摘要:

Development rates for immature stages of the pales weevil,Hylobius pales(Herbst) (Coleoptera: Curculionidae), were estimated over constant temperatures ranging from 9 to 34°C. Development occurred between 9 and 30°C for eggs and 9 and 32°C for larvae; however, the range of successful development for both prepupae and pupae (21–28°C) was much more narrow. Parameters determined for the biophysical model of Sharpe&DeMichele (1977) could be used to predict development of eggs and larvae, but prepupal and pupal development data were insufficient to permit use of this model. Standard cumulative frequency distributions were determined for each life stage and Weibull functions fitted to these data.

ISSN:1754-5692    

DOI:10.1093/ee/16.4.956

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Effect ofNiesthrea louisianicaSailer on reproduction of velvetleaf,Abutilon theophrastiMedicus, was determined by caging various numbers of the insects on single plants in the field. Number of seeds per plant ranged from 5,129 ± 1,761 with 0 insects to 1,366 ± 1,233 seeds with an original infestation of 100 first instars. A decrease in seed viability was inversely correlated with insect density from 74 ± 19% for the 0-insect treatment to 14 ± 30% for the 100 first-instar treatment.

ISSN:1754-5692    

DOI:10.1093/ee/16.4.963

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

The role of chemicals of sorghum plants in stimulating oviposition by the sorghum shootfly,Atherigona soccataRondani, was investigated using the acetone extract of the susceptible sorghum CSH-1, which elicits high ovipositional response. Maize, not a host plant, treated with acetone extract of CSH-1 elicited as much egg-laying by the sorghum shootfly as did CSH-1. The activity of the extract on maize lasted for the maximum test period of 5 d. Results of these studies demonstrate the potential of the host-plant-produced oviposition stimulants for manipulating the ovipositional behavior of the sorghum shootfly as a strategy for the control of the pest.

ISSN:1754-5692    

DOI:10.1093/ee/16.4.967

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Influence of temperature on oviposition, quiescence, and mortality ofRhinocyllus conicusFroelich, a thistle head weevil, was investigated at different constant temperatures ranging from 15 to 36°C. Mean fecundity varied from a low of 6.6 eggs per female at 15°C to 123.6 eggs per female at 22.5°C. Fecundity was more or less constant in the range 19.5–36°C. Overwintering adults began oviposition in response to increased temperature and presence of musk thistle,Carduus thoermeriWeinmann, buds. These features of oviposition suggest an adaptation ofR. conicusfor synchrony with its weed host, musk thistle. Mortality, measured as cumulative 50% mortality, at the different temperatures was compared between sexes; males had a shorter life span than females, and both sexes had shorter lives at higher temperatures.

ISSN:1754-5692    

DOI:10.1093/ee/16.4.971

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Horizontal and vertical movements of first-instar western corn rootworms,Diabrotica virgifera virgiferaLeConte, were studied in a 30-cm soil chamber filled with silt loam, sandy loam, or sand at various bulk densities. Larvae were released in one end of the chamber with a carbon dioxide (CO2) source present in the far end of the chamber in half of the uncompacted and all of the compacted tests. Horizontal larval distributions were determined after 6 h in uncompacted and 20 h in compacted soils. In all uncompacted soils, larvae became evenly distributed in the absence of CO2within 6 h; in the presence of CO2,>66% of the larvae moved at least 25 cm toward the CO2source. Increases in soil bulk density inhibited larval movement to varying degrees. Vertical distributions were measured after 20 h in uncompacted soil in the absence of the CO2source. Significantly more upward rather than downward movement occurred.

ISSN:1754-5692    

DOI:10.1093/ee/16.4.975

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Allozyme frequency data supported by colonization records and field observations were used to show that the Italian thistle (Carduus pycnocephalusL.) race ofRhinocyllus conicusFroelich recently has transferred to and adopted as new hosts two thistles native to California,Cirsium californicumGray andCirsium proteanumJ. T. Howell. Other races ofR. conicusestablished in California include weevils originating from Europe on the musk thistle (Carduus nutansL.) and milk thistle (Silybum marianum[L.] Gaertner).R. conicusfrom Italian thistles and musk thistles are genetically distinct from the milk thistle race displaying a Rogers' (modified) genetic distance of 0.3 units

ISSN:1754-5692    

DOI:10.1093/ee/16.4.979

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

The effect ofLygus hesperusKnight feeding on Douglas-fir seedlings was measured in seedlings representing two elevation zones, for each of two seed zones, for each of two seedling age classes in a forest nursery during 1984. Damage frequency and height reduction both indicated significant effects of seed source. Examination of seedling distance from the nursery's west boundary with an alfalfa field (a major source ofL. hesperusin the nursery) indicated a significant effect of proximity to alternate hosts. These results suggest that seedling susceptibility to damage byL. hesperusis a function of seedling condition and location within the vegetation matrix.

ISSN:1754-5692    

DOI:10.1093/ee/16.4.984

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Laboratory, greenhouse, and field tests were made in Florida to determine the potential of the entomogenous nematodes,Neoaplectana glaseriSteiner orNeoaplectana carpocapsaeWeiser (Mexican strain), as biological control agents for the root weevil,Diaprepes abbreviatus(L.). In the laboratory, when nematodes were applied to the soil surface at rates of 25, 250, and 2,500 per cm2, mortality of 3-mo-oldD. abbreviatuslarvae ranged from 24 to 88%.N. glaseriandN. carpocapsaehad no significant effect on neonate larvae or pupae. In the greenhouse, whenN. glaseriorN. carpocapsaewere introduced toD. abbreviatusinfested citrus seedlings, larval populations were significantly (P<0.05) reduced. In field tests, when nematodes were applied at 250 per cm2, mortality of 3-mo-oldD. abbreviatuslarvae was 35 and 65% forN. glaseriandN. carpocapsae, respectively. In laboratory, greenhouse, and field tests,N. carpocapsae(Mexican strain) was significantly (P<0.05) superior toN. glaserias a biocontrol agent forD. abbreviatuslarvae.

ISSN:1754-5692    

DOI:10.1093/ee/16.4.987

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Postdiapause development rates and$\bar V$O2were determined inTrypoxylon politummaintained outdoors and in the laboratory under constant temperatures of 8, 14, 18, 22, 26, 30, and 34°C. This wasp may begin postdiapause development outdoors when the mean daily temperature is as low as 6–7°C if the temperature rises above the theoretical development threshold of 14.9°C for some time during the day. The wasp does not develop at constant temperatures of ≤ 14°C, or at ≥ 34°C. The rate of development increases linearly with temperatures from 18 to 26°C, but declines at 30°C. Prepupal respiratory rates increased significantly at 22°C; the rates of propupal and pupal stages increased at 26°C. Optimal development, with regard to energy utilization (respiration) occurred at 22°C.$\bar V$O2and age exhibit a catenary relationship at temperatures at which development occurs. The total oxygen consumed during development exhibited a linear relationship with temperature from 22 to 30°C. Thermal accumulations acquired in completing development at 18, 22, and 26°C are very similar. The outside group's thermal acquisition was only 80% of the total at 18–26°C. At 18°C, development appeared to be complete, but wasps failed to eclose and died within the cocoon after reaching the adult stage

ISSN:1754-5692    

DOI:10.1093/ee/16.4.990

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Population density ofDiaphnocoris chlorionis(Say) on the honeylocust cultivars ‘Moraine’, ‘Skyline’, and ‘Sunburst’ varied from year to year; defoliation was consistently highest on ‘Moraine’. Only ‘Moraine’ was defoliated sufficiently to elicit refoliation. Root starch levels were reduced corresponding with the period of refoliation, but compensation occurred before leaf flush the following spring. More wood-boring buprestid beetles were collected from the heavily defoliated ‘Moraine’ trees than from the other cultivars, although numbers were low.

ISSN:1754-5692    

DOI:10.1093/ee/16.4.996

出版商:Oxford University Press    

年代:1987

数据来源: OUP