bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrophoresis as a tool for estimating levels of hymenopterous parasitism in field populations of the cereal aphid, Sitobion avenue
Authors: Walton M. P. , Powell W. , Loxdale H. D. , Allen‐Williams L.
Published: April 2011

Polyacrylamide gel electrophoresis was used to monitor levels of parasitism in field populations of the cereal aphid, Sitobion avenae (F.) (Hemiptera: Aphididae). Electrophoretic keys previously prepared from laboratory‐reared parasitoids were used to identify parasitoids within field‐collected aphids. Using this approach, the primary parasitoids Aphidius rhopalosiphi De Stefani Perez, Aphidius ervi (Haliday), Aphidius picipes (Nees), Praon volucre Haliday, Ephedras plagiator Nees and Aphelinus abdominalis Dalman were detected. Some unidentified banding patterns were also obtained, most of which were probably attributable to the presence of hyperparasitoids. Electrophoresis was compared with the more conventional sampling techniques of live‐rearing and mummy counts as a means of estimating percentage parasitism. Electrophoresis was found to be a much quicker method than live‐rearing and gave similar results for both levels of parasitism and parasitoid species composition, whereas mummy counts tended to give lower estimates than the other two methods.

L'électrophorèse, outil pour l'estimation du taux d'hyménoptères parasites dans les populations naturelles de Sitobion avenae

L'électrophorèse sur gel de polyacrylamide a servi à déterminer l'importance du parasitisme de populations naturelles de S. avenae F. Des clés électrophorétiques, préparées à partir de parasitoïdes élevés au laboratoire, ont été utilisées pour identifier les parasitoïdes provenant des pucerons récoltés dans la nature. Ainsi ont été décelés les parasites primaires: Aphidius rhopalosiphi De Stefani Perez, A. ervi Haliday, A. picipes Nees, Praon volucre Haliday, Ephedrus plagiator Nees et Aphelinus abdominalis Dalman. Quelques bandes non‐identifiées devraient être attribuées à des hyperparasitoïdes. L'électrophorèse a été comparée aux techniques d'échantillonnage plus conventionnelles de décompte des momies et d'élevage des individus vivants utilisées pour estimer le taux de parasitisme. L'électrophorèse et les méthodes d'élevage donnent généralement des résultats semblables pour les 2 niveaux de parasitisme et la composition en espèces de parasitoïdes, tandis que le décompte des momies tend à donner des résultats inférieurs.
Readiness to lay in the blowfly Lucilia cuprina is unaffected by imposition site‐deprivation or egg‐load
Authors: Browne L. Barton , van Gerwen A. C. M. , Vogt W. G.
Published: April 2011

Oviposition by Lucilia cuprina Wiedemann (Diptera, Calliphoridae) was examined in relation to period of oviposition site‐deprivation and egg‐load. Effects of oviposition site‐deprivation were examined by comparing oviposition performance of individual females that had matured their batch of oocytes within the previous 24 h with that of females which had reached ovarian maturity 8 days previously. Egg‐load was manipulated by causing females of this anautogenous species to consume different amounts of protein‐rich material. In no‐choice experiments, individual females of the different categories were given access for 4 h to oviposition substrate, soaked with (i) liver exudate, (ii) the exudate diluted 16‐fold or (iii) the undilated exudate containing the oviposition deterrent sodium chloride at a concentration of 2 M. These solutions elicited oviposition from different proportions of females, but neither these proportions, nor the interval between introduction of the oviposition site and the initiation of oviposition, was significantly affected by the period of oviposition site‐deprivation or the number of eggs matured by the females.

L'empressement mis à pondre par Lucilia cuprina ne dépend pas de la privation des lieux de pontes ou de la rétention des ovocytes mûrs

L'effjet de la privation de lieu de ponte a été étudié en comparant les pontes de femelles isolées ayant formé leurs œufs mûrs dans les 24 heures précédentes, à celles de femelles ayant atteint leur maturité sexuelle 8 jours avant. La rétention ovocytaire est provoquée en faisant consommer aux femelles de cette espèce anautogène différentes quantités d'aliments riches en protéines. La ponte de femelles dont le contingent total de leurs ovocytes s'est développé, – c'est‐à‐dire 260 –, après consommation ad libitum de foie de mouton pendant 48 heures, a été comparée à celle de femelles ayant formé 190 ovocytes mûrs après ingestion d'une quantité limitée de jus de foie.

Dans des expériences sans choix, les femelles isolées de différentes catégories ont eu accès pendant 4 heures au substrat de ponte trempé: 1) dans du jus de foie, 2) dans du jus dilué 16 fois, 3) dans du jus de foie non dilué mais contenant NaCl (inhibiteur de la ponte) à la concentration de 2 M. Le jus non dilué a provoqué une forte stimulation, induisant la ponte de 80% des femelles. Le jus dilué et celui contenant NaCl n'ont induit la ponte que de 40% des femelles avec des niveaux de stimulation bien plus faibles. La date d'introduction du lieu de ponte et le taux de rétention des ovocytes mûrs n'ont eu auçun effet sur la proportion de femelles réagissant à ces 3 types de stimulation.
Management of Prays citri in lemon orchards by mass trapping of males
Authors: Sternlicht M. , Barzakay I. , Tamim M.
Published: April 2011

Preliminary field trials on the control of Prays citri (Millière) (Lepidoptera: Yponomeutidae) by mass trapping were carried out from 1976 using synthetic sex pheromone (Z‐7‐tetradecenal) baited traps. A clear tendency was revealed for a reduction in flower infestation by the larvae of this pest, providing that the minimum required number of traps (120 per ha) were employed and maintained throughout the entire year. In 1980–1983, commercial field trials were conducted over 30 ha of lemon trees. Rubber septa dispensers were loaded with 0.5–0.6 mg synthetic pheromone and refilled every four months. For comparison, about 30 ha lemon trees were sprayed 3–6 times a year with an organophosphate (azinphos‐methyl) insecticide treatment. One plot of 0.22 ha was used as control. Results from all three areas were compared for mean male catch per trap per day, mean number of moths emerging per flower, and fruit yield for the two years prior to the trials and the three years of the trials in all plots. Lemon trees without control measures showed a decline in fruit yield. Controlling the moth by mass trapping of males, was significantly (P < 0.05) cheaper and somewhat more efficient than spraying 3–6 times/year with insecticides.

Lutte par piégeage massif de mâles contre Prays citri dans des vergers de citronniers

Des essais préliminaires de lutte contre P. citri Millière (Lep. Yponomeutidae) par piégeage de masse ont été menés en 1976 en utilisant la phéromone sexuelle (Z‐7‐tétradécénal) comme appât. On a observé une nette tendance à la réduction de l'infestation des fleurs par les chenilles a été observée lorsque le nombre nécessaire de pièges (120/ha) a été maintenu toute l'année. En 1980–83 des essais commerciaux ont été réalisés sur un verger de 30 ha de citronniers. Des diffuseurs ‘rubber septa’ étaient remplis avec 0,5–0,8 mg phéromones synthétiques et rechargés tous les 4 mois. Par comparaison, un verger de 30 ha a été pulvérisé 3 à 6 fois par an avec un organophosphate (méthyle d'Azinphos). Le témoin était constitué par une parcelle de 0,22 ha. Les captures moyennes quotidiennes de mâles par piège, le nombre de papillons obtenus par fleur e les récoltes de fruits pendant les 2 années précédant ces interventions et les 3 années de duréc des traitements ont permis de comparer la situation sur les 3 aires. Les citronniers témoins ont présenté une diminution de production de fruits. La protection par le piégeage massif des mâles est significativement moins chère (P < 0,05) et semble plus efficace que 3 à 6 traitements insecticides par an.
Olfactory sensitivity of gomphocerine grasshoppers to the odours of host and non‐host plants
Authors: White P. R. , Chapman R. F.
Published: April 2011

Antennal responses to host and non‐host odours were recorded, using the electroantennogram technique, from four gomphocerine grasshoppers with different feeding habits: Bootettix argentatus (monophagous on Larrea, a dicotyledonous plant), Ligurotettix coquilletti (oligophagous on dicotyledonous plants), Cibolacris parviceps (polyphagous) and Chorthippus curtipennis (graminivorous). The patterns of responses across the plant odours were similar for all four grasshopper species, but there was a relatively greater response to the odour of Larrea in B. argentatus and L. coquilletti which specialise on this plant. This suggests that there is considerable overall similarity in the make up of the olfactory receptor populations of these four grasshoppers species, but that some specificity for hostplant odour does exist at the antennal level.

Sensibilité olfactive d'orthoptères Gomphocerinae à l'odeur de plantes hôtes et non hôtes

Les réponses antennaires ont été examinées par électroantennogramme aux odeurs de plantes hôtes et non hôtes d'orthoptères Gomphocerinae de comportements alimentaires différents: Bootettix argentatus, monophage sur une dicotylédone, Larrea; Ligurotettix coquilletti, oligophage de dicotylédones; Cibolacris parviceps, polyphage; Chorthippus curtipennis, graminivore.

Les types de réponse des quatre espèces étaient très voisins, mais les réponses aux odeurs de Larrea de B. argentatus et L. coquilletti, spécialistes de cette plante, étaient relativement plus fortes. Ces résultats suggèrent une similarité globale considérable dans la composition des populations de récepteurs olfactifs de ces quatre espèces d'orthoptères mais aussi une certaine spécificité pour les odeurs de la plante hôte au niveau antennaire.
Thirty‐five years of diapause research with the Colorado potato beetle
Authors: de Kort C.A.D.
Published: April 2011

An ever increasing biological knowledge will make us better and better equipped for manipulating biological processes and for warning us in time against possible dangers which an unguided technology can bring to man and its biotic environment' (de Wilde, 1982).
Influence of adult diet on the reproductive biology and survival of the western corn rootworm, Diabrotica virgifera virgifera
Authors: Elliott N. C. , Gustin R. D. , Hanson S. L.
Published: April 2011

Adult corn rootworm beetles, Diabrotica virgifera virgifera LeConte, were maintained on three dietary regimes which mimicked the progression of corn tissues that would be available in the field for beetles eclosing when corn was in the following growth stages: (A) after tassels had emerged but prior to silking and pollen shed; (B) while plants were silking and shedding pollen; and (C) after pollination was complete and silks had turned brown. A fourth regime (D) was established in which green corn silks, pollen, and leaves were provided throughout the study. The mean number of eggs laid per female over the 12‐week duration of the study was 125, 235, 179, and 441 for regimes A, B, C, and D, respectively. Median length of life was 7.2, 7.2, 6.7, and 8.8 weeks for regimes A, B, C, and D respectively. Beetles in regime A laid a greater proportion of their eggs at an older age than did beetles from regimes B and C. To further investigate the influences on survival of changes in food quality of corn as plants and beetles aged, newly‐eclosed beetles and beetles that had been maintained in caged plots of corn growing in a greenhouse for various lengths of time were caged on corn at different stages of growth, and the proportion of beetles surviving for 48 h was determined. Survival decreased as plants aged for both groups of beetles, but decreased at a faster rate for old than for young beetles.

Influence de l'alimenation sur la reproduction et la survie de Diabrotica virgifera virgifera

D. virgifera virgifera LeConte a été place sur des régimes nutritifs mimant l'évolution des tissus du maïs disponsibles dans le champ lorsque les insectes éclosent est aux stades suivants du maïs: 1) après émergence de l'épi mâle, mais avant l'apparition des barbes et l'emission du pollen; 2) lors de la présence de barbes et de l'émission de pollen; 3) après la pollinisation et quand les barbes ont bruni. Un quatrième régime a été fourni pendant toute l'experience comprenant des barbes vertes, du pollen et des feuilles. Les pontes moyennes des femelles pendant les 12 semaines de l'étude on été 125, 235, 179 et 441 pour les régimes 1, 2, 3 et 4. Les dates de mort de la moitié des adultes a été 7,2, 7,2, 6,7 et 8,8 semaines pour respectivement les mêmes régimes. Les femelles du régime 1 pondent à un âge plus avancé que les femelles des régimes 2 et 3. L'influence des changements de la qualité alimentaire du maïs au fur et à mesure du vieillissement des plantes et de Diabrotica, a été déterminée par la survie au bout de 48 heures d'insectes éclos depuis peu et d'autres maintenus en cage sur des lots de maïs à différents stadcs poussant en serre depuis des temps plus ou moins longs. Plus les plantes sont âgées, plus la survie des 2 groupes de Diabrotica diminue, mais plus vite chez les lots d'insectes âgés.
Measuring wood preference in termites
Authors: Waller D. A. , Jones C. G. , La Fage J. P.
Published: April 2011

Feeding preferences of xylophagous termites have been determined by comparing differences in wood biomass removed, percentage of wood consumed or degree of damage rated in arbitrary categories. When test woods differ in physical characteristics such as density, these measures are not comparable. We examined the response of the Formosan termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae) to wood that differed in physical characteristics by compressing blocks to 40% greater than the natural density. Termites ate significantly greater percentages, but similar amounts of biomass, of uncompressed over compressed natural pine. In contrast, they ate significantly greater amounts of biomass, but similar percentages, of compressed over uncompressed mahogany. Whether percentage or amount of biomass removed should be used as a measure of preference depends on what regulates insect meal size. If termites consume meals of fixed biomass, then biomass consumed is the correct measure; percentage removed is appropriate if they consume meals of fixed volume.

Comment mesurer la préférence pour le bois chez les termites?

Les préférences alimentaires des termites xylophages ont été mesurées en comparant les différentes biomasses de bois prélevées, les pourcentages de bois consommé et l'importance des dégâts en fonction de catégories arbitrairement définies. Quand les caractéristiques des bois examinés différent, par exemple la densité, ces comparaisons ne sont plus possibles. Nous avons examiné les réactions de Coptotermes formosanus Shiraki (Iso., Rhinitermitidae) en présence de bois différant par leurs caractéristiques physiques, par compression du bois jusqu'à une densité dépassant de 40% la densité naturelle. Les termites consomment alors significativement moins en pourcentage, mais les biomasscs consommées sont voisines de celles que l'on observe avec du bois du pin normal. Par contre, elles consomment significativement plus de biomasse, mais les mêmes pourcentages d'acajou compressé ou normal. Savoir quel critère doit être préférentiellement utilisé: Le pourcentage ou la fraction de biomasse prélevé, dépend de la nature des facteurs de régulation de la taille du repas chez les termites. Si les termites consomment des repas de biomasse déterminée, alors la biomasse consommée est un bon critère; s'ils consomment un repas de volume déterminé, alors le pourcentage prélevé est un critère satisfaisant.
The roles of temperature and food quality in affecting the performance of the alder aphid, Pterocallis alni
Authors: Gange A. C. , Pryse J. E.
Published: April 2011

Six successive summer generations of the alder aphid (Pterocallis alni (DeGeer) (Homoptera: Callaphididae)) were reared simultaneously in the field and under controlled temperature conditions in the laboratory. The growth and reproduction of each generation were recorded. The available food quality for the aphids was measured by weekly analysis of foliar soluble nitrogen concentrations. Although there was a significant change in leaf soluble nitrogen during the season, the decline was only 23% and this did not appear to have an adverse effect on the performance of this aphid. Instead, the major environmental factor affecting the aphid is temperature. This is evidenced by the facts that when aphids were reared at constant temperatures, there were no differences in generation performance, even though food quality varied seasonally. In addition, all generations of the aphid posess the same number of ovarioles, indicating that there is no pre‐programmed anticipation of a seasonal deterioration in food quality in this aphid species.

Influences de la température et de la qualité de la nourriture sur le puceron, Pterocallis alni

P. alni DeGeer (Homopt. Callaphididae) vit sur Alnus glutinosa Gaertner pendant toute l'année. L'aulne étant un arbre fixant l'azote, cette étude a été entreprise pour examiner la croissance et la reproduction de ce puceron sur cet arbre afin d'expliquer les changements de la dynamique de sa population. 6 générations successives estivales ont été élevées dans la nature et en température constante au laboratoire. La qualité de l'aliment a été mesurée chaque semaine par une microkjeldahl analyse des concentrations foliaires en azote soluble. La qualité de l'aliment varie saisonnière, mais ne diminue que de 23%; elle semble n'avoir que peu d'effets sur le puceron, puisque la fécondité dans la nature n'est réduite que pendant une génération. Quand la température est maintenue constante, il n'y a pas de différences entre les performances des différentes générations de pucerons. Ainsi, les changements saisonniers dans la croissance et la reproduction des pucerons sont provoqués par la température et non par la qualité de l'aliment.
Insecticidal properties of Lactarius fuliginosus and Lactarius fumosus
Authors: Dowd Patrick F. , Miller Orson K.
Published: April 2011

Acetone and ether: acetone extracts of the mushrooms Lactarius fuliginosus (Fr. ex Fr.) Fr., L. fumosus fumosus Peck and L. fumosus. fumosoides (Smith and Hesler) Smith and Hesler were toxic to the corn earworm, Heliothis zea (L.), while water extracts were inactive. Ether: acetone extracts of L. fuliginosus and L. fumosus fumosus were toxic to the large milkweed bug, Oncopeltus fasciatus (L.), and in some cases caused precocious development. Profiles of compounds separated chromatographic ally and visualized with chromene reagents, literature reports of chromenes from L. fuliginosus, and known insecticidal/anti‐hormone effects of chromenes suggest that chromenes may be responsible for the activity of some of the extracts.

Propriétés insecticides de Lactarius fuliginosus et L. fumosus

L'activité insecticide d'extraits solubles du champignon européen L. fuliginosus Fr. et des espèces américaines étroitement apparentées L. fumosus var. fumosus Peck et L. fumosus var. fumosoides Smith & Hesler a été examinée. Les extraits à l'acétone et à l'éther: acétone des 3 champignons ont été toxiques pour Heliothis zea L., mais non les extraits aqueux. Les extraits éther: acétone de L. fuliginosus et de L. fumosus var. Fumosus ont été toxiques pour Oncopeltus fasciatus F. et ont induit dans quelques cas une métamorphose précoce. Les métabolites secondaires étaient presque aussi semblables entre L. fumosus var. fumosus et L. fumosus var. fumosoides qu'entre ces 2 variétés et L. fuliginosus. Les chromènes peuvent être responsables d'une partie de l'activité biologique contre les insectes.
The influence of clone and morph on the parameters of intrinsic rate of increase in the cereal aphids Sitobion avenae and Rhopalosiphum padi
Authors: Simon J. C. , Dedryver C. A. , Pierre J. S. , Tanguy Sylvie , Wegorek P.
Published: April 2011

This study aimed at evaluating the influence of intrinsic factors (clone, morph) on the parameters of the intrinsic rate of increase of Sitobion avenae (F.) and Rhopalosiphum padi (L.). For each species, apterous and alate exules of three clones originating from French oceanic regions were compared at 20 °C.

The clonal factor had a significant effect on both time from birth until onset of reproduction (TBR) and intrinsic rate of increase (r). This effect was lower than that of the morph. Moreover, in the case of R. padi, a strong clone‐morph interaction was observed.

Both apterous and alate morphs were shown to have a higher rate of increase in R. padi than in S. avenae.

Various models were fitted to aphid daily rate of reproduction. Both types of model and quality of fit depended mainly on the morph.

Les effets du clone et du morphe sur les paramètres du taux d'accroissement de deux espèces de pucerons des céréales, Sitobion avenae et Rhopalosiphum padi

Cette étude a cu pour but d'évaluer l'importance de facteurs intrinsèques (clone et morphe) sur les paramètres du taux d'accroissement de Sitobion avenae (F.) et Rhopalosiphum padi (L.).

Pour chaque espèce, trois clones originaires de regions océaniques françaises ont été comparés à 20 °C pour les morphes exules ailés et exules aptères.

L'effet du clone est significatif sur l'âge reproducteur (durée comprise entre la naissance du puceron et le début de sa phase de reproduction) et sur le taux intrinsèque d'accroissement naturel. Il est plus faible que celui du morphe avec lequel il intéragit dans le cas de R. padi.

Les différences interspécifiques relevées mettent en evidence les capacités d'accroissement supérieures de R. padi par rapport à celles de S. avenae, dans le cas des ailés comme dans celui des aptères.

Enfin, différents modèles ont été appliqués aux données de reproduction journalière des pucerons. Le type et la qualité des ajustements varient essentiellement en fonction du morphe.
Hydroxamic acids affecting barley yellow dwarf virus transmission by the aphid Rhopalosiphum padi
Authors: Givovich A. , Niemeyer H. M.
Published: April 2011

2,4‐Dihydroxy‐7‐methoxy‐1,4‐benzoxazin‐3‐one (DIMBOA), a hydroxamic acid (Hx) occurring in wheat, was shown to deter feeding by the aphid Rhopalosiphum padi (L.), and to reduce BYDV transmission to the plant. Dual choice tests with wheat leaves showed the preferential settlement of aphids on leaves with lower levels of DIMBOA. Electric monitoring of aphid feeding behaviour showed that in seedlings with higher DIMBOA levels fewer aphids reached the phloem and they needed longer times to contact a phloem vessel than in those with lower levels. When aphids carrying BYDV were allowed to feed on wheat cultivars with different DIMBOA levels, fewer plants were infected with BYDV in the higher DIMBOA cultivars than in the lower ones. Preliminary field experiments showed a tendency for wheat cultivars with higher Hx levels to be more tolerant to infection by BYDV than lower Hx level ones.
Behavioral changes and growth inhibition in last instar larvae of Heliothis zea induced by oral and topical application of precocene II
Authors: Binder B. F. , Bowers W. S.
Published: April 2011

In diet choice tests, newly‐ecdysed fifth instar Heliothis zea larvae randomly chose diet containing 4 mM precocene II or diet without precocene II but initially preferred to feed on diet without precocene II. After two days, however, they were found more frequently on diet containing precocene II. Nevertheless, larval growth and development were inhibited when forced to eat diet containing precocene II. Removal of the maxillae, the site of the primary gustatory receptors, did not prevent the growth inhibition caused by larval consumption of diet with precocene II. Topical treatments with precocene II also caused larval growth inhibition, and daily treatments were more detrimental to the larvae than a large single dose. Addition of methylenedioxyprecocene (6,7‐methylenedioxy‐2,2‐dimethylchromene) to the diet did not reverse the observed larval growth inhibition and this compound was itself significantly toxic. These results indicate that larval growth and development are disrupted after precocene II ingestion, but not because of preingestive discrimination by olfaction and gustation.
Egg allocation of the autoparasitoid Encarsia tricolor at different relative densities of the primary host (Trialeurodes vaporariorum) and two secondary hosts (Encarsia formosa and E. tricolor)
Authors: Avilla J. , Anadón J. , Sarasúa M. J. , Albajes R.
Published: April 2011

Parasitism, offspring sex ratio and superparasitism of the facultative autoparasitoid Encarsia tricolor Foërster (Hymenoptera: Aphelinidae) when given access to arenae with different proportions of the primary host (Trialeurodes vaporariorum (Westwood)) and two species of secondary hosts (E. tricolor and Encarsia formosa Gahan) were studied.

Parasitism and offspring sex ratio were not affected by female age in the range 3–10 days old. When the secondary hosts were young E. tricolor pupae, eggs were mostly laid on primary hosts, so the offspring sex ratio was more female‐biased than expected, and secondary hosts were not superparasitized at all. When the secondary hosts were fully grown E. formosa larvae, superparasitism was small and offspring sex ratio was more male‐biased than expected.

E. tricolor females were able to discriminate between hosts previously parasitized by themselves and non‐parasitized hosts.
Host finding in the pine weevil Hylobius abietis: effects of conifer volatiles and added limonene
Authors: Nordlander G.
Published: April 2011

The attraction of Hylobius abietis (L.) (Coleoptera: Curculionidae) to α‐pinene was recently shown to be inhibited by limonene. This study shows that added limonene also affects the response of H. abietis to odours from natural host material. The experiments included both pieces of Scots pine suspended in pitfall traps and planted pine seedlings that had either been manually wounded or left intact. By adding a limonene dispenser, the catch of pine weevils in pine‐baited traps was reduced by about 80–90% in spring and autumn and by about 40–50% in summer. Limonene substantially reduced the rate at which manually wounded seedlings were attacked by weevils in spring and autumn. For intact seedlings, a limonene‐induced reduction in attack rate was found only in autumn. In the absence of limonene, a small wound made on the stem of a seedling increased its probability of being attacked by about fivefold. This figure was estimated by comparing data from all experimental periods with a model assuming a constant ratio of attack rates for the two kinds of seedlings.
Effects of temperature on acaricidal and insecticidal activities of the benzoylureas flucycloxuron and diflubenzuron
Authors: Grosscurt A. C. , Wixley R. A. J.
Published: April 2011

Effects of temperature on the activity of flucycloxuron on larval stages of Panonychus ulmi (Koch), based on LC50 values, were highly significant (P < 0.001) with temperature coefficients of −1.7 in both the ranges of 15° to 25 °C and 20° to 30 °C. The slopes of probit regression lines at 15° and 20 °C were significantly steeper than those at 25° and 30 °C. As a consequence the temperature coefficients based on LC90 values were −4.4 and −2.2, for the 2 temperature ranges. The ovicidal activity of flucycloxuron on P. ulmi was low and was only statistically detectable at 20 °C (LC90 of 84 mg a.i./l). In studies with larvae of Aedes aegypti (Linnaeus), Leptinotarsa decemlineata (Say), Plutella xylostella (Linnaeus), Spodoptera exigua (Hübner) and Spodoptera littoralis (Boisduval) probit regression lines were parallel over temperature. The activity of flucycloxuron on these five insect species was not affected by temperature. Based on LC50 values, diflubenzuron showed positive temperature coefficients on P. xylostella of +2.1 at 15° to 25 °C and +2.5 at 20° to 30 °C. For S. littoralis the temperature coefficient was positive (+2.4) at 15° to 25 °C but negative (−1.9) at the 20° to 30 °C range. Temperature coefficients of diflubenzuron were neutral for A. aegypti, L. decemlineata and S. exigua. In the design and analysis of these studies special allowance was made for date effects and variation in natural mortality over temperature.
Effect of larval age and dosage of nuclear polyhedrosis virus on the susceptibility of diamondback moth, Plutella xylostella
Authors: Padmavathamma K. , Veeresh G. K.
Published: April 2011

A laboratory experiment was conducted to study the efficacy of nuclear polyhedrosis virus (NPV) with nine concentrations against all stadia of Plutella xylostella (L). The susceptibility of the larvae was correlated negatively with the period of development of the larvae and positively with the virus concentrations. The highest mortality of 84% was recorded in first stadium larvae compared to lowest mortality of 38% in fourth stadium larvae. The LC50 was 5.5 × 101 and 4.0 × 104 polyhedral inclusion bodies (PIB)/ml for first and fourth stadium larvae, respectively.
The effect of groundcover and herbicide treatment on twospotted spider mite density and dispersal in southern Oregon pear orchards
Authors: Flexner J. L. , Westigard P. H. , Gonzalves P. , Hilton R.
Published: April 2011

A total of 49 groundcover plant species representing 47 genera in 22 families were identified from a survey of 5 pear orchards. Density of twospotted spider mite (Tetranychus urticae Koch) inhabiting these plants was estimated visually several times during the field season. Plants were ranked in 1 of 3 categories depending on mite densities found on these plants during the summer. T. urticae was found to be highly abundant (category 3) on 26 species, at lower densities on 10 species (category 2), and was rarely or never found on the remaining 12 species (category 1). Dispersal of mites from groundcover plants into trees was found to be highly variable within and between orchards. Within orchard dispersal appeared to be related to the distribution and abundance of category 3 host plants in the orchard. Variability between orchards may also be affected by groundcover management techniques and levels of acaricide resistance in T. urticae. The use of herbicides to control groundcover plants significantly increased the dispersal of T. urticae into the orchard trees.
Effect of physiological state and fungal inoculation on chemically modulated host‐plant finding by Carpophilus hemipterus and Carpophilus lugubris
Authors: Blackmer J. L. , Phelan P. L.
Published: April 2011

Host orientation by Carpophilus hemipterus L. and Carpophilus lugubris Murray (Coleoptera: Nitidulidae) was investigated in a horizontal wind tunnel to ascertain if these species differ in their response to aseptic and fungal‐inoculated hosts, and also to determine how age, nutritional status, diel period, and locomotory opportunity affect these behavioral responses. Both species responded to food odors beginning on Day 3 of adult life by walking upwind to the source; flight activity and flights to the odor source began for C. hemipterus on Day 4, but C. lugubris continued to walk to the source and rarely flew regardless of age. Both species displayed maximum response to food odors from 6 to 9 days after emergence and showed bimodality in host orientation during the photophase. C. hemipterus maintained with artificial diet took flight as frequently as when maintained with water only, as long as they were deprived of diet for 36 h before the test; however, after takeoff, beetles maintained with diet were less likely to fly to food odor in comparison to beetles maintained with water. C. lugubris maintained with diet until 36 h before the test displayed a reduction in walks upwind to sources of food odor compared to beetles maintained with water. Three hours of unrestricted locomotion under a high‐pressure sodium lamp did not enhance upwind orientation to host odors by C. hemipterus maintained with diet or water, or by C. lugubris maintained with water; however, such preexposure to a sodium lamp resulted in reduced takeoffs in C. hemipterus maintained with artificial diet. Both species were attracted to all fruit and vegetable substrates offered; however, aseptic substrates were less attractive than were substrates inoculated with Saccharomyces cerevisiae Hansen or Candida krusei (Castellani) Berkhout for C. lugubris. Despite the broad host range exhibited by these two nitidulid species, each responded to chemical cues from long‐range (2.5 m), a trait once assigned to specialists.
Fecundity and egg fertility in the adult Colorado beetle (Leptinotarsa decemlineata) surviving larval infection by the fungus Beauveria bassiana
Authors: Fargues J. , Delmas J.‐C. , Augé J. , Lebrun R. A.
Published: April 2011

Secondary effects of the entomopathogenic hyphomycete Beauveria bassiana (Bals.) Vuill. were investigated on adults of Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae) treated as newly moulted 4th‐instar larvae. Fecundity and egg hatching were monitored in surviving females mated with surviving males. When reared at 22 °C, adult survivors showed a lessening of their reproductive potential during their whole life. According to the fungal inoculum dosage, the reductions of the total number of eggs laid per female and the mean number of eggs per egg mass ranged from 20% to 56% and from 18% to 46%, respectively. In contrast, at 25 °C, the fecundity of survivors was not affected by the fungal infection. This variability of the secondary effects of B. bassiana according to temperature conditions might be related to the lower infection level of treated larvae at 25 °C. Moreover, at both temperatures, eggs laid by females surviving fungal infection as larvae were as fertile as eggs laid by control insects. It is concluded that secondary effects of B. bassiana on the fecundity of the Colorado Potato Beetle are temperature‐dependent and that they could become negligible at high temperatures under field conditions.

Fécondité et fertilité du dorvphore (Leptinotarsa decemlineata) contaminé par l'hyphomycète Beauveria bassiana au 4ème stade larvaire

Les effets secondaires de l'hyphomycète entomopathogène, Beauveria bassiana (Bals.) Vuill. sur la fécondité et la fertilité des insectes survivant à l'infection fongique ont été étudiés chez les adultes du doryphore Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae) issus de larves contaminées en début de 4ème stade. Les insectes maintenus à 22 °C ont présenté une réduction de leur potentiel reproductif. Ainsi, suivant la dose d'inoculum fongique, le nombre total d'oeufs pondus par femelle et le nombre moyen d'oeufs par ooplaque ont baissé de 20% à 56% et de 18% à 46%, respectivement. En revanche, à 25 °C la fécondité des adultes survivants n'a pas été affectée par la maladie. Cette variabilité en fonction des conditions thermiques peut être liée à la diminution de l'effet‐dose du champignon sur les larves à 25 °C par rapport à 22 °C. Par ailleurs, quelles que soient les conditions thermiques (22 °C ou 25 °C) on ne constate aucun changement significatif de la fertilité des oeufs pondus par les femelles survivantes. Les auteurs concluent que les effets secondaires de B. bassiana sur la fécondité du doryphore dépendent des conditions thermiques et qu'ils pourraient devenir n6gligeables à des températures é1evées en plein champ.
Effects of potassium levels over the range occurring in host plants on the growth of an insect herbivore (Manduca sexto)
Authors: Wulfson L. S. , Stamp N. E.
Published: April 2011

Third instar tobacco hornworms (Manduca sexta L.: Sphingidae) on low dietary potassium had a lower relative growth rate than individuals on diets with potassium concentrations reflecting those in host‐plants, due to decreased consumption rate, lower efficiencies of conversion of ingested and digested food (ECI and ECD), and a prolonged growth/feeding phase. Furthermore, these larvae, when placed on a diet with a moderate potassium concentration through the fourth stadium, ended up being smaller due to lower ECI and less biomass gained, and had a prolonged growth phase, which suggest an irreversible cost of the previous low potassium diet. Third instar hornworms on high potassium diets had lower ECI and ECD, and they had a prolonged growth phase. These individuals, when placed on a moderate potassium diet in the fourth stadium, gained less biomass, than those previously offered hostplant‐like‐potassium diets. Body potassium concentrations (% dw) at the end of the third stadium were similar among treatment groups. With increasing potassium concentrations in the diet, utilization efficiencies of potassium decreased and potassium concentrations in the frass increased. Correspondingly, water content (% fw) of the newly‐molted fourth instar larvae declined with increasing potassium, indicating a passive loss of water during potassium excretion. Low and high dietary potassium reduced survivorship of third instar larvae; fourth instar caterpillars previously fed the low potassium diet also had poor survivorship. We conclude that, within the normal range of potassium concentrations in the hostplants, caterpillar performance is largely unaffected by potassium concentration, but that potassium‐poor and potassium‐rich diets, such as those hornworms may sometimes experience, can reduce growth and survivorship.
Effects of protease inhibitors and dietary protein level on the black field cricket Teleogryllus commodus
Authors: Burgess E. P. J. , Stevens P. S. , Keen G. K. , Laing W. A. , Christeller J. T.
Published: April 2011

Growth and survival responses were determined for black field crickets Teleogryllus commodus (Walker) (Orthoptera: Gryllidae) on artificial diets containing a range of levels of dietary protein, and protease inhibitors (PI's) at 0.33% (weight volume, w:v). The effect on cricket gut enzyme activities of adding PI's to a high protein diet was measured. All PI's which had in vitro binding activity against either trypsin or elastase (the two major cricket gut endopeptidases) reduced growth, but those which bound to both enzymes had the greatest effect. None of the PI's acted as a source of nutritional protein. Cricket growth rate increased with the addition of casein up to 3% w:v, but not with a similar addition of wheatgerm. The impact of PI's on growth was greatest on a 1.5% casein diet. On a high protein (3% casein) diet, the gut activity of trypsin was increased by potato proteinase inhibitors 1 and 2 while the activity of elastase and leucine amino peptidase were increased by soybean trypsin inhibitor and potato proteinase inhibitor 2. Increasing dietary casein up to 3.3% improved cricket survival. The potential of PI's as plant resistance factors against crickets was confirmed.
Exploitation of food resources by the cockroach Blattella germanica in an urban habitat
Authors: Rivault C. , Cloarec A.
Published: April 2011

The exploitation of food resources by the German cockroach, Blattella germanica (L.) (Dictyoptera: Blattellidae) was investigated experimentally in relation to distance from shelters and depletion of neighbouring food patches. In addition, the dynamics of exploitation of a patch were analysed. Observations were made after dark in a public swimming baths building and each one lasted 3 h. Food patches were placed in rows, at different distances from the shelters. The number of cockroaches in food dishes, in a 20 cm diameter circle round each food dish and in a 60 cm diameter circle round this first circle were recorded.

Food items nearest the shelters were exploited first. Exploitation of row 2 and of row 3 food items started later, after row 1 food patches had been depleted. Under these conditions, the moment a food patch was exploited was related to its distance from shelter. Exploitation of food patches occurred in a step‐by‐step manner, one patch attracting animals when a nearby patch had been depleted, and not following a model of ideal free distribution.

Although our experimental food patches were exploited in relation to their distance from shelter, we were able to demonstrate that distance did not influence the dynamics of exploitation of a food item. The mean number of cockroaches on a food patch, whatever its spatial position, increased regularly, reached a maximum at t = −10 min, and then decreased rapidly after all the food had been completely consumed, at t = 0 min. The mean number of animals in the 20 cm diameter circle round a food source peaked at t = 0 min, then decreased rapidly. This area appeared to be a transit area. The mean number of animals in a 60 cm diameter circle round the food source peaked later, and then decreased slowly. Animals remained in this area longer than in the area closer to the food dish, but their presence there was concomitant with the depletion of the food box.
Monitoring populations of the almond seed wasp, Eurytoma amygdali, with sex pheromone traps and other means, and optimal timing of chemical control
Authors: Katsoyannos B. I. , Kouloussis N. A. , Bassiliou A.
Published: April 2011

During the four years 1986–1989 we monitored an adult male population of the almond seed wasp, Eurytoma amygdali Enderlein, in the region of Thessaloniki, using sex pheromone traps, each containing 25 living virgin females. The emergence of adults from infested almonds of the previous year was also monitored in cages in the field, as well as the progress of fruit infestation and egg hatching in the almonds of the Retsou variety. Finally, two chemical control experiments were done against the newly hatched larvae to determine the optimal time for chemical control.

During the 4‐year study the start of adult captures occurred between April 13 and April 24, and the maximum between April 17 and May 11. In most cases, adult emergence from infested almonds in field cages began with a delay of 2 to 14 days in relation to the start of trap captures, and was affected by factors such as the date of cage installation. In all years most eggs hatched within 12–18 days of oviposition.

A treatment with phosphamidon at a concentration of 0.06%, applied to tree branches of the Retsou variety with a hand‐sprayer on May 23, 1987, when 54.1% of the eggs had hatched, was very effective (final infestation in July was 4.7% as compared to 89.1% of the untreated control). Three treatments with phosphamidon 0.06%, applied each on different tree branches, on May 14, 20, and 25, 1988, when the percentage of egg hatching was 7.8%, 65.3%, and 93.5%, respectively, were all very effective (final infestation in July was 1.6%, 3,6%, and 4.2% respectively, as compared to 93,6% of the untreated control). However, the presence of mines in the perisperm and outer endosperm, caused by the feeding larvae before they were killed, was more conspicuous in the almonds treated when the percentage of egg hatching was high.

Our data suggest that the almond seed wasp can be effectively controlled with a single treatment of a systemic insecticide against the newly hatched larvae, preferably applied when the percentage of egg hatching is low to medium (between 10%, and 50%). In the area of Thessaloniki, during 1986–89, 10% and 50% of egg hatching occurred about 21 and 27 days respectively after the beginning of male adult captures in pheromone traps.
Spider orb web as bioassay for pesticide side effects
Authors: Samu F. , Vollrath F.
Published: April 2011

Pesticides may affect the predatory and reproductive behaviour of beneficial arthropods short of having direct effects on their survival. We present a bioassay designed to test (ultimately in the field) such hidden effects of agrochemicals in their application concentrations. As a paradigm we chose the web‐building behaviour of the cross spider Araneus diadematus Clerck (Araneidea, Argiopidae) and we selected four commonly used pesticides: Oleo Rustica 11E (mild insecticide), Fastac (pyrethroid insecticide), Bayfidan and Sportak (fungicides). Neither fungicides nor the mild insecticide seem to affect web‐building behaviour significantly, whereas the pyrethroid insecticide suppressed web‐building frequency and severely affected web size and building accuracy.
Diapause induction in the codling moth, Cydia pomonella: effect of prediapause temperatures
Authors: Steinberg S. , Podoler H. , Applebaum S. W.
Published: April 2011

The effect of four prediapause temperatures (18, 22, 26 and 30 °C) on the photoperiodic response of the codling moth, Cydia pomonella (L.), was studied under controlled conditions. The highest rates of diapause were recorded, for all day‐lengths, at temperatures of 22 and 26 °C while relatively lower rates of diapause were elicited at 18 and 30 °C. The same trend was demonstrated by projecting the values of the critical photoperiod which induces 50% diapause (= CPhP50) over the prediapause temperature. The change in diapause incidence as a function of photoperiod, at all prediapause temperatures, exhibited a response characteristic of long‐day insects, i.e. high rates of diapause at short days (12–13.5 h) and a decrease in diapause incidence at long days (14–15 h). The results for temperatures 22, 26 and 30 °C support the view that lower prediapause temperatures enhance diapause induction, at a given photoperiod, while higher temperatures tend to avert or diminish the process. On the other hand, the low rates of diapause obtained at 18 °C contradict this view. Nevertheless, high correlation was found between the laboratory evidence and field data, indicating the adaptability of the Israeli codling moth to subtropical climate.
Can polyphagous predators control the bird cherry‐oat aphid (Rhopalosiphum padi) in spring cereals?: A simulation study
Authors: Ekbom B. S. , Wiktelius S. , Chiverton P. A.
Published: April 2011

Predation by two carabid species, Bembidion lampros (Herbst.) and Pterostichus cupreus L., on the cereal aphid, Rhopalsiphum padi L., was described using a discrete event simulation model. The results were incorporated into an aphid population growth model. The aphid model was run using actual temperatures, R. padi emigration rates, field densities and distributions from three years with distinctly different aphid population levels. Predation was incorporated at different time periods. Predation during the arrival of emigrants and establishment of aphid populations had approximately the same effect as predation over the entire aphid period, whereas predation during the 20 days prior to peak had very little effect on resulting peak populations. We conclude that a) yearly levels of R. padi infestation are mainly determined by the volume and intensity of emigrants; b) peak levels are sensitive to changes in predator density; and c) in some cases an outbreak of R. padi may be prevented by the action of spring active polyphagous predators alone.