摘要:

The forest microhabitat distribution of overwinteringApanteles melanoscelus(Ratzeburg) was assessed by sampling live and dead trees and small ground plots. The logarithm of the average number of cocoons per lowest 2 m of dead tree or stump was used to predict cocoon population densities. Extensive sampling during fall and winter, laboratory rearing and dissection of collected cocoons, and partial correlation analysis showed that mortalities caused by some hyperparasites were negatively correlated with each other, suggesting competition between them. Multiple regression analysis demonstrated that the mortality caused by someA. melanoscelushyperparasites [Eurytoma appendigaster(Swederus) (Hymenoptera: Eurytomidae) and Eulophidae spp.] varied in a positive, density-dependent manner with differences inA. melanosceluscocoon numbers. Such information is useful in suggesting which hyperparasites are important so that research on decreasing their impact onA. melanosceluspopulations can be done.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1228

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Spalangia endiusandMuscidifurax raptormultiparasitized house fly pupae. However,S. endiustended to avoid ovipositing in pupae parasitized byM. raptor, whereasM. raptordid not avoid pupae parasitized byS. endius. Behavioral observations indicated that both species could, in some cases, discriminate and subsequently refrain from ovipositing on an already parasitized pupa, but only after drilling into the puparium. Multiparasitism decreased as the time after initial parasitization increased. These findings indicate that the parasitoids use cues, possibly venom, inside the puparium for host discrimination. Multiparasitism should be accounted for in laboratory studies on the reproductive potential of these parasitoids. Furthermore, our results indicate that where these two species are mass released simultaneously, multiparasitism may commonly occur.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1232

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

The interaction of two-spotted spider mites,Tetranychus urticaeKoch, with greenhouse-grown radish plants was analyzed in terms of the importance of soil moisture levels and applied fertilizers that differed in nitrogen level and the ratio of nitrogen to phosphorus and potassium. Low soil moisture levels produced both smaller plants and lower total mite populations, although the same mite intensity (number per g of foliage) was attained regardless of moisture level. Fertilizer composition had no effect on the dry weights of uninfested plants or on mite population size, but the highest intensities were associated with fertilizers that had high N to P and K. Mite infestation of the foliage caused a large reduction in the dry weight of the storage and root tissues but did not consistently reduce foliage or total plant dry weight. Radish plant response to mite infestation was consistently influenced by the composition of the applied fertilizer when soil moisture was adequate.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1239

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Periodical cicada nymphs (Homoptera: Cicadidae:Magicicadaspp.) that were collected as they emerged from the ground, isolated, and allowed to eclose in individual containers sometimes developed infective conidia of the fungusMassospora cicadinaPeck, but never resting spores. The time required for the cicada's abdominal sclerites to fall off (i.e., for the animal to become highly infective to others) and the proportion of nymphs developing the infection did not differ between the sexes. By contrast, in an adult population, the prevalence of secondary infections producing resting spores was much higher in males. The proportion of individuals infected as nymphs was positively correlated with the time since the habitat was last disturbed, and negatively correlated with the number of cicadas emerging per m2. Cicadas in one of the six study sites had been studied in the prior emergence—17 years earlier—which provided the opportunity to determine what changes had occurred in cicada density and the proportion infected by the fungus. Density had dropped by one-half, and the proportion of infected individuals generating resting spores had increased by 9-fold. These data suggest possibilities for use of the fungus as a biological control agent, although the resting spores appear to be highly vulnerable to environmental disturbance.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1245

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

The female yellowheaded fireworm produces a pheromone to attract males. GC analysis of washes of ovipositors of single virgin females revealed eight compounds that were identified by microchemical techniques and comparison with authentic materials. (E)-11, 13-Tetradecadienal, (Z)-11-tetradecen-1-ol acetate, (E)-11-tetradecen-1-ol acetate, 1-tetradecanol acetate, 2-pentadecanone, 2-heptadecanone, (E)-11, 13-tetradecadien-1-ol acetate, and hexadecanal. Field tests indicate that only (E)-11, 13-tetradecadienal is required to capture males, and thus this compound represents a female sex pheromone of the species.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1253

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Spodoptera frugiperda(J. E. Smith) larvae parasitized byOphion flavidusBrulle continued to feed after parasitoid oviposition. Consumption of a pinto bean diet was measured from parasitoid oviposition to parasitoid emergence or until pupation by control larvae. ParasitizedS. frugiperdalarvae of two size groups consumed 17 and 22% less diet, respectively, than control larvae. Parasitized larvae consumed less food, gained less weight, and produced less feces than unparasitized larvae at 48 and 72 h after exposure to a female parasitoid. Parasitized larvae had significantly larger (P<0.05) approximate digestibility index values and significantly smaller efficiency of conversion of digested food index values at 48 h than control larvae.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1257

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Chlorpyrifos, bendiocarb, trichlorfon, and isofenphos were applied as surface sprays to Kentucky bluegrass turf, and effects on nontarget arthropods were measured. The most abundant families of predaceous Insecta, Araneida, and Acari were Staphylinidae, Erigonidae, Parasitidae, and Eupodidae. Chlorpyrifos and isofenphos had the greatest impact on predaceous arthropods, with some taxa significantly reduced for at least 6 weeks. Effects of bendiocarb and trichlorfon were generally less severe and more temporary. Oribatid mite populations were apparently unaffected by the insecticides. Bendiocarb increased trap catches of ants for up to 2 weeks after application.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1260

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Hercon dispensers, adsorbed with (Z,E)-9, 11-tetradecadienyl acetate (1.5 g/ha) and located 65 m apart (one dispenser per 0.4 ha), effectively disrupted communication inSpodoptera littoralisfor about 4 weeks. This was inferred from the reduction in trap captures and in number of virgin female traps that captured at least one male in the pheromone-treated vs. control plots. The release rate of the pheromone from the Hercon dispenser was of the first order: an average of 1.4 mg/cm2per day was released during the first days, and ca. 0.6 mg/cm2per day during days 9 to 24. Most of the pheromone (ca. 87%) was emitted within the first 24 days. The laminated structure protected the pheromone effectively, and oxidation or isomerization was prevented without any addition of stabilizer or antioxidant. The method of emitting pheromone from widely separated Hercon dispensers seems promising for applied control ofS. littoralis.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1265

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

The soybean,Glycine max(L.) Merr., plant introduction ‘PI 227687’ and the susceptible cultivar ‘Davis’ were grown in a greenhouse and evaluated in the laboratory for leaf-feeding resistance to the soybean looper,Pseudoplusia includens(Walker). The effects of an exotic parasitoid,Microplitis demolitorWilkinson, on the development of the looper were also tested. Larvae reared on the plant introduction had longer developmental times, reduced larval weights, and lower consumption of leaves compared with those reared on ‘Davis’. Parasitism byM. demolitorgreatly reduced larval weight and leaf consumption for loopers reared on both cultivars. Although both parasitized and non-parasitized larvae reared on ‘PI 227687’ suffered mortality, the larvae did survive long enough for parasitoid development.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1270

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Diomus flavifrons(Blackburn), a coccinellid predator, was introduced from South Australia into Texas for the control of citrus mealybug on citrus. The beetle was successfully reared on citrus mealybug eggs with a developmental time of 28.7 days (24°C and 60% relative humidity). Egg incubation averaged 5.1 days; the four larval instars' developmental period averaged 5.1, 2.8, 2.2, and 7.7 days, respectively; and the pupae averaged 5.9 days for development. Adult longevity averaged 29.1 days for mated females and 77.6 days for virgin females when fed solely on eggs and 8.4 days when food was withheld. The fecundity of mated females averaged 146.9 eggs per female. AdultD. flavifronswere capable of surviving by feeding on mature mealybugs. Egg consumption averaged 815.4 eggs per adult over a 70-day period.

ISSN:0046-225X    

DOI:10.1093/ee/12.4.1275

出版商:Oxford University Press    

年代:1983

数据来源: OUP