摘要:

A total of 528 samples totaling 37,639 house fly and 11,447 stable fly pupae were collected from 34 confined bovine feedlots and dairies in eastern Nebraska and examined for pteromalid parasites. Parasitism averaged 14.2% for house flies and 7.9% for stable flies. Levels of parasitism were consistent from feedlot to feedlot but were higher on the dairies. Seven parasite species were identified:Muscidifuraxspp. made up 56%,Spalangia cameroni11%,S. nigroaenea31%,S. nigra1%, and others 1% of the 5,881 parasites attacking house flies;Muscidifuraxspp. made up 25%,S. cameroni26%,S. nigroaenea44%,S. nigra4%, and others 1% of the 979 parasites attacking stable flies.Muscidifuraxspp. were recovered significantly (P= 0.01) more often from house flies, andS. nigrawere recovered significantly (P= 0.01) more often from stable flies. Parasite activity was initially observed during the first week in June and increased to a mean of 20.9% during October. The activity and the species of parasites attacking fly pupae were influenced by the habitat in which the hosts were found

ISSN:0046-225X    

DOI:10.1093/ee/12.2.567

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Populations ofMisumenopswere studied in two southern Arizona cotton fields during 1979 and 1980. Spiders were found to be a major component of the general predators (44.2 to 57.6%), andMisumenops celer(Hentz) represented from 45.1 to 75.5% of the spiders collected on a seasonal basis. In general, populations increased steadily through the season unless interrupted by insecticide application. The importance of surrounding vegetation in maintaining populations ofMisumenopsis discussed

ISSN:0046-225X    

DOI:10.1093/ee/12.2.572

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

A small population of the sunflower leafcutting bee,Eumegachile (Sayapis) pugnata(Say), was managed to determine its efficacy as a sunflower pollinator and to evaluate its potential as a “domesticated” pollinator. Artificial wooden nesting sites were made available for the population obtained from adjacent forest and range lands the previous year. After release, both females and males visited and effectively pollinated most hybrid cultivars tested. Characteristics that were found favorable to its management were: bees would nest gregariously; overwintering populations could be stored, incubated, and released in synchrony with sunflower bloom; bees could be obtained by trapping wild populations; and populations could be transported from field to field during the nest provisioning stage. Immature mortality factors were analyzed, and potential predators, parasites, and diseases were identified.

ISSN:0046-225X    

DOI:10.1093/ee/12.2.576

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Tobacco budworm,Heliothis virescens(F.), growth rates showed a significant interaction between diet and temperature. Larvae and pupae that were reared on artificial diet were heavier than those reared on soybean and cotton, with corresponding weights being less at 20°C than at 25 and 30°C. Larvae fed soybean or cotton required seven instars to complete larval development; seven instars were required on artificial diet only at 20°C. Larval survival was 24% (20°C), 34% (25°C), and 17% (30°C) higher on soybean than on cotton. The prepupal and pupal periods were longest at 20°C and shortest at 30°C, but only the pupal period was influenced by larval diet (development shorter on soybean than on cotton at 20 and 30°C). Pupal weight for insects fed soybean increased as temperature increased, but this relationship was reversed for insects fed cotton. Preoviposition period was not significantly influenced by either diet or temperature. More eggs were laid by females at 20°C than at 25 and 30°C, with larger numbers of eggs laid by females reared on cotton than on soybean or artificial diet. Diet did not affect longevity of moths or viability of eggs, whereas increased temperatures from 20 to 30°C decreased longevity of moths and egg hatchability

ISSN:0046-225X    

DOI:10.1093/ee/12.2.582

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Outbreaks of the Douglas-fir tussock moth,Orgyia pseudotsugata(McDunnough), have recurred periodically since 1953 on the Eldorado National Forest in California. The most recent population increase (1974–1978) culminated below an outbreak density, and the number of insects declined again without causing tree defoliation. Details of this culmination and decline were recorded in life tables for the 1978 and 1979 generations. Life processes and mortalities in each life stage were evaluated by k factor analysis for their effects on intergeneration change. The most important factor affecting change was the disappearance of larvae, which accounted for 63% of the total generation mortality. Parasitization of larvae, pupae, and eggs was responsible for 29% and predation of pupae and eggs accounted for 9% of the total. Much of the larval disappearance appeared to be caused by predators, especially arboreal arthropods which commonly preyed on early instars. Although other factors were also involved, these predators apparently played a significant regulatory role by suppressing population buildup in time to prevent serious defoliation.

ISSN:0046-225X    

DOI:10.1093/ee/12.2.587

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Temporal changes in spatial distribution patterns of aphids infesting winter strawberries in coastal California were determined using Green's Coefficient, Cx, Iwao's regression of mean crowding on the mean, and Lloyd's “Patchiness Index.” Both C, and the Patchiness Index indicated the aphids were initially overdispersed, but became random as populations increased. Distribution remained random following population collapse, suggesting that density-independent mortality factors suppressed populations. Iwao's regression method provided analogous results when populations were temporarily stratified

ISSN:0046-225X    

DOI:10.1093/ee/12.2.595

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

NeitherApanteles melanoscelus(Ratzeburg) norCompsilura concinnata(Meigen) females discriminated against gypsy moth larvae parasitized by variously aged individuals of the other species. In host larvae parasitized by both species, neither parasite consistently destroyed the other, and both parasites emerged from about 11% of the hosts. Dissections did not reveal any obvious instances of physical attack or physiological suppression of one species by the other, and parasite developmental rates appeared to be the same in multiple-parasitized hosts as in single-parasitized ones. The study suggests that these two parasites are tolerant of each other when in the same host and that probably no direct intrinsic competition occurs between them

ISSN:0046-225X    

DOI:10.1093/ee/12.2.599

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

In a growth chamber test,Lysiphlebus testaceipes(Cresson) was used to parasitize biotypes C and E of the greenbug,Schizaphis graminum(Rondani), on two selections of oats. One oat cultivar, ‘C.I. 4888,’ was resistant to the greenbug, whereas the other, ‘Nora,’ was susceptible to all known greenbug biotypes in the great plains. Even though the plant resistance had no significant effect on the fecundity of the parasitoid, the test proved that the recent greenbug biotype change had not reduced the effectiveness ofL. testaceipes, and that plant resistance and biological control could be compatible components in pest management of the greenbug

ISSN:0046-225X    

DOI:10.1093/ee/12.2.603

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

The thermoinactivation ofAmyeloiscalicivirus (ACV) was tested with samples incubated at 40 and 45°C for 2 to 8 h, 50°C for 0.25 to 6 h, and 55°C for 1 to 60 min. Larval thermal resistance was investigated at constant temperatures of 30, 32, and 34°C. Comparative potencies of viral samples after heat treatment were estimated from dose-mortality assays and from measurements of larval weight and length as an indication of the relative intensity of larval stunting caused by chronic infection. There was no significant (P>0.05) change in viral activity at 40°C, but a sharp decline was noted after 6 h at 45°C. Similarly, viral activity was almost completely lost after 1 h at 50°C. There was a lag phase during the first 10 min at 55°C, but then activity declined rapidly to reach minimal value after about 45 min incubation. Thermal resistance of larvae was strongly evident at 34°C and virus-treated larvae were not significantly different (P>0.05) from untreated controls. In some respects, the thermal responses of ACV were similar to those reported for infectious f1acherie virus of the silkworm and the pathogenic nonoccluded virus of the citrus red mite

ISSN:0046-225X    

DOI:10.1093/ee/12.2.605

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Correction. In the article “Two-Stage Cluster Sampling for Pine Tip Moths” by Paul M. Gargiullo, C. Wayne Berisford, and Leon V. Pienaar, which appeared in the February 1983 issue ofEnviron. Entomol.a printer's error resulted in the following equations being incorrect.

ISSN:0046-225X    

DOI:10.1093/ee/12.2.610a

出版商:Oxford University Press    

年代:1983

数据来源: OUP