摘要:

Burley tobacco harvested immediately after treatment with 0.5 Ib/acre of endosulfan and cured for four months contained average total endosulfan residues of 23.2 ppm. Residue levels in the top, middle, and bottom leaves were 49.6, 13.2, and 6.7 ppm, respectively. On the top leaves, endosulfan I comprised 13 percent, endosulfan II 78 percent and endosulfan sulfate 9 percent of the total. The sulfate accounted for approximately 20 percent of the total residues on the middle and bottom leaves, with a corresponding decrease in the concentration of endosulfan II. When the time between treatment and harvest was increased to 28 days, the average total residues on the cured tobacco was 2.2 ppm, with almost equal quantities on top, middle, and bottom leaves. Treatment at 42 and 70 days prior to harvest resulted in 0.64 and 0.34 ppm total residues and 1.15 and 0.41 ppm highest residues in the bottom leaves. Comparing the levels of residues in freshly harvested tobacco with those in cured tobacco showed that the loss during curing decreased as the time between treatment and harvest increased to 14 days (53 percent loss), but remained constant thereafter.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.845

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Several halo- and cyanopyrroles related to the trail pheromone ofAtta texana(Buckley), were prepared and tested by a faster and more sensitive bioassay than was previously available. Responsiveness of the ants in descending order to these compounds, based on the substituent in the number two position, is: esters, methyl ketones, aldehydes. Slight activity was observed when the nitrogen atom of the pyrrole ring was alkylated.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.851

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

The effects of temperature and relative humidity on egg hatching, survival of first-stage larvae, and entrance into the soil byOtiorhynchus sulcatus(F.) were studied. Soil-surface temperatures under and outside strawberry foliage and the relative humidity under strawberry foliage were measured in the field.Newly-laid white eggs were more susceptible to extremes of temperature and relative humidity than they were after 3–4 days when they had become pigmented. Constant temperatures above 26.7° or below 15.6°C greatly reduced hatching. One or three exposures of three or six hours at 26.7° or 32.2°C interspersed with 15.6°C had less effect.Constant relative humidity of less than 65 percent reduced hatching to almost nil. A six- or 12-hour exposure to 33 percentRHduring incubation at 85 percentRHhad no effect. As many as 5-exposures to 33 percentRHinterspersed with 85 percentRHhad little effect.Survival of first-stage larvae was greatly reduced at relative humidity of less than 85 percent. The larvae would not enter layer of air-dried soil over moist soil, if the dry soil was over 15 millimeters deep, unless sufficient time was allowed for establishment of moisture gradient.Soil-surface temperatures and relative humidities under strawberry foliage would seldom harm eggs, especially those pigmented. Dryness of the soil surface could be serious detriment to newly hatched larvae.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.855

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Laboratory populations that served as host forAphelinus asychis(Walker) were composed of different combinations of the greenbug,Schizaphis graminum(Rondani); the corn leaf aphid,Rhopalosiphum maidis(Fitch); and the yellow sugarcane aphidSipha flava(Forbes). Although the greatest number of mummies was observed at different temperature and longevity combinations for each species, the same general trend appeared when the number of mummies became large; the number of aphids parasitized increased with increasing temperature to an optimum temperature, and then decreased.A. asychispreferred the greenbug, followed by the corn leaf aphid, and then by the yellow sugarcane aphid.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.859

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Discrete frequency distributions obtained from samples of various arthropods commonly found in Texas cotton fields were fitted to 6 discrete mathematical frequency-distribution models. The observed frequency distributions most frequently fit the negative binomial expectations, suggesting a clumped pattern of dispersion. These same arthropods were seldom observed to be randomly dispersed as indicated by poor agreement with the Poisson expectations.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.863

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Individual leaves of cotton plants were treated with14C-labeled chlordimeform by petiole injection or by foliar application. About 45 percent of the applied foliar dose was absorbed immediately, and the balance volatilized from the surfaces of leaves in 2 hours. The radioactive metabolites of chlordimeform that were tentatively identified includedN'-( 4-chloro-o-tolyl)-N-methylformamidine, 4'-chloro-o-formotoluidide and 4-chloro-o-toluidine. Also detected in small concentrations were two unidentified organosoluble materials, unextractable radioactivity that accumulated in aged leaf tissues, and some water-soluble radioactivity that appeared to consist, for the most part, of conjugated material. TheN-demethyl derivative of chlordimeform was somewhat persistent in leaves and was therefore the major radioactive product recovered at four weeks after treatment.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.869

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

The release of 574,850 male and femaleLaspeyresia pomonella(L.) (sterilized with 40 krad of gamma irradiation) into a 20-acre apple orchard near Yakima, Washington, provided comparative field data concerning the effects of season and of type trap (pheromone and light) on catches of codling moths. The 15-watt blacklight, six-watt blacklight, eight-watt bactericidal lamp, and six-watt Argon lamps in light traps were 25.4, 17.7, 14.7, and 0.94 percent as effective, respectively, as pheromone (sex) traps baited with 10 virgin females. The average correlation between the native population and subsequent entries within the orchard was 0.72. An expected infestation of 6.96 percent in 1,554,100 apples was limited to 0.51 percent (92 percent reduction) by release of the sterile codling moths.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.873

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Unidentified mixed pollen collected byApis melliferaL. was decontaminated with ethylene oxide (EtO). Amino acid analyses of untreated and fumigated pollen revealed that levels of all amino acids examined except proline were lower in fumigated pollen. Thirty-one percent of the methionine, an amino acid essential to honey bees, was destroyed by treatment of pollen with EtO.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.881

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Comparisons betweenPsylla pyricolaFoerster populations on a resistant and a susceptible pear topworked into the same trunk stock show that resistance to this pest is due to Ovipositional preference and nymphal antibiosis. Fewer eggs are laid on the resistant cultivar. than on the susceptible cultivar, and nymphal mortality is higher on the resistant cultivar than on the susceptible cultivar. The level of resistance present in the resistant cultivar was sufficient to suppress the pear psylla even though the adjacent susceptible cultivar was defoliated by the pest.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.883

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

A network is described which will provide real-time information for agricultural pest management systems. Its initial function is to provide critical information concerning biological interactions related to economic pest problems. The principal shortterm objectives of the network are to: provide a data base from which system modeling can continue; provide environmental information for the purpose of controlling growth chambers; provide a means of synchronizing various components of existing models (plants, pests, parasites etc); predict field events and alert biologists as to the timing of critical biological measurements. The long-term use of network will be to verify predictive models and to provide a time-temperature base for sensing the state of the pest system.

ISSN:0046-225X    

DOI:10.1093/ee/2.5.889

出版商:Oxford University Press    

年代:1973

数据来源: OUP