摘要:

In laboratory feeding preference tests using peanuts, soybeans, cowpeas, chinese cabbage, and sorghum,Aphis craccivora(Koch) (the cowpea aphid),Myzus persicae(Sulzer) (the green peach aphid), andRhopalosiphum maidis(Fitch) (the corn leaf aphid), all showed a preference for settling onto a host, regardless of the host species used, compared with wandering at random in the feeding arena and not feeding on any host plant.A. craccivorashowed the greatest propensity to wander in the feeding arena, whileR. maidishad the greatest tendency to settle and feed on the leaf disks. When offered combinations of two host plants,M. persicaepreferred chinese cabbage in four comparisons and soybean in two,A. craccivorapreferred soybean in two comparisons and chinese cabbage in two comparisons, andR. maidispreferred chinese cabbage in four comparisons and sorghum in three. Chinese cabbage, soybeans, cowpeas, and sorghum were preferred by the three aphid species over peanuts. Based on feeding preferences in this series of tests it is impossible to separate the relative abilities of the three aphids species to serve as vectors of peanut mottle virus (PMV) in peanuts. The three aphid species reproduced well on the plants on which they were reared. OnlyA. craccivorawas able to reproduce on either peanuts or soybeans in caged reproduction tests.

ISSN:1754-5692    

DOI:10.1093/ee/13.4.970

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

Five dominant spider families were found on Virginia soybeans, two on the ground (Lycosidae and Linyphiidae) and three on the foliage (Oxyopidae, Thomisidae, and Salticidae). Total foliage-dwelling spiders peaked in early August and again in early September 1981, and in early to mid-August in 1982. Ground spiders peaked in June with the greatest abundance of Lycosidae. While higher spider populations were collected from foliage in soybeans double-cropped after barley harvest and in full-season soybeans that were drill-planted, the ground spiders were more numerous in both barley- and wheatsoybean double-cropped systems. Over 25,000 spider specimens from 17 different families were observed in soybean ecosystems during this 2-year study.

ISSN:1754-5692    

DOI:10.1093/ee/13.4.975

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

Responses of laboratory-rearedTrichogramma pretiosumRiley to selected densities and distributions of augmented numbers ofHeliothis zea(Boddie) eggs were measured in cotton. In studies conducted near Tifton, Ga., rates of parasitization increased progressively from 24.4 to 31.0 to 36.0 to 43.7%, respectively, when 1, 3, 15, and 75 eggs were applied per 0.9 row m. The percentage of parasitization was also conditionally increased by the application of a hexane extract ofH. zeamoth scales (kairomones) at a dosage of 1 ml/0.3 m. The increase was apparently dependent on low levels of naturally occurring kairomone. Rates of parasitization also increased progressively beyond that of the control when 60 supplementalH. zeaeggs were applied per m of row, on rows two and six of eight-row plots, on alternate rows, and on all eight plot rows. In studies near Kerman, Calif., rates of parasitization onH. zeaeggs spaced 1/0.9 row m on kairomone-treated leaves increased from 24.3 to 53.6% when 60 supplementalH. zeaeggs were applied per 0.9 rowm. Data suggest that higher host densities intercept and retain proportionally moreT. pretiosum,which in turn yield higher rates of parasitization.

ISSN:1754-5692    

DOI:10.1093/ee/13.4.981

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

In choice experiments in the laboratory,Rogas lymantriaeWatanabe preferredLymantria dispar(L.) larvae overOrgyia leucostigmaJ. E. Smith, and development from oviposition to mummification was significantly longer inO. leucostigmathan inL. dispar.There were no differences in sex ratio ofR. lymantriaereared in the different hosts; hence,O. leucostigmais a suitable alternate host forR. lymantriae.Despite being reared onL. disparin the laboratory for over 50 generations,R. lymantriaeparasitizedL. disparin the field; future releases to establishR. lymantriaeshould be made whereL. disparandO. leucostigmaoccur together.

ISSN:1754-5692    

DOI:10.1093/ee/13.4.986

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

Life tables and tables of age-specific fecundity were constructed for the predaceous bugDufouriellus ater(Dufour) for relative humidity of between 53 and 62% and temperatures of 20, 25, 30, and 35°C. These tables were used to calculate the innate capacity for increase, the finite rate of increase, the generation time, the gross rate of reproduction, and the net rate of reproduction. The results indicated thatD. ateris capable of population increase over the entire range of temperature examined, although 20°C is very near the lower limit. Within this range, population increase was maximum at 35°C.

ISSN:1754-5692    

DOI:10.1093/ee/13.4.990

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

Lima and snap bean varieties that are currently being used to culture the Mexican bean beetle (MBB)and its parasite,Pediobius foveolatus(Crawford), were examined to identify the most efficient variety for the culture of MBB. ‘Top Crop,’ ‘Provider,’ ‘Spartan Arrow,’ and ‘Burpee's Stringless’ snap beans and ‘Henderson’ lima beans were compared by constructing life tables for MBB on each variety. Varietal growth rates and responses to MBB culture conditions were also compared. Mean durations of immature MBB development were significantly different between all varieties, being shortest on ‘Spartan Arrow’ at 19.9 days. The preoviposition period was shortest and oviposition period longest on ‘Provider,’ being 8.9 and 27.2 days, respectively. Larval and pupal survivorships were higher on ‘Henderson’ (61.7%) and ‘Provider’ (60.4%) than on the other varieties. MBB females produced significantly more egg masses (16.5) and eggs (839.7) on ‘Provider’ than on any other variety. The highest net reproductive rate occurred on ‘Provider’ (222.5 female progeny per female), but the shorter generation times were on ‘Spartan Arrow’ (48.0 days) and ‘Henderson’ (48.1 days). As a result of these differences, MBB on ‘Provider’ and ‘Henderson’ exhibited higher intrinsic rates of increase (0.1172 and 0.1112, respectively). These results and observations on growth rates of the varieties and their responses to MBB culture conditions indicated that ‘Henderson’ lima beans was the best variety of those studied for culturing MBB.

ISSN:1754-5692    

DOI:10.1093/ee/13.4.995

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

Adult and larval European apple sawflies (EAS),Hoplocampa testudinea(Klug), were assayed for propensity to avoid resource sites (apple blossoms and growing apples, respectively) already occupied by conspecifics (i.e., assayed for host discrimination). Under laboratory conditions, adults oviposited significantly less frequently in blossoms containing oviposition wounds and eggs than in healthy, uninfested ones. Similarly, significantly fewer adults attempted oviposition in blossoms containing artificial oviposition wounds than in intact blossoms. These results suggest that wound tissue exudates provide information to EAS adults on the infestation state of individual blossoms. EAS larvae, following emigration from their first hosts, invaded uninfested apples significantly more often than apples harboring living conspecifics. Similar results were obtained when resident larvae were killed before testing. We were unable to determine the stimulus(i) larvae employ in the hostdiscrimination process.

ISSN:1754-5692    

DOI:10.1093/ee/13.4.1000

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

The attraction of three chironomid species,Glyptotendipes paripesEdwards,Chironomus crassicaudatusMalloch, andPolypedilum halterale(Coquillett), to incandescent light of different colors and wattages was studied. Field-captured adults were released from the center of a dark room (9 by 9 m) equipped with a New Jersey light trap in each corner. The effects of color were determined by using 100-W lamps of red, orange, yellow, green, blue, and white. The effects of light intensity were studied by using 100, 60, 40, and 25-W white lamps. Measurements of light intensity of each lamp were taken. Among the colors tested in two separate combinations, white light attracted the maximum numbers of adults and red light the least. The three species exhibited a similar behavior. Among white light of different intensities, the maximum attraction ofG. paripesoccurred toward the highest intensity and the minimum toward the lowest intensity. The midge species responded more to the quantity (power or intensity) than to the quality (color or wavelength) of light.

ISSN:1754-5692    

DOI:10.1093/ee/13.4.1004

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

Field experiments were carried out to determine if a copper-based fungicide known to deter feeding by the Colorado potato beetle,Leptinotarsa decemlineata(Say), in the laboratory, could suppress the growth ofL. decemlineatapopulations in the field when used regularly for plant disease protection on tomatoes, potatoes, and eggplants. Larval densities on plants treated with a fungicide formulated with copper hydroxide [Cu(OH)2] were between 44 and 100% lower than on untreated control plants or plants treated with a more commonly used fungicide, mancozeb. The greatest reductions occurred on tomatoes, the least suitable host of the three forL. decemlineatagrowth and survival.

ISSN:1754-5692    

DOI:10.1093/ee/13.4.1010

出版商:Oxford University Press    

年代:1984

数据来源: OUP

摘要:

The spatial dispersion ofTetranychus cinnabarinuswas studied for 2 year sin in insecticide-treated and untreated cotton. Spider mite distributions and population density were not affected by the pesticides tested. The linear regression of log variance against log mean (r2= 0.95) provided a better fit to the data than did the linear regression of mean crowding on the mean (r2= 0.80). The former regression was used as a basis for a sampling plan designed to estimate population densities ofT. cinnabarinuswith fixed levels of precision.

ISSN:1754-5692    

DOI:10.1093/ee/13.4.1015

出版商:Oxford University Press    

年代:1984

数据来源: OUP