摘要:

A population ofLaspeyresia pomonella(L.) established on apples was compared with one from walnut as to the longevity of moths and oviposition capacity of females in relation to developmental condition of larvae (diapause vs. nondiapause) and to the weight of pupae. Comparisons were made with field collected material and among populations reared from 1st–3rd generations in the laboratory and after 12 generations. There was no difference in longevity between walnut and apple races nor between moths from diapausing and non-diapausing larvae, with the exception that moths from field collected diapausing larvae of the walnut race were short-lived. Variability sharply reduced as the populations adapted to laboratory conditions. Male moths lived longer than females, and isolated moths longer than paired sexes. Longevity was directly related to pupal weight, with a more pronounced response in males. Oviposition was lowest by moths from field collected diapausing larvae. From 57–80% of the populations were lost in the process of adapting to the laboratory, e.g., females from field collections which did not mate. Variability in oviposition was reduced in adaptation to laboratory rearing. Oviposition/female was related to pupal weight in both strains and both strains had equivalent pupal weights. However, laboratory reared moths of the walnut strain oviposited 49 more eggs/moth than the apple strain.If there is no correlation between mating adaptation under laboratory conditions and oviposition capacity, it may be concluded that the walnut strain had a higher reproductive potential than the apple strain.

ISSN:1754-5692    

DOI:10.1093/ee/3.3.402

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Reproduction in 2 biotypes ofSchizaphis graminum(Rondani) were compared under a controlled environment. Biotypes B and C were compared when both apterous and alate virginopara served as parents. Aphids were reared on winter wheat seedlings under simulated fall growing conditions of 17.2°C temp and a photoperiod of 12 h. Both biotypes produced approximately the same number of progeny, and within a biotype the ratio of winged to wingless offspring remaind parallel for both apterous and alate parents. However, biotype C produced approximately 25% alate offspring, as opposed to 1% for biotype B during the same period.

ISSN:1754-5692    

DOI:10.1093/ee/3.3.407

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Sorghum was treated with certain rates of the systemic insecticides acephate, disulfoton, CGA 12658 (Ent. no. 27,920), carbofuran, Counter® [S-(tert-butylthio) methylO,O-diethyl phosphorodithioate], and aldicarb. Sorghum treated with the latter 3 products had the lowest populations of greenbugs,Schizaphis graminum(Rondani), 37 days after planting and the lowest parasite mummy populations 58 days after planting. These populations were not significantly different from untreated check populations.At 37 days after planting sorghum treated with certain rates of carbofuran, C.G.A. 12658, and aldicarb had parasite mummy populations which were significantly lower in their numerical differences from the untreated check populations.The parasites were tentatively identified asLysiphlebus testaceipes(Cresson) andPachyneuron siphonophorae(Ashmead).

ISSN:1754-5692    

DOI:10.1093/ee/3.3.409

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

A significant, although low, number of the hymenopterous parasites,Lysiphlebus testaceipes(Cresson), emerged from mummies of the parasitized greenbugs,Schizaphis graminum(Rondani) during refrigeration at 3.3°C. After refrigeration, high numbers of adult progeny emerged at 24°C from parasite mummies stored at –4.4, –1.1, and 3.3°C for 7 days. The difference in the emergence numbers between the temperatures was non-significant, as were the differences between adult progeny numbers from mummies produced by virgin parasites and female parasites placed with males for copulation. Low numbers of adult parasites emerged at 24.0°C from mummies stored for 30 days at all 3 temperature levels and for 60 days at –1.1 °C. Development and emergence required 2–5 days more for those few parasites which emerged from mummies stored at –1.1°C, excluding the refrigeration period, when compared to uninterrupted development at 24.0°C which required 9–11 days.

ISSN:1754-5692    

DOI:10.1093/ee/3.3.412

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Sequential sampling plans forNabisspp. andGeocorisspp. on soybeans were developed from data obtained by use of the ground-cloth beat method from 1970–72. The sampling models were developed to classify populations of predators into low, medium and high categories. The spatial distribution of both genera fitted the Poisson series most frequently. Average sample number and operating characteristic curves were also calculated.

ISSN:1754-5692    

DOI:10.1093/ee/3.3.415

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Activity times ofPogonomyrmex occidentalis(Cresson) were found to vary with soil surface temperatures. Polynomial equations describe the relationship between the number of foraging ants leaving the colony and surface temperatures.Thirty-nine percent of forage particles brought into the colony were seeds and 24% were litter. The remainder consisted of dead insect material, insect prey, fecal matter, and rocks being brought in for mound construction.Studies conducted on populations in lightly- and heavily-grazed pastures showed no significant differences in the rate of forage extraction, foraging distance, time per foraging trip, or availability of forage (seeds). The ants removed about 2% of the seed biomass available to them.

ISSN:1754-5692    

DOI:10.1093/ee/3.3.420

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Radial growth and stand density of 30 loblolly pine stands throughout southeast Texas which had been attacked byDendroctonus frontalisZimmerman were characterized by measurement of annual increment and basal area. Annual increment was found to be significantly reduced in the last 2 cm of growth, but not related to tree diameter classes which indicates the trees were in a declining condition. Stand density was found to be very high in the infestation spots and was suggested to enhance perpetuation of localized infestations. The combination of reduced radial growth and high stand density was suggested to represent an optimal condition, in terms of susceptible host type, for the development ofD. frontalis.

ISSN:1754-5692    

DOI:10.1093/ee/3.3.425

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Comparison of the efficacy of spring and summer releases ofRhinocyllus conicusFroelich onCarduusthistles revealed that colonization is enhanced by releases made in early spring. Spring releases of only 25 non-diapausing adult weevils resulted in better colonization than releases numbering 1,000 weevils in late summer.

ISSN:1754-5692    

DOI:10.1093/ee/3.3.429

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Daily catches ofSynanthedon pictipes(Grote and Robinson) males in Door County, Wis., in traps baited with virgin females were correlated positively with maximum daily temperature and negatively with mean wind speed.The mean of the daily catch distribution was positively correlated to the onset of the “warm” period of the day. Maximum correlation (r= 0.92) was obtained when the “warm” period was defined by air temperature of 21°C or greater. No significant correlation (r= 0.3) was found between the mean of daily catch distribution and the termination of the warm period.Male catches gradually diminished to zero in a few hours of daily trapping although females were still calling. This phenomenon is interpreted as reflecting local depletion of the male population within the trap's “territory”.The components determining the effectiveness of a trapping system are briefly presented. The importance of the time when pheromone emission begins is discussed. The variability in the time of male response is incorporated into a mathematical model that predicts the number of matings on a given day.

ISSN:1754-5692    

DOI:10.1093/ee/3.3.431

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

The rates of parasitism of 1, 5, 10, and 50 mated pairs of the parasite,Voria ruralis(Fallen), on a known age and density of larvae of the cabbage looper,Trichoplusia ni(Hübner), in field cages were 8.9, 42.5, 62.2, and 85.1%, respectively. However, the percentages of parasitism per female at these respective densities were 8.9, 8.5, 6.2, and 1.7. Thus, an increased rate of superparasitism occurred when the density was higher than 10 females/cage.

ISSN:1754-5692    

DOI:10.1093/ee/3.3.439

出版商:Oxford University Press    

年代:1974

数据来源: OUP