Pathogens and parasites of adults of the great spruce bark beetle, Dendroctonus micans (Kugelann) (Coleoptera: Curculionidae, Scolytinae) from Turkey

In this study, the pathogen and parasite spectra of Turkish populations of the great spruce bark beetle Dendroctonus micans (Kugelann) (Coleoptera: Curculionidae, Scolytinae) are analysed. In addition to the previously studied infective green alga Helicosporidium, three more pathogens and parasites, i.e. the yeast Metschnikowia sp., the neogregarine Mattesia sp. and a nematode, were recorded here for the first time. The pathogens and parasites occur in different quantities and combinations in outbreaks of the beetle at five Turkish localities.     

Oviposition and larval performance of Monochamus alternatus (Coleoptera: Cerambycidae) on the Japanese cedar Cryptomeria japonica

To determine whether Monochamus alternatus can use the Japanese cedar (Cryptomeria japonica) as a host tree, experiments were conducted in a laboratory using three insect populations of different localities. Adult females chose Pinus densiflora bolts as oviposition substrate when supplied with cedar and pine bolts simultaneously, whereas some females from one locality oviposited on cedar bolts when supplied with them exclusively. Seventy-three percent of 40 eggs hatched in cedar bolts. When the first instar larvae were inoculated on cedar bolts, the development was stunted greatly and all died during the larval stage. Two of 20 larvae that were inoculated on cedar bolts at the third instar entered the diapause and one larva developed into an adult female, which produced viable eggs but was much smaller than those obtained from pine bolts. The results did not exclude the possibility that M. alternatus can use recently killed C. japonica trees as a host.     

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.     

Effect of temperature on development, mortality, fecundity, and reproduction of Aphis rumicisL. (Homoptera: Aphididae) on broadleaf dock (Rumex obtusifolius) and Swiss chard (Beta vulgaris vulgaris var. cida)

Temperature effects on developmental period, survival rate, and reproductive capacity of Aphis rumicis L. were studied on Broadleaf dock and Swiss chard at four constant temperatures (17.5°C, 20°C, 22.5°C, and 25°C). The developmental time of immature stages ranged from 10.9 days at 17.5°C to 6.5 days at 25°C on Broadleaf dock, and 11.8 days at 17.5°C to 6.5 days at 25°C on Swiss chard. The total percentage of survivorship of immature stages varied from 54.2% and 67.6% 17.5°C–25°C on Broadleaf dock, and 49.7% and 62.4% at 17.5°C–25°C on Swiss chard. The largest r _m value occurred with 0.2845 at 25°C on Broadleaf dock and with 0.2785 at 25°C on Swiss chard. The results obtained on this study indicated that Swiss chard was a less favorable host of the A. rumicis than Broadleaf dock. The optimal temperature for A. rumicis growth, developmental time, and reproduction was 22.5°C–25°C.     

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.     

Influence of host plant species of Bemisia tabaci (Genn.) (Hom., Aleyrodidae) on some of the biological and ecological characteristics of the entomophagous Serangium parcesetosum Sicard (Col., Coccinellidae)

The entomophagous Serangium parcesetosum Sicard (Col., Coccinellidae) is an effective predator of some whitefly species. However, information on the influence of the preys host plant species on its biological and ecological characteristics is still lacking in the literature. Therefore, the current study focuses on the possible influence of three greenhouse and two field host plant species of Bemisia tabaci (Genn.) (Hom., Aleyrodidae) on the number of eggs laid by S. parcesetosum. In addition, because of the economic importance and widespread planting of cucumber in greenhouses and cotton in the field, these plants were selected for further investigation into the development, mortality, longevity and reproduction of S. parcesetosum at a high temperature in the laboratory. Results showed that S. parcesetosum was able to lay eggs on all five host plant species of B. tabaci, whether greenhouse or field plants. However, among the three greenhouse plant species studied, S. parcesetosum females laid the highest number of eggs on cucumber followed by tomato and then sweet pepper. Of the two field plant species, significantly higher numbers of eggs were laid on tobacco than on cotton. S. parcesetosum could develop either on cucumber or on cotton as preferable host plant species for B. tabaci. There were significant differences in mean developmental duration of larval instars of the same sex between both host plant species; the duration was significantly shorter on cucumber than on cotton. There were no significant differences for mean total developmental duration from egg to adult emergence between both host plant species within the same sex; females showed a mean of 15.9 days and males of 15.1 days on cucumber, while on cotton the means were 17.2 days for females and 16.2 days for males. Total mortality percentage of S. parcesetosum during development from egg to adult stage was lower on cucumber than on cotton, 20.6 and 23.8%, respectively. Longevity of S. parcesetosum varied according to host plant species and sex with a mean of 63.4 days for females and 50.3 days for males on cucumber, and 92.4 days for females and 52.5 days for males on cotton. On cucumber, mean period of oviposition of S. parcesetosum was significantly longer than on cotton. Mean total fecundity was significantly higher on cucumber than on cotton, with means of 97.7 and 31.0 eggs/female, respectively.     

Studies on the abundance, biology and harmfulness of leaf beetles (Coleoptera: Chrysomelidae) in natural bush vegetation in Isparta, Turkey

Leaf beetle occurrence and abundance on certain shrubs and bushes were surveyed during 2002–2003 in several natural habitats of Isparta. The 34 leaf-beetle species collected are listed and classified according to their relative percentage of the total caught and to their associated host plants. In all habitats sampled, leaf beetles showed a preference for plants from the genera Quercus and Crataegus. Some abundant species causing serious damage to their food plants are discussed.     

Incidence of Mesoplatys ochroptera Stål (Coleoptera: Chrysomelidae) on Sesbania sesban in pure and mixed species fallows in eastern Zambia

The sesbania beetle, Mesoplatys ochroptera Stål (Chrysomelidae: Coleoptera), is a serious defoliator of Sesbania sesban in eastern and southern Africa. Developing integrated pest management practices against the beetle is an important aspect of the adoption of S. sesban as an improved fallow species. Field studies were conducted in eastern Zambia with the objective of determining the incidence of M. ochroptera on S. sesban in pure and mixed species fallows. M. ochroptera did not successfully feed or breed on species other than S. sesban either in the pure or mixed species fallows. The density of adult and immature stages of M. ochroptera was higher in mixtures of S. sesban with Mucuna pruriens, Macrotyloma axillare, Macroptilium atropurpureum or Crotalaria grahamiana compared to a pure S. sesban fallow. Although mixed fallows of S. sesban with M. axillare and M. pruriens may produce fodder, increase the amount and quality of organic inputs and improve nutrient cycling in the soil, they appear to be incompatible with management of M. ochroptera. Mixing S. sesban with G. sepium neither increased larval and adult populations of M. ochroptera feeding on S. sesban nor damage to it. While this mixture appeared to favour development of pupae to the adult stage, it increased mortality of emerging adults. Therefore, it is concluded that mixing S. sesban with G. sepium is more robust in nutrient cycling, improving resource utilisation and management of M. ochroptera on S. sesban.This revised version was published online in November 2005 with corrections to the Cover Date.     

寄主树木、寄主和环境因子对松褐天牛深沟茧蜂寄生率的影响研究

[目的]松材线虫病是我国对森林危害和威胁最严重的病害,控制其传播媒介昆虫松褐天牛是防治松材线虫病的主要手段。作者发现的松褐天牛深沟茧蜂(Iphiaulax monochamusi Yang)是寄生松褐天牛中老龄幼虫的重要天敌。为明确松褐天牛深沟茧蜂的寄生率与寄主树木、寄主和环境因子的关系,开展了本研究。[方法]通过解剖46株松褐天牛危害致死的马尾松,调查了松褐天牛深沟茧蜂寄生率与马尾松、松褐天牛和环境因子之间的关系。[结果]调查研究表明:寄主树木的高度、胸径和树龄对松褐天牛深沟茧蜂寄生率没有显著影响,松褐天牛的数量对松褐天牛深沟茧蜂寄生率亦没有显著影响,而松褐天牛幼虫龄期和松褐天牛幼虫在树干上的位置显著影响松褐天牛深沟茧蜂寄生率。松褐天牛深沟茧蜂寄生率与松褐天牛龄期呈显著正相关,其偏好寄生3~5龄幼虫;就天牛在其危害寄主树木上的位置而言,松褐天牛深沟茧蜂偏好寄生马尾松主干上部和在韧皮部危害的松褐天牛幼虫,其对位于马尾松树干上部的寄主幼虫寄生率最高,达27.38%,对在韧皮部生活、危害的寄主幼虫寄生率为20.18%,显著高于位于木质部生活的寄主幼虫寄生率(5.46%)。逐步回归分析表明:影响松褐天牛深沟茧蜂寄生率的关键环境因子是寄主树木的坡位和其它天敌寄生率,其中,坡位与松褐天牛深沟茧蜂呈显著正相关,其它天敌寄生率与松褐天牛深沟茧蜂寄生率呈显著负相关。[结论]以上研究初步明确了松褐天牛深沟茧蜂的寄生率与寄主树木、寄主害虫和天敌之间的关系,为今后利用该重要天敌控制松褐天牛打下了基础。     

Host instar suitability of <Emphasis Type="Italic">Bemisia tabaci</Emphasis> (Genn.) (Hom.: Aleyrodidae) for the parasitoid <Emphasis Type="Italic">Eretmocerus mundus</Emphasis> (Hym.: Aphelinidae)

Efficient use of parasitoids in pest control depend on the knowledge of the biological relationships between host and parasitoid. Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae) is one the most important natural enemies of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) that is found in fields and greenhouses in Adana, Turkey. Although more studies have been done to determine the relationships between E. mundus and B. tabaci, the differences among strains of E. mundus could have important biological concequences. In this study, biological characteristics of native population of E. mundus parasitization of B. tabaci (Q biotype) were determined using bean plants Phaseolus vulgaris (L.) at a constant temperature of 25 ± 1°C, relative humidity 70 ± 10% and 16:8 (L:D) photoperiod regimen. All B. tabaci nymphal instars were parasitized by E. mundus, but the mean number of daily-parasitized nymphs was highest in the second instars (15.3). In addition, second instar females had the shortest mean development time (15.2 days). Mean development times of parasitoids obtained from first, second, third and fourth B. tabaci instars varied from 15.2 to 16.2 days and 15.2 to 15.9 days for female and male, respectively. Proportion of female (♀/♂+♀) varied from first (0.53) to second (0.34) host instars. Impact of results on potential biological control of B. tabaci was discussed through conservation native natural enemies.     

Abundance and pest classification of scolytid species (Coleoptera: Curculionidae, Scolytinae) follow different patterns

Scolytids have been studied more than any other group of forest insects, but most investigations have been restricted to only a few pest species. This bias hampers our understanding of variation in abundance and pest status. Even the simple question whether the abundance of scolytids can predicted by the same independent variables as their pest status is still a matter of debate. To explore this issue, we estimated their abundance using non-attracting flight-interception traps set in a wide range of forests across Czech Republic, Germany, and France. Pest status was taken from current literature. As independent variables, we considered host range, host abundance, and several traits of the considered species in linear models using generalized least squares with a correlation structure derived from the phylogenetic tree of the beetles. Host range was calculated as the root phylogenetic diversity index. The variation in the abundance across scolytids was well explained by resource-related parameters (R² = 0.53). In contrast to abundance, the pest status was significantly related to species-specific traits, such as body size and maximum number of generations. However, the explained variance was much lower (R² = 0.19). Although our analysis showed that abundance and pest score follow different patterns, we stress the importance of monitoring all species using non-selective traps. Considering the increasing global trade and the rapidly changing climate, such a broad ecological monitoring is necessary to detect new interactions and/or invading species that may influence our forests ecosystems.     

First record of the wood boring weevil, <Emphasis Type="Italic">Pentarthrum huttoni</Emphasis>, in Austria (Coleoptera: Curculionidae)

The wood boring weevil, Pentarthrum huttoni Wollaston, is reported for the first time from Austria. It was recorded from coffins in the crypt of St. Michael’s church in the centre of Vienna. Extensive tunnelling of the larvae and surface damage by the adults caused disintegration of the historically significant wooden 18^th century coffins. Beetles were also detected in rotten cardboard on the loamy soil of the crypt. Infestation by this Cossonine weevil is promoted by the very damp conditions in the crypt, a consequence of the closure of ventilation funnels in the 1940s.     

Phyllotreta nigripens (Coleoptera: Chrysomelidae), a new host of Nosema phyllotretae (Microsporida) in Turkey

In the present study we describe a Nosema infection in a Phyllotreta nigripens population. The parasite was identified as Nosema phyllotretae. The spores are oval, 3.97±0.47 μm (2.85–4.75) in length and 2.19±0.36 μm (1.90–2.85) in width. The polar filament has commonly 14 coils. The spore wall is 138–200 nm thick and made up of a clear endospore (88–140 nm) and a uniform exospore (40–70 nm). The polar filament measures 100–125 nm in diameter in the mature spirals. The polaroplast is thin lamellar. This study presents P. nigripens as a new host for N. phyllotretae and a second infection locality in Turkey.     

Opportunistic changes in the host range of<Emphasis Type="Italic"> Lysiphlebus testaceipes</Emphasis> (Cr.), an exotic aphid parasitoid expanding in the Iberian Peninsula

Lysiphlebus testaceipes (Cr.), an exotic aphid parasitoid, but widespread along the West Mediterranean and Atlantic coastal areas, was regularly found in the northeastern part of the Iberian Peninsula parasitizing several aphid hosts, inland and in the Pyrenees. It was found that the environmentally induced restriction of available host species together with the opportunistic response and host alternation of the parasitoid contributed to the successful and on-going expansion and establishment of L. testaceipes from the coast to the inland montane areas of the Iberian Peninsula. Also, a comparison of the overall host range of L. testaceipes in several areas of the West Mediterranean/Atlantic (southern France, Spain, Portugal) demonstrated a rapid increase in the host range in these areas.     

Genetic comparison of <Emphasis Type="Italic">Ips duplicatus</Emphasis> (Sahlberg, 1836) (Coleoptera: Curculionidae,Scolytinae) populations from Europe and Asia

The distribution of the double spined spruce engraver beetle Ips duplicatus ranges from Scandinavia and northeastern Europe to northern Asia. In Europe, I. duplicatus usually is associated with I. typographus on Picea abies, and due to morphological similarities and similar gallery constructions the damage and significance of I. duplicatus are often not recognised and thus underestimated. I. duplicatus has been recently reported from the southern part of Poland, the Czech Republic, Slovakia, northern parts of Austria and Germany; records are missing from many other central European countries (e.g., Hungary). The species became an important pest in some parts of central Europe, and continuous outbreaks of this bark beetle have been reported in Inner Mongolia, China, since the 1950s. The aim of this study was to compare I. duplicatus populations from Europe and Asia by genetic means using the analysis of the mitochondrial DNA. Individuals of I. duplicatus populations from China, Poland, the Czech Republic and Slovakia were collected, and 520 bp fragments of the cytochrome oxidase I (COI) gene were analysed. Four haplotypes were detected and a sequence divergence of 0.8% was found between the populations from China and Europe. These differences associate with behavioural differences in the pheromone bouquet and behavioural response of the two groups. Within Europe three haplotypes were found, but due to the small sample size no significant geographical distribution was demonstrated.     

Potential of the entomopathogenic nematodes Steinernema feltiae , S. weiseri and Heterorhabditis bacteriophora for the biological control of the sugar beet weevil Bothynoderes punctiventris (Coleoptera: Curculionidae)

The sugar beet weevil, Bothynoderes punctiventris Germ. (Coleoptera: Curculionidae), is one of the most damaging pests of sugar beets in Turkey and has been traditionally controlled by application of large amounts of insecticides. The current study used laboratory microcosms to evaluate the possibility of using entomopathogenic nematodes as an alternative control method. The nematodes Steinernema feltiae (strain TUR-S3), Steinernema weiseri (BEY) and Heterorhabditis bacteriophora (TUR-H2) had previously been isolated from Turkey. Nematode-induced mortality generally increased as soil temperature increased from 15 to 25°C but decreased when larvae were located deeper in soil. Heterorhabditis bacteriophora caused the highest larval mortality at 25°C at all depths (5–20 cm). Steinernema feltiae and S. weiseri were more effective than H. bacteriophora at 15°C at all depths. Increasing the application rate of infective nematode dauer juveniles (DJs) affected the number of DJs that penetrated each insect larva and the number of DJs produced per insect. The highest production of DJs per larva occurred at application rates of 50 DJs/larva for S. feltiae and S. weiseri and 100 DJs/larva for H. bacteriophora. Reproduction decreased again at higher application rates. Heterorhabditis bacteriophora had the highest reproductive capability. The results indicate that S. feltiae and S. weiseri might be more effective against this pest early in the growing season when soil temperature is low and that H. bacteriophora might be more effective later in the season when temperature increases.     

Seasonal population trends of<Emphasis Type="Italic"> Liriomyza huidobrensis</Emphasis> (Blanchard, 1926) (Diptera: Agromyzidae) on cucumber (<Emphasis Type="Italic">Cucumis sativus</Emphasis> L.) in Western Turkey

Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae) is an important pest in cucumber greenhouses in Izmir, Western Turkey. This study was carried out during the spring and autumn seasons of 1999 and 2000 in two adjacent cucumber greenhouses, each 1,000 m² in size. Population densities of adult L. huidobrensis in insecticide-treated and non-treated greenhouses were compared by using yellow sticky traps. Ten traps were placed in the non-treated greenhouse and ten traps in the insecticide-treated greenhouse. Yellow sticky traps were changed weekly and the number of flies counted in order to compare the two greenhouses. In addition to monitoring the leaf miner population, in each greenhouse 100 plants were checked and the ratio of infested plants, the ratio of infested leaves per plant and the number of mines per leaf were recorded weekly. The population density of the leaf miner was almost the same in both insecticide-treated and non-treated greenhouses. Thus, it was concluded that using yellow sticky traps will be healthier and more cost effective than using pesticides. Furthermore using pesticides is risky for the environment and the use of yellow sticky traps can easily reduce the number of pesticide applications. If yellow sticky traps are used in the greenhouse in a completely isolated environment and the appropriate insecticide is used when it is necessary, this will provide successful and integrated management against L. huidobrensis.     

The infestation of Vicia faba L. (Fabaceae) by Aphis fabae (Scop.) (Homoptera: Aphididae) under the influence of Lamiaceae (Ocimum basilicum L. and Satureja hortensis L.)

Abtract The system Vicia faba–Aphis fabae fabae was studied under the influence of Ocimum basilicum (basil) and Satureja hortensis, in a wind tunnel, in the greenhouse and in field experiments. In the wind tunnel at 20°C both Lamiaceae were deterrent for A. fabae, and S. hortensis proved to be more deterrent than O. basilicum. In experiments in the greenhouse at low temperatures (average minimum 14.6°C, average maximum 24.1°C), A. fabae colonised first and significantly more intense Vicia fabae (field beans) not surrounded by O. basilicum or S. hortensis. At high temperatures (average minimum 18.0°C, average maximum 38.5°C) this relation was inverted: Vicia faba surrounded by the two Lamiaceae were preferred for colonisation (Ocimum basilicum significantly). It showed that pots with Lamiaceae were no obstacle for the aphids to reach Vicia faba. In strip cropping in the field, the repellent effect of Ocimum basilicum proved to be stronger than of Satureja hortensis. In 2002 there was observed only a tendency of lower aphid attack of field beans intercropped with Lamiaceae, while in 2004 and 2005 the infestation of Vicia faba by Aphis fabae was significantly lower in plots intercropped with basil. In plots with Satureja hortensis as intercrop, Vicia faba were significantly lower infested, after 3 weeks. The differences between the results of the wind tunnel/greenhouse at low temperatures, and the field experiments concerning the deterrence by Satureja hortensis cannot be explained. But basing on our results with Ocimum basilicum and those published by other authors, it is recommended to follow up intercropping, after a sincere analysis in every case, in favour of agronomists.     

Strawberry blossom weevil Anthonomus rubi Herbst (Col.: Curculionidae): relationships between bud damage, weevil density, insecticide use, and yield

The activity of overwintered strawberry blossom weevils, Anthonomus rubi Herbst, measured as cut buds and adult weevils, was recorded weekly in sprayed and unsprayed quadrats in young and old strawberry plantings. The study was done in nine ‘Korona’ fields in a district with high A. rubi density, in the southeast of Norway, in 2000. During the period of study, the cumulative number of cut buds and adult weevils found by tapping whole plants above a bowl were highly correlated. An increase in sampled weevils was followed by an increase in cut buds 1–2 weeks later. Thus, sampling adults has potential for predicting the bud damage. In five of the six fields where yield was measured, a negative relationship between cut buds and the saleable yield was found. The effect of spraying was relatively low: A. rubi activity was reduced by 21% and the saleable yield increased by 16%. We conclude that present spraying practices are not very efficient in preventing A. rubi damage in the area studied.