Key to palaearctic species of the genusPsyllaephagus [Hym.:Encyrtidae]

The article contains a key to 42 species of the genusPsyllaephagus Ashmead, 1900—parasites ofPsylloidea, mainly from southern regions of Palaearctics.Psyllaephagus tobiasi Trjapitzin, 1967 is synonymized withP. belanensis (Hoffer, 1963).

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Résumé Il est fourni la clé de 42 espèces du genrePsyllaephagus Ashmead, 1990, parasites de psylles, principalement des régions méridionales de la zone paléarctique.Psyllaephagus tobiasi Trjapitzin, 1967 est mis en synonymie avecP. belanensis (Hoffer, 1963).

     

Life histories ofPsyllaephagus yaseeni (Hym., Encyrtidae) andTamarixia leucaenae (Hym., Eulophidae), parasitoids of the leucaena psyllidHeteropsylla cubana

Age specific fecundity of two parasitoids,P. yaseeni andT. leucaenae, of the leucaena psyllidH. cubana, were studied under laboratory conditions. At 25 °C,P. yaseeni had a greater fecundity (R₀=192.9)_thanT. leucaenae (R₀=71.2);T. leucaenae however had a lower sex ratio (about 99 % females) thanP. yaseeni (about 50 % females). Innate capacity for increase (r_m=0.236) ofT. leucaenae was higher thanP. yaseeni (r_m=0.188). Developmental rates of the parasitoids were examined at constant and fluctuating temperatures and equations of the rate of development against temperature were calculated. At 25 °C, mean generation times were 28.0 and 18.1 days forP. yaeseeni andT. leucaenae respectively. At temperatures of 21.5, 25, and 30 °C total development times (egg to adult) were 28.5, 21.9, and 14.7 days inP. yaseeni and 19.2, 12.6, and 9.5 days inT. leucaenae respectively. The level of parasitism was low and pupal mortality was high at the lower temperature of 21.5 °C for both parasitoids. Both parasitoids showed poor survivorship at 100 % RH,P. yaseeni survived particularly well (32 days) at a temperature of 21.5 °C and 44 or 76 % RH. P. yaseeni allocated about 58 % females to first instar psyllid nymphs but only 12 % females to second instars. About 99 % of allT. leucaenae births were females. Significantly largerT. leucaenae females emerged from fifth instar parasitized nymphs than third or fourth instars.     

Biological control of the cassava mealybug Phenacoccus manihoti (Hom., Pseudococcidae) by Epidinocarsis lopezi (Hym., Encyrtidae) in Malawi

From 1985 to 1989 five large scale surveys were made to document the spread of the cassava mealybug (CM) Phenacoccus manihoti Matile‐Ferrero (Hom., Pseudococcidae) and the releases and successful establishment of its exotic parasitoid Epidinocarsis lopezi (De Santis) (Hym., Encyrtidae) through most cassava‐growing areas of Malawi. In a multiple regression analysis involving 29 meteorological, agronomic and plant variables from 476 fields, the duration of E. lopezi's presence was the major factor influencing CM population densities. In the first year the CM was recorded in a particular place, 25% of all tips had more than 100 CM. Wherever E. lopezi had been present for two years or more, CM populations were reduced on average seven times and tips infested with more than 100 CM became rare (1%). In parallel, damage on cassava tips stabilized at a low level. Similarly, along Lake Malawi, 84.9% of all tips had more than 10 CM in 1986; this value stabilized at 3.3%‐4.0% in 1988–1989. Indigenous coccinellids were often abundant in the first year of the CM infestation, but their populations collapsed later, while the frequency of fields with E. lopezi increased. In 1987, farmers abandoned 28.4% of all fields where E. lopezi was just introduced as compared with 2.7% where the parasitoid had been present for two years or more. Overall, satisfactory control was achieved by E. lopezi in all but a few fields concentrated on extremely poor soils characterized by sand dune vegetation. The socioeconomic implications of this ongoing and apparently successful biological control program are discussed.     

Studies on an Israel strain ofAnagyrus pseudococci (Girault) [Hym., Encyrtidae]. II. Some biological aspects

Résumé Quelques aspects biologiques d'une race locale deAnagyrus pseudococci (Girault), un parasite des Pseudococcines, ont été étudiés sous des conditions du laboratoire et de la serre. Ces parasites ont été élevés sur leur h?te,Planococcus citri (Risso). La durée du développement, la longévité des adultes et la fécondité ont été étudiées sous des combinaisons différentes de température et d'humidité relative La longévité des parasites adultes n'a pas été effectuée par des fluctuations d'humidité relative à une température de 28°C. La fécondité et le taux de femelles dans la descendance augmentent avec l'age de l'h?te ainsi qu'en fonction de l'élévation de la température.      

Competitive displacement ofAnagyrus antoninae [Hym.: Encyrtidae]. by its ecological homologueNeodusmetia sangwani [Hym.: Encyrtidae]

The displacement ofAnagyrus antoniaae Timberlake byNeodusmetia sangwani (Rao) was demonstrated by reduced parasitism by the former in two localities after the latter was introduced into these sites. The competitive factors were: (1) the host-regulative action ofN. sangwani maintained a low host reciprocal balance, and (2) the inability of the female ofA. antoninae at the prevailing host density to find hosts sufficient for reproduction. The lack of competitiveness ofA. antoninae was a result of its inability to develop at high vapor deficits.     

A new species ofPseudaphycus [Hym.: Encyrtidae], with notes on theAngelicus group

The genusPseudaphycus Clausen and related genera are considered to belong in the subfamilyTetracneminae. P. debachi, n. sp., a parasite of the striped mealybugFerrisia virgata (Cockerell) from Mexico, is described and compared morphologically to several closely-related members of theangelicus group of species.

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Résumé Le genrePseudaphycus Clausen et les genres voisins sont considérés appartenir à la sous-famille desTetracneminae. L'espèceP. debachi, n. sp., parasite de la cochenilleFerrisia virgata (Cockerell) du Mexique, est décrite et comparée morphologiquement à plusieurs membres très voisins du groupe d'espècesangelicus.

     

Establishment Of Comperiella Bifasciata (Hym.: Encyrtidae) On Aonidiella Aurantii (Hom.: Diaspididae) In Cyprus

Reference is made to the introduction, rearing, colonization and establishment of Comperiella bifasciata Howard to improve the effectiveness of biological control of the California red scale,Aonidiella aurantii (Maskell), in Cyprus. The parasitoid was colonized during 1985- 89 and in 1993- 94 it was recovered in all the surveyed areas. It has been permanently established and is more abundant in orchards with microclimatic conditions characteristic of intermediate and interior areas whereAphytis melinus DeBach is the dominant red scale parasite.Aphytis chrysomphali (Mercet) prevails only in some of the coastal areas with mild and rather humid microclimates. In the surveyed orchards the overall adult relative abundance of the three main parasitoids, A. melinus, A. chrysomphali and C. bifasciata was 54.1%, 42.1%, and 3.8%, respectively.     

Variation in Encardia (Hym., Ichneumonidae) with a key to the species

The Ethiopian genus Encardia Tosquinet is redefined and a key is given to the two species, picta Tosquinet and rufantennata Benoit, now recognised. Type data are given for the twelve nominal taxa now included in E. picta together with data on the three variations found in wing colour pattern.     

Copidosoma truncatellum (Dalman) and C.floridanum (Ashmead) (Hymenoptera, Encyrtidae), two frequently misidentified polyembryonic parasitoids of caterpillars (Lepidoptera)

Abstract In this paper it is shown that Copidosoma floridanum , a polyembryonic parasitoid of the caterpillars of Plusiinae, has almost invariably been misidentified as Copidosoma truncatellum. Both species, and also a third (chilensis) which has been synonymized incorrectly with truncatellum , are diagnosed and characters to separate them reliably are presented.     

Variation du comportement chezMetaphycus lounsburyi [Hym.: Encyrtidae]

Résumé L'étude du comportement de trois populations naturelles deMetaphycus lounsburyi Howard de Californie, Espagne, Italie, montre d'importantes (comportement de ponte, accouplements hétérogamiques) ou de faibles différences (réceptivité de l'h?te, décalage des niches écologiques), sans différences morphogiques.M. lounsburyi est considéré comme une super-espèce. Deux semi-espèces sont reconnues (méditerranéenne, californienne importée d'Australie) qui sont jugées comme suffisamment isolées génétiquement, pour être utilisées dans les mêmes vergers en vue de la lutte biologique contre la cochenille noire de l'olivier et des agrumes,Saissetia oleae (Olivier).

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Summary Behavioural study of 3 natural populations ofM. lounsburyi Howard from California, Spain, Italy, shows large (egg-laying behaviour, heterogamic matings) or little differences (host acceptance, shifting of ecological niches), without morphological differences.M. lounsburyi is considered as a super-species. Two semi-species are recognized (Mediterranean, Californian imported from Australia) which are sufficiently isolated genetically, to be used in the same orchards for biological control against the Olive and Citrus Black Scale,Saissetia oleae (Olivier).

     

Control ofSaissetia oleae (Hom.: Coccidae) in Cyprus through establishment ofMetaphycus barletti andM. Helvolus (Hym.: Encyrtidae)

In Cyprus the black scale,Saissetia oleae (Olivier) is a pest primarily of olive,Olea europaea L., but it also attacks several other plants, among which areCitrus spp. and oleander,Nerium oleander L. The parasitoidsMetaphycus bartletti Annecke &; Mynhardt andMetaphycus helvolus (Compere) have been imported from France, massreared and permanently established in Cyprus. Following limited releases of these parasitoids, populations ofS. oleae have been reduced from outbreak levels to almost non-existence and remained at such low levels even after discontinuation of these releases.     

Pteromalidae etEulophidae nouveaux d'Europe (Hym., Chalcidoidea)

Summary In the present paper the Author has described three new genera ofPteromalidae, two new species of the genusEnaysma Del. and one of the genusEpilampsis Del. (Euloph. Entedontinae). The first Pteromalid genus,Stenoselma, is closely related to the well knownAnisopteromalus Ruschka; the second new genus,Apelioma, has been proposed forDinotiscus (Dinotus) pteromalinus Thomson; the third,Aggelma, has been described for the new speciesabdominalis, collected in Central Europe onPinus montana. The other new species ofEntedontinae has been bred from leaf-miners (Lepidoptera).      

Influence of crucifer cropping system on the parasitism ofPlutella xylostella (Lep., Yponomeutidae) byCotesia plutellae (Hym., Braconidae) andDiadegma semiclausum (Hym., Ichneumonidae)

Field experiments were conducted to study the influence of cabbage monoculture and mixed cropping on the parasitism of diamondback moth,Plutella xylostella (L.), a destructive pest of all crucifers, by 2 larval parasites,Diadegma semiclausum Hellén andCotesia plutellae Kurdjumov. There was no significant difference in parasitism by either species whether cabbage was planted in insecticide-free monoculture or in mixed cropping with 8 noncrucifers which were sprayed twice a week with chemical insecticides mevinphos, methamidophos and permethrin. Population ofP. xylostella increased as the cabbage plants grew older. Parasitism byC. plutellae was higher soon after cabbage transplanting but decreased as the plants grew older. Parasitism byD. semiclausum was very low soon after cabbage planting but increased as the plants grew older. A significant negative correlation was found betwen parasitism byC. plutellae andD. semiclausum. In a caged field study where only one parasite species was used in an individual cage, parasitism ofP. xylostella by both species decreased as theP. xylostella population increased. This is believed to be due to the absence of competition between the two parasites inside the cage. There was no relationship between host-plant age and parasitism ofP. xylostella larvae by either parasite species.     

Impact of mating on Anagyrus kamali Moursi (Hym., Encyrtidae) lifetime fecundity, reproductive longevity, progeny emergence and sex ratio

Abstract: The solitary endoparasitoid Anagyrus kamali Moursi (Hym., Encyrtidae) and the Hibiscus mealybug Maconellicoccus hirsutus Green (Hom., Pseudococcidae), were used as a parasite/host model to test the effect of mating on several fitness parameters, i.e. longevity, lifetime fecundity, progeny emergence and sex ratio. At 27 ± 2°C, 8 h light : 16 h dark, mating significantly affected the survival of male parasitoids. Virgin males lived longer (32.2 ± 9.51 days) than mated males (23.9 ± 7.52 days). Female longevity (40.7 ± 16.3 days for virgins and 36.2 ± 10.7 days for mated females) was not affected by mating. The lifetime fecundity of female parasitoids and their oviposition period was not significantly affected by mating. However, the number of hosts parasitized was greater for mated wasps (7.54 ± 4.85 hosts parasitized/day) compared with virgin ones (5.12 ± 2.19 hosts parasitized/day). This resulted in greater progeny production from mated A. kamali females. The progeny of virgin females consisted only of males, whereas the mated ones had a more female‐biased sex ratio. The lowest sex ratio (0.41 M/F ± 0.123) was attained when females had free access to males and were multi‐mated.     

Notes onPatasson Walk.,Anaphes hal. andCleruchus detritus n. sp. (Hym., Mymaridae)

Résumé L'auteur signale les résultats d'élevages et relève certaines synonymies concernant quelques espèces dePatasson Walker etAnaphes Haliday. Il mentionne l'existence deAnaphes autumnalis Foerster en Islande. Il décrit ensuite les formes aptère et ailée de l'espèce nouvelleCleruchus detritus de Suisse.      

Parasitoids of obscure mealybug,Pseudococcus viburni (Hem.: Pseudococcidae) in California: establishment of Pseudaphycus flavidulus (Hym.: Encyrtidae) and discussion of related parasitoid species

To improve natural suppression of the obscure mealybug, Pseudococcus viburni (Signoret), the parasitoids Pseudaphycus flavidulus (Brèthes) and Leptomastix epona (Walker) (Hymenoptera: Encyrtidae) of Chilean origin were released in California's Central Coast vineyards from 1997 to 1999. A survey for parasitoids of P. viburni was conducted in the Edna Valley appellation wine grape region from 2005 to 2007, 6–8 years after classical biological control releases were discontinued. Two survey methods were used. First, field collections of obscure mealybugs from commercial vineyard blocks (2005–2007) and, second, placement of “sentinel mealybugs” on potted (1 L) grape vines (2006 only). From both survey methods, P. flavidulus was recovered, albeit levels of parasitism were low (less than 0.6%). We also placed longtailed mealybug, Pseudococcus longispinus (Targioni Tozzetti), on potted plants concurrent with placement of sentinel obscure mealybugs in the vineyard in order to measure parasitoid activity on this closely-related mealybug species. No P. flavidulus were recovered from P. longispinus. Other encyrtid parasitoids reared from either P. viburni or P. longispinus were Anagyrus pseudococci (Girault), Leptomastix dactylopii Howard, Leptomastidea abnormis (Girault), Coccidoxenoides perminutus Girault, and Tetracnemoidea peregrina (Compere). A hyperparasitoid, Chaetocerus sp., was also reared. The data are discussed with respect to biological control of vineyard mealybugs and newly developed controls for the Argentine ant, Linepithema humile (Mayr) (Hymenoptera: Formicidae). Because Pseudaphycus species reared from mealybugs are superficially very similar a taxonomic key and discussion of host relationships for selected Pseudaphycus species are provided.