摘要:

Field parasitism of the face fly,Musca autumnalisDe Geer, by insect parasites and the nematode,Heterotylenchus autumnalisNickle, was investigated in south central Nebraska. Four species of insect parasites were collected from face fly puparia:Aphaereta pallipesSay,Muscidifuraxsp.,Eucoilasp., andAleocharasp.A. pallipeswas found only during the first 4 wk of the study (6–24 June), whereas the other three parasites were intermittently found, at low levels, for the remainder of the study (24 June–26 September). Total seasonal insect parasitism averaged 4.3%. Seasonal parasitism by the nematodeH. autumnalisaveraged 5.8% and peaked at 18% on 9 September.

ISSN:1754-5692    

DOI:10.1093/ee/16.4.902

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Only (Z)-9-tetradecenyl acetate (<1 ng per female) could be identified by capillary gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS) in sex pheromone extracts of spruce coneworm,Dioryctria reniculelloidesMutuura&Munroe. Confirmation of this component as the Z isomer and identification of a potential second component, (Z)-7-dodecenyl acetate, were accomplished by electroantennogram bioassay and field tests. Blends of these compounds in ratios of 3:0.15 and 3:0.3 µg were significantly more attractive than (Z)-9-tetradecenyl acetate alone. A third chemical, (Z)-7-dodecenal, when present with the other compounds, produced a lure more competitive with female-baited traps but not significantly better than the two-component lure. Pheromone-baited traps placed in the middle and upper crown of white or black spruce caught significantly more insects than traps in the bottom of the crown of either tree species.

ISSN:1754-5692    

DOI:10.1093/ee/16.4.905

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Fish meal-baited water traps were used for assessing abundance and species composition of shoot flies, which are major pests of late-planted local sorghum cultivars in Senegal. Although 23 species ofAtherigonawere collected and recorded from five regions,Atherigona soccataRondani was the most common and abundant species. Females represented 80–97% of total flies trapped during 1977–81. Abundance was greatest during August–September. More flies were trapped in sorghum fields and grassy weeds than in fields with pearl millet. Correlations between rainfall, temperature, and relative humidity and fly numbers were present at all sites but an interaction existed between these parameters. Maximum temperature did not favor fly abundance. Late-planted sorghum was more severely attacked by shoot flies. Number of flies trapped was not significantly or consistently related to percentage of plants with fly eggs or dead hearts 14 and 28 d after plant emergence.

ISSN:1754-5692    

DOI:10.1093/ee/16.4.910

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Relative reduction in growth of root and shoot systems of the woody plant,Euonymus fortunei(Turcz) Hand.-Mazz., caused by the euonymus scale,Unaspis euonymi(Comstock) (Homoptera: Diaspididae), was determined, and the distribution and development of scales on the plants were investigated at the end of one generation. Weight of total abscised leaves increased, whereas weight and area of intact leaves, stem weight, and plant height decreased with increasing scale density. Root weight was not affected by scale infestation, but the root/shoot ratio increased with increasing density of scales. More females than males settled on the stems, whereas the sex ratio was nearly equal on the leaves. The proportion of scales reaching maturity was higher for females on stems than on leaves, and higher for males on leaves than on stems. This indicated either differential mortality or slower development of the sexes, depending upon settling site.

ISSN:1754-5692    

DOI:10.1093/ee/16.4.917

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Observations on the density and distribution of bees visiting two male-sterile (MS) and one male-fertile (MF) cultivar of sunflowers over a 3-yr period in commercial seed production fields in California revealed the honey bee,Apis melliferaL., to be the most abundant pollinator, making 98.9% of all visits. Honey bees were uniformly distributed across the male-sterile rows. Comparisons of bee density (mean number of bees per head) by cultivar indicated a preferential pattern of visitation in the order MS206 (1.25, 1.46, and 0.62, in three plots)>MS207 (0.18, 0.19, and 0.22)>MF207 (0.08, 0.07, and 0.07). Difference in nectar production may be a possible cause of discrimination, in addition to differences in inflorescence type, size, and color. Discrimination by honey bees may be an important limiting factor in pollination because bees confining their visits to one parent would reduce pollen flow.

ISSN:1754-5692    

DOI:10.1093/ee/16.4.922

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Adult female Banks grass mite (BGM),Oligonychus pratensis(Banks), exhibited a behavior that has been associated with aerial dispersal in other small, wingless arthropods. This behavior consisted of a raised posture with a consistent orientation. When exposed to wind and light, those BGM exhibiting the aerial dispersal posture consistently oriented away from light regardless of position of the wind source in relation to the light. Mites did not exhibit the aerial dispersal behavior in absence of either wind or light. Mites held on inert arenas at 25% RH exhibited the aerial dispersal behavior with increasing frequency over a 6-h period, after which the level of response remained at ca. 12%. Increased relative humidity resulted in lengthened time to reach the maximum response; at 95% RH none of the mites exhibited the behavior within a 12-h test period. In contrast,>47% of the twospotted spider mites (TSM),Tetranychus urticaeKoch, collected from corn exhibited the aerial dispersal behavior at 25% RH after 6 h, and the response curve for TSM continued to increase to a level of 62%

ISSN:1754-5692    

DOI:10.1093/ee/16.4.928

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Taylor's power law analysis was performed on among- and within-subsample mean and variance estimates of the number ofUrophora affinisFrauenfeld andUrophora quadrifasciata(Meigen) galls per spotted knapweed seed head. Highly significant correlation coefficients suggested that Taylor's power relationship fits the data well. A comparison of thebparameters from Taylor's analyses suggested that the spatial dispersion ofU. affiniswas more clumped than that ofU. quadrifasciata. The spatial dispersion ofU. quadrifasciataappeared to become more uniform in the presence ofU. affinis. Means and estimated variances (among and within subsamples) were used to develop numerical sampling equations for the two fly species. A cost (work effort) analysis was performed on the among- and within-subsample units. Optimal subsample sizes calculated for overall mean gall densities ofU. affinisandU. quadrifasciata(averaged over all sampling sites) were 18.95 and 21.86 seed heads per subsample, respectively. To protect against sampling low population sites, it is recommended that 15 subsamples of 25 seed heads each be collected per sampling site and used to assess population levels of the two fly species. Information presented in this paper should improve accuracy and efficiency in future sampling ofU. affinisandU. quadrifasciataand aid in determining those sites warranting future releases of the flies.

ISSN:1754-5692    

DOI:10.1093/ee/16.4.933

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

In laboratory tests, the maximum proportion of oothecae of the oriental cockroach,Blatta orientalisL., parasitized by the evaniid wasp, Prosevania punctata (Brullé), was 51%. Significantly (P<0.05) more 1-d-old oothecae than 28-d-old oothecae, and oriental cockroach oothecae than American cockroach oothecae, were parasitized. In field surveys, the greatest percentage of oriental cockroach oothecae parasitized byP. punctatawas 35%, which decreased as the cockroach infestation level increased. An education program for residents significantly (P<0.05) reduced the percentage of residents who thought the wasps were a problem or killed them. However, 60% of the residents still killed evaniid wasps when they found them.

ISSN:1754-5692    

DOI:10.1093/ee/16.4.938

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Data are presented on range, density, and distribution ofHemileuca oliviaeCockerell in Chihuahua, Mexico. Populations were found near Cuauhtemoc, Anahuac, and at various locations between Chihuahua City and El Sueco, but were absent from overgrazed and agricultural lands, and grasslands in the Chihuahua Desert. Egg clusters were distributed randomly at a height of 21.2 ± 9.5 cm from the base of grass stems, primarilyBouteloua gracilis(H.B.K.) Lag. Development ofH. oliviaewas asynchronous within and between sites. Sixth instars had a clumped distribution and a maximum recorded density of 24.44 per 100 m2

ISSN:1754-5692    

DOI:10.1093/ee/16.4.945

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

FemaleAnthonomus grandis grandisBoheman prefer to oviposit in cotton flower buds that are pristine. Laboratory studies showed that they laid ca. 4-fold more eggs in pristine squares than in previously oviposited squares with the ovipositional nipple exposed and 2-fold more eggs in pristine squares than in previously oviposited squares with the ovipositional nipple concealed. Field observations showed that females failed to oviposit in 81% of squares that contained ovipositional punctures, 62% of squares that were otherwise damaged, and 15% of pristine squares encountered. Discriminatory behavior began to break down after a female encountered three to four damaged squares. Laboratory tests indicated that both physical and chemical signals are involved in the discriminatory behavior.

ISSN:1754-5692    

DOI:10.1093/ee/16.4.951

出版商:Oxford University Press    

年代:1987

数据来源: OUP