摘要:

In tests of response of adult apple blotch leafminers,Phyllonorycter crataegella(Clemens), to sticky-coated rectangles of various hues and shades hung in apple trees, captures were consistently greater (though not always significantly so) on red rectangles than on green, orange, blue, yellow, black, gray, white, clear Plexiglas, or aluminum foil-covered rectangles. Captures were greater on horizontal red rectangles (sticky surface up) positioned at 0.5 m height and within 0.5 m of the tree trunk than on red rectangles of other orientations or positions. Such rectangles offer considerable promise for monitoring adult populations of this important apple pest.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.562

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Seventeen entries from 10 crop species including sorghums, small grain cereals, and grasses were evaluated as seedlings to determine or confirm the biotypic status of six isolates of greenbugs,Schizaphts graminum(Rondani). Eight plant entries were rated for damage 20 days postinfestation with 10 first-instar greenbugs, and 13 entries were studied for antibiosis effects on number of days to reproductive maturity, fecundity, and longevity. Four greenbug isolates showed strong biotypic differences. These included biotypes B, C, E, and the Ohio isolate, herewith designated biotype F. Biotype F is nearest to biotype A in terms of plant response, but it differs in its ability to kill ‘Amigo’ wheat,Triticum aestivumL., and in morphology, having no dorsal stripe. Biotype F was also able to kill ‘Reubens’ Canada bluegrass,Poa compressaL., which was highly resistant to the other greenbug isolates tested. The Maryland isolate seemed to be nearest to biotype C in terms of biological and host plant responses although similarities to biotype E also existed. Greatest differences of the Oklahoma isolate included increased longevity on various plants and a higher virulence on ‘Kentucky 31’ tall fescue,Festuca arundinaceaSchreb.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.567

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Bioassay of soil to whichAnticarsia gemmatalisnuclear polyhedrosis virus (NPV) had been applied showed that viral activity was reduced during the summer, but much of the virus remained active. Viral activity in the upper layer of soil was generally greater following tillage, and the level of virus activity on plants was related to the concentration of NPV applied to the soil at planting. Tillage and rainfall resulted in increased mortality of larvae fed leaflets from low on the plant, but not from high on the plant. An epizootic developed in a field experiment only after rainfall.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.573

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

The greenbug,Schizaphis graminum(Rondani), is an important pest of cereal crops, but can be managed through use of resistant crop varieties. Research concerning the nature of resistance and the development of resistant varieties requires careful experimentation, which is often conducted in plant growth chambers. However, significant variation in tests conducted with plants in growth chambers has been reported. Therefore, the objective of this research was to determine suitable experimental designs and optimum sample sizes for greenbug antibiosis tests in plant growth chambers. In our study, a greenbug antibiosis test was conducted in a growth chamber, utilizing a Latin square design to detect possible row-to-row or column-to-column variation. No significant row-to-row or column-to-column variation was found. Thus, simpler designs can be used in our chamber. However, uniformity trials should be conducted in each chamber to determine direction of possible gradients before developing appropriate statistical designs and conducting actual tests. To aid the researcher, a coefficient of variation (CV) table for different combinations of replications and subsamples was developed. In addition, the theoretical number of required replications for a given power of the test at significance levels of 0.01 and 0.05 and detectable percent differences of 5, 10, and 20% was also developed. The CV table and power of the test curves may be used to determine the number of replications required in future tests in chambers of this nature.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.581

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

The parasitic waspEncarsia (=Prospaltella) lahorensis(Howard) was released into citrus whitefly,Dialeurodes citri(Ashmead), populations on gardenia,Gardenia jasminoidesEllis, in Birmingham, Huntsville, and Auburn, Ala. Introductions failed in Birmingham and Huntsville, but the wasp became established in Auburn in residential areas and test plots.D. citripopulations were dramatically reduced after 1 year, and 3 years after release the insect is not a pest in areas whereE. lahorensisis present.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.585

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

House fly,Musca domesticaL., pupae parasitized by three species of pteromalid wasps,Spalangia cameroniPerkins,Urolepis rufipes(Ashmead), andMuscidifurax zaraptorKogan&Legner, were released into house fly and stable fly,Stomoxys calcitrans(L.), breeding habitats on three dairies during the spring season. In conjunction with these releases, freeze-killed house fly pupae were placed in the same areas to serve as hosts for the emerging parasites.S. cameroniandU. rufipesdid not use the freeze-killed pupae as hosts, butM. zaraptorreadily oviposited on and produced progeny from the introduced hosts. Freeze-killed pupae remained suitable as hosts forM. zaraptorfor up to 4 weeks at the cooler spring temperatures. Large numbers of second-generation progeny after 8 weeks suggested that the use of early spring releases ofM. zaraptorand freeze-killed hosts may effectively build up early season populations of this pteromalid species for the control of house flies and stable flies present on midwestern livestock confinements.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.590

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Preparation of almond orchards for harvest by withdrawal of irrigation may result in prolonged periods of water stress. It is during these periods (from July to mid-August) that mite populations often increase and are associated with partial defoliation. The impact of spider mites and water stress, alone and in combination, was investigated on gas exchange and water potential of almond leaves during the 1982 and 1983 growing seasons. The impact of water stress on mite densities was also studied in 1982. In both years, water stress caused highly significant reductions in leaf water potential, whereas mites alone had no measurable impact. In 1982, significantly higher mite eggs and motile stages developed on water-stressed foliage as compared with unstressed foliage. The effect of mites on gas exchange of water-stressed leaves was greater than on unstressed leaves in 1982 as indicated by significant interactions. Significant interactions representing the same trend did not occur in the 1983 trial. When water stress was severe, as in 1983, no additional impact of mites on gas exchange was detected.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.594

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Influences of food source, photoperiod, collection date, and time (hour within the diel cycle and day within the ovipositional period) on egg-laying of the pea leaf weevil,Sitona lineatus(L.), were used to evaluate ovipositional cycles in the laboratory. Ovipositional rhythms have two major divisions: a complete ovipositional rhythm and a diel ovipositional cycle. The complete ovipositional rhythm consisted of three levels: 1) second-degree polynomial curve, 2) 30-day cycle, and 3) daily oscillation and increase in amplitude of the daily oscillation as the ovipositional rhythm progressed. The diel ovipositional cycle was dominated by two general periods: increased oviposition (10 a.m.–9 p.m.) and decreased oviposition (12 p.m.–9 a.m.) with intervening transitional periods. The lack of a dark cycle affected the diel ovipositional cycle by reducing the magnitude of the afternoon peaks and the morning transition period. Type of food did not significantly affect the diel cycle or complete ovipositional rhythm. Melanization ofS. lineatuseggs started ca. 13 h after oviposition and was completed within 17 h at 21°C in constant light. A significantly slower melanization rate was noted for eggs of weevils fed alfalfa foliage than those fed pea foliage.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.601

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Developmental rate, mature weight, number of eyed embryos, and size of the largest embryo of apple aphids,Aphis pomi(De Geer), reared at constant temperatures, were nonlinear functions of temperature, with gradual decline phases above optima that occurred at relatively moderate temperatures. Rearing experiments using paired combinations of high, moderate, and low temperatures demonstrated departures from expected values for these bionomic parameters, calculated by extrapolating results of single temperature rearings. These results suggest unequal responses to temperature by different developmental stages, residual effects, or both, including delayed acclimation and apparent non-reversible injury. Development, weight, and ovarian parameters of fundatrices, oviparae, and males are compared with those of viviparous apterae.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.607

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Parental rearing temperature, rearing nutrition, and morph influenced progeny birth weight and postnatal bionomic processes in the apple aphid,Aphis pomiDe Geer. Parental rearing at high temperature resulted in severely reduced progeny birth weight, postnatal relative growth and developmental rates, number of eyed embryos in the ovaries at maturity, and reproductive rate. Values of these parameters were also reduced by parental rearing at low temperature but less severely. Progeny of apterae reared with poor nutrition and progeny of alatae were also small at birth but partially compensated with greater relative growth. Progeny of alatae developed more slowly than progeny of apterae but had as many eyed embryos at maturity. Progeny of malnourished apterae developed at the same rate as progeny of well-fed apterae but contained fewer eyed embryos. Weight of the largest embryo in the aphid ovary was linearly correlated with aphid weight. A linear relationship was found for number of eyed embryos versus mature weight, but the regression slope was steeper for aphids reared below 10°C than for those reared above. Reproductive rate of apterae reared and kept at 20°C peaked 1 week after maturity, then declined exponentially. During the first 2 weeks, reproductive rate was proportional to number of eyed embryos. Adult aphid weight and embryo weight declined with reproductive age. Apterae reared at high or low temperatures had fewer eyed embryos and lower reproductive rates. Reduction in reproductive rate was greater than reduction in embryo number, and was most severe when aphids reared at low temperatures were transferred to high temperatures for reproduction, or vice versa.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.614

出版商:Oxford University Press    

年代:1986

数据来源: OUP