摘要:

The fungicides benomyl, chlorothalonil, thiabendazole, and fentin hydroxide were applied alone and in combination with methyl parathion or methomyl to soybeans. Larval population levels ofPlathypena scabra(F.),Anticarsia gemmatalis(Hübner), andPseudoplusia includens(Walker) were monitored as well as selected arthropod predators and the incidence of the fungal entomopathogensNomuraea rileyi(Farlow) Samson andEntomophthora gammae(Weiser).Application of fungicides at the recommended rates failed to suppress an epizootic ofE. gammaeinP. includenspopulations. The incidence ofN. rileyiwas suppressed in a low density population ofA. gemmatalis. When larval density increased, no difference was detected in the incidence ofN. rileyiinfection in treated and untreated plots. Differences in predator population levels were not observed in a 1976P. includenstest but generally lower predator populations were noted in the 1977P. includens-A. gemmatalistest in fungicide and/or insecticide treated plots.Fentin hydroxide alone and treatments which included methyl parathion or methomyl reduced larval populations ofP. scabraandA. gemmatalis. Only treatments containing methomyl reduced larval populations ofP. includens. Pseudoplusia includenspopulation resurgence was detected following treatments with benomyl and methyl parathion, chlorothalonil + methyl parathion and fentin hydroxide + methyl parathion.Anticarsia gemmatalispopulation resurgence followed treatment with fentin hydroxide + methomyl.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.823

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

Ground ear corn was fed to an Angus cow in increasing percentages to study the effect of fecal pH, percent fecal moisture, and percent fecal crude protein on larval mortality and pupal weight of the face fly,Musca autumnalisDeGeer. As the percent ground ear corn in the bovine diet increased, the percent mortality of face fly larvae developing in the feces tended to increase, with 100% mortality occurring in the feces after the bovine had consumed 5.448 kg of ground ear corn. Fecal pH fell from 6.92 to 5.58 and percent moisture and percent crude protein varied slightly as the percent ground ear corn in the diet increased.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.829

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

The stability of resistance to the greenbug,Schizaphis graminum(Rondani) (C-biotype), of resistant and susceptible selections of sorghum (Sorghum bicolor(L.) Moench), rye (Secale cerealeL.), barley (Hordeum vulgareL.), and oats (Avena sativaL.) was tested under 3 temperature regimes. Tolerance appeared to influence foliage loss more than antibiosis or nonpreference. Foliage losses and differences between susceptible and resistant selections of cool season grasses (rye, barley, and oats) increased as temperature decreased. In sorghum, foliage loss and susceptible-and-resistant-selection differences increased as temperature increased.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.831

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

A model to evaluate potential reductive impact of populations of green peach aphid,Myzus persicae(Sulzer), by predators was generalized to include effects of temperature on the rate of aphid reproduction and the functional response of the predator complex.Coccinella transversoguttata richardsoniBrown was the most abundant predator in field experiments with large numbers of green peach aphids on sugarbeet plants,Beta vulgaris, L.,Geocoris pallensStål, syrphids, andScymnus marginicollisMannerheim were also abundant. Predators had a major role in determining the abundance of aphids, but their effect was greater at the higher densities because the more voracious species responded preferentially to high aphid populations.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.835

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

Adult face flies exhibit a graded response to the toxicological effects of substituted xanthene dyes and visible light. Relative efficiencies decreased in the order: rose bengal>erythrosin B>phloxin B>eosin yellowish>tetrachlorofluorescein>fluorescein. Face flies are also susceptible to a light-independent toxic reaction caused by rose bengal. The efficiency of this reaction is similar to that observed in house flies and much higher than that observed in imported fire ants and boll weevils.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.843

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

Larval and pupal populations of the spruce budworm,Choristoneura fumiferana(Clemens), were sampled for natural prevalence of fungal pathogens in northern Maine during 1975–77. Three species were isolated and identified:Entomophthora sphaerospermaFresenius,E. egressaMac-Leod and Tyrrell, and a species ofConidiobolusBrefeld. Prevalence of these pathogens was shown to vary with sample location, crown position of the host, host density, host instar, and temperature and relative humidity trends. Lower crown samples yielded significantly higher fungal disease prevalence. Significantly higher disease prevalence was also found in more dense spruce bud worm population samples.E. sphaerospermaoccurred on hosts with a mean between larval instars 5 and 6 (5.79) compared with a mean between the 6th instar and the prepupal stages (6.69) forE. egressa, and a mean between the prepupal and pupal stages (7.10) forConidiobolus sp. Cool, wet periods of weather appeared to enhance disease prevalence. These findings were examined in terms of entomopathogen epizootiology. The lower crown level and higher host population density may provide an environment more amenable to the spread of disease.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.847

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

The technique of mark, release, and recapture was employed to investigate the movement of adults of the black vine weevil,Otiorhynchus sulcatus(F.), in a residential area in Connecticut. Weevils recaptured either 21, 35, or 57 days after release traveled mean distances of 6.8, 17.2, and 31.2 m, respectively. Most were recovered70 m. Movement usually occurred between plants located around the same building or in the same bed. At the time of recapture, most weevils were on or under shrubs planted near the comers of buildings or near the ends of hedges. About 68% of the weevils recovered were associated with the same plant species on which they were released. Possible reasons for dispersal and thus host changes are briefly discussed.Only 5.7% of the total weevils released (n=2323) were recaptured. One factor reducing the % of recovery was predation by the pavement ant,Tetramorium caespitum(L.).

ISSN:0046-225X    

DOI:10.1093/ee/7.6.854

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

The incidence of entomopoxvirus infections in larval midge populations of an undescribed species in theChironomus decoruscomplex from 2 southern California flood-control channels was monitored during 2 successive summers. The population densities and prevalence of disease were inversely related to the rate of water flow at each sampling site. Results from laboratory rearings of field-collected larvae suggested that the impact of the virus on the midge populations was greater than that indicated by infection rates alone and that the virus may play an important role in population regulation. Studies with field collected egg masses suggested that the virus is introduced to the channels by transovum transmission.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.858

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

The seasonal development ofFiorinia externaFerris,Tsugaspidiotus tsugae(Marlatt) (Homoptera: Disaspididae), and their parasite,Aspidiotiphagus citrinus(Craw.) (Hymenoptera: Aphelinidae) on hemlock was studied at two sites in southwestern Connecticut. Descriptions of the parasite life stages developing within each scale and of the host stages attacked are given.AlthoughA. citrinuscompleted 2 generations on both scales during 1977, its seasonal development on each differed considerably in response to the sharply contrasting life histories of univoltineF. externaand bivoltineT. tsugae.Evidence is presented that synchronism between ovipositing adult parasites and suitable life stages of their hosts had an important influence on percent parasitism and on the dynamics of scale populations. OnT. tsugae, where the seasonal abundance of parasite and host were synchronous, percent parasitism and scale population growth remained relatively constant for 3 generations. However, onF. externawhere seasonal abundance of parasite and host were asynchronous, parasitism and population growth fluctuated greatly from generation to generation.Several features of the scale insect community on hemlock which influence the permanency of the parasite-host relationship and the probable success of biological control are discussed.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.863

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

Blood-seekingChrysops atlanticusPech. females begin to respond to a host shortly after sunrise and will remain at a high level of responsiveness until shortly before sunset. Based upon hourly counts, the largest numbers visit the human host shortly after sunrise and shortly before sunset. When counts begin in the afternoon, however, a peak also occurs at 1300 h. The data suggest that destructive sampling methods may bias the results of studies of saltmarsh deer fly biting cycles and lead to misinterpretations of apparent cyclic patterns. One hour past sunrise appears to be the most favorable time for applying insecticidal sprays.

ISSN:0046-225X    

DOI:10.1093/ee/7.6.871

出版商:Oxford University Press    

年代:1978

数据来源: OUP