摘要:

Pauesiasp., a parasite of the black pine aphid,Cinara cronartiiTissot&Pepper, which is indigenous in pines in the United States, was collected from aphids in the United States and released in aphid-infested pine plantations in South Africa during the winter of 1983. By spring the parasite had dispersed up to 15 km from a release site in a commercial plantation near Barberton. Seven weeks after release in a small plantation at Buffelspoort, parasitized aphids had spread throughout the plantation (1 ha). For the remainder of the aphid season, mummies continued to be seen in every part of the plot, were present in most aphid colonies, and every sample of live aphids contained some parasites. Later, the aphid population collapsed, andPauesiasp. could have been the cause. A few parasitized aphids were found in the following autumn among the rare oversummering aphids. indicating thatPauesiasp. have survived the summer and become established in South Africa. Five coccinellids, two syrphids, and four ant species were associated with the aphid especially in young stands.

ISSN:0046-225X    

DOI:10.1093/ee/14.5.597

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Distributional loci forCeratitis capitata(Wiedemann) were mapped for all major islands in Hawaii. Generally, loci were located in or near leeward dry areas at both high and low elevations. Fruit utilization varied by locality as well as by host species. Host fruit utilization byC. capitataexceeded that ofDacus dorsalisHendel in certain areas; in others, the situation was reversed. In some areas these two species appeared to coexist in apparent harmony; in others,C. capitatawas displaced by D.dorsalis.

ISSN:0046-225X    

DOI:10.1093/ee/14.5.602

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Diapausing prepupae of the sunflower moth,Homoeosoma electellum(Hulst), did not survive>7 consecutive days at −5°C in the laboratory. However, chilling diapausing prepupae in darkness at 0°C for up to 14 days resulted in significantly quicker pupal development and a greater survival than either chilling them for a longer period of time in darkness or holding them at a higher temperature or longer photophase. Prepupae survived winter field conditions at Bushland, Tex., to pupate successfully and produce emerging adults. Mean initial emergence for 1981–1983 occurred on Julian day 137, compared with a predicted mean initial emergence on Julian day 134 ± 12 based on 7 years of soil temperature data and a developmental threshold of 15.24°C. Computation of degree-day accumulations from soil temperature data from a depth of 10 cm from 51 locations throughout the Great Plains enabled development of a simple model for predicting mean initial emergence of the sunflower moth in areas where it survives. Data from independent field studies on sunflower moth overwintering closely fit the predictions of our model for the southern Great Plains.

ISSN:0046-225X    

DOI:10.1093/ee/14.5.607

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

The resistant soybean,Glycine max(L.), genotype PI 227687, and the susceptible cultivar ‘Davis’ were evaluated for their effects on development ofCopidosoma truncatellum(Dalman) and its host,Pseudoplusia includens(Walker). Parasitized and nonparasitized larvae were fed either ‘Davis’ (susceptible cultivar) or PI 227687 (resistant genotype). ParasitizedP. includensfed ‘Davis’ consumed 40.7% more leaf area than nonparasitized larvae fed ‘Davis’. ParasitizedP. includenslarvae fed PI 227687 consumed 46.4% more leaf area than nonparasitized larvae on the resistant genotype. Feeding period of parasitized larvalP. includenswas 2 days longer than that of nonparasitized larvae. One-day-old pupal weights of nonparasitizedP. includensfed PI 227687 were significantly lower than for those fed ‘Davis’. ParasitizedP. includensfed ‘Davis’ had significantly greater 1-day-old mummy weights than those fed PI 227687. There was no significant difference in number of parasitoids emerging from host mummies between treatments. Pupation period ofC. truncatellumwas significantly longer for parasitoids that developed inP. includensfed PI 227687 than for those from larvae fed ‘Davis’. There was no significant difference in time required for pupation ofP. includenson either host plant. Overall mortality of nonparasitizedP. includensfed ‘Davis’ was 10%, and nonparasitizedP. includensfed PI 227687 had an overall mortality of 70%. ParasitizedP. includensfed both soybean genotypes experienced 100% mortality. Even though the number of parasitoids able to develop per host is not significantly altered, the high mortality of host larvae before pupation ofC. truncatellummay adversely affect population levels of this parasitoid in fields of resistant soybean.

ISSN:0046-225X    

DOI:10.1093/ee/14.5.612

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Crude extracts of five plant species which in previous experiments significantly limited corn wireworm,Melanotus communisGyllenhal, feeding damage were tested for deterrence of the southern corn rootworm,Diabrotica undecimpunctata howardiBarber. When offered extract-treated and untreated corn seeds, rootworms damaged significantly fewer treated seeds than untreated seeds with four of the extracts. In a “no-choice” test design, with the three most effective extracts, there was a significantly lower frequency of damage to treated baits compared to control baits.

ISSN:0046-225X    

DOI:10.1093/ee/14.5.617

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

A dilution-plate method for assaying viableBeauveria bassianapropagules in alfalfa field soil was used to determine fungal inoculum density.B. bassianaeffect on adult populations ofSitona hispiduluswas also investigated by determining the incidence of the fungus in field populations of adults and by exposing adults to known concentrations ofB. bassianain field soil. The 95% CL of inoculum density was between 1,790 and 3,103 colonies per gram of dry soil. The number of infected adults was<10% and did not increase with levels as high as 106conidia per gram of dry soil.

ISSN:0046-225X    

DOI:10.1093/ee/14.5.620

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Sunflower species (Helianthus) were evaluated for resistance to a stem weevil,Cylindrocopturus adspersus(LeConte). In greenhouse tests, foliar feeding byC. adspersusadults was significantly less in 11 of 18 annual and in 13 of 34 perennial species tested than in commercial hybrid ‘894’. The number ofC. adspersuslarvae recovered was significantly lower in eight annual and all perennial species than in hybrid 894. Significantly fewer larvae ofC. adspersusoccurred in 27 perennial species ofHelianthusin the field during 3 consecutive years (1981–1983) than occurred in nearby wildH. annuusL. or hybrid 894. However, the number ofC. adspersuslarvae found in F1progeny of interspecific crosses between the wild species and cultivated hybrid parental lines in the field was equivalent to the number of larvae found in the cultivated parents.

ISSN:0046-225X    

DOI:10.1093/ee/14.5.624

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Influence of temperature on development and mortality of immature stages ofRhinocyllus conicusFroelich was investigated under different constant temperatures in the laboratory. Development time functions based on the parabola were used to model the data. Because the larvae develop within musk thistle (Carduus thoermeriWeinmann) heads, developmental times of the larvae were measured indirectly. Determination of the four larval stages ofR. conicuswas based on distribution of head-capsule sizes of field-collected larvae. Hatching threshold was 11°C and threshold temperatures for development were 16–20°C for the different larval and pupal stages. This temperature range may be an adaptation ofR. conicusfor synchronization with musk thistle. Highest mortalities for immature stages ofR. conicusoccurred in the first and fourth instars.

ISSN:0046-225X    

DOI:10.1093/ee/14.5.629

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

The wheat curl mite,Eriophyes tulipae(Kifer), and the maize weevil,Sitophilus zeamais(Motschulsky), were evaluated as potential vectors ofAspergillus flavusLink ex Fries for use in the screening of maize (Zea maysL.) cultivars for genetic resistance toA. flavus. The mite did not effectively vectorA. flavusspores into the kernel. The maize weevil (dusted withA. flavusspores), however, can be an effective vector of this pathogen in areas such as Missouri where natural levels of infection are erratic.

ISSN:0046-225X    

DOI:10.1093/ee/14.5.634

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Effects of constant temperatures and thermoperiods on larval and pupal development and survival were investigated in the tufted apple bud moth,Platynota idaeusalis(Walker). Development and survival were either the same, decreased, or increased under thermoperiods as compared to mean temperatures depending upon the temperature regime tested. Development and survival at 12-h fluctuating temperatures between 20 and 33°C were the same as mean constant temperatures of 24 and 27°C. Fluctuating temperatures with thermophases>33°C decreased development time and survival as compared to thermophases ≤33°C. Cool fluctuating temperatures increased development rate and survival relative to mean constant low temperatures of 13 and 18°C and they also permitted development and survival to occur at thermal levels below the lower development threshold as calculated by constant temperatures.

ISSN:0046-225X    

DOI:10.1093/ee/14.5.637

出版商:Oxford University Press    

年代:1985

数据来源: OUP