摘要:

The level of developmental stability ofChrysopa perlaL. (Neuroptera: Chrysopidae) collected from control and contaminated sites in the vicinity of an agrochemical manufacturing facility was assessed using fluctuating asymmetry and phenodeviant analyses. There were no significant differences in the level of asymmetry between control and contaminated sites for four characters. The number of phenodeviants for two characters was significantly greater at sites located in close proximity to the facility compared with a control site. Results are discussed with reference to the relationship between asymmetry and phenodeviants as indicators of stability and the use of developmental stability as a means of assessing environmental quality.

DOI:10.1093/ee/22.6.1362

出版商:Oxford University Press    

年代:1993

数据来源: OUP

摘要:

Factors affecting attraction of the Mexican fruit fly,Anastrepha ludens(Loew), to the odor of a bacterium isolated from the fly, were evaluated in laboratory experiments. The odor was not attractive to newly emerged adults. For sugar-fed, yeast-hydrolysate-deprived flies, attraction to the bacterial odor began when flies were 1d old, peaked when flies were 5–7 d old, then declined steadily as flies aged further. Generally, bacterial odor was attractive to sugar-fed flies and unattractive to sugar-deprived flies. The odor was most attractive to sugar-fed, yeast-hydrolysate-deprived flies but was also highly attractive to flies fed both sugar and yeast hydrolysate. Flies were attracted to bacterial odor during all times of the photophase although attraction was less very early and very late in the photophase than at other times. Flies irradiated with gamma rays were about 20% less responsive to the odor than unirradiated flies.

DOI:10.1093/ee/22.6.1367

出版商:Oxford University Press    

年代:1993

数据来源: OUP

摘要:

Studies were conducted to assess the availability and acceptability of eggs of forest tent caterpillar,Malacosoma disstriaHubner, toTrichogramma minutumRiley for use in inundative releases. Oviposition by the forest tent caterpillar occurred 4–19 July and lasted 7–10 d in southern Ontario. At least 50% of the egg-laying activity occurred during the first 3–4 d. Oviposition was initiated on the same day as female moth emergence, 2 d after male moth emergence. Pheromone traps baited with two-component lures predicted oviposition within 2 d. NoTrichogrammaemerged successfully from 0- to 7-d-old host eggs, although the survival of tent caterpillar embryos exposed at this age to the parasitoids was reduced significantly (from 97.5 to 42.3%). The greatest number ofTrichogrammaemerging from caterpillar egg masses (72.7%)was observed in those eggs exposed to parasitoids 21 d after oviposition, with 43.5 and 12.5% emergence from egg masses exposed at 14 and 28 d after oviposition, respectively. A tent caterpillar egg mass contained 109.8 ± 14.8 (mean ± SE) eggs; parasitoids emerged from 14.4 ± 3.5 of these eggs (13.1% egg parasitism). The number of parasitoids emerging from each parasitized egg ranged from 5.0 to 11.0;69.5% were female and development at 20°C took 14.2 ± 0.2 d. Removal of the spumaline layer from the egg masses increased emergence of parasitoids very slightly. NoTrichogrammasuccessfully overwintered in forest tent caterpillar eggs, although a single dead parasitoid (0.2%)was observed infrequently in eggs simultaneously with a dead pharate larva.Trichogrammapossibly can be used in inundative releases againstM. disstria; however, further studies are needed to determine why the parasitoid kills but does not emerge from tent caterpillar eggs<14 d old.

DOI:10.1093/ee/22.6.1375

出版商:Oxford University Press    

年代:1993

数据来源: OUP

摘要:

Colorado has experienced high levels of Russian wheat aphid,Diuraphis noxia(Kurdjumov), damage and is considered an important site for release of biocontrol agents. In June 1990, field surveys were initiated to provide baseline data on the identity and prevalence of existing aphid pathogens, parasites, and predators. Sampling was conducted in spring-planted grain in irrigated and dry-land fields near Fort Collins and Akron.D. noxiawas the most abundant aphid; populations were high in both irrigated and dry-land fields. Parasite prevalence was low<5%) in all fields.D. noxiawas the most frequently parasitized aphid, and the most common parasite wasDiaeretiella rapae(M'Intosh). Syrphid fly larvae were the only predators consistently found feeding on aphids within theD. noxia–damaged (rolled) leaves. However, syrphid populations were low,<0.3 larvae per aphid-infested tiller. The ineffectiveness of the existing complex of parasites and predators in suppressingD. noxiapopulations underscores the need for introductions of more efficient biocontrol agents. Pathogenic fungi were active in nearly all fields; three species were found. In irrigated fields,Entomophthora chromaphidisBurger&Swain was the most common pathogen during the spring, with peak prevalence of 13% on 22 June.Pandora(=Erynia)neoaphidis(Remaudière&Hennebert) was not detected until late June, but it rapidly reached epizootic levels (44% infection by 18 July). Highest prevalence (20%) ofConidiobolus obscurus(Hall&Dunn) coincided with that ofP. neoaphidis. Prevalence of fungal pathogens in dry-land fields did not exceed 2.5%. The observation of only low levels of entomophthoralean fungal infection in the nonirrigated fields suggests that reliable use of these natural control agents against aphids in the semiarid West will require manipulation of environmental conditions through irrigation.

DOI:10.1093/ee/22.6.1383

出版商:Oxford University Press    

年代:1993

数据来源: OUP

摘要:

Artificial honeydews were applied to alfalfa plots in field experiments during the second (1992) and third (1991 and 1992) crops in northern Utah. Individual plots received a single application of sucrose dissolved in water; protein supplement and water; sucrose, protein supplement, and water; or water alone. Sweep samples were taken for entomophagous arthropods over a period of 4 d (second crop) or 10 d (third crop) after treatment spray applications. Application of sucrose, but not of protein supplement, resulted in reduced densities of aphids (relative to those in plots sprayed with water only). Adult lacewings and lady beetles consistently responded positively to application of sucrose. Lacewings during the second and third crops in 1992 and lady beetles during the third crop in 1991 also responded positively to application of protein supplement, with greatest densities occurring in plots sprayed with both materials. Positive responses to application of sugar by adults of the alfalfa weevil parasitoid,Bathyplectes curculionis(Thomson), and adult hover flies, bigeyed bugs, and minute pirate bugs (but not spiders or adult damsel bugs) were also detected in one or more experiments. None of these groups, however, responded consistently or clearly to application of protein supplement. In the absence of rain, positive responses by particular natural enemies to sugar, protein supplement, or both, persisted for up to 7 d after application. Our experimental results add to those of previous research indicating that local populations of a variety of entomophagous insects, including parasitoids with non-aphid hosts, can be increased in crops by application of artificial honeydew.

DOI:10.1093/ee/22.6.1392

出版商:Oxford University Press    

年代:1993

数据来源: OUP

摘要:

Cassida rubiginosa(Müller) (Coleoptera: Chrysomelidae) adults laid eggs on Canada thistle where they were released, regardless of thistle density. Densities ofC. rubiginosaand plant development varied within a field and between patches of Canada thistle in natural populations. Ramets infected with the rust disease,Puccinia punctiformis(Strauss) Röhl. (Uredinales: Pucciniaceae), were not more attractive than healthy ramets toC. rubiginosa. Ramets systemically infected with the rust disease did not bloom and suffered high mortality.Eucelatoria dimmocki(Aldrich) (Diptera: Tachinidae) andItoplectis conquisitor(Say) (Hymenoptera: Ichneumonidae) parasitizedC. rubiginosalarvae.Spilochalcis side(Walker) (Hymenoptera: Chalcididae) emerged from pupae. No parasitoids were found attacking oothecae.

DOI:10.1093/ee/22.6.1402

出版商:Oxford University Press    

年代:1993

数据来源: OUP

DOI:10.1093/ee/22.6.1408

出版商:Oxford University Press    

年代:1993

数据来源: OUP

DOI:10.1093/ee/22.6.1409

出版商:Oxford University Press    

年代:1993

数据来源: OUP