摘要:

Laboratory studies were conducted to determine if there were biological or behavioral differences among populations ofTrissolcus basalis(Wollaston) (Scelionidae: Hymenoptera) collected from France, Italy, and Spain. Observations of isolated and mated females indicated little difference in fecundity, adult longevity, male and female progeny produced, length of oviposition period, and percentage of parasitism ofNezara vttidula(L.) (Heteroptera: Pentatomidae) eggs. Females from all locations showed greater fecundity and rates of parasitism during the first week after emergence. The French population showed a significantly higher emergence rate fromN. viridulaeggs than those from Italy or Spain. When maleT. basaliswere continuously present with females, fecundity, number of male progeny, and percentage of parasitism were significantly higher than when females were isolated. Over the lifetime ofT. basalisfemales, the sex ratio of adult progeny favored female; however, there was a progressive shift from predominantly female to male progeny as the female aged. Adult males lived longer than females. No significant differences in adult male or female longevity were detected across geographic populations. However, the Italian population took significantly more time to complete immature development than the French or Spanish population.N. viridulaegg mortality was significantly higher when femaleT. basaliswere continuously present than when absent, indicating that parasites may cause some mortality in addition to that resulting from parasitism. There were no significant differences in mating, egg selection, or oviposition times among the geographic populations. Females from Italy spent significantly less time in markingN. viridulaeggs than those from Spain or France. The results of these studies suggest that the three populations compose a singleT. basalisbiotype.

ISSN:1754-5692    

DOI:10.1093/ee/19.2.387

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Parasitism of cornstalk borers was evaluated near Rio Bravo, Tamaulipas, Mexico, from 1984 to 1988. Additional surveyswere made on grain sorghum and johnsongrass. A total of 12,897 larvae and pupae ofDiatraea lineolata(Walker),D. saccharalis(F.), andEoreuma loftini(Dyar) was collected from 10,820 host plants. Total parasitism throughout this study was 6.8%, with no small larval or pupal parasites detected in corn. Six indigenous parasites were reared from all borer species and host plants.Chelonus sonorensisCameron attacked onlyE. loftiniand was the most common native parasite with 18% overall parasitism. Percentage of parasitism byChelonus sonorensiswas highest (34%) during the fall seasons, particularly at the vegetative corn stage. The remaining indigenous parasites appeared sporadically at very low levels of parasitism and includedDigonogastrasp.,Orgilus gelechiaevarus(Cushman),Glyptapantelessp.,Spilochalcissp., andEucelatoriasp. The exotic parasitesCotesia fiavipes(Cameron) andAllorhogas pyralophagusMarsh were field released during the fall of 1985.A. pyralophaguswas not recovered from field collections.Cotesia fiavipeswas recovered fromD. saccharalisandD. lineolataimmediately after releasesbegan and became the most abundant parasite of those borer species thereafter.Cotesia fiaoipeswas recovered most frequently during the fall during the reproductive and senescent corn stages. Average parasitism byCotesia flavipesduring the fall was 13% onD. saccharalisand 5% onD. lineolatawith the highest parasitism (53% onD. saccharalis) during the fall of 1987. The consistent recoveries ofCotesia fiavipesfrom 1985 to 1988 suggest that this parasite is permanently established in northern Tamaulipas, Mexico

ISSN:1754-5692    

DOI:10.1093/ee/19.2.393

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Odor of fermented yellow chapote (Sargentia greggiiS. Wats.) fruit was 3.6 times more attractive than yeast hydrolysate to hungry, laboratory-strain Mexican fruit flies,Anasttepha ludens(Loew), over short distances (<0.3 m) in laboratory experiments. Starvation for periods of 1–3 d increased responsiveness to chapote odor over the no-starvation level. Age had little effect on responses of flies between 1 and 30 dafter eclosion. However, newly emerged flies did not respond. Chapote odor attracted flies at all times during the 14-h photophase, but responses, especially of males, declined late in the photophase. Response levelsincreased with odor concentration throughout the range of test concentrations. Gamma irradiation reduced responses of females by 25% but did not affect responsesof males. Females were 1.7 times more responsive than males to chapote odor. Male-produced pheromone did not attract virgin females that were 0–7 d old (sexually immature) but attracted virgin females that were 8–37 d old (sexually mature). Odor of fermented chapote and maleproduced pheromone are maximally attractive to different segments of the adult population.

ISSN:1754-5692    

DOI:10.1093/ee/19.2.403

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Elasmus albizziaeBurks is a parasitoid of the mimosa webworm,Homadaula anisocentraMeyrick. Honeylocust foliage samples containing first-generation mimosa webworm cocoons were collected in Ames, Iowa, by using a stratified random sampling plan during 1985, 1986, and 1987. Survey objectives were to determine the percentage of parasitized first-generation webworm prepupae and to assess the potential ofE. albizziaein an integrated pest management program. Conservative determinations of first-generation parasitism of mimosa webworm prepupae byE. albizziaewere 44,39, and 47% for 1985, 1986, and 1987, respectively. Precise effects of this parasitism on webworm populations have not been determined. Mortality levels imposed byE. albizziaeshould, however, be taken into account when management practices are considered. The parasitoids are exposed during host-seeking activity and would be vulnerable to broad-spectrum insecticides applied when first-generation webworm larvae were spinning cocoons on honeylocust foliage. When insecticidal treatment is warranted for management, it is recommended thatBacillus thuringiensisinsecticides be adopted as the treatment of choice over broad-spectrum insecticides to minimize damage to the parasitoid complex.

ISSN:1754-5692    

DOI:10.1093/ee/19.2.409

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The cutwormMeltpotis indomttaWalker is the most important defoliator of honey mesquite,Prosopts glandulosaTorrey var.glandulosa, in the southwestern United States. Several aspects of its population dynamics were investigated in the insectary and field at Temple, Tex., because of its potential value in a biological control program. Females deposited about 750 eggs, and a generation was completed in about 45 d in an insectary at natural temperature and photoperiod. Insectary populations increased 1.12 times per day and doubled every 6.3 d. In the field, larvae eclose from egg masses presumably deposited in crevices under mesquite bark, feed nocturnally on the leaves, and pupate in the soil. The highest level of cutworm activity was observed in 1980 on the Edwards Plateau where the population density in the soil beneath a heavily defoliated mesquite stand was 70.1 larvae and 15.6 pupae/m2. Light trap samples showed moths were active as early as mid-April in 1982 in central Texas. Adult emergence continued into October during 1981 and 1983, giving no indication thatM. indomttaunderwent a pupal diapause. Weather conditions and parasitism of larvae and pupae were important factors regulating populations ofM. indomtta. The potential effectiveness ofM. indomttaas a biological control agent of mesquite was also examined. It was concluded thatM. indomttawould be only a partially effective agent because the defoliating activity of the larvae does not permanently damage mesquite.

ISSN:1754-5692    

DOI:10.1093/ee/19.2.415

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Eggs and larvae of the braconid parasite,Dacnusa dryas(Nixon), were encapsulated by third instars of the alfalfa blotch leafminer,Agromyza frontella(Rondani). Capsule formation was followed by death of the parasites and melanization and size reduction of the cadaver. The incidence of encapsulation of solitary parasites was consistently low, decreasing the effective rate of parasitism by an average of 10%. Supernumeraries were encapsulated without exceptions. The importance of encapsulation to the stability of the host-parasite association is discussed.

ISSN:1754-5692    

DOI:10.1093/ee/19.2.423

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

A standardized laboratory bioassay was used to quantify the lethal and sublethal responsesof larval and adult cottonwood leaf beetles,Chrysomela scriptaF., toBacillus thuringiensis var. san diego, formulated as M-One standard powder (Mycogen Corporation, San Diego). The median lethal concentration (LC50) for second instars, after a 96-h exposure toB. thuringiensis var. san diego, was 21,000 Colorado potato beetle international units per milliliter water. The LC50estimates for the third instars and adults were 20 and 40 times higher than for second instars, respectively. Larval LC50estimates were halved when mortality for the entire larval period was included in the LC50estimate. Adult mortality continued for approximately 14 d after initial exposure toB. thuringiensis var. san diego. The adult LC50calculated at 14 d was half the 4-d estimate. Age of adults at treatment did not significantly affect the LC50. Median lethal times (LT50) were similar for larvae and adults, with overlapping confidence limits ranging from 2.1 to 3.5 d. Larvae surviving treatments as second and third instars showed a significant dose-dependent decrease in adult dry weight at eclosion and an increase in the larval developmental period.

ISSN:1754-5692    

DOI:10.1093/ee/19.2.428

出版商:Oxford University Press    

年代:1990

数据来源: OUP

ISSN:1754-5692    

DOI:10.1093/ee/19.2.432

出版商:Oxford University Press    

年代:1990

数据来源: OUP

ISSN:1754-5692    

DOI:10.1093/ee/19.2.433

出版商:Oxford University Press    

年代:1990

数据来源: OUP

ISSN:1754-5692    

DOI:10.1093/ee/19.2.434a

出版商:Oxford University Press    

年代:1990

数据来源: OUP