Chalcidoid parasitoids of Chromatomyia horticola (Gour.) (Dip. Agromyzidae) in Sivas Province, Turkey

Chromatomyia horticola (Goureau, 1851) (Diptera Agromyzidae) is a polyphagous species and very common worldwide. In this study, parasitoids of Chromatomyia horticola were investigated on various plants during 2003 in the Sivas province. Infested leaves were sampled weekly and kept in the laboratory to observe and count emerging leafminers and parasitoid adults. Eight parasitoid species were reared belonging to Eulophidae and Pteromalidae (Chalcidoidea). Diglyphus iseae (Walker), Pediobius metallicus (Nees) and Diglyphus pachyneurus Graham represent the predominant parasitoid species. Among the parasitoids reared, Aprostocetus flavifrons (Walker), Merismus sp., and Chrysocharis crassiscapus (Thomson) have been newly recorded in Turkey and Aprostocetus flavifrons, Chrysocharis crassiscapus, Diglyphus pachyneurus Graham, and Merismus sp. were recorded for the first time from C. horticola.     

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.     

New Chalcidoidea (Hymenoptera) parasitoids of <Emphasis Type="Italic">Dasineura saliciperda</Emphasis> (Dufour) (Diptera,Cecidomyiidae) in Bulgaria

Abstract The parasitoid complex of Dasineura saliciperda (Dufour) (Diptera, Cecidomyiidae) on Salix fragilis L. was studied in 1997 and 2002 in two localities in Bulgaria. As a result, 5 species from 3 families of Chalcidoidea (Hymenoptera) were reared from pest galls: Eurytoma afra Boheman, Eurytoma salicis Walker (Eurytomidae), Torymus microcerus (Walker) (Torymidae), Gastrancistrus sp. and Mesopolobus sp. (Pteromalidae). E. afra and T. microcerus are new species for the fauna of Bulgaria, and E. salicis – a new parasitoid of the host. Total parasitism of D. saliciperda in the studied years ranged between 44.1 and 53.5 %. E. afra was the most important, destroying 21.9-53.5 % of the pest.     

Aphidius colemani Vier. (Hymenoptera, Braconidae, Aphidiinae) detected in cereal fields in Germany

Studies conducted in the 2000 cropping season at two different localities, Flaeming and Magdeburger Boerde in Germany, have provided new information on cereal aphid (Sitobion avenae (F.), Metopolophium dirhodum (Walker), and Rhopalosiphum padi (L.)) parasitoids in winter wheat; their species composition, relative abundance, hosts, and location effects. The average aphid population density was higher at Magdeburger Boerde and lower at Flaeming. Among the aphid species, Sitobion avenae was more abundant at Flaeming and Metopolophium dirhodum at Magdeburger Boerde. In total, eight species of primary parasitoids were recorded: Aphidius colemani Viereck, Aphidius rhopalosiphi DeStefani Perez, Aphidius uzbekistanicus Luzhetzki, Aphidius ervi Haliday, Aphidius picipes (Nees), Ephedrus plagiator (Nees), Praon gallicumStarý, and Praon volucre (Haliday). The predominant parasitoid species were Aphidius colemani and Aphidius rhopalosiphi on Metopolophium dirhodum and Aphidius uzbekistanicus on Sitobion avenae. A low number of hyperparasitoids were also recorded. Aphidius colemani was recorded for the first time in the open winter wheat fields in Germany, although it has been used as a biocontrol agent in glasshouses in many European countries and overseas. An analysis of the aforementioned information shows that Aphidius colemani detected as a parasitoid of cereal aphids in Germany is likely a result of an accidental escape of parasitoids from a glasshouse, as well as their successful overwintering and establishment in the area. This study provides baseline information essential for assessing future changes in aphid parasitoid species guild and dynamics in cereal fields in Germany.     

Studies on the parasitoid complex of Choristoneura murinana (Hbn.) (Lep.: Tortricidae) in Turkey

The parasitoid complex of Choristoneura murinana (Hbn.), a pest of Abies cilicica Carr., was studied in Isparta, Turkey. Shoots and needles of A. cilicica with C. murinana larvae and pupae were collected and examined under laboratory conditions in 2002 and 2003. As a result of this study, 14 parasitoid species of C. murinana were determined: Apanteles obscurus Nees. (Hym.: Braconidae), Brachymeria intermedia Nees (Hym.: Chalcididae), Mesopolobus mediterraneus Mayr, Mesopolobus dubius Walker, Pteromalus chrysos Walker, Pteromalus sp. (Hym.: Pteromalidae), Monodontomerus aereus Walker (Hym.: Torymidae), Itoplectis maculator (Fabricius), Apophua bipunctoria Thunberg, Triclistus globulipes Desvignes, Dirophanes maculicornis Stephens, Hyposoter sp., Dusona sp. (Hym.: Ichneumonidae) and Aprostocetus sp. (Hym.: Eulophidae). In the studied parasitoid complex, A. obscurus, B. intermedia and I. maculator were the most important in reducing pest numbers. The level of total parasitism of the C. murinana was 19.4% in 2002 and 22.3% in 2003.     

Primary studies on the parasitoid fauna of Coccoidea in cultivated and non-cultivated areas in the east Mediterranean region of Turkey

The parasitoid fauna of Coccoidea in cultivated and noncultivated areas was studied in the east Mediterranean region of Turkey in 1994–1997. In total, 25 parasitoid species belonging to Aphelinidae, Encyrtidae, and Eulophidae (Hymenoptera) were reared from 21 different scale hosts. On crop plants, mainly citrus and peach, 13 parasitoids from eleven Coccoidea hosts were determined while 14 parasitoid species were obtained from twelve scale insects on non-cultivated plants. Seven parasitoid species are new records for the Turkish insect fauna. Only one of them was found on citrus, while the other six species were sampled in non-cultivated areas. The most common parasitoids encountered wereAphytis melinus DeBach,Encarsia berlesei (Howard) (Aphelinidae),comperiella bifasciata Howard (Encyrtidae), andMetaphycus flavus (Howard) (Eulophidae) in cultivated areas andCoccophagus lycimnia (Walker) (Aphelinidae) in non-cultivated areas. All other parasitoids species were obtained only from a few scale insects hosts.     

Insects reared from stems and branches of goat willow (<Emphasis Type="Italic">Salix caprea</Emphasis> L.) in Bulgaria

Seven xylophagous insect species were established in stems and branches of Salix caprea L. during the period 1998–2003 in Bulgaria: Agrilus lineola lineola Redtenbacher (Coleoptera: Buprestidae), Aromia moschata (Linnaeus), Oberea oculata (Linnaeus), Saperda populnea (Linnaeus), Saperda similis Laicharting (Coleoptera: Cerambycidae), Synanthedon formicaeformis (Esper) (Lepidoptera: Sesiidae) and Rhabdophaga clavifex (Kieffer) (Diptera: Cecidomyiidae). From them, six parasitoid species were reared: Dolichomitus mesocentrus (Gravenhorst), Dolichomitus populneus (Ratzeburg) (Hymenoptera: Ichneumonidae), Stephanus serrator (Fabricius) (Hymenoptera: Stephanidae), Aprostocetus metra (Walker), Euderus caudatus (Thomson) (Hymenoptera: Eulophidae) and Billaea irrorata (Meigen) (Diptera: Tachinidae). D. populneus, E. caudatus and B. irrorata were connected with S. populnea; D. mesocentrus and S. serrator with S. similis; and A. metra with R. clavifex. Two parasitoids (A. metra and E. caudatus) had not previously been reported for the fauna of Bulgaria. The parasitoid–host relationships D. mesocentrus–S. similis and S. serrator –S. similis were established for the first time in this study.     

Reproductive strategies and food sources used by Acerophagus n. sp. near coccois, a new successful parasitoid of the invasive mealybug Phenacoccus peruvianus

Phenacoccus peruvianus Granara de Willink (Hemiptera: Pseudococcidae) is a new invasive mealybug that causes important damages in ornamental plants in urban landscapes and nurseries in Southern Europe. Recently, a new species of genus Acerophagus Smith (Hymenoptera: Encyrtidae) has been recorded as the main parasitoid of P. peruvianus in Spain, displacing the native parasitoid Leptomastix epona Walker (Hymenoptera: Encyrtidae). In this work, we have determined some traits of the reproductive and feeding strategies of Acerophagus sp.: fecundity, immature developmental time, host instar suitability, and preference when parasitizing P. peruvianus, and the effect of natural occurring sugar sources on adult longevity. Acerophagus sp. egg load reached its maximum when it was 5 days old. Second and third nymphal instars and adults were suitable for parasitism and immature development (efficient encapsulation was low). Immature development lasted between 20 and 22 days. Acerophagus sp. developed as a solitary parasitoid in the second instar and as a gregarious parasitoid in older instars (2–4 parasitoids per host). All the emerged offspring were females. Acerophagus sp. always preferred older instars when different host instars were available. Finally, adults lived more than 20 days when fed on honey, but they lived fewer than 3 days when fed on naturally occurring sugar sources (host honeydew and host plant flowers, Bougainvillea glabra). The consequences of these characteristics on biological control and parasitoid rearing are discussed.     

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?%.     

Parasitoid and host egg ages have independent impact on various biological traits in a Trichogramma species

Trichogramma (Hymenoptera: Trichogrammatidae) are species used worldwide for the biological control of Lepidopteran pests, notably through inundative releases on millions of hectares. The optimal use of Trichogramma parasitoids in crop protection requires an accurate knowledge of their biology. More specifically, the importance of age factor in parasitoids during the time they forage in crops for host eggs (after initial release) and how the aging of host eggs could impact parasitoid biological traits may be important for overall efficiency in terms of crop protection. In this context, the importance of parasitoid female and host egg ages on parasitism rate and the development of offspring was studied in laboratory conditions on Trichogramma cacoeciae Marchal (Hymenoptera: Trichogrammatidae) and the eggs of the pest Lobesia botrana Denis and Schiffermüller (Lepidoptera: Tortricidae). Host eggs tested were 1–2- and 3–4-day-old, while the ages of T. cacoeciae adult females varied from 1-day-old to 4-day-old post-emergence. When L.?botrana eggs were 3–4-day-old, they were less parasitized by T. cacoeciae than 1–2-day-old eggs, and this was not linked to the age of T. cacoeciae females. The age of parasitoid females has an effect on parasitism, as 1-day-old females produced fewer parasitized eggs than 2, 3, and 4-day-old females. For the total number of L. botrana eggs killed by T. cacoeciae, the two factors did not show significant effects. When L. botrana eggs were 1–2-day-old, parasitoid emergence increased according to the age of parasitoid females with the highest success observed for 3-day-old females. The lowest emergence rates were obtained with T. cacoeciae females 1-day-old. The development time was also longer with the young 1-day-old parasitoid females. This study demonstrated that both the aging of parasitoids and host eggs play a role in the subsequent development of parasitoid offspring. The importance of these results in the context of biological control programs involving Trichogramma parasitoids is discussed.     

New parasitoids of<Emphasis Type="Italic"> Saperda populnea</Emphasis> (L.) (Col. Cerambycidae) in Bulgaria

The parasitoid complex of Saperda populnea (L.) (Col., Cerambycidae) was studied during the period 2002–2003 at different sites in Bulgaria. Galls containing cerambycid larvae were collected on branches of aspen (Populus tremula L.), goat willow (Salix caprea L.) and hybrid poplars and were studied under laboratory conditions. As a result, four new species for the parasitoid complex of S. populnea in Bulgaria were recorded: Dolichomitus tuberculatus (Geoffroy), Xylophrurus lancifer (Gravenhorst), Gelis ornatulus (Thomson) (Hym., Ichneumonidae) and Dendrocerus serricornis (Boheman) (Hym., Megaspilidae). D. serricornis and G. ornatulus are new species for Bulgarian fauna. D. tuberculatus and X. lancifer were found as primary parasitoids, and G. ornatulus and D. serricornis as hyperparasitoids. The primary parasitoids developed solitarily in the host larvae. D. serricornis was reared gregariously from a puparium of Billaea irrorata (Meig.) (Dipt., Tachinidae). The host of G. ornatulus was not identified, but the hyperparasitid could be connected with Iphiaulax impostor (Scop.) (Hym., Braconidae). The mortality of S. populnea caused by the parasitoids was 2.0–6.3%.     

补充营养对白蜡吉丁肿腿蜂寄生效率和发育进程的影响

[目的]为了探明补充营养是否对白蜡吉丁肿腿蜂雌蜂的寄生效率、生殖能力和寿命有显著影响。[方法]本文通过在白蜡吉丁肿腿蜂搜寻到寄主前期为其提供寄主血淋巴和蜂蜜补充营养,调查有前期补充营养经历的肿腿蜂对寄主麻天牛的寄生率、母蜂生殖能力和子代蜂发育进程的变化。同时,给予刚羽化的肿腿蜂雌蜂短期的补充营养的过程,调查其寿命长短的变化情况。[结果]研究结果表明,寄主血淋巴和糖类物质均可以作为供肿腿蜂补充营养的潜在食物源。寄生前期取食寄主血淋巴和蜂蜜的肿腿蜂寄生率显著高于前期仅补充蒸馏水的个体。补充营养后可促使寄生蜂卵的成熟,可以使肿腿蜂更快的开始产卵进程。前期取食寄主血淋巴的肿腿蜂生殖能力显著高于寄生前期仅补充蒸馏水的个体,取食蜂蜜的肿腿蜂产卵量较前2组均无显著差异。寄生蜂母蜂是否补充营养对其子代的发育过程和性比无显著影响。此外,生存分析结果表明,刚羽化的肿腿蜂补充营养后,其寿命显著延长。取食寄主血淋巴或蜂蜜的寄生蜂寿命均约为羽化后无营养补充经历雌蜂个体的2倍。[结论]以上结果表明,白蜡吉丁肿腿蜂在寄生过程开始前期的补充营养过程可以显著的增强其对寄主害虫的控制作用和延长其寿命。取食蜂蜜或寄主血淋巴对肿腿蜂生殖和寿命的增强作用相近。建议在害虫的生物防治中,可以通过在天敌释放区周边配植一定的蜜源植物以此实现对天敌昆虫资源更有效的利用和保护。     

Bioecological characteristics of Bracon intercessor Nees (Hymenoptera: Braconidae) as a parasitoid of the poplar clearwing moth, Paranthrene tabaniformis (Rott.) (Lepidoptera: Sesiidae) in Bulgaria

The major bioecological characteristics of Bracon intercessor Nees (Hymenoptera: Braconidae), a parasitoid of the poplar clearwing moth, Paranthrene tabaniformis (Rott.) (Lepidoptera: Sesiidae), were studied from 1987 to 2003. Poplar shoots infested with P. tabaniformis larvae were collected in 11 localities in Bulgaria and examined in the laboratory, and infestations were also studied in the field. B. intercessor was recorded in seven localities and was found to be a gregarious external larval parasitoid of P. tabaniformis. Two generations of the parasitoid developed on the host. The first (summer) generation was associated with early and mid-stage (up to third instar) host larvae, and the second (overwintering) generation with third- to fifth-instar larvae. The average number of parasitoid individuals feeding on a host was 4.5 and 12.4 in summer and overwintering generations, respectively. The maximum number recorded was 25 individuals per host in the overwintering generation. B. intercessor overwintered as a mature larva on the host and completed its development in early spring. The adults from the overwintering generation appeared in April, about 1 month prior to emergence of P. tabaniformis. The life cycle of B. intercessor was not in close synchrony with the development of P. tabaniformis in the spring, but the parasitoid adults which fed on honey-sugar solution lived for up to 31 days (males) and 86 days (females), respectively. This suggests that, in the field, B. intercessor females eclosing in the spring could survive until the host larvae appear if nectar is available. Adults of the summer generation emerge from July to September when sufficient suitable host larvae are available. B. intercessor was responsible for 1.5% of the average mortality of the P. tabaniformis overwintering larvae. The host mortality caused by the summer generation of the parasitoid ranged from 3.2% to 5.8%.     

Laboratory rearing of the solitary egg-larval parasitoid, Chelonus oculator Panzer (Hymenoptera: Braconidae) on a newly recorded factitious host Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae)

Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) is recorded as a new factitious host for the solitary egg-larval parasitoid, Chelonus oculator Panzer (Hymenoptera: Braconidae). A short biology and rearing method of the parasitoid on the new host were studied at 30±1°C, 60–70% relative humidity, with a photoperiod of 16:8 (L: D). Chelonus eclosed from 74.60% of parasitized hosts. No significant difference was found between development times of male and female parasitoids. Development of the parasitoid was completed in 28.14±0.47 days in male, and 28.87±0.58 days in female. However, a significant difference was found between adult sizes of male and female parasitoids. Adult dry mass was found 0.88±0.04 mg in male, and 1.99±0.11 mg in female. In addition, C. oculator was successfully reared from P. interpunctella in twenty generations with the explained method. Significant knowledge about biology of C. oculator is still lacking. However, the parasitoid can be candidate for future research as a biological control agent against some important lepidopteran pests, and P. interpunctella may be suitable factitious host for mass rearing of C. oculator.     

Species composition, structure and impact of larval parasitoids of poplar twig borer,Gypsonoma aceriana (Dup.) (Lepidoptera, Tortricidae), on poplar ornamental trees in Sofia

Studies on the species composition and structure of parasitoid complex of poplar twig borer,Gypsonoma aceriana (Dup.), on poplar ornamental trees in Sofia and their role in reducing the number of this pest have been conducted during the period 1990–1997. Six larval parasitoids—Bracon variator Nees,Orgilus obscurator (Nees),Microdus tumidulus Nees,Apanteles erevanicus Tob. (Braconidae),Pristomerus rufiabdominalis Ucida andPristomerus vulnerator (Panz.) (Ichneumonidae) were identified. Most numerous wereM. tumidulus (41.0%),A. erevanicus (30.6%) andP. rufiabdominalis (19.1%).A. erevanicus andM. tumidulus were dominating during the different years. The parasitoids ofG. aceriana were solitary, asB. variator is an ektoparasite, and the rest—endoparasites. They attack young host larvae and emerge at the end of the pupal stage. The life cycle of parasitoids, that have double generation, are well synchronised with the pest development. This was expressed in the high levels of parasitism, which in some cases reached 61.5%, and as a whole for the different generations they were 5.9–44.4%.A. erevanicus andM. tumidulus were the most important in reducing the number of the pest.     

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.     

Parasitic Ichneumonoidea on the horse chestnut leaf miner, Cameraria ohridella (Lepidoptera: Gracillariidae) in Slovakia

Parasitic Hymenoptera from the suprafamily Ichneumonoidea attacking the horse chestnut leafminer Cameraria ohridella Deschka & Dimic (Lepidoptera: Gracillariidae) were studied in southwest Slovakia during 2000 and 2001. The search for such species resulted in the determination of eight ichneumonid species, Gelis agilis (Fabricius), Itoplectis alternans (Gravenhorst), I. clavicornis (Thompson), I. maculator (Fabricius), Scambus annulatus (Kiss), S. brevicornis (Gravenhorst), Zatypota percontatoria (Müller), Adelognathus sp. and a braconid Colastes braconius Haliday. The most abundant species was S. annulatus. All these species recorded are polyphagous and often facultative hyperparasitoids, except C. braconius, which departs from this norm in not being hyperparasitic. The presence of more diversified native parasitoids and hyperparasitoids from the Ichneumonoidea predicate a slow successive adaptation of the parasitoid fauna to the invasive host, Cameraria ohridella.     

New and little-known lepidopteran (Lepidoptera) phytophages on the poplars (Populus spp.) in Bulgaria

Investigations were carried out during the period 1997-1999 on lepidopteran entomofauna deleterious to poplars (Populus spp.) in Bulgaria. The phytophages were collected in larval and pupal stage and were reared under laboratory con-ditions to the adult stage. In two regions of Bulgaria, Sofia and Montana, 18 new and little-known phytophages in seven families were established on the trees in Populus genus: Limenitis populi (L.) (Nymphalidae); Anacampsis populefia (Cl.), Gelechia turpella (Den. & Schiff.) (Gelechiidae); Synanthedon melliniformis (Lasp.) (Sesiidae); Euproctis similis (Fuessl.) (Lymantriidae); Drymonia velitaris (Hufn.), Notodonta tritophus (Den. & Schiff.) (Notodontidae); Amphipyra pyramidea (L.), Catocala nupta (L.), Cosmia trapezina (L.), Enargia paleacea (Esp.), Eupsilia transversa (Hufn.), Ipomorpha subtusa (Den. & Schiff.), Parastichtis ypsilon (Den. & Schiff.), Scoliopteryx libatrix (L.) (Noctuidae); Gastropacha quercifolia (L.), Phyllodesma tremulifolia (Hb.) and Poecilocampa populi (L.) (Lasiocampidae). G. turpella and S. melliniformis are new records for Bulgaria and D. velitaris was found for the first time in Northern Bulgaria. Thirteen species (L. populi, E. similis, D. velltaris, N. tritophus, A. pyramidea, C. nupta, C. trapezina, E. transversa, I. subtusa, P. ypsilon, G. quercifolia, P. tremulifolia and P. populi) were established for the first time in Bulgaria to have a trophic relationship with poplars. G. turpella and L subtusa were occurred in the highest population densities – up to 1.6 larvae/m and up to 1.1 larvae/m respectively. The remaining species occurred in low population densities in the studied habitats and were not considered to be pests on the poplars.     

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.     

松褐天牛肿腿蜂对松褐天牛低龄幼虫控制作用的研究

研究测定了松褐天牛肿腿蜂对松褐天牛1～3龄幼虫的控制作用,采用林间和室内罩网相结合的方法研究了2组松褐天牛肿腿蜂对松褐天牛幼虫的寄生情况.结果显示:在室内试验条件下,松褐天牛肿腿蜂产卵之前的刺蛰、补充营养取食能直接造成松褐天牛1～3龄幼虫死亡,对1、2及3龄幼虫的平均致死率分别为95.66％、85.91％、57.88％,并可产卵寄生2、3龄幼虫;林间释放2组松褐天牛肿腿蜂后,在刺蛰和补充营养取食后能有效寄生寄主的肿腿蜂雌蜂数量比例变化较大,有效肿腿蜂率最高为14.9％,最低为2.3％.松褐天牛肿腿蜂寄生行为不受寄主聚集程度的影响,但刚羽化出茧肿腿蜂雌蜂的寄生效率比经饲喂后的雌蜂高近5倍.从肿腿蜂单一个体来看,每头雌蜂补充营养取食和产卵寄生致死的松褐天牛幼虫数为2.1～7.7头.松褐天牛肿腿蜂雌蜂的补充营养习性及刺蛰、取食致死寄主行为在防治中有很重要的作用,表明该种肿腿蜂是防治松褐天牛的重要天敌,在生物防治松褐天牛幼龄幼虫上具有良好的应用前景.