New parasitoids of Paraphytomyza populi (Kltb.) (Diptera, Agromyzidae) in Bulgaria

The parasitoid complex of Paraphytomyza populi (Kltb.) (Diptera: Agromyzidae) was studied in Sofia, Bulgaria in 1997. Poplar leaves with P. populi larvae and pupae were collected from poplar stump shoots and examined in a laboratory. As a result, eleven parasitoid species were established: Chorebus albipes (Haliday) (Hymenoptera, Braconidae), Pediobius metallicus (Nees), Danuviella subplana Erdos, Chrysocharis nephereus (Walker), Chrysocharis pubicornis (Zetterstedt), Diglyphus crassinervis Erdos, Diglyphus isaea (Walker), Diglyphus albiscapus Erdos, Cirrospilus diallus Walker, Cirrospilus pictus (Nees) (Hymenoptera, Eulophidae) and Elasmus sp. (Hymenoptera, Elasmidae). Six species (D. crassinervis, D. isaea, D. albiscapus, C. diallus, C. pictus and Elasmus sp.) have been recorded as new parasitoids of P. populi. The genus Danuviella was found for the first time in Bulgaria. Five species (C. albipes, P. metallicus, D. subplana, D. crassinervis and D. albiscapus) are new records for the fauna of the country. The total mortality of P. populi caused by parasitoids was 19.1% and 49.0% for the overwintering and the summer generations, respectively. P. metallicus was the most important in reducing the pest number.     

New parasitoids of Paraphytomyza populi (Kltb.) (Diptera, Agromyzidae) in Bulgaria

The parasitoid complex of Paraphytomyza populi (Kltb.) (Diptera: Agromyzidae) was studied in Sofia, Bulgaria in 1997. Poplar leaves with P. populi larvae and pupae were collected from poplar stump shoots and examined in a laboratory. As a result, eleven parasitoid species were established: Chorebus albipes (Haliday) (Hymenoptera, Braconidae), Pediobius metallicus (Nees), Danuviella subplana Erdos, Chrysocharis nephereus (Walker), Chrysocharis pubicornis (Zetterstedt), Diglyphus crassinervis Erdos, Diglyphus isaea (Walker), Diglyphus albiscapus Erdos, Cirrospilus diallus Walker, Cirrospilus pictus (Nees) (Hymenoptera, Eulophidae) and Elasmus sp. (Hymenoptera, Elasmidae). Six species (D. crassinervis, D. isaea, D. albiscapus, C. diallus, C. pictus and Elasmus sp.) have been recorded as new parasitoids of P. populi. The genus Danuviella was found for the first time in Bulgaria. Five species (C. albipes, P. metallicus, D. subplana, D. crassinervis and D. albiscapus) are new records for the fauna of the country. The total mortality of P. populi caused by parasitoids was 19.1% and 49.0% for the overwintering and the summer generations, respectively. P. metallicus was the most important in reducing the pest number.     

Studies on the parasitoids of Gelechia senticetella (Stgr.) (Lepidoptera: Gelechiidae) in Bulgaria

The parasitoids of Gelechia senticetella (Stgr.) (Lepid.: Gelechiidae), a pest of Juniperus excelsa M.B., were studied in the Tissata reserve in Bulgaria. They were reared in laboratory conditions from pest larvae and pupae collected in 1991, 1992 and 2000. As a result of this study, 16 species of parasitoids of G. senticetella were recorded: Habrobracon stabilis Wesm., Hormius moniliatus (Nees), Phanerotoma tritoma Marsh. (Hym.: Braconidae), Diadegma consumptor (Grav.), Liotryphon cydiae (Perk.), Scambus pomorum (Ratz.), Scambus foliae (Cush.), Pimpla turionellae (L.), Eudelus simillimus (Tasch.), Mesochorus sp. (Hym.: Ichneumonidae), Sympiesis acalle Walk., Aprostocetus sp. (Hym.: Eulophidae), Eupelmus urozonus Dalm. (Hym.: Eupelmidae), Copidosoma thompsoni Merc. (Hym.: Encyrtidae), Calliprymna bisetosa Grah., and Mesopolobus sp. (Hym.: Pteromalidae). H. stabilis and P. tritoma were discovered as new species for the fauna of Bulgaria. Three species (E. simillimus, Mesochorus sp. and Aprostocetus sp.) are hyperparasitoids, and the remaining species are primary parasitoids. Most of the parasitoid species attack the larvae of G. senticetella and kill the hosts before pupation. In the studied parasitoid complex, D. consumptor and H. moniliatus were the dominant species. In 1991, the level of total parasitism of the host in the Tissata reserve was 24.3%, in 1992 – 57.9% and in 2000 – 12.7%. D. consumptor was the most important parasitoid destroying 26.6% of the pest larvae in 1992.     

Parasitoids of Saperda populnea (L.) (Coleoptera: Cerambycidae) on aspen (Populus tremula L.) in Bulgaria

The parasitoids of Saperda populnea (L.) (Col.: Cerambycidae) were studied in Bulgaria during the period 1997–2001. Galls with pest larvae were collected from young aspen trees at eight locations (Sofia, Kokaliane, Plana, Churek, Gorni Lom, Gintzi, Dolno Kamartzi and Klisura) and examined under laboratory conditions. Four species were reared from 1118 galls containing overwintering pest larvae: Iphiaulax impostor (Scop.) (Hym.: Braconidae), Dolichomitus populneus (Ratz.), Schreineria populnea (Gir.) (Hym.: Ichneumonidae) and Billaea irrorata (Meig.) (Dipt.: Tachinidae). All of the parasitoids were solitary. Schreineria populnea was found as a new parasitoid of the host in Bulgaria. B. irrorata emerged mainly from late-stage S. populnea larvae; the remaining species from both early- and mid-stage larvae. In the parasitoid complex of S. populnea, the most numerous were B. irrorata (59.8%) and D. populneus (29.4%). The percentage of host larval parasitism varied from 2.4 to 33.3, with an average of 9.7%. B. irrorata was the most important in reducing the pest number. The average mortality of S. populnea caused by the tachinid was 5.8%, and the highest mortality observed in individual study was 20.2%.     

Parasitoids of Saperda populnea (L.) (Coleoptera: Cerambycidae) on aspen ( Populus tremula L.) in Bulgaria

The parasitoids of Saperda populnea (L.) (Col.: Cerambycidae) were studied in Bulgaria during the period 1997–2001. Galls with pest larvae were collected from young aspen trees at eight locations (Sofia, Kokaliane, Plana, Churek, Gorni Lom, Gintzi, Dolno Kamartzi and Klisura) and examined under laboratory conditions. Four species were reared from 1118 galls containing overwintering pest larvae: Iphiaulax impostor (Scop.) (Hym.: Braconidae), Dolichomitus populneus (Ratz.), Schreineria populnea (Gir.) (Hym.: Ichneumonidae) and Billaea irrorata (Meig.) (Dipt.: Tachinidae). All of the parasitoids were solitary. Schreineria populnea was found as a new parasitoid of the host in Bulgaria. B. irrorata emerged mainly from late-stage S. populnea larvae; the remaining species from both early- and mid-stage larvae. In the parasitoid complex of S. populnea, the most numerous were B. irrorata (59.8%) and D. populneus (29.4%). The percentage of host larval parasitism varied from 2.4 to 33.3, with an average of 9.7%. B. irrorata was the most important in reducing the pest number. The average mortality of S. populnea caused by the tachinid was 5.8%, and the highest mortality observed in individual study was 20.2%.     

Studies on Aleurothrixus floccosus (Maskell) (Homoptera, Aleyrodidae) and its parasitoid, Cales noacki Howard (Hymenoptera, Aphelinidae) in the East Mediterranean Region of Turkey

Survey studies of Aleurothrixus floccosus (Maskell) (Homoptera, Aleyrodidae) and its parasitoid Cales noacki Howard (Hymenoptera, Aphelinidae) were made in 4 provinces; namely Adana, Mersin, Hatay and Osmaniye, which are the main citrus growing areas of the East Mediterranean region of Turkey. Inoculative parasitoid releases were made in regions where no or low natural parasitism occurred after obtaining preliminary results on presence of the parasitoid. The population dynamics of A. floccosus and C. noacki were examined in Silifke (Mersin), Dörtyol (Hatay) and Yüreir (Adana), where the A. floccosus population was remarkably high at the beginning of the study in 1999. However, after parasitoid release, the pest population declined in all the sites and did not attain the same high levels again. Five predators, three parasitoids and one entomopathogen species were determined as natural enemies of A. floccosus. In addition, seven plant species, six of them belong to Rutaceae, were found as host plants for A. floccosus.     

Studies on Aleurothrixus floccosus (Maskell) (Homoptera, Aleyrodidae) and its parasitoid, Cales noacki Howard (Hymenoptera, Aphelinidae) in the East Mediterranean Region of Turkey

Survey studies of Aleurothrixus floccosus (Maskell) (Homoptera, Aleyrodidae) and its parasitoid Cales noacki Howard (Hymenoptera, Aphelinidae) were made in 4 provinces; namely Adana, Mersin, Hatay and Osmaniye, which are the main citrus growing areas of the East Mediterranean region of Turkey. Inoculative parasitoid releases were made in regions where no or low natural parasitism occurred after obtaining preliminary results on presence of the parasitoid. The population dynamics of A. floccosus and C. noacki were examined in Silifke (Mersin), Dörtyol (Hatay) and Yüreir (Adana), where the A. floccosus population was remarkably high at the beginning of the study in 1999. However, after parasitoid release, the pest population declined in all the sites and did not attain the same high levels again. Five predators, three parasitoids and one entomopathogen species were determined as natural enemies of A. floccosus. In addition, seven plant species, six of them belong to Rutaceae, were found as host plants for A. floccosus.     

New Ichneumonidae (Hymenoptera) parasitoids of forest insect pests in Bulgaria

During the period 1989–1998 investigations were carried out on the parasitoids of some forest insect pests in Bulgaria. Twenty-one ichneumonid species are reported for the first time in Bulgaria as parasitoids of different coleopteran, lepidopteran, and hymenopteran hosts. From these, 6 parasitoids are new records for the parasitoid complexes of the hosts:Exochus decoratus Holmgr. onEudemis profundana (Den. & Schiff.) andGelechia turpella (Den. & Schiff.);Lissonota culiciformis Grav.—onParanthrene tabaniformis (Rott.);Lissonota unicincta Holmgr.—onG. turpella; Xorides gracilicornis (Grav.)—onXylotrechus sp.; andEriborus terebrator Aubert—onClostera anastomosis (L.). Most parasitoids developed as primary parasitoids in the hosts.Itoplectis alternans (Grav.) is a primary parasitoid ofNycteola asiatica (Krul.) and a hyperparasitoid ofE. terebrator: Acropimpla pictipes (Grav.) is secondary parasitoid onAnacampsis populella (Cl.). With the exception of two species ofOlesicampes genus, which destroyed over 50% ofStauronematus compressicornis (F.) andPristophora conjugata (Dahlm.) larvae, andE. terebrator which killed 15.4% ofC. anastomosis population, the rest of the parasitoids occurred in low densities, and did not play an important role in reducing the number of their hosts.     

Two new species of egg parasitoids (hymenoptera: Encyrtidae) of wood-boring beetle pests from China

Oobius agrili sp.n. andAvetianella xystrocerae sp.n. (Hymenoptera: Encyrtidae) are described from China. Morphological characters of the new species are illustrated.O. agrili is an egg parasitoid of the emerald ash borerAgrilus planipennis Fairmaire (Coleoptera: Buprestidae) andA. xystrocerae is an egg parasitoid of the wood borerXystrocera globosa (Olivier) (Coleoptera: Cerambycidae). The two new species are potential biocontrol agents of economically important pest insects. The type specimens are deposited in the Institute of Zoology, Chinese Academy of Sciences, Beijing (IZCAS). http://www.phytoparasitica.org posting May 17, 2005.     

The scale Nemolecanium graniformis (Wunn) (Homoptera: Coccidae) in Greece

The phenology and natural enemies of Nemolecanium graniformis (Wunn) (Homoptera: Coccidae) in infesting Abies cephalonica, were studied in Greece during 1998–1999. This oviparous species develops one generation per year in Central Greece (Attica) and overwinters as 2^nd instar nymph. Young adult females appear by the end of July, and the first instar nymphs by the middle of August. By the middle of October, the whole population of the scale is recorded as 2^nd instar nymphs. The parasitoids Coccophagus lycimnia (Walker), Coccophagus Westwood sp., Aphycoides Mercet sp. and the predator Exochomus quadripustulatus L. (Coleoptera: Coccinellidae), were observed as natural enemies of the scale. The average fecundity of N. graniformis was 188.4 eggs.     

The scale Nemolecanium graniformis (Wunn) (Homoptera: Coccidae) in Greece

The phenology and natural enemies of Nemolecanium graniformis (Wunn) (Homoptera: Coccidae) in infesting Abies cephalonica, were studied in Greece during 1998–1999. This oviparous species develops one generation per year in Central Greece (Attica) and overwinters as 2^nd instar nymph. Young adult females appear by the end of July, and the first instar nymphs by the middle of August. By the middle of October, the whole population of the scale is recorded as 2^nd instar nymphs. The parasitoids Coccophagus lycimnia (Walker), Coccophagus Westwood sp., Aphycoides Mercet sp. and the predator Exochomus quadripustulatus L. (Coleoptera: Coccinellidae), were observed as natural enemies of the scale. The average fecundity of N. graniformis was 188.4 eggs.     

Parasitoids and predators of pseudococcidae (hemiptera: coccoidea) in Ankara, Turkey

Natural enemies of mealybugs were surveyed in Ankara, Turkey, during the years 2001 to 2003. Twenty-three predatory species belonging to the insect orders Coleoptera (Coccinellidae, 17), Diptera (Chamaemyiidae, 3) and Neuroptera (Chrysopidae, 2; Hemerobiidae, 1); and 22 parasitoid species belonging to Hymenoptera (Aphelinidae, 2; Encyrtidae, 14; Platy-gasteridae, 1; Pteromalidae, 3; Signiphoridae, 2) were determined. The following ten species are newly recorded for the Turkish fauna:Sidis biguttatus Motchulsky,Nephus sinuatomaculatus Sahlberg (Coccinellidae),Leucopomyia alticeps Czerny,Parochthiphila (Euestelia) decipia Tanasijtshuk (Chamaemyiidae),Leptomastidae matritensis Mercet,Prochiloneurus bolivari Mercet,Rhopus sp.nr.acaetes (Walker),Stematosteres sp.,Eunotus acutus Kurdjumov, andChartocerus kurdjumovi (Nikol’skaya) (Chalcidoidea). http://www.phytoparasitica.org posting July 19, 2006.     

Leafminers in vegetables,ornamental plants and weeds in Indonesia: Surveys of host crops,species composition and parasitoids

Extensive surveys of vegetable, ornamental and weedy plant species were conducted in highland and lowland vegetable production areas in Indonesia with the aim of recording leafminer species present and their associated natural enemies. The most common dipterous species reared from samples was the pea leafminer, Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae). This introduced pest was particularly serious in highland vegetables in Java, Sumatra and South Sulawesi, causing yield losses as high as 60-70%. Another alien species, the vegetable leafminer, Liriomyza sativae Blanchard, contributed to problems in lowland areas on the north coast of West Java, where cucumbers were heavily damaged. An Asian leafminer species, Chromatomyia horticola Goureau, was more common in snow peas (Pisum sp.). Intensive sampling of leafminer-infested leaves from surveyed host plants yielded 11 species of hymenopteran parasitoids: 10 eulophids (Asecodes sp., Chrysocharis sp., Cirrospilus ambiguus (Hansson and LaSalle), Closterocerus sp., Hemiptarsenus varicornis (Girault), Neochrysocharis formosa (Westwood), Neochrysocharis sp., Pnigalio sp., Quadrastichus sp., Zagrammosoma sp.) and 1 eucoilid (Gronotoma sp.). The most abundant parasitoid species was H. varicornis. Levels of parasitism varied among crops and growing seasons, but were usually low, especially on potato (< 3%). Surveys revealed that most farmers (63%) attempted to control leafminers by applying insecticides twice weekly although these applications were neither effective nor economical according to responses of about 72% of the farmers. An integrated pest management approach is suggested that emphasizes IPM training for vegetable farmers and includes reductionor elimination of broad spectrum chemicals that would adversely affect parasitoids that may already be present as well as those that may be introduced. The initiation of a classical biological control programme is recommended to enhance the limited parasitoid complex present in Indonesia and increase levels of biological control.     

Egg and larval parasitoids of the beet armyworm<Emphasis Type="Italic">Spodoptera exigua</Emphasis> on maize in Turkey

The present study was conducted to determine egg and larval parasitoids of the beet armywormSpodoptera exigua Hübner (Lepidoptera: Noctuidae), which is an important but sporadic pest in Turkey. High beet armyworm population levels were recently observed in fields of first and second crop maize in the southeast Mediterranean region of Turkey. The parasitoid species complex and its impact on the pest were analyzed in a 4-year study in first and second crop maize. The braconid larval parasitoidsMicroplitis rufiventris Kokujev,M. tuberculifer Wesmael,Meteorus ictericus Nees,Chelonus obscuratus (Herrich Schäffer) (an egg-larval parasitoid),Apanteles ruficrus (Haliday); the ichneumonid larval parasitoidsHyposoter didymator (Thunberg) andSinophorus xanthostomus Gravenhorst; and the egg parasitoidTrichogramma evanescens (Westwood) were found to be the natural enemies attacking the pest. Among the parasitoid species the solitary endoparasitoidH. didymator was the most prevalent species, being reared from 40.5% of the parasitized larvae found. Higher parasitism rates were recorded on first crop than on second crop maize in every year. Possible reasons for this difference in larval parasitism between two growing seasons include lower population of the pest and reduced insecticide applications in first crop maize fields which permitted higher parasitism. However, parasitoid activity was insufficient to counterbalance the population growth of the pest on subsequent second crop maize.     

The East-Mediterranean cereal leaf miner <Emphasis Type="Italic">Syringopais temperatella</Emphasis> Lederer and its larval parasitoids in Israel

Leaves of durum wheat infested with mines of the cereal leaf miner Syringopais temperatella Lederer (Lepidoptera: Scythridae) were collected from fields in Israel in spring 2016 and 2017. The parasitoids and moths reared from the leaf mines in the lab were identified and counted according to sex. The sex ratios of S. temperatella were 1:0.73 (♀ :♂) in 2016 and 1:0.41 in 2017. A cross-correlation analysis revealed that males appeared three days ahead of females (p<0.05). The following parasitoids were reared: Eulophidae (Cirrospilus vittatus Walker, Diglyphus chabrias (Walker), D. isaea (Walker), D. sensilis Yefremova, D. pusztensis (Erd?s & Novicky), Necremnus tidius (Walker), Neochrysocharis formosus (Westwood), Pnigalio gyamiensis Myartseva & Kurashev, P. pectinicornis Linnaeus), Pteromalidae (Norbanus sp.) and Braconidae (Habrobracon stabilis (Wesmail), Apanteles sp.); and Icheumonidae (Campoplex sp.). In all cases, the parasitoids emerged substantially prior to the mass appearance of the moths. The hatching dynamics of ecto- and endoparasitoids were also asynchronous. Most species of ectoparasitoids hatched three days ahead of the endoparasitoids (p<0.05). Syringopais temperatella recorded on clover revealed a similar dynamics of male appearance ahead of female, with a of female-to-male ratio of 1:0.25, and fewer parasitoid species.     

Parasitoid community of the loreyi leaf wormMythimna (Acantholeucania) loreyi: Novel host-parasitoid associations and their efficiency in the eastern mediterranean region of Turkey

The loreyi leaf worm,Mythimna (Acantholeucania) loreyi Duponchel (Lepidoptera, Noctuidae), is a pest of gramineous crops and causes significant economic damage to maize. In field surveys on maize to determine the parasitoid community and its impact on the pest in the eastern Mediterranean region of Turkey, nine parasitoid species were found associated with immature stages ofM. loreyi: The hymenopteran (Braconidae and Ichneumonidae) parasitoidsCotesia (=Apanteles) ruficrus (Haliday),Chelonus oculator Panzer,Meteorus ictericus Nees,Hyposoter didymator (Thunberg),Sinophorus sp.; and the dipteran (Tachinidae) parasitoidsPseudogonia rufifrons Wiedeman,Exorista rossica Mesnil,Gonia picea (Robineau-Desvoidy) andLinnaemya vulpina (Fallen) — the last three recorded for the first time as parasitoids ofM. loreyi in Turkey.C. ruficrus was the dominant parasitoid species, being recovered from 38.5% of the larvae collected and was also the most prevalent species, existing in 91.0% of the fields in whichM. loreyi was found. Total parasitism levels achieved by braconid species was 41.4%, by ichneumonid parasitoids 4.8%, and by tachinid parasitoids 1.9%. In a separate field experiment, seasonal population fluctuations and natural efficiency ofC. ruficrus onM. loreyi were found to be 35.1% and 42.4%, respectively. Population levels ofC. ruficrus were closely related to fluctuations in the population ofM. loreyi, with parasitism ranging between 0 and 77.3% during the study. http://www.phytoparasitica.org posting Aug. 28, 2005.     

Parasitoids Associated with <Emphasis Type="Italic">Mussidia</Emphasis> spp. (Lepidoptera: Pyralidae) in Kenya

The pyralid Mussidia nigrivenella, a pest of cotton, maize and Phaseolus bean in West Africa, has never been reported as a crop pest in East and Southern Africa, although reportedly it exists in the wild. It is hypothesized that the difference in pest status of M. nigrivenella between western and eastern Africa was either due to differences in natural enemy compositions or that there exist several populations and/or species of Mussidia, which vary in their host plant range. Thus, a catalogue of parasitoids of Mussidia spp. was established through surveys in mid-altitude and coastal Kenya, between 2006 and 2007. Mussidia spp. eggs, larvae and pupae were collected from fruits of plants known to host Mussidia spp. and were examined for parasitoid-related mortality. The trichogrammatid Trichogrammatoidea sp. nr. lutea was obtained from eggs of Mussidia fiorii. A braconid egg-larval parasitoid, Phanerotoma sp., was reared from the larvae of unknown species of Mussidia (which we are referring to as Mussidia “madagascariensis”, Mussidia “quanzensis”) and M. fiorii, while the bethylid Goniozus sp. and the braconid Apanteles sp. were obtained from Mussidia nr. nigrivenella. Moreover, the ichneumonid larval parasitoid Syzeuctus sp. was obtained from M. fiorii, while the tachinid Leskia sp. was obtained from Mussidia “madagascariensis”. Overall, mortality caused by parasitoids was negligible; hence they were not considered key mortality factors in the population dynamics of the Mussidia spp. in Kenya.     

Evaluating side effects of newer insecticides on the vine mealybug parasitoid <Emphasis Type="Italic">Anagyrus</Emphasis> sp. near <Emphasis Type="Italic">pseudococci</Emphasis>, with implications for integrated pest management in vineyards

Control of the invasive vine mealybug Planococcus ficus (Signoret) can be achieved through integration of different management strategies such as the application of chemical treatments and biological control. However, compatibility between these control methods is considered crucial when adopting integrated pest management (IPM) programs against this insect pest. The recently used insecticides Prev-Am®, a contact biopesticide, and spirotetramat, a systemic tetramic acid insecticide, were assessed in laboratory conditions for their side effects on the vine mealybug parasitoid Anagyrus sp. near pseudococci with reference to chlorpyriphos-methyl, an organophosphate insecticide conventionally used for mealybug control in vineyards. Regarding contact toxicity, chlorpyriphos-methyl caused 100% parasitoid mortality 24 h after treatment, but parasitoid mortality from Prev-Am® or spirotetramat was almost absent. Neither the total parasitoid offspring/female nor the sex ratio of the progeny was negatively affected by Prev-Am® or spirotetramat relative to the untreated control. According to the IOBC classification for laboratory trials, both Prev-Am® and spirotetramat were rated harmless (IOBC category 1), whereas chlorpyriphos-methyl was categorized as harmful (IOBC category 4) to A. sp. near pseudococci. None of the insecticides adversely affected the development of the parasitoid pupal stage inside mealybug mummies or the survival of the emerged parasitoids. The practical implications of the results for implementing mealybug IPM programs in vineyards are emphasized and discussed.     

Potential of parasitoids to control populations of the weevil Ceutorhynchus obstrictus (Marsham) on winter oilseed rape

Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae) is a major pest of oilseed rape in Europe and North America. The last decade has seen growing interest in the occurrence, importance and efficiacy of its parasitoids as biocontrol agents. The infestation of pods by C. obstrictus larvae and their parasitism rates were assessed in a total of nine commercially-grown crops and fifteen experimental plots of winter oilseed rape in 2004–2007. Pod samples were collected at the pod maturation stage and incubated in emergence traps. Emerged larvae, their exit holes and parasitoids were counted and identified; the percentage of infested pods and parasitism rates were calculated. Pod infestation by larvae increased continuously over the study period. The parasitism level was lowest in 2005 and increased thereafter up to 96%. The most abundant parasitoid was Trichomalus perfectus (Walker), but Mesopolobus morys (Walker) and Stenomalina gracilis (Walker) (Hymenoptera: Pteromalidae) were also reared from host larvae. This study showed that naturally-occurring ectoparasitoids of C. obstrictus were capable of becoming established as viable populations and have the potential to contribute to biological control of C. obstrictus.     

Bark-Beetle Parasitoids Population Surveys Following Storm Damage in Spruce Stands in the Vosges Region (France)

This paper presents the results of a long-term study designed to follow the population dynamics of hymenopteran parasitoids associated with Ips typographus L. (Coleoptera: Scolytidae) in northeastern France (Alsace and Vosges) in spruce stands devastated by the December 1999 storms. Population densities were estimated by periodic samplings in the pre-emerging insect populations developing under the bark of attacked trees. Data were collected between July 2000 and October 2001. I. typographus population density (per m²) increased respectively by 28%, 105%, and 212% in one year in the three sites surveyed. Six hymenopteran ectoparasitoids were found: Coeloides bostrichorum Giraud and Dendrosoter middendorffi Ratzeburg (Hymenoptera: Braconidae); Rhopalicus tutela (Walker), Roptrocerus xylophagorum (Ratzeburg), Roptrocerus mirus (Walker) and Dinotiscus eupterus (Walker) (Hymenoptera: Pteromalidae). After two years, the parasitoid populations increased in terms of average density but parasitism rates remained at a relatively low level, ranging from 0% to 40%, with 60% of the trees having a parasitism rate below 5%. Data outlined the recurrent coexistence of competing parasitoid species.