摘要:

SUMMARYThe development of sciarids was reduced in old casing and in casing to which a commercial composting additive was added in large amounts. In laboratory tests, adding water, soya bean, cotton seed or oatmeal to finished mushroom composts reduced the mean development time of the larvae ofLycoriella auripila.Soya bean meal significantly increased the number of adult sciarids which matured. While the presence of mushroom mycelium in large quantities inhibited the development of sciarids, smaller amounts increased either the number of larvae maturing or their rate of development in different tests. Larvae were seen to feed on mycelium. The addition of sucrose solution either reduced or prolonged development time in different tests. Nitrogenous additives encouraged the growth of ‘weed moulds’. Both these and the number of sciarids which developed were reduced by adding a solution of calcium nitrate. The results suggested that more selective composts, favouring rapid mycelial colonization, would provide ‘cultural’ control of mushroom s

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01595.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYThe effect of increasing spore concentration ofAlternaria solani(Early blight disease) on the shoot growth of young tomato plants was analysed. Changes in growth were related to the severity of infection which increased with increasing inoculum. Leaf production was not affected but dry weights and especially leaf expansion were decreased. The effective leaf areas of the five inoculated leaves (L1‐L5 numbered from the plant base) were drastically decreased by expanding necrotic lesions and, to a lesser extent, by premature leaf fall. Healthy leaves expanding soon after inoculation (L6, L7) were markedly affected by the disease on the lower leaves and had decreased specific leaf areas (ratio of leaf area to leaf dry weight) but later formed (from L8) leaves were less affected and had greater specific leaf areas than equivalent leaves on uninoculated plant

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01596.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYThe growth of wheat seedlings which were already mycorrhizal when transplanted to a field deficient in phosphorus was improved compared with non‐mycorrhizal controls, and grain yield was increased three‐fold by the fungus, indicating thatEndogonestimulated growth and increased yield. Differences between mycorrhizal and non‐mycorrhizal wheat were eliminated by the application of phosphate fertilizer, indicating that the fungus does not enhance wheat growth in soils containing enough available phosphate. It is probable that the mycorrhizal effect is primarily to improve the supply of phosphate. There were clear relationships between spore number in the soil and mycorrhizal development and between the extent of root infection and increased growth. The extent of root infection was greatest in mycorrhizal plants in soil not supplemented with phosphate and it decreased in inoculated plants in the plot supplemented with superphosphate.The non‐centrospermous and non‐zygophyllaceous weeds growing on the experimental field had typical vesicular arbuscular infection and indigenousEndogonespores in their rhizospheres. The centrospermous plants were non‐mycorrhizal and had noEndogonespores in their r

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01597.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYSerological cross‐reactions among eighteen virus isolates of the tombusvirus group were compared in precipitin tube and immunodiffusion serological tests. The isolates were also compared by immunoelectrophoresis in agar gel.Although precipitin tube tests showed considerable and reproducible differences between the various isolates, the results were too greatly affected by other factors to be of value in assessing strain relationships.When pairs of isolates were compared for spur formation in gel‐diffusion tests, the results suggested that most isolates could be placed in one of two groups; one group comprised isolates from pelargonium (leaf curl), the other consisted of petunia asteroid mosaic virus and artichoke mottled crinkle virus isolates from Italy and tomato bushy stunt isolates from soil around this Institute and from cherry. Four isolates did not fall into either of these groups; they nearly always formed spurs when compared among themselves, or with viruses in either of the two groups. Pairs of isolates that could be distinguished from each other in spur‐formation tests using antiserum homologous to one of them could not always be differentiated when antiserum heterologous to both isolates was used.Immunoelectrophoresis gave consistent results with several methods of virus preparation; it indicated grouping and separation of the isolates in general agreement with the results of gel‐diffusion tests: all pelargonium leaf curl isolates were grouped together with slow migration towards the cathode. The petunia asteroid mosaic isolate and the isolates from cherry and from soil from this Institute (GCRI) moved slowly towards the anode. Tomato bushy stunt virus type strain migrated rapidly to the cathode, differing greatly from all other isolates. The method offers a relatively simple means of typing isolates of the tombusviru

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01598.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYHigh volume sprays of dichlofluanid (0.1 % a.i.) reduced total fruit numbers but gave better control ofBotrytis cinereainfections of tomato stems, leaves and fruit than sprays at 0.05 or 0.025% a.i. Surface residues from the sprays at 0–1, 0.05 or 0.025% a.i. were respectively 5.4, 1.6, 0.7 μg/g fresh weight of ripe fruit at harvest. Tank‐mixed zineb (0.12% a.i.) and captan (0.2% a.i.) were less effective and increasing the spray intervals from 1 wk to 2 and 3 wk reduced the fungitoxicity of captan and zineb more than that of dichlofluanid. Harvest residues on ripe fruit were 7.1, 2.8 or 2.4 μg/g when dichlofluanid (0.1 % a.i.) sprays were applied at 1, 2 and 3 wk intervals respectively. Good control ofB. cinereawas achieved if the whole plant was sprayed initially with dichlofluanid as soon as the second truss was flowering and subsequent sprays were restricted to the upper section of stem including the four or five youngest trusses of buds, flowers and fruit.When used as a post‐infection spray there was a period ofc.8 wk before dichlofluanid markedly reduced the incidence of grey mould. Tank‐mixed zineb (0.12% a.i.) controlledBotrytisfruit spotting but not leaf and stem infections.Botrytisstem lesions extended more rapidly on zineb‐sprayed plants than on unsprayed plants or on plants treated with captan or di

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01599.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYField trials in south eastern counties of England over the period 1967‐72 have been carried out on sites infested by the cereal cyst‐nematode,Heterodera avenae.In the main, spring barley was the cereal used, since this is the dominant cereal grown, and during this period resistant cultivars became available. Behaviour of soil populations of this nematode was erratic, but resistant cultivars from the Welsh Plant Breeding Station, based on Rika/Proctor, consistently lowered the nematode population in the soil, and outyielded more modern susceptible cultivars on infested soils. Evidence was found, in 1972, of a reduction in viability of cysts, associated with dise

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01600.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYIn sandy clay loam under glass 11.2 kg a.i. Du Pont 1410 alone or with 448 kg Di‐Trapex CP/ha, 441 kg dazomet with 448 kg Telone or 448 kg Di‐Trapex CP/ha, prevented potato cyst‐nematodes,Heterodera pallida, increasing on KNVF tomato rootstocks. In the heated glasshouse where the soil was treated with 441 kg dazomet/ha alone, the nematodes increased in the top 10 cm of soil, whether the soil was sealed with Polythene sheeting or water and whether dazomet was applied as dust or prill (small granules). Methyl bromide at 1276 kg/ha did not control the nematodes in soil 20–30 cm deep in one of the treated plots. Tomatoes grew well after all treatments except Du Pont 1410 which had little, if any, effect on grey sterile fungus (Pyrenochaeta lycopersici). Dazomet with Telone or dazomet with Di‐Trapex CP inhibited root damage by t

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01601.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYIncorporating either Du Pont 1410 or Nemacur P at 11‐2 kg a.i./ha in peaty loam topsoil in Spring, controlled potato cyst‐nematodes (Heterodera rostochiensis) to 20 cm deep as well as did 5.6 kg incorporated in Winter before ploughing followed by another dose of 5.6 kg incorporated in the seedbed in Spring. In pots Du Pont 1410 remained effective after several months incubation in soil at 5 or 10oC. Dazomet at 440 kg/ha incorporated in the topsoil in Winter (220 kg before ploughing and 220 kg after ploughing) did not control the nematodes as consistently as 5.6 or 11.2 kg a.i./ha of Du Pont 141 o or Nemacur P, even when the dazomet‐treated plots were covered with Polythene sheeting to prolong fumigation. In large containers, aldicarb at 45 mg a.i./13 l soil increased the yield of Arran Banner potatoes as much when incorporated to 13 cm deep in moderately infested peaty loam as when incorporated to 25 or 38 cm deep, but not as much as when all the soil (to 51 cm deep) was treated. Treating the soil to 13 cm deep did not control the nematodes 13–25 cm deep even though some of the nematicide was probably leached into this layer. In field plots, the nematodes were better controlled when Du Pont 1410 or Dowco 275 was rotavated into the top 10 cm than into the top 20 cm of a peaty loam soil. Rotavating soil twice instead of once after applying aldicarb, Du Pont 1410 or Dowco 275 to the soil surface did not increase nematode control. Although small amounts of aldicarb incorporated into the topsoil in Spring controlled the nematodes, the same amounts concentrated in the seed furrows, just before susceptible potatoes were planted in them,

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01602.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYSugar beet were grown for short periods with different amounts of moisture in the soil and air. Growing plants in wet soil (23 % moisture on dry weight) compared with dry soil (15% moisture) increased growth of the shoots and roots and plant dry weights by 15% in young plants and 10% in mature plants. Growing plants in wet air containing 10.9 g m‐3of water (equivalent to a saturation deficit of 2.5 mb) compared with dry air containing 6.4 g m‐3of water (saturation deficit = 8.5 mb) increased the dry weights of both young and mature plants by 8%, mostly by increasing the sizes of their storage roots. Wet air and wet soil increased the net assimilation rates of both young and mature plants. Wet soil, but not wet air, increased leaf areas of young plants by accelerating leaf expansion, and both increased the leaf area of mature plants by slowing senescence of the older leaves. Wet soil increased the water potential of the leaves of both young and mature plants and, by doing so, increased their stomatal conductances and rates of photosynthesis. Wet air also increased stomatal conductances and rates of photosynthesis of leaves of plants of both ages, but without changing their water potentials. Stomatal conductances and photosynthetic rates were greater for young leaves than mature on the same plant and at the same water potential. It is suggested that at certain stages in the crops growth photosynthetic efficiency could be increased by applying additional water as a mist to increase the moisture content of the air around the c

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01603.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYIn white clover plants grown and nodulated in a common soil environment the subsequent yield of vegetative propagates was generally greater when nodulated by rhizobium from the nodules of the parent or related plants than with that from unrelated plants. There were, however, exceptions to this, suggesting that clover productivity may be improved by selecting high coefnciency partnerships and sowing inoculated seed.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01604.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY