摘要:

SUMMARYExperimental warfarin treatments designed to reduce house‐mouse (Mus musculus) and common rat (Rattus norvegicus) populations in corn‐ricks are described. Baiting rick bases at permanent poison points or in rat holes was found not to be completely successful in controlling either rats or mice. Bait placed 1 ft. inside ricks in containers or wrapped in paper was effective in reducing the level of mouse infestation. In ricks treated after erection, baits wrapped in paper were more easily applied.Samples of threshed grain taken from each sack showed that ricks baited internally contained fewer mouse droppings but more poison bait residues than ricks baited at ground level o

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1961.tb03654.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYProvisional estimates of the total numbers of adultEphestia elutellaemerging from warehouse rooms of about 4000 cu.ft. were between 228,300 and 509,300 in ‘moderately infested’ rooms and 1,670,000 in a ‘heavily infested’ room.Moths caught on commercial fly‐papers are a useful index to the emergence date of adultE. elutella.A trial in a Liverpool warehouse in 1958 showed that lindane in a commercial whitewash mixture, applied to walls and ceilings to produce an initial deposit of 40 mg. γ‐BHC/sq.ft., will remain effective againstE. elutellabetween May and December. To obtain this deposit it was necessary to apply over twice this dosage. Very few active moths were seen and a negligible larval migration took place from trap bags which had been the only foodstuffs stored there.Observations over the same period in a warehouse which had been treated commercially at a heavy dosage, in December 1957, showed similar results.Cage tests in the laboratory and in the field indicated that malathion water‐dispersible powder, applied at an initial deposit of 162 mg. malathion/sq.ft., would theoretically be as satisfactory as lindane‐whitewash mixture. In warehouses, however, the former was not so effective as the latter, probably because of the marked fumigant effect of gamma‐BHC.There were indications that lindane‐whitewash mixtures alone might control infestations of endemicE. elutellai

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1961.tb03655.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYSheep have been dipped in various concentrations of aldrin and dieldrin and the rate of loss of insecticide on the wool has been determined using a biological assay method. In one experiment with aldrin, the biological assay method was confirmed by chemical analysis. Depletion is rapid immediately following dipping for a period of 2–4 weeks, after this it is much slower. It has been shown that when dipping is carried out at the normal time, i.e. May to June, the chemical persists for a period of 3–4 months. When sheep are dipped in late July and August, however, the period of protection is much greater. The distribution of insecticide over the fleece has been examined; the area with least pick‐up of insecticide is in the tail region where the wool is coarse. Weather and rate of wool growth could not be correlated with rate of insecticide

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1961.tb03656.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYLeaves of tomato plants grown in water culture in growth rooms were inoculated with sap from healthy tomato leaves or with sap containing tomato spotted wilt virus (t.s.w.v.). Changes in the free amino acids and amides of stems and of inoculated leaves, stem growth and infectivity were determined. Samples were analysed 5, 9, 13 and 17 days after inoculation using two‐dimensional paper chromatography.Inoculation with sap from healthy leaves, mixed with celite and sodium sulphite, caused small increases in glutamic acid, asparagine, glycine and serine in the inoculated leaves, and in glutamic and aspartic acids in the stems.In leaves inoculated witht.s.w.v., glutamine and asparagine increased greatly, reaching maxima at day 13. Both infectivity and amide levels were greater with more concentrated inoculum. The total free amino acids increased in leaves inoculated witht.s.w.v.by 150–180%. Increases were found in α‐alanine (day 9, 13 and 17) and in aspartic acid, valine, glycine and the leucines (day 13).Systemic infection of stems increased total free amino acids by 200–300% and amides by more than 400%. Serine, threonine, phenyl‐alanine, proline and the leucines increased at day 9 and reached maxima at day 13. Glutamine, asparagine, glutamic acid, aspartic acid, valine, tyrosine, α‐alanine, glycine and γ‐amino‐butyric acid increased at days 13 and 17.Changes in total free amino acids in stems and leaves were closely correlated with changes in infectivity.Five days after inoculation and 3 days before symptoms appeared, the levels of serine and threonine in the stems of plants receiving a dilute inoculum werelessthan those in controls.It is suggested that accumulation of NH2compounds in an infected plant may interfere with virus synthesis; this may explain the observed cyclical changes in infectivity.Free tyrosine and hydroxylysine were recorded for the first time in leaves and stems of healthy tomato plants and tyrosine and methionin

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1961.tb03657.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYThe growth of King Edward potatoes of a stock freed from paracrinkle virus was slightly but consistently superior to that of an infected stock, when grown in controlled environments. Although the leaves of the infected plants showed no evident symptoms, their lower water content suggested incipient N‐deficiency. Changes in daylength and night temperature affected virus‐free and infected plants similarly. Long days and high night temperature decreased tuber formation, and the higher tuber and total dry weights in short days probably resulted from increased leaf area and reduced stem gro

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1961.tb03658.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYXiphinema diversicaudatumis widely distributed in southern Britain, mainly in heavy soils, but also in the peat soil of the Fens and in medium textured soils in the south‐west. Patches of plants infected with arabis mosaic virus (AMV) in a range of crops including some, like celery and marrow, not before known to be hosts, coincide with patches of soil infested withX. diversicaudatum.Roots of some plants infested with the nematode carried small galls; not all such plants were infected with, or even susceptible to, AMV. AdultX. diversicaudatumtransmitted AMV more readily than larvae, but none of 103 nematodes, transferred when moulting, infected healthy plants.X. diversicaudatumwere still infective after 24 days in moist peat, free from plants.X. diversicaudatumis common in several districts in soil from old hedgerows but not in the adjacent fields. Hedgerow trees seem to be hosts of the nematode and at least one, elder, is also a host of AMV. In other districts, plants with AMV occur in crops near to infested hedges or isolated trees, and on land taken into cultivation after being derelict. In the Tamar Valley, Devon,X. diversicaudatumis common in pastures; white clover in these often contains AMV. Planting such fields with strawberry leads to disease outbreaks.A fewX. diversicaudatumoccur down to 3 ft. in soil, but most are at 3–9 in. At a site where arable land has reverted to woodland, the nematodes apparently have spread from a hedge into the woodland at an average rate of 1 ft. per year over a period of 75 years. It is suggested that bothX. diversicaudatumand AMV are common constituents of natural woodland in Britain and that their incidence has decreased since the advent of agricult

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1961.tb03659.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYViable filter‐passing particles have been obtained from gall‐tissue cultures ofCorynebacterium fascians.On gelatine media filtrates of the cultures first produced a faint clouding of the liquefied gelatine; this was due to masses of granules of very variable size. In some cultures further development took place, the next phase being the appearance of diplococci. Sometimes the coccal stage persisted but occasionally complete regeneration of the normalC. fascianstype rod finally ensued. This sequence of growth follows the pattern designated as the ‘L phase’, occurring in the life‐history of certain bacteria. Growth of L forms probably occurs inAgrobacterium tumefa

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1961.tb03660.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYSpores were liberated at 0.25 and 1.0m. above grass. Airborne concentrations at twenty or more points in the spore cloud were measured with specially designed and calibrated miniature suction traps, operated off a portable vacuum system. Deposition in the downwind direction was measured on artificial surfaces on the ground. Measurements were made up to 10 m. from the source.The observed increase in horizontal cross‐wind standard deviation of theLycopodiumcloud agreed well with O. G. Sutton's theory, but was incompatible with that of W. Schmidt.The coefficient of deposition,p, calculated from mean cloud concentration per c.c. and deposition to ground per cm.2, as well as the velocity of deposition,vg, varied with distance from source. Bothpandvgwere larger forLycopodiumthan forGanoderma, and at the greater distances tested,vgapproximated to the expected terminal velocities of the particles in still air.The total number (Q0) ofLycopodiumspores liberated in each experiment was known, and tentative estimates of the proportion deposited within the sampling area indicated that, under day‐time winter conditions in England, the cloud lost not less than 13 to 24% of its load within 10 m. of the sou

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1961.tb03661.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYIn twelve experiments known quantities ofLycopodiumspores (in five with spores ofPodaxis) were liberated into the open air artificially from a point source, under different meteorological conditions, and trapped on ‘Vaseline’‐coated slides, placed horizontally at: 2.5, 5.0, 10.0, 15.0, 20.0, 25.0 and 30.0 m. from the source, along from five to thirteen radii (20° apart in some experiments, and 5° or 10° apart in others).The size of spore had little effect on the relative numbers ofLycopodiumandPodaxisspores deposited at different distances (the deposition gradient), but from a cloud containing ten times as manyPodaxisasLycopodiumspores over twice as manyLycopodiumwere deposited per unit area as werePodaxisspores. The rate of deposition is thus approximately proportional to the volume of the individual spore.Estimated percentage recovery, within the sampling area, ofLycopodiumspores liberated varied from 5.4% (afternoon in wind of 4.4 m./sec.) to 91.6% (night in wind of 0.8 m./sec). Recovery ofPodaxisvaried from 0.3 % by day to 1.6% by night.The results of these experiments are examined in the light of the statistical theories of W. Schmidt and O. G. Sutton, which formulate atmospheric diffusion by eddies, and are found to be in closer agreement with the latter. The values of the parameters ‘m’ in Sutton's equation agree excellently with his theoretical values, but the values of the parameter ‘C’ a

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1961.tb03662.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SUMMARYIn several commercial‐scale experiments, bunches of bananas were treated by immersing for approximately 1 min. in 2% Shirlan WS and then rinsing in water. Reports obtained after ocean transportation and subsequent ripening of fruit in England indicated that this treatment effected poor or no control of fruit‐rot caused byGloeosporium musarumCke.&Massee. Possible reasons for this are discussed in relation to earlier laboratory tri

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1961.tb03663.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY