Studies on <Emphasis Type="Italic">Aleurothrixus floccosus</Emphasis> (Maskell) (Homoptera,Aleyrodidae) and its parasitoid, <Emphasis Type="Italic">Cales noacki</Emphasis> 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.     

Wirksamkeit des ParasitoidenEretmocerus debachi Rose und Rosen (Hym., Aphelinidae) gegenüber der Weißen FliegeParabemisia myricae (Kuwana) (Hom., Aleyrodidae)

Zusammenfassung Die Weiße Fliege,Parabemisia myricae (Kuwana) (Hom.: Aleyrodidae), stellt seit ihrer Verschleppung in die Zitrusanbaugebiete an der Südost-Mittelmeerküste der Türkei im Jahre 1982 eines der größten Probleme im dortigen Zitrusanbau dar. Zu ihrer biologischen Bekämpfung wurde im Jahre 1986 der spezifische Parasitoid,Eretmocerus debachi Rose und Rosen (Hym.: Aphelinidae) aus Kalifornien in die Türkei eingeführt. Der Parasitoid konnte sich nach Massenfreilassungen im gesamten Gebiet sehr gut einbürgern. In der vorliegenden Untersuchung wurde die Wirksamkeit vonE. debachi gegenüberP. myricae in zweijährigen Versuchen in natürlich befallenen Zitrusanlagen und auf künstlich infizierten und exponierten Zitrusjungpflanzen erfaßt.Innerhalb von zwei Wochen konnten auf den exponierten Zitrusjungpflanzen die ersten Parasitoiden festgestellt werden, wobei bis zu 10% derP. myricae-Nymphen und Puparien durchE. debachi parasitiert waren. In beiden Versuchsjahren und an allen 4 Standorten baute sich im weiteren Verlauf der Vegetation keine weitere Weiße-Fliegen-Population auf den Zitrusjungpflanzen auf. Die Populationsdichte vonP. myricae war auf den natürlichen befallenen Zitrusbäumen sehr viel geringer als auf den exponierten und künstlich infizierten Pflanzen. Dennoch traten mit den erstenP. myricae auch sofort durchE. debachi parasitierte Individuen auf. Die Parasitierungsrate erreichte teilweise 100%, so daß die Schädlingspopulation sehr schnell im weiteren Vegetationsverlauf abnahm und es zu keiner erneuten Gradation kam. Selbst auf sehr geringe Dichteerhöhungen derP. myricae-Population reagierte der Parasitoid mit einer erhöhten Parasitierung. Die Untersuchungen zeigten deutlich, daßE. debachi in der Lage ist, sowohl sehr hohe als auch sehr niedrige Populationen der Weißen Fliege in hohem Maße zu parasitieren und dadurch den Schädling erfolgreich zu bekämpfen.

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Efficiency ofEretmocerus debachi Rose and Rosen (Hym., Aphelinidae) in controlling the whiteflyParabemisia myricae (Kuwana) (Hom., Aleyrodidae)

The whitefly,Parabemisia myricae (Kuwana) (Hym.: Aleyrodidae) is a most serious problem in citrus since it was accidentally introduced into the Southeast Mediterranean region of Turkey in 1982. To control this pest biologically, the specific parasitoid,Eretmocerus debachi Rose and Rosen (Hym.: Aphelinidae), was imported from California to Turkey in 1986. The parasitoid settled very well after being mass released in the entire citrus growing area. In the present study the efficiencyE. debachi in controllingP. myricae was determined in naturally infested citrus orchards and on potted, artificially infested and exposed citrus seedlings over two years.Within two weeks, the first parasitods were determined on the exposed citrus seedlings at which 10% of theP. myricae-nymphal and-puparial stages were parasitized. In both years and at all four experimental sites no further population increase of the whitefly was observed on the citrus seedling over the entire vegetation period. TheP. myricae-densities were much lower on the naturally infested trees than they were on the exposed and artificially infested citrus seedlings. Nevertheless, the firstE. debachi were observed with the occurrence of the firstP. myricae. The parasitization rate reached sometimes up to 100%, so that the pest population decreased significantly in the following month to almost zero level. Even to smallest population increases ofP. myricae, the parasitoid reacted with increasing parasitization. The experiments proved, thatE. debachi was capable to parasitize high and low population densities of the whitefly completely and in consequence successfully controlled the pest.

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Indigenous parasitoids as effective natural enemies of <Emphasis Type="Italic">Phyllocnistis citrella</Emphasis> (Lepidoptera: Gracillariidae) in Korea

This study is aimed to investigate the occurrence of Phyllocnistis citrella Stainton (citrus leafminer; CLM), which has recently caused increasing damage to citrus farms in southern South Korea, and its natural enemies, which can act as biological control agents. In the present study, CLM monitoring using sex pheromone traps were conducted in the major citrus farms in the Jeju region in South Korea. Also a survey of parasites was carried out to detect the effective control agent for CLM. During the investigation from 2011 to 2015, a relatively large number of adult CLM (2,386,990) were observed in the sex pheromone traps. The mean annual occurrence of CLM was 477,398, which showed an increasing trend with the increase in temperature. A survey of parasites was conducted in November 2015. Six parasites were found, of which, Quadrastichus sp. and Sympiesis sp. showed the highest rates of parasitism. The mean rate of parasitism during the survey period was 3.97 %. We discovered four new species of parasites of CLM in South Korea.     

Citrus gummosis incidence and role of ants (Lasius grandis) and snails (Helix aspersa) as vectors of the disease in Tunisia

Surveys were conducted between November 2011 and December 2013 to determine the distribution and the incidence of citrus gummosis in Tunisia. Forty‐two citrus orchards in three different citrus areas were surveyed. Symptoms of gummosis were observed in 59.52% of the orchards. The highest incidence was observed in the Cap Bon area. The involvement of some invertebrates in the epidemiology of citrus gummosis was also confirmed. Species of ants (Lasius grandis), snails (Helix aspersa and Rumina decollata) and worms (Armadillidium vulgare) collected from 2012 until 2014 were tested for the presence of Oomycetes. Phytophthora nicotianae and Phytopythium vexans were isolated from the bodies of Lasius grandis and also from bodies and faeces of Helix aspersa. However, no Oomycetes were isolated from the bodies of Rumina decollata and Armadillidium vulgare. In vitro assays, Helix aspersa was fed with P. nicotianae‐ and Ph. vexans‐infected citrus bark showed the existence of those pathogens in 79.1% of the faeces of snails. In vivo assays, snails and ants were able to transmit the pathogens vertically from the base of potted 2‐year‐old trees citrus variety Clementine Mandarin cv. Hernandina, to other parts of the tree.     

Seasonal population dynamic and within-plant distribution of the whitefly,Aleurotuberculatus takahashi David et Subramaniam (Hom., Aleyrodidae), and its parasitoid,Eretmocerus longipes Compere (Hym., Aphelinidae) in citrus and jasmine plantations in Fuzhou region of the southeastern China

Field investigations on seasonal population dynamic and within-plant distribution of the whiteflyAleurotuberculatus takahashi David et Subramaniam (Hom., Aleyrodidae), and its parasitoid,Eretmocerus longipes Compere (Hym., Aphelinidae) in citrus and jasmine plantations were conducted at Fuzhou, Fujian, PR China in 1996. Population levels of the whitefly and its parasitoid were approximately one times higher on jasmine plantation than on citrus. The seasonal trend of the whitefly parasitization rate on citrus was similar to that on jasmine. Maximum parasitization rates on citrus and jasmine were determined on 30. Sept. valuing 17.5% and 32.0%, respectively. Later in the season this rate gradually dropped gradually down to zero level till the end of sampling period. Populations ofA. takahashi andE. longipes were differently distributed in regard to leaf age on citrus and to plant layers on jasmine.A. takahashi was most abundant on youngest citrus leaves (age class I) averaging 14.03 indiv./leaf and on leaves in the top layer of jasmine with 20.02 indiv./leaf, whileE. longipes preferred to settle on youngest citrus leaves (age class I) (3.41 indiv./leaf) and on leaves in the middle layer of jasmine (2.95 indiv./leaf). Beside the whitefly population was distributed in a contagious pattern with K>8 on mature citrus leaves (age class III), the whitefly and parasitoid populations displayed an aggregated distribution pattern with 0<K<8 on all the leaf ages of citrus and all 3 layers of jasmine. Furthermore, the distribution of the parasitoid was even more aggregated than that of the whitefly within all leaf position tested. Regression analysis was used to fit a model of the parasitism related to the indices of whitefly (K1)/parasitoid (K2) (Y=0.1770–0.0048X, r=0.7850, p<0.05), where a=0.1770 represented the average saturation parasitism byE. longipes and b=0.0048 indicated a negative relation between the parasitism and the indices of K1/K2. From the equation it was concluded that the fitness of spatial distribution pattern between the whiteflyA. takahashi and its parasitoidE. longipes was optimal with of K1/K2-indices below 5 resulting in the highest parasitism in the field.     

Studies on the damage potential of Closterotomus (=Calocoris) trivialis and Aphanosoma italicum (Hemiptera: Miridae) on citrus

This study aimed to investigate the damage potential of two hemipteran species that are commonly recorded in citrus orchards of the eastern Mediterranean region. These were Closterotomus trivialis Costa and Aphanosoma italicum Costa (Hemiptera: Miridae). Shoots on sweet orange trees were enclosed in muslin cages into each of which eight nymphs or eight adults were introduced not only in the early development of the buds but also in the different stages of the flowering period in 2008 (i.e., 6 and 19 March, 10 April and 2 May). In the experiments, adults of C. trivialis, and nymphs and adults of A. italicum were used. According to the results, in a few cases these insects caused a significant reduction in the number of buds or flowers and fruits dropped in comparison to the controls. However, the number of fruits that finally remained on the trees was not significantly affected. Therefore, the damage potential of these mirids on the fruit production of citrus was not shown to be significant under our experimental conditions.     

Laboratory evaluation and field application of bacterial and fungal insecticides on the citrus flower moth,Prays citri miller (Lep., hyponomeutidae) in lime orchards in Egypt

The efficacy of two commercial products of Bactospeine and Bio-fly onPrays citri of lime trees was studied under laboratory and field conditions throughout the two seasons of 1996 and 1997. Laboratory results indicated that the pathogenic effect of Bactospeine,Bacillus thuringiensis (Berliner) was higher than that of Bio-fly,Beauveria bassiana in spite of the latter was applied with higher doses. Bactospeine at the rate (2 cc/1 l.w.) effected on the larvae more than on the adults, that treatment reduced no. of eggs/female by 81.70% and decreased the larval infestation by 90.08%. Bio-fly at the highest concentration (4 cc/1 l.w.) reduced the infestation with the eggs, the larvae and the pupae by 65.83%, 68.45% and 72.55%, respectively. Advanced effects of bacterial and fungal treatments on the final reduction rates ofP. citri infestation were recorded. Field applications revealed that two sprays with Bactospeine or Bio-fly gave good control ofP. citri more than one spray. Bactospeine at the rate (2 cc/1 l.w.) and Biofly at the rate (4 cc/1 l.w.) reduced the infestation by (89.82–93.43%) and (76.32–78.83%), respectively. In all cases, higher doses of bioinsecticides produced potentiation effects of infestation reduction. It is recommended that two sprays of Bactospeine at a rate (2cc/1 l.w.) are adequate effective to reduce the population of P. citri in lime orchards during the main flowering period of trees without need of chemical insecticides. An erratum to this article is available at .     

Population dynamics,phenology, and overwintering of <Emphasis Type="Italic">Bactrocera dorsalis</Emphasis> (Diptera: Tephritidae) in Hubei Province,China

Since 2004 the oriental fruit fly, Bactrocera dorsalis (Hendel) has become widespread and economically important in Wuhan, Hubei Province, central China. In this article, the population dynamics of B. dorsalis were monitored using methyl eugenol-baited traps during 2008–2009 in Wuhan. Adults were captured from early July to the end of December in a citrus orchard and peaked in October and early November. Adult population peak coincided with the ripeness period of sweet oranges in October. Infestation with B. dorsalis was more serious in 2009 than in 2008. Field surveys of host plants for this fly species combined with rearing experiments indicated that pear was the first host plant infested by B. dorsalis. We recorded the following host shift pattern: pear (Pyrus communis L.), jujube (Zizyphus jujuba L.), persimmon (Diospyros kaki L.), and sweet orange (Citrus unshiu Marcor). Our findings suggest that B. dorsalis completes four to five generations per year in this area and most serious damage occurred in the 4th generation in the citrus orchards. The availability of preferred host fruits and the low winter temperature are key factors influencing population fluctuations. Overwintering potential experiments of adults, larvae, and pupae were also carried out in the field. Results suggest that a small proportion of pupae were able to survive winter in Wuhan and emerged successfully the following year. Practical and theoretical implications of the results regarding the invasion potential and management strategy of B. dorsalis in Hubei Province are discussed.     

Olfactory reactions ofCryptolaemus montrouzieri Mulsant (Col., Coccinellidae) andChrysoperla carnea (Stephens) (Neur., Chrysopidae) in relation to period of starvation

In a laboratory study, it was tried to measure the extent of olfactory responses of two predators namelyCryptolaemus montrouzieri Mulsant andChrysoperla carnea (Stephens) to their respective preys at varied levels of their starvation. Results indicated that both the predators, irrespective of their developmenta stage, oriented more positively to their preys odour when they were deprived of food for certain period of time than they did so when tested directly without subjecting them to starvation. The first, second, third and fourth instar larvae and adults ofC. montrouzieri showed maximum response at 4 h, 8 h, 12 h, 12 h and 24 h of starvation, respectively. Similarly, the larvae ofC. carnea responded maximum with 4 h, 8 h and 12 h of hunger in first, second and third instar, respectively. However it was also evident that the continued starvation for more than certain ideal period affected the predators olfactory orientation negatively. But the adults ofC. montrouzieri differed slightly in their behavior as they could respond positively for comparatively longer period of starvation.

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Zusammenfassung In Laborversuchen wurde das Ausmaß der olfaktorischen Reaktionen der beiden PrädatorenCryptolaemus montrouzieri Mulsant undChrysoperla carnea (Stephens) auf deren BeuteinsektenPlanococcus citri Risso respektiveAcyrthosiphon pisum (Harris) und in Abhängigkeit von der Dauer einer vorangegangenen Hungerperiode, namentlich 2, 4, 8, 12, 16, 20 und 24 Stunden, ermittelt. Wie die Ergebnisse belegen, reagieren beide Prädatoren-Arten unabhängig vom jeweiligen Entwicklungsstadium stärker auf den Geruch ihrer Beute, wenn sie zuvor eine bestimmte Zeit unter Ausschluß von Nahrung gehalten worden waren. Dabei zeigte sich bei den Larven beider Arten ein typischer Verlauf der Attraktivität durch die Beute, nach dem diese mit zunehmender Dauer der Hungerperiode zunächst zunahm, um nach einem Maximum wieder deutlich abzufallen. Dieser Verlauf erwies sich für die einzelnen Larvenstadien als unterschiedlich. So wurde fürC. montrouzieri das Maximum bei den L₁-Larven mit durchschnittlich 9,33 von 15 durch die Beute angelockten Individuen bereits nach einer Hungerperiode von 4 h erreicht, für die L₂ jedoch mit 9,50 Individuen erst nach 8 und für die L₃ sowie L₄ erst nach 12 h mit 8,83 respektive 9,17 Individuen. Lediglich bei denC. montrouzieri-Adulten war eine kontinuierliche Zunahme der Attraktivität der Beute während des Untersuchungszeitraums von 24 h festzustellen, wobei das Maximum bei 10,00 Individuen lag. Analog wurde für das ersteC. carnea-Larvenstadium bei einer 4stündigen Hungerperiode mit 55,5% attrahierten Individuen das Maximum erreicht, wohingegen das zweite Stadium mit 61,1% bei der 8- und das dritte mit 65,5% bei der 12stündigen Hungerperiode die maximale Attraktion durch die Beute aufwies.

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Variation in the reproductive performance ofEpiricania melanoleuca (Fletcher) (Lep., Epipyropidae) in relation to stage and sex of the hostPyrilla perpusilla (Walker) (Hem., Lophopidae) during rearing

Rearing ofEpiricania melanoleuca (Fletcher) on adult females ofPyrilla perpusilla (Walker) augmented the productivity of the former, which is an effective nymphal and adult ectoparasitoid of the latter, in terms of yield of total and viable eggs. The applied value of this finding in field biocontrol program is highlighted.

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Zusammenfassung Wurden die ektoparasitischen Raupen vonEpiricania melanoleuca auf adulten Weibchen der Zuckerrohr-Zikade,Pyrilla perpusilla aufgezogen, vergrößerte sich die Zahl und Lebensfähigkeit der Eier, die von den daraus resultierenden Faltern abgelegt wurden. Das Ergebnis wird im Hinblick auf einen Einsatz des Parasitoiden zur biologischen Bekämpfung des Schädlings erörtert.

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Pine mistletoe (Viscum album ssp. austriacum) contributes to Scots pine (Pinus sylvestris) mortality in the Rhone valley of Switzerland

In recent years unusual high mortality of Scots pine (Pinus sylvestris) has been observed in the Swiss Rhone Valley. The exact causes, however, are not known. At a 2‐ha monitoring plot, tree mortality and crown condition have been monitored since 1996. Between 1996 and 2004, 59% of the Scots pines died, most of them following the drought periods 1996–1998 and 2003–2004, while only 15% of the deciduous trees died. Crown transparency, needle discolouration, dead branch percentage, mistletoe (Viscum album ssp. austriacum) rating, Tomicus sp. shoot feeding, male flowering effect, tree stem diameter, crown shading and social tree class assessed in 1998 were used in a logistic regression model to predict tree mortality. Crown transparency, mistletoe rating and percentage of dead branches were found significant in the model and the probability of tree mortality increased with increasing rankings of these parameters. Needle discolouration could be used to substitute ‘dead branch percentage’ as predictor. While crown transparency increased with mistletoe rating, for trees in the same transparency class, trees with medium and heavy mistletoe infection were two to four times more likely to die than trees with no or only low mistletoe infection. For the surviving trees we found that trees with mistletoes showed a significantly higher increase in transparency in the year following a drought than trees without, while in a drought year the opposite was true. At the beginning of the observations no significant differences in transparency had been found between the trees with and without mistletoe. However, by the end of the observation period trees with mistletoe had significantly higher crown transparency. We conclude that mistletoe infection can be considered as both a predisposing factor for tree death, by increasing needle loss following drought and a contributing factor by increasing water stress during drought.     

Racemat und Enantiomere von Ipsdienol zur Anlockung vonIps amitinus (Eich.) (Col., Scolytidae)

Zusammenfassung Enddarmextrakte des Kleinen Buchdruckers (Ips amitinus) ergaben, daß die Männchen während der Aggregationsphase hauptsächlich (+)-Ipsdienol und Amitinol produzieren.Cis-Verbenol,trans-Verbenol, Myrtenol, Verbenon und (–)-Ipsenol werden nur in geringen Mengen freigesetzt. Das von den Weibchen produzierte 2-Methyl-3-buten-2-ol, das beim Großen Buchdrucker als Landestimulus dient, scheint ablenkend zu wirken.Freilanduntersuchungen mit den Enantiomeren von Ipsdienol, gemischt mit Amitinol, zeigten, daß die Mischung von (+)-Ipsdienol mit Amitinol für beide Geschlechter attraktiv ist. Das Racemat/Amitinol-Gemisch zeigt eine geringe Lockwirksamkeit, während die Kombination von (–)-Ipsdienol/Amitinol gar nicht attraktiv ist.

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Racemate and enantiomeres of Ipsdienol for attractingIps amitinus (Eichh.) (Col., Scolytidae)

Hindgut extracts ofIps amitinus revealed that males of this polygamous bark beetle produce mainly (+)-Ips-dienol and Amitinol in the attraction phase.Cis- andtrans-Verbenol, Myrtenol, Verbenon and (–)Ipsenol are produced only in minor amounts. 2-Methyl-3-buten-2-ol is produced by females and seems to be inhibitive.Field experiments with different enantiomeric mixtures of Ipsdienol and Amitinol showed that the mixture (+)-Ipsdienol and Amitinol is attractive for both males and females. The mixture of racemic Ipsdienol and Amitinol seems to be less attractive; (–)-Ipsdienol and Amitinol is not attractive at all.

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绿竹造林及丰产培育技术研究

１９９６－１９９７年在福建省福安市对绿竹不同立地造林和竹林结构、留母竹株数、打蔸、扒晒、施肥及切鞭等丰产栽培技术进行了试验研究。绿竹造林以山 下部较河滩地和平地效果好。绿竹竹林结构以保留１－２年生竹和切鞭以竹丛产笋量增产效果显著,绿竹施肥以饼肥最佳,其次是施尿素２次和复合肥。４月份扒晒对产笋有增产效果     

Über die Laborzucht und Entwicklung des Pfirsich-Prachtkäfers,Capnodis tenebrionis L. (Col., Buprestidae)

Studies on rearing and development of the Peach Buprestid,Capnodis tenebrionis L. (Col., Buprestidae).

The composition of a semisynthetic medium for rearing the Peach Buprestid,C. tenebrionis, and the techniques for handling the insects and their eggs in the laboratory are described.

The period required for the biological cycle using this medium and the techniques described are about the same as the required on natural hosts. However the medium is not yet a perfect substitute for the natural food of the larvae and further experiments is carried out at present to reconsider it.

     

Application of some bacterial varieties ofBacillus thuringiensis and its bioproduct Delfin onSynanthedon myopaeformis Borkh. (Lep. Aegeriidae) in apple orchards

Field experiments were conducted using the biological agentBacillus thuringiensis to control the clearwing moth,Synanthedon myopaeformis (Lep. Aegeriidae) in apple orchards at Alexandria governorate during 1995, 1996 and 1997. Three bacterial varieties ofB. thuringiensis showed significant influence on the reduction of borer infestation. Four applications with the sporic concentration 12×10⁷ spores/ml of each ofB. th. var.kurstaki, B. th. var.alesti andB. th. var.thuringiensis induced 82.5, 51.1 and 42.1% reduction of infestation, respectively. Methods of application showed highly significant effect on infestation level. Sparying after scraping was the best method (80.0%, reduction) followed by painting after scraping (71.5%, reduction) then spraying alone (59.7%, reduction) or painting alone (43.0%, reduction). A control programme was carried out using three applications of the biomaterial, Delfin at the rate of 200 g/100 I.w. during mid-March, early June and mid-August resulted in 88.5–91.4% reduction of infestation.     

Zwei Parasitenarten(Hym., Chalc., Eupelmidae undPteromalidae von Megastigmus pictus (Först.)(Hym., Chalc., Torymidae) in Lärchensamen

Zusammenfassung Auf Grund von 1968–1970 in Polen durchgeführten Untersuchungen wurden als bisher nicht bekannte Parasiten der in Lärchensamen lebendenMegastigmus pictus (Förster) (=M. seitneri Hoffm.) (Hymen., Torymidae) die ChalcidoidenEupelmus urozonus Dalm. (Hymen., Eupelmidae) undMesopolobus zetterstedtii (Dalla Torre) (Hymen., Pteromalidae) nachgewiesen.Die Zuchten aus Samen und Zapfen von 69 polnischen Oberförstereien (104 Standorte) zeigten, daß die beiden Parasiten eine beträchtliche Rolle bei der Einschränkung der Population vomMegastigmus pictus spielen können. Die Untersuchungen bilden die Grundlage für einen eventuellen Einsatz beider Parasitenarten zur biologischen Bekämpfung des Samenschädlings.

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Summary The autor demonstrates, as a result of investigation carried out in the years 1968–1970, thatEupelmus urozonus Dalm. (Hymen., Eupelmidae) andMesopolobus zetterstedtii (Dalla Torre) (Hymen., Pteromalidae) being parasites ofMegastigmus pictus (Förster) (=M. seitneri Hoffm.) (Hymen., Torymidae), an insect damaging the seeds of the European and Polish larch.It was stated from 69 forest districts (104 localities) in the area of Poland, that these parasites are able to play a considerable role in the limitation ofMegastigmus pictus populations. An indication of the se parasites may presage the possibility of a biological restriction of damages caused by this harmful insect.

     

Integrated control of the solitary carpenter worm,Paropta paradoxa H.-Schaeff. (Lep., Cossidae) on fig trees in Egypt

According to the new trend of insect pests control in fruit orchards, biological in addition to mechanical control were evaluated for their efficiency on the reduction ofP. paradoxa population on fig trees during 1996, 1997 and 1998. Primary trials using the bacterial biopreparations of Delfin, Dipel and Bactospeine at the concentration of 200g/100 l. w. resulted in 81.8, 75.8 and 72.3% reduction of pest infestation, respectively. Pruning the infested branches, worming the larvae inside their tunnels and both mechanical treatments together along two successive years, reduced the infestation by 17.5, 47.4 and 57.9%, respectively. A control programme ofP. paradoxa was conducted using the techniques of pruning and worming besides spraying with bacterial insecticides at a rate of 200g/100 l.w. The performed mechanical and biological treatments together for one year gave 79.2–94.5% reduction of infestation, that reduction increased to 83.0–98.1% when these treatments were applied two years successively.     

Expansion of the aphid Myzocallis (Lineomyzocallis) walshii (Monell) on the red oak Quercus rubra, and adaptation of local parasitoids in the northeastern Iberian Peninsula (Hom., Aphididae, Calaphidinae; Hym., Braconidae, Aphidiinae)

An ongoing expansion of Myzocallis (L.) walshii (Monell) in the NE Iberian Peninsula was detected. The aphid species was recorded in Catalonia, Andorra and Navarra. Adaptation of local native parasitoids (at least Trioxys pallidus Haliday and T. tenuicaudus Stary) to the new immigrant was documented, together with background information on their host range in the native environments. The detection of parasitoids of M. walshii is the first published evidence in Europe. The new evidence for M. walshii in the NE Iberian Peninsula also supports the warning of the expansion of the aphid as a pest of Quercus rubra over Europe.     

Untersuchungen über Lebensdauer und Eivorrat der Wacholdersamenwespe Megastigmus bipunctatus Swederus (Hym., Chalc., Torymidae)

Investigations on longevity and fertility of Megastigmus bipunctatus Swederus (Hym., Chalc., Torymidae)Investigations on the influence of different climatic and nutritional factors on longevity and fertility of adult femaleMegastigmus bipunctatus showed that differences in relative humidity had little effect. In higher temperatures longevity and fertility were reduced; the number of undeveloped eggs was reduced more than the number of mature eggs. Food formulas containing protein in the form of chicken egg albumen had a negative effect on longevity and fertility when compared with data fromM. bipunctatus femals kept without food and water. An increase of both, life span and number of eggs, was observed after giving distilled water, aqueous honey solution or aqueous honey solution enriched with vitamin mixture. A maximum increase was obtained with femals living only on honey solution.     

Survey on the distribution of the Horse Chestnut ScalePulvinaria regalis Canard (Hom., Coccidae) in Germany in the years 1996 to 1998

In the present study, the distribution of the Horse Chestnut Scale insectPulvinaria regalis Canard in Germany in the years 1996 to 1998 and tendencies in the variation of infestation levels during the past three years were investigated by a survey. A questionnaire was sent to the offices for green areas and environmental affairs of 121 cities in Germany with a population exceeding 75.000 citizens. Additional observations by the authors were also taken into consideration. A comparison to data from 1995 was conducted. In the year 1998, this arboricultural pest occurred in 34 cities (15 in 1995) and could be found in the areas of the Rhineland and the Ruhr-Valley, from Bonn in the south up to Münster (Westphalia) in the north and from Aachen in the west to Hagen and Dortmund in the east.P. regalis could also be detected in Offenbach and Frankfurt a. M., It also occurred southward along the rivers Rhine and Neckar in the cities of Mainz, Ludwigshafen, Freiburg and Stuttgart. The most southern point whereP. regalis was detected in July 1998 was Zürich in Switzerland. The first occurrence of the 19 new observed infestations withP. regalis took place in six instances before 1995, eight in 1995, three in 1996, and one each in 1997 and 1998. The investigations about tendencies in the variation of infestation levels revealed a decrease in scale numbers only in the cities where Horse Chestnut Scales have been observed first in Germany. On the other hand, almost every place located further away from these infestation sites showed a population increase ofP. regalis. Constant infestation levels over the past three years could be found in only two cities. In most cases lime, maple and horse chestnut trees were the host plants of this scale insect.