organe. Anschliessend kriecht sie ins Abdomen, wahrend sie gleichzeitig die Wirtsgewebe auflost und Nahrungsbrei zu sich nimmt. Im Abdomen dreht sie sich abermals um, so dass ihr Kopf zum Vorderende der Puppe weist. In dieser Lage verzehrt sie den Rest des verflussigten Puppeninhalts und verpuppt sich. Die Parasitenimagines schlupfen durch das Vorderende der Wirtspuppe. —In superparasitierten Puppen wandern alle Junglarven zum Kopfende der Wirtspuppe und tragen dort ihre Konkurrenzkampfe aus, indem die uberzahligen Larven durch Bissverletzungen ausgeschaltet werden. In der Regel bleibt eine Larve am Leben und entwickelt sich weiter. — Die Junglarven werden wahrscheinlich durch chemische oder Stromungsreize zum Vorderende der Puppe gelenkt. Dieses ausgepragte Orientierungsverhalten gestattet die Ausschaltung gleichalteriger Nahrungskonkurrenten zum fruhest moglichen Zeitpunkt. Die Wanderung der Larven bringt den Parasiten allem Anschein nach noch andere Vorteile.
TL;DR: Larvae ofPteromalus puparum were reared semi-artificially on the anterior part of Pieris pupae, and artificially on host haemolymph, and are useful for studying nutritional problems in parasitis larvae.
Abstract: Les larves dePteromalus puparum ont ete elevees en conditions semi-artificielles sur la partie anterieure des chrysalides dePieris et en conditions artificielles sur l’hemolymphe de l’hote. Les deux methodes permettent d’obtenir le developpement complet des parasites avec un succes voisin de 40 % dans le premier cas et de 70 % dans le deuxieme. Dans les deux cas, la croissance larvaire est comparable a la croissance des larves elevees normalement et conduit a des adultes de taille normale. A un moment donne de leur developpement, toutes les larves quittent leur norrriture. Ce comportement, non decelable a l’interieur de l’hote normal, est particulierement net dans les elevages sur demi-chrysalides. Ces deux techniques d’elevage rendent possible l’observation directe des larves au cours de leur croissance et constituent done une methode interessante pour l’etude des problemes nutritionnels chez les parasites.
TL;DR: Redescriptions are given of nine species and a further three species are described as new and a key is provided for the separation of females of the twelve species here recognised.
Abstract: The characters ofZeteticontus andBothriothorax are compared. Redescriptions are given of nine species and a further three species are described as new. A key is provided for the separation of females of the twelve species here recognised.
TL;DR: The behaviour of the two common East African ant species, A. capensis and P. megacephala, towards various predaceous Syrphids was studied in a number of experiments and by some observations in the Kenya Highlands.
Abstract: Das Verhalten der ostafrikanischen AmeisenartenAcantholepis capensis undPheidole megacephala gegenuber rauberischen Syrphiden wurde in Kenia durch Beobachtungen und Freilandversuche zu klaren versucht. Es zeigte sich, dass es sich beiP. megacephala um eine besonders aggressive Ameise handelt, die lediglich die Gegenwart von Larven der GattungParagus (P. longiventris, P. marshalli undP. borbonicus) in den von ihr besuchten Blattlauskolonien zulasst. Kommt die Ameise mitParagus-Larven aus Aphidenkolonien mitA. capensis-Besuch in Kontakt, so totet sie diese Larven ab. Andererseits verhalt sichP. megacephala gegenuberParagus-Larven aus Blattlauskolonien mit Besuch durch ihre eigene Art wesentlich weniger feindselig. Larven grosser Syrphidenarten (Allograpta spp.,Betasyrphus spp. undAfrosyrphus varipes) werden von der Ameise regelmassig abgetotet und als Beute in die Nester eingetragen. Im Verhaltnis zwischenP. megacephala undParagus-Arten spielen Geruch, Verhalten und wahrscheinlich auch morphologische Strukturen der Schwebfliegenlarven eine im einzelnen nicht vollstandig geklarte Rolle.
A. capensis verhalt sich gegenuber Larven von grossen Syrphidenarten bedeutend weniger aggressiv alsP. megacephala. Paragus-Larven werden auch dann, wenn sie aus Blattlauskolonien mitP. megacephala-Besuch stammen, nur schwach angegriffen.P. longiventris-Larven geben, wenn sie vonA. capensis betrillert werden, eine Flussigkeit ab, die von den Ameisen aufgenommen wird. Demnach bestehen zwischen den beiden Arten Beziehungen, die schon an den Bereich der Trophobiose grenzen. Der indirekte Schaden, den die Ameisen durch ihre Trophobiose-Beziehungen zu Blattlausen anrichten, wird dadurch teilweise oder ganz ausgeglichen, dass die Syrphideneier und — larven durch die Ameisen einen Schutz vor Parasiten erhalten. Dies gilt besonders furA. capensis, da die von dieser Ameise besuchten Blattlauskolonien fur die meisten aphidophagen Schwebfliegenarten des Hochlandes von Kenia ein wichtiges, vor Parasiten geschutztes Reservoir darstellen.
TL;DR: The aphid, Neomyzus circumflexus (Buck.) is able to encapsulate the newly hatched larvae of its endoparasite and this haemocytic reaction was strongly reduced when the aphids were reared for three successive generations on an artificial diet lacking phenylalanine and tyrosine.
Abstract: Die Fahigkeit vonNeomyzus circumflexus (Buck.), Larven vonAphelinus asychis durch Blutzellen abzukapseln, ist nach drei Generationen auf einem synthetischen Nahrmedium ohne Phenylalanin und Tyrosin stark reduziert. Nach Umsetzen auf ein vollstandiges Nahrmedium erreichen Haufigkeit und Intensitat der Abwehrreaktionen erst in der dritten nachfolgenden Generation wieder ihr ursprunglisches Ausmass.
TL;DR: Habrobracon iranicus n.
Abstract: Habrobracon iranicus n. sp. wird beschrieben und mit den nachstahnlichen Arten (H. simonovi
Kok. undH. hebetor
Say) verglichen.
TL;DR: This paper outlines some work on the suitability of eggs of A. kuehniella as food for an aphidiphagous Coccinellid and the “alternative food” is compared with a favourable diet and an unfavourable one.
Abstract: La valeur alimentaire pour la Coccinelle aphidiphage,Adonia 11-notata des œufs deAnagasta kuehniella a ete comparee a celle d'une nourriture tres favorable (Aphis fabae) et d'une alimentation peu satisfaisante (Aphis nerii). Les criteres retenus pour cette comparaison ont ete la duree de developpement larvaire, la taille et le poids des larves, le taux de mortalite pendant la vie larvaire ainsi que la fecondite des adultes. D'apres ces criteres les œufs d'A. kuehniella constituent une mediocre alimentation pourA. 11-notata et ne permettent pas de faciliter l'elevage de masse de ce predateur.
TL;DR: As the indigenous natural enemies do not provide effective control of the pest, three exotic predators and one parasite were introduced into Barbados, through the Commonwealth Institute of Biological Control, in 1968 and 1969.
Abstract: During the survey of the natural enemies ofSaccharicoccus sacchari in Barbados in 1968 and 1969, the following six indigenous species of natural enemies were recorded: —Hyperaspis trilineata andNephus sp.(Coccinellidae); Oligota barbadorum (Staphylinidae); an unidentified Cecidomyid(Cecidomyidae); Pseudaphycus mundus (Encyrtidae) andAspergillus sp. (Aspergillacae). Of these,H. trilineata was found in fair numbers in the Westmoreland (St. James) area only;Aspergillus sp. was more abundant during the wet season, while the other species were recorded usually in small numbers from most parishes. As the indigenous natural enemies do not provide effective control of the pest, three exotic predators and one parasite were introduced into Barbados, through the Commonwealth Institute of Biological Control.Cryptolaemus montrouzieri, Hyperaspis sp. andNephus sp. were obtained from India andAnagyrus saccharicola from East Africa. OnlyA. saccharicola became established. It was recovered soon after its release and, augmented by additional releases, spread rapidly. In January 1972, the levels of parasitism in the dry, intermediate and high rainfall areas were: 8.3, 9.0 and 9.7%.
TL;DR: C. kincaidii, an ectoparasite ofTetragnatha laboriosaHentz, was found most commonly in spring and fall, and appeared to oviposit only on middle instar spiderlings, and winter as larvae attached to spiders.
Abstract: C. kincaidii, an ectoparasite ofTetragnatha laboriosaHentz, was found most commonly in spring and fall. Peak parasitism was 18%. They appeared to oviposit only on middle instar spiderlings, and winter as larvae attached to spiders.
TL;DR: The authors give precise information on the ecology of S. madecassus, which plays a prominent role in the control of populations ofTetranychidae in Madagascar, and the life histories and life tables of the species.
Abstract: Apres avoir rappele quelques generalites sur les especes du genreStethorusWeise, les auteurs donnent des precisions sur l’ecologie deS. madecassus, qui semble jouer un role important dans la limitation des populations de tetranyques a Madagascar. Le cycle de developpement et les tables de vie du predateur et de sa principale proie dans les milieux naturels,Tetranychus neocaledonicus, sont etudies dans une serre semi-climatisee, ou la temperature varie quotidiennement de 25 a 35°C et l’hygrometrie de 70, a 50%.
TL;DR: It is emphasized that, besides these major problems in pathology, there are inconspicuous diseases, or ones of low intensity, that still carry important implications for the success of the cultures and progress in diagnosis, prophyllaxis and therapy demands close co-operation between invertebrate breeders and pathologists.
Abstract: L’elevage en masse de divers Invertebres devenant important a cause des nouvelles orientations de la lutte biologique, la lutte contre les vecteurs et la production d’Invertebres utiles, le probleme de l’hygiene est de grande actualite. Apres un apercu historique sont presentes les principaux types de maladies virales, bacteriennes, rickettsiennes, cryptogamiques, a mycoplasmes et a protozoaires sevissant dans les elevages. Leur mecanisme d’action dans les elevages est etudie concernant la contagion directe la dissemination, l’introduction par recolte, la penetration directe des germes, le parasitisme de blessures, la vection, la transmission hereditairc, l’affaiblissement genetique, l’alimentation, la latence et l’enchainement des maladies. En analysant la consequence des maladies sur les elevages, il est souligne qu’a cote des grands problemes pathologiques il existe des maladies inapparentes ou de faible intensite ayant des consequences capitales. Enfin les possibilites de diagnostic, de prophylaxie et de therapeutique sont evoquees en insistant sur la necessite de collaboration etroite entre les eleveurs d’Invertebres et les pathologistes.