摘要:

Days to adult emergence of overwintering apple blotch leafminers,Phyllonorycter crataegella(Clemens), and one of its primary parasitoids,Sympiesis marylandensisGirault, are presented for a series of six constant temperatures between 4 and 30°C. Models for the distributed development based upon the means of individual development rates and their associated variances were constructed and validated with field data from Massachusetts. The difference in emergence between apple blotch leafminer adults and female parasitoid adults is depicted by computer mapping of a “biological window.”

ISSN:0046-225X    

DOI:10.1093/ee/14.3.305

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

The spatial distribution of the bird cherry-oat aphidRhopalosiphum padiin spring cereals was analyzed using the negative binomial commonk, Taylor's power law, and Iwao's regression technique. A commonkcould not be fitted to all data because of the large range in densities. Taylor's method was chosen instead of Iwao's because of problems with interpretation of the results. Using Taylor's regression coefficients, sequential count and sampling decision plans were developed. Their uses in the field for forecasting and monitoring for economic thresholds are discussed.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.312

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Discharge ofEntomophthora muscaeconidia from cadavers ofMusca domesticaL. was studied in the laboratory at 20, 50, and 80% RH. Primary conidial discharge began within 5 h postmortem (HPM), reached its highest intensity 10 to 12 HPM, and had essentially ceased by 24 HPM. Secondary conidial discharge began within 3 h after primary conidial discharge (HPD), reached its highest intensity ca. 6 HPD, and had essentially ceased by 12 HPD. Primary conidial discharge intensity was greatest at 50% RH, followed by 80 and 20% RH. Mean time and duration of primary conidial production were shorter at 20% RH than at 50 or 80% RH. Cadaver weight was correlated with primary conidial production. Females produced larger numbers of conidia, but production was the same for males and females when adjusted for weight differences. Of primary conidia discharged onto glass slides, ca. 31% later discharged secondary conidia that adhered to a slide placed 3 mm above. A few tertiary conidia were observed at 80% RH.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.317

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Natural Douglas-fir tussock moth,Orgyia pseudotsugata(McDunnough), egg masses, or laboratory-produced egg masses that were placed in the field, were used to determine the activity of egg parasites.Telenomus californicusAshmead is the dominant egg parasite throughout the range of the tussock moth in the United States. Percentage of eggs parasitized varied substantially, from 0 to 65%, among 10 study areas in Oregon, California, Idaho, and Arizona. Aggregation of parasite attack as measured by Taylor's power law did not change over the range of parasitization rates observed. Parasitization appeared to be positively related to the outbreak potential of xeric outbreak-prone versus mesic nonoutbreak sites, parasitization being nearly 3-fold as high on the mesic sites as on the xeric sites. We developed a regression equation that relates proportion of egg masses attacked to total parasitization of eggs among masses. The regression provides a rapid, labor-saving way to estimate percentage of parasitized eggs.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.323

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

The rate of development ofCorythucha morrilliOsborn and Drake was measured at seven temperatures on guayule,Parthenium argentatumGray. At 60% RH and 16-h light cycle the time required for development from egg to adult ranged from 34.7 days at 20°C to 17.3 days at 30°C. Little nymphal development occurred at 17.8°C, and no eggs or nymphs developed at temperatures exceeding 34.4°C. Egg and nymphal survival were greatest at the median temperatures.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.329

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Southern pine beetle,Dendroctonus frontalisZimmermann, adults were introduced to 2-m bolts of loblolly,Pinus taedaL., and shortleaf pine,P. echinataMill., to determine the effect of host species on the beetle's reproductive potential. A multivariate analysis of variance test revealed significant differences in parent gallery characteristics between host species. Although the average distance between egg niches was similar in both species, the average parent gallery was almost 90 mm longer in the shortleaf bolts. No statistically significant differences were found in average brood survival or average brood length. However, loblolly pine bolts consistently produced more brood adults. The sex ratio of emerged brood was not significantly different from 1:1 for either host species.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.332

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Hourly counts of stable flies feeding on cattle, and concurrent weather measurements, were used to describe daily feeding patterns and to estimate effects of temperature, radiation, wind, and humidity on feeding responses. Daily feeding patterns in Nebraska were consistently unimodal, with maximum rates occurring at midday. In the prevailing summer conditions, flies appeared to engorge once or less per day, and feeding rates were partially determined by time, regardless of weather. Several methods were developed for estimating daily cumulative feeding rates for unimodal patterns from one or more independent counts of feeding flies. Consideration of time improved precision of estimates by a factor of four. Effects of weather were estimated by a function,H, which expressed feeding rates in proportion to numbers of flies that had not previously fed during the day. Time was always the most important variable and increasedHexponentially. Increasing temperature independently increasedHto a maximum at about 33.2°C, with 10 and 50% of the maximum at 19.7 and 25.8°C, respectively. Increasing radiation and decreasing relative humidity both reduced feeding responses, and because of their correlations with temperature, decreased relative feeding rates at high temperatures and increased them at low temperatures. Wind interacted with radiation and relative humidity so that the more drying combinations of these variables always decreased relative feeding activity.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.336

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Colorado potato beetles were reared under controlled conditions on potato foliage at 12, 15, 20, 24, 28, 30, and 33°C to determine temperature-dependent development and feeding rates. Optimum development occurred at 28°C; it took 20.7 days to go from egg to adult. Maximum daily consumption occurred at 28°C.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.343

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Life table studies were conducted with potato leafhopper,Empoasca fabae(Harris), cohorts at three fluctuating temperature regimes. Combinations of daily low and high temperatures for the three regimes were 13 to 24, 18 to 29, and 23 to 34°C. Estimated temperature threshold for immature (egg plus nymph) development was 8.4°C. Temperature had a marked effect on natality and mortality schedules and on life table statistics of the three cohorts. Gross and net reproductive rates were largest at the regime with lowest temperatures. When computed on a day scale, intrinsic and finite rates of increase were largest, and mean generation time shortest, at the regime with highest temperatures. Values of the latter three life table statistics converged somewhat but not completely when computed on a degree-day (above 8.4°C) scale. This failure to converge was due to substantial differences in age-specific mortality on a degree-day scale among the three cohorts. Compositions of the stable stage distribution were similar for the three cohorts. Computer simulations with a Leslie matrix model suggested that, for potato leafhopper populations that are initiated by reproductive females in a given environment, the realized population growth rate will be similar to the intrinsic rate of increase for that environment, and furthermore that the realized growth rate will not be greatly influenced by large fluctuations in population stage structure.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.349

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Reproduction and colonizing behavior of pea aphids,Acyrthosiphon pisum(Harris), were studied on reproductive arrowleaf clover,Trifolium vesiculosumSavi, using four treatments: healthy, infected with bean yellow mosaic virus (BYMV), infected with aPhytophthorasp. that caused root rot, or infected with both BYMV and thePhytophthorasp. Reproduction of aphids in no-choice experiments was significantly lower on plants in the two treatments with the root rot disease than on healthy or BYMV-infected plants. The highest level of reproduction was observed on healthy plants. Aphid colonization also was lower on fungus-infected plants whether BYMV was present or not. Results of these studies suggest that a complex relationship exists between aphid vectors, virus disease, and fungal root disease in arrow leaf clover. Presence of fungal root rot disease may influence reproduction and movement of alate aphids and epidemiology of aphid-transmitted viruses during both fall and spring periods of alate aphid activity, when plants are in vegetative or reproductive stages, respectively.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.356

出版商:Oxford University Press    

年代:1985

数据来源: OUP