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1.
The reproductive tract of the parasitoidMicroctonus hyperodae was found to comprise 6.1±0.2 ovarioles containing a total of 40–60 oöcytes. After oviposition into its hostListronotus bonariensis, the parasitoid's egg volume increased by 205 times prior to hatching. At 19.1°C ovipositingM. hyperodae survived for a mean 21±4 days and laid a mean of 48±8 eggs.M. hyperodae collected from Colonia, Uruguay laid a mean of 62±15 eggs which was significantly more than the other ecotypes. Under caging conditions with an ample supply of hosts,M. hyperodae laid 51% of its eggs in the first 72 hours and on average 41% of the species' life-span occurred after the exhaustion of its egg supply. Minimum temperature forM. hyperodae oviposition was found to be c. 5°C; beyond this the rate of increase in egg-laying was approximately linear until 30°C whereafter the rate fell abruptly. There was effectively no egg-laying at 39°C. The parasitoid showed no preference for one host sex or the other either in the laboratory or under field conditions. Compared to otherMicroctonus spp.,M. hyperodae appeared to show low fecundity and high longevity. The adaptive implications of this are discussed. 相似文献
2.
The behaviour of the parasitoidMicroctonus hyperodae Loan was studied under quarantine conditions to determine its likely host range in New Zealand. The species was imported
from South America as a potential biological control agent of Argentine stem weevil,Listronotus bonariensis (Kuschel).
The study involved systematic evaluation of the parasitoid's behaviour when exposed to 24 non-host weevil species; all but
three of these were native to New Zealand. Of those tested, four were found to sustain someM. hyperodae development. However, further examination showed that in all but one species,Irenimus aequalis (Broun), parasitoid development was impeded, with up to 50% of the larvae becoming encapsulated. Overall, those weevil species
that were attacked produced only 19% of the parasitoids derived fromL. bonariensis controls.
As an adjunct to this quarantine study, a review of the habitats of the native weevil and target pest populations indicated
that refugia would probably exist for native alpine species.
I. aequalis was not considered to be threatened byM. hyperodae as this weevil has benefited from the advent of European agricultural systems to the extent that it is now recognised as
a minor pest. In view of its relatively oligophagous behaviour, the parasitoid was recommended as suitable for release.
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3.
A predictive phenological model is described for the parasitoid Microctonus hyperodae, introduced to New Zealand as a potential biological control agent against Argentine stem weevil Listronotus bonariensis. The model is based on development/temperature relationships obtained from experiments on the parasitoid in quarantine prior to its release, allowing early predictions of its phenology in different parts of the target pest's New Zealand range. In particular the model was used to predict the number of parasitoid generations each year, the degree of temporal synchrony between parasitoid adults and the susceptible adult pest stage, the order of parasitism and reproduction in the pest's life cycle as a possible basis for a simplified, discrete host/parasitoid population model, and the likely significance of ecotypic differences in development and diapause characteristics of the parasitoid. These applications demonstrate the potential for simple models to help in climate matching of classical biological control agents and estimation of their interaction with pest dynamics, using data obtainable prior to their introduction and release. In addition the model proved useful as a decision aid during the release programme, by indicating the likely effects of unusual weather and the need or otherwise for further parasitoid releases. 相似文献
4.
Microctonus hyperodae is a solitary endoparasitoid of the Argentine stem weevil, Listronotus bonariensis. Early investigation into the biology of the parasitoid indicated that there was no discrimination between parasitized and unparasitized hosts. However, dissection data from two experiments were analyzed according to three mathematical models. Model I was based on the Poisson distribution and assumed random selection of hosts. The host discrimination model (model II) assumed that parasitized hosts had reduced attractiveness to searching parasitoids. A competition model (model III) made the assumption that competition between the early immature parasitoid stages led to premature mortality, which was not accounted for in the dissection results. The dissection data indicated statistically significant departure from the Poisson model. Results from the laboratory experiment indicated that host discrimination explained the results more accurately than parasitoid larval competition. Models II and III both provided adequate fits to the field data, although the departure from the observed data was greatest for the competition model. Both intra- and inter-ecotypic host recognition were evident, and there was some indication that clonal recognition took place. This is the first evidence of host discrimination by a member of the genus Microctonus. It has provided further indication of the success of M. hyperodae as a biological control agent. 相似文献
5.
Guy Boivin 《BioControl》1988,33(2):245-248
A technique for rearingAnaphes sordidatus (Girault) on eggs of laboratory-reared carrot weevil,Listronotus oregonensis (Le Conte), is described. Individual rearing was possible by using polyethylene embedding capsules that enabled easy manipulation
of parasitized carrot weevil eggs for use in subsequent experimental procedures. The technique described resulted in 65% parasitization
of carrot weevil eggs and 90 mn per day were sufficient to obtainca. 200 parasites daily.
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6.
Mark R. McNeill Patricia J. Vittum Trevor A. Jackson 《Entomologia Experimentalis et Applicata》2000,95(2):193-200
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. 相似文献
7.
8.
Rafiq Ahmad 《BioControl》1978,23(2):161-162
Hyperodes bonariensis Kuschel underwent ovarial diapause from March to August in the Bariloche area in Argentina. Feeding on germinating seedlings ofTriticum aestivum L. andPoa annua L. in continuous dark induced the weevil for oviposition in 24 and 32 days, respectively. Breeding techniques are described forH. bonariensis and its parasitePatasson atomarius (Brethes). 相似文献
9.
The South American curculionid Listronotus bonariensis (Kuschel) is an important pest of pastures in New Zealand. Population census data were gathered for L. bonariensis in northern New Zealand pastures during 1980-1983 in the absence of parasitism and again in 1991-1996 after the introduction and establishment of the braconid parasitoid Microctonus hyperodae Loan as a biological control agent. M. hyperodae achieved high rates of parasitism, with 75-90% of overwintering L. bonariensis parasitized within 3 yr of the parasitoid establishing at a site. Multistratum analysis of variance (ANOVA), with allowance for variation in host plant resource (numbers of Neotyphodium-free grass tillers), indicated reduction in the abundance of L. bonariensis life stages in the early part of life cycle. Although providing evidence for suppression of L. bonariensis, these analyses indicated the regulatory role of M. hyperodae was weak because L. bonariensis populations continued to exhibit marked intergenerational variability in abundance. Analyses of life tables indicated larval + pupal survival contributed most to intergenerational changes in abundance, irrespective of presence or absence of M. hyperodae. However, the density dependence of the stage survivals was modified in the presence of the parasitoid, with loss of density-dependent mortality in overwintering adults and increased density dependence in population natality. Regression analyses indicated dual contribution of parasitism and host plant resource to regulation of population natality and population trend in L. bonariensis. We conclude that M. hyperodae is a useful adjunct to host plant resistance in reducing the economic status of L. bonariensis populations in northern New Zealand pastures. 相似文献
10.
Rearing experiments at different temperatures (10, 15, 20, 25 and 30°C) were made onOpius dissitus Muesebeck, a parasitoid ofLiriomyza trifolii (Burgess). Temperatures between 20 and 30°C were optimal for the development ofO. dissitus, which was able to adapt to relatively high temperatures despite its holarctic origin. 相似文献
11.
Fopius (= Biosteres) arisanus (Sonan) (= Opius oophilus Fullaway) is an egg-pupal parasitoid of tephritid fruit flies. Our breakthrough in the development of a laboratory-adapted strain of F. arisanus facilitated insectary rearing of parasitoids in large numbers. First colonized in captivity in 1989, F. arisanus has been reared routinely on the oriental fruit fly, Bactrocera (= Dacus) dorsalis (Hendel), its natural host. Parasitization by F. arisanus results in the latent death of developing hosts. Host mortality data are presented in a life table to estimate cost of parasitization on the economics of F. arisanus mass rearing. Percent kills of 10, 32, and 76% exerted by F. arisanus on the egg, larval, and pupal stages of the rearing hosts, respectively, resulted in a mean parasitoid recovery of 23.6%. The production cost was estimated by integrating life table data with the costs of rearing supplies and materials and personnel-hours requirements. Production of 1 million parasitoid adults requires the exposure of 4.2 million B. dorsalis eggs (= propagation hosts). We estimated the cost of producing 1 million parasitoids to be $2,363.30 and identified the most expensive aspects of F. arisanus rearing. Recommendations for streamlining the rearing process to reduce costs are provided. 相似文献
12.
BioControl - Laboratory studies of competition between populations of 2 parasitoids of the cotton boll weevil,Anthonomus grandis Boheman, showed that populations ofCatolaccus grandis (Burks)... 相似文献
13.
Resumen El desarrollo del bracónidoMeteorus rubens (Nees) se estudió en condiciones de laboratorio sobre las especies de noctuidosAgrotis ipsilon (Hufnagel),A. puta (Hübner),A. segetum (Denis & Schiffermüller),Peridroma saucia (Hübner),Spodoptera littoralis (Boisduval) yAutographa gamma (L.). Las larvas deA. ipsilon yA. puta fueron las únicas adecuadas para el desarrollo del parasitoide. EnA. ipsilon este bracónido parasitó y completó su desarrollo en el tercero, cuarto, quinto y sexto estadios larvarios, mostrando preferencia
por los dos últimos estadios. El número de hembras que parasitan, el porcentaje de larvas parasitadas y el número de parasitoides
emergidos por hospedante estuvo en relación directa con la edad del hospedante en el momento de la parasitación. En las larvas
parasitadas en el tercer estadio el tiempo de desarrollo del parasitoide fue significativamente mayor que en los otros tres
estadios. Sin embargo, el estadio en que fueron parasitadas las larvas no influyó en la longevidad de los adultos.
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14.
Parasitization ofIps grandicollis Eichhoff byRoptrocerus xylophagorum (Ratzeburg), and intra-specific competition withinIps broods, were studied under laboratory conditions. Largest numbers of immatureR. xylophagorum were found in logs sampled when about half theIps brood were callow adults. Rates of parasitization rarely exceeded 20 %, and were usually much lower. Numbers of parasitoids were not affected by bark thickness. In the absence of parasitism,Ips broods suffered a density-dependent mortality which increased greatly in intensity and continued to act later in development of the broods when initial densities of larvae exceeded a threshold of about 400 per 1 000 cm2 of bark. The possible significance of this mortality is discussed in relation to the ability of parasitoids to reduceIps numbers. A field experiment was done to investigate the ability ofR. xylophagorum to establish in a new habitat. Populations were established for 1 or more generations by releasing 50 females at sites prepared by supplying small numbers of logs containing immatureIps. 相似文献
15.
Rearing and release procedures forCotesia melanoscela (Ratzeburg) (Hymenoptera: Braconidae), an early-season parasitoid ofLymantria dispar (L.), were evaluated in 1995 and 1996 at the Beltsville Agricultural Research Center, Beltsville, Maryland, USA. Mass rearing procedures were developed during the winter/spring of 1995/1996 to produce diapausingC. melanoscela cocoons for experimentation. Program efficiency as measured by percent adult emergence was estimated to be 84% with a measured sex ratio of 48:52 M:F, at an estimated cost per 1 000 cocoons of U.S. $5.26 for materials and a labor requirement of approximately 6 hours. A host larvae:female parasitoid ratio of 100:1 was found to be most efficient in terms of number of parasitoid cocoons produced per female parasitoid, but a ratio of 100:2 was most efficient in terms of number of cocoons per rearing cup. OverwinteringC. melanoscela cocoons under natural conditions for 25 weeks (November placements) before expectedL. dispar egg hatch (mid-April) resulted in excellent synchrony with host egg hatch. Alternatively, holdingC. melanoscela cocoons in cold storage for 23 or more weeks at 5°C resulted in adult parasitoid emergence beginning 10 days after removal from cold storage, and proper timing of removal would result in similar synchrony of adult emergence with host egg hatch. These alternative release strategies give managers increased program flexibility. 相似文献
16.
J. P. Aeschlimann 《BioControl》1986,31(2):163-172
Surveys conducted from 1973 to 1984 showed thatAnaphes diana Girault was the predominant parasitoid ofSitona spp. eggs throughout the Mediterranean range of Spain, France, Italy, Greece, Bulgaria, Romania, Turkey and Syria. In each of these countries, the mean percentage parasitism of eggs fluctuated between 1.9 and 23.9%. The impact of the mymarid on its host increased considerably from autumn to spring. Two biotypes ofA. diana, one reproducing bisexually, the other being strictly thelytokous, occur sympatrically in the Mediterranean region. The origin of various consignments ofSitona eggs parasitized byA. diana shipped to Australia for field release of the mymarid is recorded. Egg parasitoids were found in the Damascus area (Syria) that may be adapted to and effective under the hot and dry climatic conditions of South Australia. 相似文献
17.
R. Van Thielen O. Ajuonu V. Schade P. Neuenschwander A. Adité C. J. Lomer 《BioControl》1994,39(2):179-188
Water hyacinth,Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae) was first reported in Bénin in 1977 and about 10 years later became the major floating water weed in the south east, obstructing boat traffic and fisheries. Water hyacinth multiplies in permanently fresh water in the swampy upper reaches of the Sô River and in tributaries of the Ouémé River. From there it is moved by wind and water flow to the coastal lagoons. The coastal lagoons are brackish during the dry season and water hyacinth eventually dies. In 1991,Neochetina eichhorniae (Warner) (Col.: Curculionidae) of South American origin was imported from Australia via quarantine in Britain to Bénin. A small infestation of the fungusBeauveria bassiana (Bals.) Vuill. (Hyphomycetes) was eliminated from the colony before release by sterilizing eggs and rearing a fungus-free generation. Between late 1991 and mid 1993, about 23,900N. eichhorniae were released at 11 localities along the Ouémé River and in the head waters of the Sô River. Regular monitoring revealed feeding scars by adults on leaves and tunnelling by larvae in petioles at all release sites. By October 1993,N. eichhorniae had spread up to 20 km from some release sites.Neochetina bruchi Hustache was imported in 1992. A total of about 5,700 weevils has been released in six localities since mid 1992. Recoveries of offspring were made in all but one locality. Despite the negative impact of water flow, wind, penetration of salt water, and removal of infested water hyacinth by fishermen,N. eichhorniae andN. bruchi are established in Bénin in a situation typical for coastal West Africa. 相似文献
18.
The life history ofSmicronyx guineanus andSm. umbrinus, weevils attackingStriga hermonthica, was studied in Burkina Faso, West Africa. Field experiments were conducted in 1992 and 1993 at Kaya, in fields of sorghum (Sorghum bicolor (L.) Moench and pearl millet (Pennisetum americanum (L.) K. Schum. (syn.P. typhoides (Burm.) Stapf &; Hubb). The weevils are univoltine; the adults emerge in late August, mate and eggs are laid in the ovary ofStriga inflorescence. Larval feeding in the ovary causes galling and prevents seed production. The main damage toStriga seed capsule is caused by the larvae of at least twoSmicronyx species. Last-instar larvae drop to the soil and bury themselves to a depth of 1–15 cm, pupate and enter into dormancy. Most pupae are found in the upper 5–10 cm of the soil. The pupal period lasts from late October to late July. In May, we found 75.6% of pupae against 24.4% of adults in dormancy. 相似文献
19.
A Yugoslavian strain ofCotesia rubecula (Marshall) (Hymenoptera: Braconidae) was released in spring broccoli for control of the imported cabbageworm,Pieris rapae (L.), in Montgomery Co., Virginia, in 1987.C. rubecula reproduced and parasitized imported cabbageworm larvae in fall broccoli in 1987. It was found in moderate numbers in the
summer and fall crops in 1988, and by fall had dispersed 0.8 km from the original release site. However, noC. rubecula were detected in our broccoli plots in Montgomery Country in 1989 or 1990.
The hymenopteran hyperparasitesIsdromas lycaenae (Walker)(Ichneumonidae), Spilochalcis torvina (Cresson) (Chalcididae), andTetrastichus galactopus (Ratzeburg) (Eulophidae) were found attackingC. rubecula. Hyperparasites emerged from 31.8% and 41.1% of theC. rubecula cocoons in 1987 and 1988, respectively.T. galactopus was the most numerous hyperparasite in 1987, butS. torvina was dominant in 1988. Hyperparasite activity was low during early spring, but increased in July in both years. By August
1988, only hyperparasites emerged from theC. rubecula cocoons collected in the field. In spite ofC. rubecula's success in overwintering, hyperparasites, especiallyS. torvina, may be a limiting factor in the establishment ofC. rubecula in southwestern Virginia.
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20.
Encapsulation and development of the endoparasitoid,Microplitis croceipes (Cresson), were studied in six atypical lepidopteran host species whose usual host isHelicoverpa zea (Boddie). The candidate hosts examined were: the fall armywormSpodoptera frugiperda (J. E. Smith); the beet armyworm,Spodoptera exigua (Hübner); the cabbage looper,Trichoplusia ni (Hübner); the greater wax moth,Galleria mellonella (L.); the Indian meal moth,Plodia interpunctella (Hübner); and the diamondback moth,Plutella xylostella (L.). BothS. exigua andT. ni were completely unsuitable forM. croceipes development due to the high rate of eggs that were encapsulated within three days after parasitism. Encapsulation inS. frugiperda included mainly parasitoid eggs and was first detected six days after parasitization at 25°C and two days at 30°C. Encapsulation inG. mellonella occurred only in the larval stage of the parasitoid. InP. interpunctella, parasitoid larvae reached the 3rd stadium, but none of them pupated. OnlyS. frugiperda andG. mellonella supported successful development ofM. croceipes from egg to adult. The percentage of parasitoids reaching the adult stage in these hosts was higher at 30°C than at 25°C (13% vs. 4% inS. frugiperda, and 21% vs. 3% inG. mellonella, respectively). However, these percentages were too low to substitute them as a more economical host for rearingM. croceipes. This biological information will be useful in additional laboratory studies directed toward reducing the rate of encapsulation (e.g., manipulation of host rearing temperature) to increase production ofM. croceipes on these hosts. 相似文献