摘要:

Oviposition and larval survival ofRhagoletis pomonella(Walsh) varied significantly among fruit from 25 crab apple speciesand clones evaluated in field and laboratory studies. In general, the relative oviposition preference and larval survival was similar in fruit infested naturally in the field and fruit tested in the laboratory. Flies oviposited more in clones with larger fruit, although this relationship was more pronounced in laboratory tests when fruit was infested by laboratory-reared flies than in fruit infested in the field by wild flies. ‘Aldenhamensis,’ ‘Fuji,’ ‘Vilmorin,’Malus zumi calocarpaRehd., andM. hupehensis(Pamp) Rehd. fruit was not infested in the field, but flies oviposited in fruit of all 25 species and clones in choice tests in the laboratory. Eggs hatched but larvae did not survive in fruit of ‘Henry F. DuPont,’ ‘Frettingham,’ ‘Fuji,’ ‘Sparkler,’M. hupehensis, andM. zumi calocarpa. Larval mortality was very high in fruit from ‘Vilmorin,’ ‘Sparkler,’ ‘NA 40298,’ ‘Henrietta Crosby,’ ‘Golden Gem,’ ‘Almey,’M. baccataL. (Borkh.), andM. sikktmensis(Hook.) Koehne.

DOI:10.1093/ee/19.3.565

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

To characterize the behavior of codling moth,Cydia pomonella(L.), males to sex pheromone sources, we determined the lapsed time for response, number responding, and number of attempted pseudocopulations directed to pheromone placed at various heights in or near apple trees. The time for and number of responses was similar at any height as long as the pheromone source was within and not outside the tree's canopy. Responses to pheromone and captures of moths were significantly lower for pheromone sources or traps outside the tree canopy, whether above, below or between trees. The maximum numerical response was at the 3.0-m level, 1.0–1.5 m from the top of the tree. In an unsprayed apple orchard, the number of moths caught in traps at 3.5 m was not significantly different from the number caught at 1.5 m, but in a sprayed orchard, the number caught at 3.5 m was significantly higher than at 1.5 m in six of 10 biweekly comparisons. Efficiency of low traps (1.5 m) relative to high traps depended on the position of the low trap in relation to the canopy. The canopy effect was larger than the height effect.

DOI:10.1093/ee/19.3.573

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The development, population dynamics, and predation rates on the eggs and first instars of the house fly,Musca domesticaL., of the manure-inhabiting mite,Macrocheles muscaedomesticae(Scopoli), were simulated in a FORTRAN77 model. Effects of mite crowding on fecundity were determined experimentally, and long-term population dynamics experiments were conducted under simulated field conditions for model development; other data used in development of the model were obtained from the literature. Features of the model include: nonlinear development, longevity, and attack rate routines for variable temperatures; mite fecundity as a function of temperature, mite crowding levels, physiological age, and prey quantity and type; attack rates as a function of mite crowding and prey quantity and type; mite survival as a function of crowding and habitat size and quality; and a house fly submodel that tracks deposition, aging, and destruction of fly immatures. Mite populations are updated by the model every 4 h. Comparison of predicted mite populations with actual populations from validation experiments were in close agreement, and improvements in agreement were achieved by empirical adjustments of mite survival as a function of changes in habitat quality over time.

DOI:10.1093/ee/19.3.578

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Daily patterns of activity and the effects of adult density and exposure to host plants on the onset of reproductive activities and age-specific fecundity of the diamondback moth,Plutella xylostella(L.), were determined under constant conditions of 21°C, 70%RH, and a 16:8 (L:D) photoperiod. More than 50% of adult emergence occurred in the first 8 h of the photophase. Although calling occurred throughout the scotophase,>70% of mating and oviposition took place in the first 4 h. Approximately 90% of females had begun to call, mate, and lay eggs, and the females contained ≥1 mature egg by night 4 when kept with males and host plants in individual pairs. In contrast, only 27% of females kept with males but without host plants had mated by night 4, and only 64% contained mature eggs. Individually caged females laid eggs at a rate>50% of their maximum daily oviposition on nights 3–5, and for females caged in groups of 50 males and 50 females this occurred on nights 4–10. Ovarian development also was consistently slower in the group-caged females than in the individually caged females, the former containing 16 to 93% as many mature eggs as the individually caged females, depending on age and prior exposure to plants. Male sexual maturation was not complete at adult emergence, and only 54% of day-l males were able to fertilize 4-d-old, virgin females. By night 4,98% of males were able to do so regardless of whether or not they were exposed to host plants. Females mated to day-4 males that were exposed to plants for the first three nights produced significantly more viable eggs compared with females mated to day-4 males that were not previously exposed to host plants.

DOI:10.1093/ee/19.3.587

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The feeding behavior ofNephotettix virescens(Distant) on rice varieties with different levels of resistance was studied using an AC electronic monitor for insect feeding (EMIF) system. Varieties used were TN1 (susceptible), IR36 (moderately resistant), and ASD7, IR60, and IR64 (resistant). Six typical waveforms were recorded and each type corresponded to a certain activity of the insect during the feeding process as indicated by histological sections of the leaf observed. Significantly more phloem feeding was observed on the susceptible plants than on the moderately resistant and resistant plants. Fifty percent of the total test period was spent feeding on the susceptible variety and only 25% on the resistant varieties.

DOI:10.1093/ee/19.3.594

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Adult activity and ovarian dynamics of the variegated cutworm,Peridroma saucia(Hübner), were studied during 3 yr by using blacklight traps. Initial mating in females coincided with ovarian development, with females continuing to mate up to six times during their lives. Adult catches, ovarian dynamics, and degree-day calculations indicated thatP. sauciahas three generations each year in Iowa. Very few preovipositional females were collected during the spring flight. This observation and the strong association of adult activity during the spring with weather patterns resulting in southerly winds suggested thatP. sauciaadults migrate into the state each spring when weather conditions are favorable. Flights during June through November contained a large portion of preovipositional females. Degreeday calculations also revealed that adults collected during June and July were the progeny of spring migrants, but temporally distinct influxes of migrants may produce distinct peaks of adult activity during June and July. Degree-day calculations and the collection of a few preovipositional females during the spring suggested thatP. sauciamay overwinter as pupae, which may produce adults that contribute to the influx of migrants in the spring.

DOI:10.1093/ee/19.3.603

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Samples ofRhopalosiphum maidis(Fitch) taken from corn in Idaho and Montana from 1985 to 1987 were karyotyped and found to be 2n = 8, whereas those from barley and barnyard grass (Echinochloa crus-galli(L.) P. Beauv.) were 2n = 10. Samples from wheat in Idaho in 1987 had a mixture of karyotypes (2n = 8, 9, and 10). The results indicate highly selective colonization of corn and barley by different genotypes ofR. maidis, so it is unlikely that this aphid can carry barley yellow dwarf virus (BYDV) between these two crops.E. crus-gallimay be an important reservoir host for BYDV isolates vectored byR. maidisto barley and winter wheat.

DOI:10.1093/ee/19.3.609

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The seasonal phenology ofZoophthora phytonomi(Arthur) was studied in southern Ontario from 1976 through 1988. The first incidence of disease in the alfalfa weevil,Hypera postica(Gyllenhal), occurred after the accumulation of 204 degree-days (DD) above a base threshold of 9°C from 1 April. In 11 of the 13 yr, epizootics began 57 DD later and lasted for 10 to 14 d, killing up to 99% of the larvae and 50% of the cocooned stages. It is proposed that there are three peaks of conidial production of the fungus in the alfalfa weevil that occur at intervals of 55 to 60 DD. The first occurs when the larvae are small and is coincident with epizootics of the disease in the clover leaf weevil,H. punctata(F.), whose larvae mobilize, increase, and transfer the inocula in early spring. The second occurs at peak incidence of the third alfalfa weevil instar, and the last, just subsequent to peak fourth instar. Larvae infected during the fourth instar die in their cocoons and produce resting spores, which overwinter in the ground litter. The influence of microclimatic factors on epizootics is discussed in relation to threshold densities of the host.

DOI:10.1093/ee/19.3.612

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The purpose of this study was to determine if there is a latitudinal gradient in the photoperiodic responses of populations of pea aphid,Acyrthosiphon pisum(Harris). The approach was to measure photoperiodic responses of all clones at a standard photoperiod of 14:10 (L:D) at 20°C, and compare populations by making use of information on the relationship between photoperiod and the morphs of progeny produced and their sequence. Tests involved 90 clones from four latitudes, ranging from 44°45'N to 53°12′N. Results showed that the four populations differed from one another in their responses. The northerly clones generally gave short-day responses, and the southerly clones gave comparatively longer-day responses to the single test photoperiod.

DOI:10.1093/ee/19.3.618

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The parasitoidDacnusa sibiricaTelenga is currently used for seasonal inoculative biological control of the leafminersLiriomyza bryoniae(Kaltenbach) andLiriomyza trifolii(Burgess) on glasshouse vegetables in northwest Europe. The braconid is effective from the beginning of the season until July, when average temperatures vary between 15 and 20°C. To estimate the potential reproduction (R0) of the parasitoid, the effect of temperature (15, 20, and 25°C) on its fecundity, longevity, and oviposition rate was examined in the laboratory. Fecundity and longevity decreased with increasing temperatures, but did not differ significantly between 20 and 25°C. Oviposition rate was highest at 20°C, apparently the optimum temperature for oviposition.The R0ofD. sibiricadecreased with increasing temperatures. Therefore,D. sibiricais expected to be less effective for the biological control of leafminers on tomato at high temperatures. The use of potential population growth, R0or rm, to evaluate parasitoids' effectiveness is discussed.

DOI:10.1093/ee/19.3.625

出版商:Oxford University Press    

年代:1990

数据来源: OUP