摘要:

An investigation of selected literature indicates that numerous sources of resistance to insect attack have been obtained from plants that evolved in the absence of the insect to which they are resistant. These instances of resistance are not the result of natural selection and this may be beneficially significant in the use of such resistance in agriculture. If agricultural scientists are to capitalize upon such resistance, care must be taken to sequester and preserve the potentially important sources of resistance as well as the important domesticated plants that are currently in jeopardy.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.661

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

Teneral females of the twospotted spider mite,Tetranychus urticaeKoch, were utilized in standardized tests to gain information on the nature of the resistance of PI 251303, a tomato line previously shown to be highly resistant to this phytophagous mite. A choice tube technique, previously developed to study behavioral responses of this species to chemical stimuli, and a topical application technique were utilized to determine characteristics of repellency and antibiosis of essential oils of tomato foliage. These oils were obtained by steam distillation and fractionated by GLC. Both repellent and toxic components were found in these fractions. The 2 compounds most toxic toT. urticaewere subjected to mass and infrared spectral analyses which indicated that the compounds are sesquiterpenoids.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.670

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

Aedes vexans(Meigen) is a mosquito important to man in areas of low topographic relief in inland USA. Sources are both flood plains and upland depressions. Choice of flood plains as oviposition sites is affected by nature of vegetative canopy, moisture of the soil, plant detritus, frequency of flooding, and changes in the surface created by degree of siltation. Included are figures showing topographic relief, vegetative cover, and a dispersion diagram of eggs at a site typical of a wooded flood plain.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.675

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

The hypothesis that host-plant selection by the alticine flea beetle,Agasicles hygrophilaSelman and Vogt, may be influenced by the nutritive properties of alligatorweed was investigated. Alligatorweed deficient in phosphorus, calcium, and magnesium and plants receiving complete nutrition were used to study flea beetle attraction, feeding, and fecundity. Plants receiving complete nutrition were almost always preferred in feeding and fecundity tests to mineral-deficient plants. All responses were significant except fecundity in the minus-magnesium group and a choice test on attraction in the calcium group. The ratio of leaf tissue consumed per egg produced by the female was the same in both control and experimental groups.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.682

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

The rind hardness of the lowest internode enclosed by the uppermost leafsheath in which first instarDiatraea saccharalis(F.) larvae were found was determined for 8 commercial sugarcane varieties. A highly significant negative correlation (r= –.97) was found between the internode first accessible to attack and mean percent internodes subsequently bored byD. saccharalislarvae: The possibility of using this technique to differentiate host resistance toD. saccharalisin sugarcane breeding programs is promising.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.687

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

The foraging activity of 4 species of harvester ants as affected by soil surface temperature, saturation deficit at the soil surface, light and forage availability was studied in a desert grassland area 40 km NNE of Las Cruces, N.M.Pogonomyrmexsp. were capable of locomotor activity at temperatures between ca. 5° and 53°C andNovomessor cockerellibetween 4° and 52°C.Pogonomyrmexsp. exhibited maximum foraging intensity at 45°C andN. cockerelliat 20°C. Forager population sizes varied among species: 1000–6000 inP. rugosus, ca. 1000 inP. californicusandN. cockerelli; and ca. 200–600 inP. desertorum. P. rugosusexhibited peak foraging activity and had the greatest number of colonies active following drought periods, ceasing foraging when granaries were filled, and foraged at night during midsummer.P. desertorumandP. californicuswere strictly diurnal and did not exhibit hoarding behavior.P. desertorumresponded to soil wetting by shifting activity between watered and unwatered controls directly in response to differences in soil surface temperature. Soil wetting stimulated intense activity inP. rugosusat a time when controls were inactive. Foraging in harvester ants seemed to be primarily affected by forage availability, secondarily by microclimate, with historical factors and interspecific competition as contributing parameters in some species.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.689

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

Differences in population development of the twospotted spider mite,Tetranychus urticaeKoch, were observed on 5 hop varieties. Data collected from plants grown in the greenhouse and in the field indicated a positive correlation between farnesol content of the host plant and susceptibility to twospotted spider mite infestation.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.697

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

Eggs ofPlodia interpunctella(Hübner) were irradiated at different ages to determine the production and inheritance pattern of genetic damage and to assess the possible use of P1or F1adults for release in a sterile-insect release for population control. P1fertility and the numbers of F1adults were greatly decreased by 4-krad but not by 1- or 2-krad exposures to gamma irradiation. However, 2 krad was the highest dose that allowed an adequate percentage of the irradiated eggs (22.6%) to complete development to the adult. All combinations of age and dose that produced progeny (F1) were tested, and F1progeny were almost fully fertile and produced normal numbers of F2progeny. Irradiation of eggs for mass production of either sterile or partially sterile adults was found not to be feasible.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.701

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

Use of disparlure to disrupt mating of low-density populations of gypsy moths,Porthetria dispar(L.), was tested in central Massachusetts in 1974. In one area with a naturally low population, disparlure in slow-release microencapsulated form was applied to 2.6-km2plots at the following rates: 5 g lure/ha, 2 consecutive treatments each at 10 g lure/ha 2½ wk apart, and 20 g lure/ha; a 4th plot served as an untreated control. Results obtained by treatment with 5 g lure/ha were considered inadequate, mating success of exposed females was reduced 47% compared with the control; male captures in monitor traps and post-treatment egg-mass counts also indicated ca. 50% control. Treatments with the higher dosages were more successful: mating success of exposed females was reduced 94–97%, and male captures and post-treatment egg-mass counts were also markedly suppressed.In a 2nd area, 2 treatments with insecticide were applied to a 6-km2island in the Quabbin Reservoir to reduce its potentially high gypsy moth population to a low level. One-third of the island received no further treatment, ⅓ was treated once with 20 g lure/ha as microcapsules, and ⅓ was treated by mass trapping with 25 high potency disparlure-baited traps/ha. The 3 treatments all showed the same degree of mating by exposed females, 2.4–3.2% relative to mating on an untreated (control) island, on which mating was 85.4%, despite a low initial population. Captures in monitor traps totalled 14 in the area treated only with insecticide compared with 5 each in the other 2 areas and 467 in the untreated control. Although egg-mass counts were low in all areas, none were found in the area treated with both insecticide and microencapsulated disparlure.In both areas, high potency monitor traps showed promise as a means of measuring effectiveness of treatment within disparlure-treated areas.The 1974 results strongly indicate that the air-permeation technique employing slowrelease encapsulated disparlure at the rate of 20 g lure/ha is effective in reducing mating success in low-level infestations or in infestations reduced to a low level with an insecticide.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.705

出版商:Oxford University Press    

年代:1975

数据来源: OUP

摘要:

A 3-layer laminated plastic dispenser of disparlure, the sex pheromone of the gypsy moth,Porthetria dispar(L.), was effective in laboratory and field trials for an entire season and emitted lure at a fairly uniform rate whether its ends were open or sealed. Because lure content of the dispensers dropped very little after a season of exposure, the rate of emission of the laminates should be increased to increase attraction and make more efficient use of the lure. Cotton wicks performed as well as the laminated dispensers in the field, but in the laboratory their emission rates dropped sharply initially and then continued at a rate ca. 10-fold less than that of the laminates. Triangular traps caught more males than Johnson traps when both were baited with the same dispenser.

ISSN:0046-225X    

DOI:10.1093/ee/4.5.712

出版商:Oxford University Press    

年代:1975

数据来源: OUP