摘要:

This study sought to assess the impact of an insecticide and a herbicide combination on nontarget arthropods in a cornfield. In each year of the experiment, 1.62 ha was divided into 16 plots. Barren strips of land, 3 m wide, were maintained around all 16 plots. A 4 × 4 Latin square arrangement of the following treatments was used: (1) Furadan; (2) Furadan and a Lasso-Bladex mixture; (3) Lasso-Bladex mixture; and (4) no pesticides. Pitfall traps were placed in the field, each plot containing three traps. All 48 traps were run continuously from early summer to mid-October in 1980 and 1981. Throughout each summer, ground beetles (Coleoptera: Carabidae) and other nontarget arthropods were captured and identified. Furadan had very little effect on number of arthropods trapped in either year of the study. Weedier plots, those not receiving the Lasso-Bladex treatment, had more of certain nontarget arthropods trapped within them. Relative importance values were calculated for each type of arthropod to ascertain if a given species' position, within a community, had been shifted by a pesticide. The relative importance of most of the arthropods did not significantly differ among the four treatments in either year.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1171

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Beaked galls ofMayetiola rigidae(Osten Sacken) occurred on 51 accessions ofSalixspecies, hybrids, and cultivars out of 125 accessions examined at the Beltsville Agricultural Research Center. In some cases, young galls died while the larvae in them were still small, indicating hypersensitivity to midge attack. Larval mortality also occurred in fully grown galls. In these, the tissue lining the larval chamber either darkened and died, or proliferated into the chamber. Larvae in these galls typically developed to the 3rd instar before dying. Susceptibility to midge infestation was most pronounced in accessions ofS. capreaL.,S. cinereaL.,S. muscinaDode, their hybrids, and a few other species, and least in accessions ofS. alba, S. eriocephalaMichx.,S. purpureaL., their hybrids, and a few other species; 74 accessions were not galled. A total of 25 were galled, but larvae failed to complete development, and 26 accessions bore galls from which adults emerged. Form and size of the beaked galls were usually characteristic for eachSalixsp.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1175

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

The distribution and relative abundance of the oriental fruit fly,Dacus dorsalisHendel, were determined in native forests and surrounding areas on Kauai. Generally, relatively low numbers were captured in native forests. Low numbers were trapped at high elevations (>800 m), intermediate numbers at middle elevations (400 to 800 m), and high numbers at low elevations (>400 m). Low populations in areas of native forest appeared to be associated primarily with infestation of (1) strawberry guava,Psidium cattleianumSabine, in nearby middle and upper elevation localities, and (2) common guava,P. guajavaL., in upland and lowland exotic forest areas.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1185

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

The persistence ofBacillus thuringiensisBerliner on second-year loblolly pine cones was determined with laboratory bioassays using second-stageDioryctria amatella(Hulst) larvae. The LC50and LC90values were 1.3 × 102and 1.5 × 104IU/ml of spray immediately afterB. thuringiensisapplication. Activity loss occurred through day 14; however, based on changes in LC50, values, 81, 47, and 14% of original activity remained 4, 7, and 14 days after application, respectively. These values indicated substantial activity loss; however, when mortality produced by the greatestB. thuringiensisrate (7.7 × 104IU/ml) was examined, little reduction in mortality was detected during the first 7 days. A possible explanation for greaterB. thuringiensispersistence on pine cones than previously reported on foliage of other plants may be related to cone structure and site of initial larval feeding.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1190

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Adult European com borer (ECB),Ostrinia nubilalis(Hübner), populations were monitored with three different sampling methods (blacklight trap, dropnet, flush bar) during flights 1 and 2, 1980–1981. There was evidence that rainstorms (1.28 to 2.50 cm) accompanied by moderately violent (30 to 40 km/h) and violent winds (65 to 80 km/h) destroyed much of the aggregated ECB adult populations in a grassy area (action site) during flight 1, 1980. Relatively light precipitation (ca. 0.25 cm) with mild winds (0 to 15 km/h) occurred for periods during the second flight of ECB, 1980, and during the first flight of ECB, 1981. Light (0.03 to 0.25 cm), moderate (0.26 to 1.02 cm), and heavy rains (1.03 to 2.50 cm) fell throughout flight 2, 1981, but were not accompanied by violent winds. During this flight, based on sample data from all three methods, the adult population levels in four action sites were not affected by the rain. We conclude that adult ECB population levels may not be reduced by precipitation alone. But when precipitation is accompanied by violent winds, adult ECB population levels can be greatly reduced.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1193

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Suitability of feeding hosts of the two-banded Japanese weevil,Callirhopalus bifasciatus(Roelofs), was evaluated by comparing fecundity of adults fed different foliar diets in the laboratory. Host plants, arranged in order of increasing suitability (i.e., mean fecundity of weevils), wereKalmia latifoliaL.,Rhododendron maximumL.,Ligustrum vulgareL.,Cornus floridaL., andRosa multifloraThunb. Fecundity was negatively correlated with preoviposition period (i.e., period of ovarian development between adult emergence and initial oviposition) and leaf toughness and was positively correlated with frequency of feeding, reproductive rate, water content of fresh leaves, and N content of dry leaves. Egg laying by weevils on each foliar diet was greater during the first half than the second half of the oviposition period. Decrease in the second half corresponded closely to a reduction in foliar N. Fecundity increased significantly when adult diet was switched fromK. latifolia,R. maximum, orL. vulgaretoR. multifloraduring consecutive 6-day periods and decreased significantly when it was changed fromR. multifloratoK. latifoliaorR. maximum. Measurement of the preoviposition period may be a practical technique for evaluating the suitability of adult feeding hosts.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1197

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Rice varieties having a moderate level of resistance to the brown planthopper,Nilaparvata lugens, were evaluated to determine the mechanisms of resistance. The host plant-insect interactions were studied in the greenhouse and insectary to determine the levels of antibiosis and tolerance in the moderately resistant varieties. Parameters measured as the tolerance indicator were plant damage, plant weight loss, and yield reduction due to insect feeding. The insect biomass production, growth index, and population growth rate on the test varieties were used as antibiosis indicators. A regression of plant weight loss, due toN. lugensfeeding, onN. lugensweight for five varieties indicated that the variety ‘Utri Rajapan’ has a high level of tolerance and no antibiosis. The resistance in ‘IR46,’ ‘Kencana,’ and ‘Triveni’ is due to a combination of antibiosis and tolerance. The relative amount of each of the two resistance components was measured by using the tolerance-antibiosis index. Field studies confirmed results obtained in the greenhouse and insectary studies. Although ‘Utri Rajapan’ had field populations ofN. lugensequal to that of the susceptible check, yield reduction was only 25%, compared with 100% in the susceptible check.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1204

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Developmental rates of the egg of the navel orangeworm,Amyelois transitella(Walker), were determined at various constant temperatures. The lower developmental threshold (12.8°C) and thermal constant were determined by regression analysis of temperature data and corresponding rates of egg development. A mean of 1,332 degree hours (°C) was required for the complete development of the egg. Laboratory and field validations of the temperature threshold for development were conducted.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1215

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Flights and captures of malePlodia interpunctella(Hübner) were observed in a warehouse room containing pheromone traps baited with different doses and blends of (Z,E)-9,12-tetradecadien-1-ol (ZETOH) and (Z,E)-9,12-tetradecadien-1-ol acetate (ZETA). Flights were divided into two categories: preapproach and approach flight, the approach being differentiated from preapproach flight by the simultaneous occurrence of increased frequency and angle of turning, decreased net velocity, and net movement toward a trap. Approaches and captures were analyzed with respect to dose and blend. Alone, ZETOH failed to elicit responses significantly different from the control (zero dose), whereas ZETA elicited approaches and landings in traps. Significantly more landings and approaches occurred with blends of ZETOH:ZETA in a 2:8 ratio than with 4:6 or 6:4 blends, but the ratio of captures to approaches did not vary among blends. The frequency of approaches and captures increased with dose but the ratio of captures to approaches decreased when trap release rates exceeded 10 ng/h. Practical and theoretical implications of the results are discussed.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1218

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Eggs ofCyclocephala immaculataOlivier absorb water from the soil, increasing ca. threefold in weight during the first 10 days of embryonic development. Eggs developed normally at soil moistures of 12.5% and above, but shriveled and died in drier soils. Length of incubation period, survival, and final egg weight did not differ at soil moistures within the range required for survival; however, few eggs were laid in dry soil or when soil moisture approached field capacity. Oviposition in soil moisture gradients indicated that the depth at which eggs are laid can vary in response to moisture levels. The chorion of the egg is covered densely and uniformly by minute tubercles, but specialized hydropyles are absent. The eggs are most susceptible to desiccation when newly laid or close to hatching, but are relatively resistant during the middle stage of development. These differences are associated with changes in the thickness of the serosal cuticle.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1223

出版商:Oxford University Press    

年代:1983

数据来源: OUP