摘要:

The effects of various constant temperatures on longevity, fecundity, reproductive rate, and developmental rate of the asparagus aphid,Brachycorynella asparagiMordvilko, and its parasitoid,Diaeretiella rapae(M'Intosh), were investigated. Moderate temperatures (23°C) were optimal for aphid survival and reproduction. Similarities in aphid biology between Michigan and Washington, where the aphid is a severe pest, suggest that the difference in pest status between the two states is not attributable to biotype differences.D. rapaereproductive and developmental rates were highest at 30°C, but longevity was reduced considerably, reducing total fecundity. Temperature responses suggest that biotype differences are present between this population and otherD. rapaepopulations reported in the literature. Results do not indicate what factors limitD. rapaeeffectiveness in the field.

ISSN:1754-5692    

DOI:10.1093/ee/19.4.890

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Numbers and community structure of oribatid mites in 11 plots in a Sierra Nevada pine plantation treated with lindane at 11.3 g/m2active ingredient (AI) were compared with 11 control plots 10 yr after application. Twenty-two species were found. Five of the nine most abundant species were severely depressed in numbers in the lindane plots. Of the 13 least abundant species in the control plots. 12 were not found in the treated plots. Four types of measurements of community structure were made. The number of species per plot was significantly depressed from the first sample through the 10-yr posttreatment sample. The heterogeneity of the community was lowest after 10 yr. The rank correlation of species in control versus treatment plots was slightly higher than the lowest point, which was at 93 d after treatment. The effect of the single application on the oribatid community remained great for 10 yr.

ISSN:1754-5692    

DOI:10.1093/ee/19.4.898

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Adult face fly,Musca autumnalisDe Geer, stable fly,Stomoxys calcitrans(L.), and horn fly,Haematobia irritans(L.), populations on four Kentucky horse farms were monitored weekly from late April to mid-October 1987 and 1988 using dry ice-baited canopy traps and visual counts of flies on pastured horses. Face flies were most abundant during May 1987 and June of both years followed by peak stable fly activity during mid-June, July, and August of both years and peak horn fly activity during mid-September of both years. Canopy trap collections of face flies were correlated with visual counts of face flies on pastured horses for 1987 and 1988. Horn flies were not collected in the canopy traps, and stable flies were not observed on pastured horses. Using visual count data to determine the degree of population aggregation, horn fly populations were found to be more contagious than face flies as populations increased on pastured horses. From the canopy trap data, face fly and stable fly populations had similar aggregation indices or similar distribution patterns as populations increased.

ISSN:1754-5692    

DOI:10.1093/ee/19.4.901

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Four Arizona willows (Salix bebbiana, S. exigua, S. laevigata, S. lasiolepis) were offered to adult beetles and larvae ofDisonycha pluriligata(LeConte) in a series of food choice experiments. AdultDisonychawere very selective, feeding 93.4% of the time on one species.Disonychalarvae were also very specific, although less so than adults, feeding on the preferred willow species 80.0% of the time. The order of acceptance (S. exigua, S. bebbiana, S. lavigata, andS. lasiolepis) by adults and larvae was almost the same. The survivorship of larvae fed on these willows also showed a uniform pattern across the species that followed adult and larval choice. When offered a choice between male and femaleS. exigua, adults fed on females more than males, but larvae did not discriminate. In comparison with data on Finnish chrysomelid beetles on willows,Disonychawas more specific in utilization patterns of willow species in the field, in experiments on adult choice, and in survivorship of larvae on hosts. Larval choice was not tested in the Finnish study.

ISSN:1754-5692    

DOI:10.1093/ee/19.4.905

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Six parasitoid species attack galls of the chalcidHemadas nubilipennis(Ashmead) found on the vegetative shoots of lowbush blueberry,Vaccinium angustifoliumAiton. The six species areMacroneura vesicularis(Ritzius) (Hymenoptera: Eupelmidae),Habrocytussp. (Hymenoptera: Pteromalidae),Eurytoma solenozopheriaeAshmead (Hymenoptera: Eurytomidae),Ormyrus vacciniicola(Ashmead)(Hymenoptera: Pteromalidae), Eudecatomavacciniicola(Balduf) (Hymenoptera: Eurytomidae), andTetrastichussp. (Hymenoptera: Eulophidae). Each species emerges from galls near the emergence period ofH. nubilipennisand oviposits in immature galls. It is suggested that parasitoids do not feed on or kill theH. nubilipennislarvae before they are mature; therefore, parasitoids do not influence either the size or shape of attacked galls.

ISSN:1754-5692    

DOI:10.1093/ee/19.4.911

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Orchard temperatures and pheromone trap catch data and crawler hatch data for nine orchard-years were used to validate the accuracy of physiological time models in simulating the time intervals for one generation between male flight peaks, and crawler peaks, as well as the interval between male flight peaks and crawler peaks (embryonic development) of four seasonal generations of the San Jose scale,Quadraspidiotus perniciosus(Comstock) in North Carolina orchards. Linear (degree-days) models simulated within ±1 wk the interval for all male flight peaks between overwintering and F1generations, while a nonlinear model simulated within ±1 wk all but one male flight peak between overwintering and F1generations. The models were less accurate for simulating intervals of flight peaks between F1to F2and F2to F3generations. Likewise, model simulations of the time interval for one generation between crawler hatch peaks, and the time required for embryonic development, were more accurate for F1and F2than F3and F4generations. Simulation results of the linear and nonlinear models were similar with 40 of the 49 simulations comparing linear versus nonlinear models not differing by more than 6 d of each other. Validation of the models for San Jose scale was complicated in one apple orchard by the presence of Forbes scale,Quadraspidiotus forbesi(Johnson).

ISSN:1754-5692    

DOI:10.1093/ee/19.4.916

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The influence of trap color and a combination of trap color plus San Jose scale,Quadraspidiotus perniciosus(Comstock), sex pheromone on sticky trap catches of aphelinid parasitoids of the San Jose scale was studied in an unsprayed apple orchard in Johnston County, N.C., in 1986 and 1987, and a sprayed commercial peach orchard in Nash County, N.C., in 1987. The responses of parasitoids to five enamel paints were compared in 1986, and similar responses to three enamel paints with and without the San Jose scale pheromone were compared in 1987. The adult parasitoids (3,958 total) collected on the traps represented ten aphelinid species:Ablerus clisiocampae(Ashmead),Aphytis diaspidis(Howard),Encarsiasp.,A. melanostictusCompere,Coccobiussp.,Coccophagoides murtfeldtae(Howard),E. aurantii(Howard),E. perniciosi(Tower),Marietta carnesi(Howard), andM. mexicana(Howard). Black traps attracted significantly moreC. murtfeldtaeandEncarsiasp. (endoparasitic species) than did other colors, suggesting a response to the contrast between the bark and foliage of the tree. Yellow and black traps attracted significantly moreA. diaspidis, an ectoparasitic species, than white traps at both orchards in 1987. Colored traps baited with San Jose scale pheromone attracted significantly moreE. perniciosi, an endoparasitic species, than colored traps without San Jose scale pheromone. This indicates that San Jose scale pheromone is a kairomone for the parasitoid. In comparisons with colored traps baited with pheromone, black traps attracted significantly moreE. perniciosithan did yellow or white traps in the unsprayed apple orchard in 1987. This suggests an interaction between olfactory and visual cues in host location by this species.

ISSN:1754-5692    

DOI:10.1093/ee/19.4.926

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

A 2-yr study of strawberry leafroller,Ancylis comptana(Froelich), populations in central Iowa showed that short daylengths and low temperatures maintain diapause during autumn and that this autumnal diapause ends without a specific cue by the end of December. The completion of diapause does not require chilling. The postdiapause developmental rate ofA. comptanais linearly related to temperatures between 14 and 30°C; adult emergence requires 154 degree-days (DD) above a lower thermal threshold (t) of 10.5°C. Field cage studies demonstrated that 50% emergence of adultA. comptanafrom overwintering larvae can be predicted accurately based upon the accumulation of approximately 150 DD>10°C.

ISSN:1754-5692    

DOI:10.1093/ee/19.4.932

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Two clones of paper birch from different geographic origins were used to determine short-term effects of water deficit and partial defoliation on photosynthetic rate, stomatal resistance, and sucrose levels in leaves, and on the performance of fourth-instar gypsy moth,Lymantria dispar(L.). Water stress, sufficient to cause wilting at midday, reduced photosynthesis by 90% and increased stomatal resistance 10 times. Sucrose levels in leaves were initially the same in stressed and unstressed plants, but after 10 d of stress sucrose was higher in leaves of water-stressed plants of one clone (‘S5’ birch), but not in the other (‘WM-148’ birch). Fourth instars, placed on ‘S5’ plants when midday wilting first occurred, produced more frass and had higher relative growth rates than larvae on well-watered plants. These changes were not observed for a second cohort of larvae placed on the same clone about 10 d after wilting first occurred. On clone ‘WM-148’, which was more suitable than the ‘S5’ clone, larval performance was not different on water-stressed plants versus well-watered plants, whether they were introduced immediately or 10 d after wilting first occurred. Relative growth rate was lower for larvae feeding on partially defoliated plants versus undefoliated plants of both clones.

ISSN:1754-5692    

DOI:10.1093/ee/19.4.937

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Observations on egg mass density, number of eggs per mass, parasitism, and viability of eggs of the gypsy moth,Lymantria dispar(L.), were carried out over 19 yr at 17 permanent study plots in New Jersey. Egg mass size (eggs per mass) in the current generation was inversely related to density in the previous generation. Eggs were parasitized entirely byOoencyrtus kuvanae(Howard); parasitism averaged 25.9% overall. Percentage parasitism of eggs in a mass was negatively correlated with size. Percentage parasitism in the current generation was directly proportional to egg mass density in both the previous and current generations, falling below 10% in the most sparse populations and climbing above 35% in the most dense. The viability of unparasitized eggs in 1981–1989, when populations underwent outbreaks in most plots, was strongly negatively correlated with the percentage defoliation of oaks and less so (albeit significantly) with average monthly temperatures in October and February.

ISSN:1754-5692    

DOI:10.1093/ee/19.4.943

出版商:Oxford University Press    

年代:1990

数据来源: OUP