bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of synthetic sex pheromone for management of diamondback moth, Plutella xylostella, in cabbage
Authors: Schroeder P.C. , Shelton A.M. , Ferguson C.S. , Hoffmann M.P. , Petzoldt C.H. 
Published: October 2003

AbstractOver a 2‐year period field trials were conducted to assess the potential to disrupt mating ofPlutella xylostella (L.) using a commercial rope formulation of a 70:30 mixture of (Z)‐11‐hexadecenal and (Z)‐11‐hexadecenyl acetate, two components of the sex pheromone of the female. Screened field cages were placed into blocks of cabbage which were either treated with the pheromone or left untreated. Different densities of P. xylostella pupae were placed into each cage and then larval and pupal counts were made of the subsequent generation. In addition, sentinel females at mating stations were placed in each cage to assess the influence of the pheromone on the ability of males to locate and mate with females. Likewise, we used pheromone traps to assess whether the pheromone treatment influenced the ability of males to locate a pheromone source. In both years larval and pupal populations, produced as a result of the original inoculation, did not differ between pheromone‐treated and untreated fields. The effect of pheromone treatment on larval and pupal numbers did not change with changes in inoculated P. xylostella density, however, the density of P. xylostella released caused significant differences in the density of the subsequent generation. No significant differences were detected between the number of sentinel female adult P. xylostella that successfully mated in pheromone‐treated fields compared with untreated fields. Significant differences in the numbers of male P. xylostella caught in pheromone‐baited traps occurred between pheromone‐treated and untreated fields in the first trial of 1993, and in the first trial in 1994 but not in the second trial. Such differences are often thought of as indications of mating disruption, although our other data presented in this study and reports from other studies indicate this is not always the case. Previous studies on mating disruption of P. xylostella in larger scale field tests have been performed but the results have been variable and often ambiguous. Overall, our results indicate that mating disruption of P. xylostella with the present technology does not appear to work even under the very controlled situations which we utilized to eliminate insect movement between plots.
Synergism of imidacloprid and entomopathogenic nematodes against white grubs: the mechanism
Authors: Koppenhöfer Albrecht M. , Grewal Parwinder S. , Kaya Harry K. 
Published: October 2003

AbstractEntomopathogenic nematodes and the chloronicotinyl insecticide, imidacloprid, interact synergistically on the mortality of third‐instar white grubs (Coleoptera: Scarabaeidae). The degree of interaction, however, varies with nematode species, being synergistic for Steinernema glaseri (Steiner) and Heterorhabditis bacteriophora Poinar, but only additive for Steinernema kushidai Mamiya. The mechanism of the interaction between imidacloprid and these three entomopathogenic nematodes was studied in the laboratory. In vials with soil and grass, mortality, speed of kill, and nematode establishment were negatively affected by imidacloprid with S. kushidai but positively affected with S. glaseri and H. bacteriophora. In all other experiments, imidacloprid had a similar effect for all three nematode species on various factors important for the successful nematode infection in white grubs. Nematode attraction to grubs was not affected by imidacloprid treatment of the grubs. Establishment of intra‐hemocoelically injected nematodes was always higher in imidacloprid‐treated grubs but the differences were small and in most cases not significant. The major factor responsible for synergistic interactions between imidacloprid and entomopathogenic nematodes appears to be the general disruption of normal nerve function due to imidacloprid resulting in drastically reduced activity of the grubs. This sluggishness facilitates host attachment of infective juvenile nematodes. Grooming and evasive behavior in response to nematode attack was also reduced in imidacloprid‐treated grubs. The degree to which different white grub species responded to entomopathogenic nematode attack varied considerably. Untreated Popillia japonica Newman (Coleoptera: Scarabaeidae) grubs were the most responsive to nematode attack among the species tested. Untreated Cyclocephala borealis Arrow (Coleoptera: Scarabaeidae) grubs showed a weaker grooming and no evasion response, and untreated C. hirta LeConte (Coleoptera: Scarabaeidae) grubs showed no significant response. Chewing/biting behavior was significantly increased in the presence of nematodes in untreated P. japonica and C. borealis but not in C. hirta and imidacloprid‐treated P. japonica and C. borealis. Our observations, however, did not provide an explanation for the lack of synergism between imidacloprid and S. kushidai.
Surface films as mosquito larvicides: partitioning the mode of action
Authors: Corbet Sarah A. , Tiley Catherine , Moorhouse Tom , Giam Colin , Pursglove Stephanie , Raby Joanne , Rich Merynne 
Published: October 2003

AbstractOils and other surface films used against mosquito larvae may act by flooding the tracheal system with oil, by disrupting the surface forces that allow larvae to rest at the surface, by toxicity, or by eliciting chemosensory responses. In an attempt to identify diagnostic symptoms of these modes of action we treated fourth‐stage larvae of Culex pipiens L. form molestus Forskål (Diptera: Culicidae: Culicinae) with agents operating in a single mode (Ondina oil for flooding with oil, nicotine for toxicity, and the detergent Triton X‐100 for disruption of surface forces), in two modes (silicone oil) or in three (eucalyptus oil, citronellal, or caproic acid ethyl ester). We monitored the time course of flooding and immobilisation, used experiments to separate volatile toxicity from toxicity of the aqueous solution, and used video and The Observer software to analyse larval behaviour.Larvae that experienced tracheal flooding applied their mouthparts to the siphon (tail nibbling), often losing contact with the surface while doing so and falling to the bottom. Nicotine immobilised larvae without interfering with surface forces, and the larvae remained immobile hanging from the air‐water interface for long periods. In detergent, larvae made repeated unsuccessful attempts to thrust the siphon through the surface. The behaviour‐modifying chemicals caproic acid ethyl ester, eucalyptus oil and citronellal all operated in more than one mode. They all decreased the proportion of time larvae spent at the surface, whereas Ondina oil and silicone fluid increased it.Using this approach it should be possible to identify the modes of action of novel larvicidal agents. This could form a basis for rational design of larvicides giving an optimal compromise between efficacy against mosquito larvae and minimal damage to non‐target organisms.
Ability of a generalist insect, Schistocerca gregaria, to overcome thioglucoside defense in desert plants: tolerance or adaptation?
Authors: Mainguet A.M. , Louveaux A. , El Sayed G. , Rollin P. 
Published: October 2003

AbstractDesert locusts, Schistocerca gregaria (Forskål) (Orthoptera, Acrididae), are generalist herbivores that, in the Sahara desert, may at times feed only on Schouwia purpurea (Forskål) (Brassicaceae), that is 10 times richer in thioglucosides than currently observed in other crucifers (>100 μmoles/g d.w.). Thioglucosides, when ingested, release products that are usually toxic to generalist insects.We studied the short‐term (8 days) and long‐term (21–26 days) consequences of a Schouwia‐only diet on the digestion of these insects. The response was compared to the effects of a diet of Brassica oleracea, a crucifer well consumed in laboratory rearing conditions (7 μmoles/g glucosinolates d.w.).We found that the production of a myrosinase was induced in the midgut as early as 8 days following exposure to glucosinolates. No negative short‐term effects were observed on the growth of the insect, but the activity of β‐glucosidases decreased in the midgut. The long‐term exposure to the Schouwia diet affected activities of β‐glucosidases and β‐galactosidases, growth and assimilation efficiency. The limited adaptation of the desert locust to plant glucosides is compensated by an ability to tolerate high concentrations of allelochemicals for a short period.
Change in response of Rhopalosiphum padi spring migrants to the repellent winter host component methyl salicylate
Authors: Glinwood Robert T. , Pettersson Jan 
Published: October 2003

AbstractOlfactometry showed that the response of spring migrants of the bird cherry‐oat aphid, Rhopalosiphum padi (L.) (Homoptera: Aphididae), to the repellent winter host volatile methyl salicylate changes with age of the adult aphid. Between three and four days after becoming adult, and having left the winter host Prunus padus L., aphids lost their negative response to the chemical. The change in response was not associated with contact with a summer host, oats. In a settling choice bioassay, migrants avoided oats which had been exposed to volatile methyl salicylate. Aphids with removed antennal tips did not avoid the exposed plant, indicating that plant choice was influenced by cues from the plant surface. The results are discussed in relation to the use of methyl salicylate in integrated control.
Inheritance of resistance against biotype 2 of the Asian rice gall midge, Orseolia oryzae
Authors: Pani J. , Sahu S.C. 
Published: October 2003

AbstractThe inheritance of resistance in the rice cultivars Phalguna, ARC5984, ARC 5158, Veluthacheera, and T1477 to the Asian rice gall midge biotype 2 was studied under both natural and artificial infestation conditions against the susceptible cultivars Jaya and IR20. A single recessive gene in Veluthacheera and two recessive complementary genes in T1477 control resistance. Phalguna and ARC5984 possess a single dominant gene while ARC5158 has a single dominant and a single recessive gene for resistance. Allelism studies showed that genes for resistance in Veluthacheera and T1477 are allelic but non‐allelic to the resistance genes in Phalguna and ARC5984, which are allelic to each other. Genes for resistance in ARC5158 are allelic to resistance genes of the other four donors. There was no cytoplasmic inhibition of resistance by the susceptible parents.
Long‐term effects of soybean protease inhibitors on digestive enzymes, survival and learning abilities of honeybees
Authors: Pham‐Delègue Minh‐Hà , Girard Cécile , Le Métayer Martine , Picard‐Nizou Anne‐Lorraine , Hennequet Christelle , Pons Odile , Jouanin Lise 
Published: October 2003

AbstractWe have investigated the effects of long‐term ingestion of two serine proteinase inhibitors (PIs), the Kunitz Soybean trypsin inhibitor (SBTI) and the Bowman‐Birk inhibitor (BBI) on survival, learning abilities involved in the foraging behaviour, and digestive physiology of the honeybee (Apis mellifera L., Hymenoptera). A threshold‐dose was established, above which adverse effects of long‐term ingestion of the PIs tested are to be expected. The experiments reported herein could be extended to other PIs or gene products used to confer insect resistance, and be part of a general procedure used to assess the innocuousness of transgenic melliferous plants to honeybees.
Feeding behaviour and reproductive biology of Colorado potato beetle adults fed transgenic potatoes expressing the Bacillus thuringiensis Cry3B endotoxin
Authors: Arpaia Salvatore , De Marzo Luigi , Di Leo Grazia M. , Santoro Maria E. , Mennella Giuseppe , van Loon Joop J.A. 
Published: October 2003

AbstractColorado potato beetle (Leptinotarsa decemlineata Say) adult longevity and fecundity were studied on transgenic potato clones expressing a Cry3B endotoxin of Bacillus thuringiensis (Bt). Adult longevity and fitness were studied for the first 3 weeks after emergence. Beetle reproductive biology on highly resistant clones, intermediary resistant clones and control potato plants was monitored by dissecting females after 7–15 days of feeding and also by analysing haemolymph protein content after 3 days of feeding. Feeding behaviour on transgenic plants expressing high toxin concentrations and on control plants was monitored individually for 36 newly emerged adult beetles feeding on leaf disks during the first two meals. Lethal Time50 for adult beetles feeding on transgenic clones as the sole source of food was not significantly shorter than for beetles on control clones reared in a growth chamber. Differences tended to be larger when the experiment was conducted in a greenhouse with a less optimal temperature range (LT50= 9.52 and 10.45 days for two transgenic clones and 13.86 for control). In contrast, female egg production on transgenic plants was almost totally inhibited. Dissection studies indicated that adult males living on high‐level Bt‐expressing transgenic potatoes were still able to mate and produce mobile sperm, but the females were impaired in their reproductive ability since their ovaries were generally not fully developed. An examination of the haemolymph revealed the protein concentration in females living on transgenic plants to be dramatically reduced (≅ 50%), and electrophoresis showed a reduced content of vitellogenin in these samples.Feeding behaviour of adult Colorado potato beetles was not affected by the different food plants; this indicates that transgenic potato plants were readily accepted as host plants by beetles. The effects of these findings on the use of transgenic plants as a means of L. decemlineata control are discussed.
Movement behaviour of the pine weevil Hylobius abietis in relation to soil type: an arena experiment
Authors: Kindvall Oskar , Nordlander Göran , Nordenhem Henrik 
Published: October 2003

AbstractPine weevil, Hylobius abietis (L.) (Coleoptera: Curculionidae), movement behaviour on different substrates was studied in an indoor arena using a video camera and digital image processing technique. We analysed individual variation in movement characteristics, i.e. turning angles, movement directions, and distance moved per unit time on the bare and level arena surface which consisted of mineral soil (sand) and/or humus sections in various spatial configurations. Pine weevils on humus did not turn back when they came to the border with the sand. However, most individuals moved faster on sand than on humus. Thus, the results suggest that interactions between substrate differences and individual movement behaviour may to some extent explain why pine weevils have been observed to feed less frequently on coniferous seedlings planted on mineral soil than on those planted on humus.
Catching Ariadne by her thread: how a parasitoid exploits the herbivore's marking trails to locate its host
Authors: Hoffmeister Thomas S. , Roitberg Bernard D. , Lalonde Robert G. 
Published: October 2003

AbstractChemical signals that can be associated with the presence of a host insect often work as arrestants in close range host location by parasitoids, leading to longer searching times on patches where such signals are present. Our current view of parasitoid host location is that by prolonging the search times in patches, randomly searching parasitoids enhance their chance of detecting host insects. However, prolonged search times are not necessarily the only modification in parasitoid behaviour. In this study, we examine the exploitation of host‐fruit marking pheromone of rose‐hip flies, Rhagoletis basiola Osten‐Sacken (Diptera: Tephritidae) by the specialized egg‐larval parasitoid Halticoptera rosae Burks (Hymenoptera: Pteromalidae). We provide evidence that the instantaneous probability that a host egg will be located by a searching parasitoid wasp differs markedly between pheromone‐marked and unmarked fruits. The arresting response to the marking pheromone, i.e., the prolonged time a wasp is willing to search on marked fruits, can only account for a small fraction of the difference in successful host location on marked and unmarked fruits. We further demonstrate that the time wasps require to locate the host egg is independent of the size of the rose‐hip harbouring the fly egg, and thus is independent of the area the wasp potentially has to search. A comparison of our findings with results of different search algorithms for parasitoid wasps suggests that wasps use the fly's pheromone marking trail as a guide way to the fly's oviposition site and thus the host egg.
The temperature‐dependent duration of development and parasitism of three cereal aphid parasitoids, Aphidius ervi, A. rhopalosiphi, and Praon volucre
Authors: Sigsgaard Lene 
Published: October 2003

AbstractTemperature dependencies were established for the egg‐to‐mummy and mummy‐to‐adult phases, for mummy mortality, and for parasitism of Aphidius ervi Haliday, Aphidius rhopalosiphi De Stefani‐Perez, and Praon volucre (Haliday) (Hymenoptera, Aphidiidae), three parasitoids of Sitobion avenae (Fabricius) (Homoptera, Aphididae), at 8 °C, 12 °C, 16 °C, 20 °C, and 25 °C on winter wheat (cv. Haven). A physiological model described temperature‐dependent development over the full temperature range, whereas a linear model was fitted for data above 8 °C and used to estimate the lower temperature thresholds and day‐degrees (° D) required for development. The thresholds for A. ervi were 2.2 °C for egg‐mummy development and 6.6 °C for mummy‐adult development, those for A. rhopalosiphi were 4.5 °C and 7.2 °C, and those for P. volucre were 3.8 °C and 5.5 °C. The time to develop into mummies and adults differed significantly between the three species: A. ervi development into mummies required an average of 159 ° D, while development into adults took an average of 73 ° D. The corresponding average times required for A. rhopalosiphi and P. volucre to develop mummies were 124° D and 126° D, while their development into adults required an average of 70° D and 150° D, respectively. Mummy mortality was 25–35% at 8 °C and less at the higher temperatures tested, but began to increase again at 25 °C, showing a quadratic relationship between mortality and temperature. Parasitization was very low or, in the case of P. volucre, absent up to 12 °C and thereafter increased with increasing temperature. The relationship between parasitization, recorded as percent aphids mummified, and temperature was linear at the temperatures tested and depended on species. A. ervi superparasitized 11.1% aphids at 20 °C and 16.6% aphids at 25 °C, whereas superparasitism was low in A. rhopalosiphi and absent in P. volucre. From 16 °C to 25 °C the P. volucre sex ratio increased. For A. ervi and A. rhopalosiphi there was no trend with temperature, but at 20 °C and 25 °C it was close to even. Field data for 1996 and 1997 allowed for a comparison of actual and expected emergence of overwintering mummies. In both years, parasitoids were predicted to have emerged from overwintering mummies well in advance of the onset of aphid infestation, and more than a month earlier than the first parasitized aphids were found in winter wheat. Observations from trap plants in other crops supported the predictions of the models. Other factors that can affect biological control by cereal aphid parasitoids are discussed.
Serratia marcescens as a rapid indicator of Microctonus hyperodae oviposition activity in Listronotus maculicollis and potential application of the technique to host‐specificity testing
Authors: McNeill Mark R. , Vittum Patricia J. , Jackson Trevor A. 
Published: October 2003

Abstract Listronotus maculicollis (Dietz) (Coleoptera: Curculionidae) is a potential novel host of the braconid parasitoid Microctonus hyperodae Loan, but initial studies have shown that levels of parasitism are lower than in the natural host L. bonariensis (Kuschel). A novel bacterial indicator test was used to determine whether the lower level of parasitism was due to behavioural factors, lack of oviposition, or host resistance. The incidence of ovipositor penetration by the parasitoid M. hyperodae into adult L. maculicollis was measured by immersing the ovipositor of the parasitoid in the facultative pathogen, Serratia marcescens Bizio. Adult weevils were then exposed to parasitoids for up to 72 h and rapid mortality used as an indicator of oviposition penetration. Survival was assessed after six days and surviving weevils were dissected and examined for parasitoid larvae. Mortality among L. maculicolis exposed to parasitoids treated with S. marcescens was significantly higher (P<0.001) than the controls but significantly lower (P<0.001) than in the natural host, L. bonariensis. Dissection of weevils exposed to uncontaminated parasitoids revealed that parasitism in L. maculicolis was significantly (P<0.001) less than parasitism in L. bonariensis. Serratia marcescens‐induced mortality plus parasitism of surviving weevils in the parasitoid plus bacteria treatments produced a similar overall effect. Application of bacteria to the parasitoid ovipositor provided a rapid, simple test for ovipositor penetration, which shows potential for separation of behavioural and physiological defence mechanisms in parasitoid/host range studies.
Toxicity of insecticides to obliquebanded leafroller, Choristoneura rosaceana, larvae and adults exposed previously to neem seed oil
Authors: Lowery D. Thomas , Smirle Michael J. 
Published: October 2003

AbstractAdult and sixth instar obliquebanded leafroller, Choristoneura rosaceana (Harris), exposed previously as fifth instar larvae to sub‐lethal concentrations of neem, Azadirachta indica A. Juss., seed oil contained in artificial diet were more susceptible to topically applied pyrethroid, carbamate and organophosphate insecticides than C. rosaceana reared on control diets. Increased susceptibility to insecticides did not result from reduced vigour, as measured by reductions in adult or larval weights, but is instead correlated with previously demonstrated reductions in detoxication enzyme activities. The modest increases in susceptibilities, not exceeding ca. 4.5‐fold, for C. rosaceana exposed to neem were achieved with subjects from a susceptible laboratory colony; a larger response could be expected for resistant field populations having elevated detoxication enzyme levels. Neem‐based insecticides could be useful tools for the management of orchard pests that have developed resistance to synthetic neurotoxins. These findings also contribute to a better understanding of the numerous physiological changes that occur in larval Lepidoptera following exposure to neem extracts.