摘要:

The effects of host and parasitoid density on rates of parasitism byTrichogramma minutum, T. pretiosum, andT. exiguumwere tested in l.8-liter (13 cm diam by 13 cm high), 43-liter (23 by 36 by 52 cm), and 4,000-liter (2 by 2 by 1 m) arenas. Soybean foliage andHeliothis virescenseggs served as substrate and hosts, respectively. Rates of parasitism were significantly higher at the highest wasp density in all arenas. The effects of host density were not consistent among arenas. Rates of parasitism byT. minutumwere the highest in the l.8-liter and the lowest in the 4,000-liter arenas. Rates of parasitism byT. pretiosumexhibited the opposite trend. Rates of parasitism byT. exiguumdid not differ significantly from those ofT. minutumin the l.8-liter arena andT. pretiosumin the 4,000-liter arena. The cause of this lack of congruence in the relative performance ofT. minutumandT. pretiosumin the different sized arenas was not determined, however it may be a result of differential vertical stratification of searching activity by these two species.

ISSN:0046-225X    

DOI:10.1093/ee/14.6.762

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Traps baited with gum turpentine of southern pines and deployed in north Florida from 1980–1983 captured numerous adults of the black turpentine beetle (BTB),Dendroctonus terebrans(Olivier); pales weevil,Hylobius pales(Herbst); pitch-eating weevil,Pachylobius picivorus(Germar); Carolina pine sawyer,Monochamus carolinensis(Olivier); southern pine sawyer,M. titillator(F.); and southern pine engraver beetles,Ipsspp. Ethanol had a synergistic effect when mixed with turpentine as a bait for the BTB, pales weevil, pitch-eating weevil, and sawyers. Maximum numbers of insects were captured by traps with black columns equipped with wick-type bait dispensers that released relatively large volumes of a mixture of turpentine and ethanol. Peak captures of the BTB occurred shortly after sunset on overcast days when windspeeds were less than 0.8 km/h. BTB, weevils, and sawyers were captured by traps during all but the coldest months of the year. Numbers of insects captured fluctuated throughout the year but there were from two to three distinct peak flight periods.

ISSN:0046-225X    

DOI:10.1093/ee/14.6.768

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Bioassays against the immature stages of the sweetpotato whitefly,Bemisia tabaci(Gennadius), were conducted with 0.2 and 2.0% aqueous solutions of neem-seed extract in laboratory and greenhouse studies. Cotton,Gossypium hirsutumL., foliage treated with neem-seed extract resulted in a reduction of egg viability and oviposition, prolonged larva periods, and larva mortality. Although the mode of action of the extract is unknown, we observed that adults were repelled, thus reducing oviposition. The failure of treated larvae to complete ecdysis would indicate an antiecdysteroid activity.

ISSN:0046-225X    

DOI:10.1093/ee/14.6.776

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Adult populations of nuisance chironomid midges were collected daily over a 2-year period by using New Jersey light traps at five waterfront locations of a city bordering the southern shore of Lake Monroe in central Florida. Species of Chironominae,Glyptotendipes paripesEdwards,Chironomus crassicaudatusMalloch,Chironomus decorusJohannsen, and Tanypodinae spp. (mostlyCoelotanypus scapularis(Loew),Coelotanypus concinnus(Coq.), andProcladius subletteiRoback) were the most abundant midges. The 2-year maximum nightly catch of these midges taken in active traps amounted to 184,133, 134,233, 3,990, and 16,191 adults, respectively. Partitioning of the total sum-of-squares in an analysis of variance indicated that catches were relatively homogeneous over the trap locations. Time of year (date) and differences in phenology among the studied species of Chironominae and subfamily Tanypodinae were the factors contributing the greatest amount to the variation in trap catches. Autocorrelation analysis identified a weak periodicity in catches of ca. 600 degree-days above 0°C, which may correspond to the developmental time for a generation of the predominant species.

ISSN:0046-225X    

DOI:10.1093/ee/14.6.780

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Nonlinear models for nondiapause development in the tufted apple budmoth,Platynota idaeusalis(Walker), were developed from estimated parameters obtained from constant-temperature studies under long-day photoperiodic regimes (16:8 [L:D]). Temperature-dependent development was evaluated with laboratory and field strains ofP. idaeusalisreared on semisynthetic diet and excised apple leaves. These data were incorporated into appropriate models to Simulate adult emergence at variable temperatures. Models were validated by laboratory and field strains ofP. idaeusalisreared on semisynthetic diet and apple foliage (either excised leaves or in tree cages) under field conditions and comparing actual percentile adult emergence with predicted percentile adult emergence. Predicted and observed development was faster for the field strain than the laboratory strain and faster for larvae reared on synthetic diet than larvae reared on apple foliage. In most instances, model predictions were within 2 days of actual emergence. All models predicted three generations ofP. idaeusalisper year when temperatures prevalent to the piedmont area of North Carolina were used.

ISSN:0046-225X    

DOI:10.1093/ee/14.6.785

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Termination of larval diapause in the tufted apple budmoth,Platynota idaeusalis(Walker), is a dynamic process in which insect development is influenced by both the nature and the timing of the various stimuli to which it is exposed. Parameters investigated in this study with respect to diapause termination included time of inoculation (egg hatch) in the field, temperature, and photoperiod. Each factor was shown to affect significantly diapause development in diapausing larvae. However, the magnitude of the effect of each consistently diminished as the season progressed. Comparisons of laboratory and field strains ofP. idaeusalis, reared under similar conditions, showed no significant differences in their respective diapause responses to each of the factors investigated. Larvae inoculated out of doors earlier in autumn exhibited a less intense diapause than those inoculated later. Diapause termination was accelerated when larvae were exposed to higher constant temperatures and longer stationary daylengths, or both. Because natural temperatures rarely rise above 27°C (the optimum temperature tested for diapause termination) between November and March in North Carolina, larval diapause inP. idaeusalisis most likely terminated by increasing daylengths in the spring, with temperature acting as a modifying influence in the overall rate of diapause development.

ISSN:0046-225X    

DOI:10.1093/ee/14.6.790

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Diapausing larvae of a laboratory and field strain of the tufted apple budmoth,Platynota idaeusalis(Walker), were reared on semisynthetic diet and maintained out of doors for observations between November 1980 and April 1981. Larvae maintained on semisynthetic diet continued to feed and molt during diapause, as long as temperatures remained consistently above 10°C. Quantitative estimates of feeding, larval weights, and head-capsule widths in diapausing larvae were also recorded. CO2output was measured in a laboratory strain of larvae reared on semisynthetic diet and excised apple leaves under long (16:18 [L:D]) and short (11:13 [L:D]) daylengths at constant 21°C. No increase in respiration was observed in any larvae immediately preceding larval–pupal ecdysis, regardless of food source or photoperiod. Diapausing larvae had lower respiratory rates than did nondiapausing larvae, particularly when comparisons were made based on larval weight classes, rather than chronological age.

ISSN:0046-225X    

DOI:10.1093/ee/14.6.797

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Pitfall traps were used to collect surface-active Collembola at intervals of 10–100 m from a γ radiation source on Long Island, N.Y., during the summer of 1968. Thirty-two species of Collembola were collected along the radiation transect. Community diversities were similar at all intervals except 10 m. Collembola appeared resistant to γ radiation; only chronic, very high γ radiation exposure seriously affected population levels and community diversity of surface Collembola.

ISSN:0046-225X    

DOI:10.1093/ee/14.6.805

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Similar to that of otherRhagoletisspecies, color response of the walnut husk fly,R. completaCresson, varies with the shape of an object. Yellow was the preferred color when combined with a rectangular trap shape. Green rectangles were also quite attractive. When given a choice of yellow, green, red, and blue spheres, husk flies preferred green spheres, especially those whose reflectance pattern matched that of the walnut husk. Yellow spheres were as attractive as green spheres but only during the first weeks of fly emergence when reproductive activity was still low. The response ofR. completato green spheres can be explained in relation to its reproductive behavior. Green spheres apparently mimic the nuts, which are the mating as well as the oviposition site for the husk fly. No difference was detected in color response between male and female husk flies. Ammonia odor, generally considered a feeding-type olfactory stimulus, enhanced the response to yellow rectangles and green spheres several fold but at a loss of selectivity. This research supports the use of yellow rectangles and green spheres for monitoring.

ISSN:0046-225X    

DOI:10.1093/ee/14.6.810

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

The relationship between known densities of house flies,Musca domesticaL., and fly-abundance indices obtained with baited jug-traps and white spot cards in a caged-layer poultry house was determined. Baited jug-traps hung from the ceiling and spot cards fastened to feed troughs gave fly-abundance indices most sensitive to changes in house fly density; spot cards fastened flush against the rafters were slightly less sensitive, and spot cards hung vertically from the rafters were least sensitive. With increasing mean daily temperature (range, 22 to 34°C), estimates of fly-abundance density obtained with baited jug-traps, spot cards fastened to the feed trough, and spot cards fastened hanging from the rafters increased, while the estimates obtained with spot cards fastened flush against the rafters decreased. The relationship between fly-abundance indices obtained with baited jug-traps and spot cards (in different locations) was determined by linear regression. Equations are given for calculating the numbers of sampling devices required at different fly-abundance thresholds for obtaining indices with a desired coefficient of variability.

ISSN:0046-225X    

DOI:10.1093/ee/14.6.815

出版商:Oxford University Press    

年代:1985

数据来源: OUP