bluuebunny/crossref_metadata_2025 huggingface dataset:
Extent of disease in populations of Heterodera, with especial reference to H. schachtii
Authors: TRIBE H. T.
Published: February 2008

Analysis was made of the extent of disease in 112 populations of Heterodera schachtii, comprising 88 populations of cysts obtained from soil samples and 24 populations of females and cysts taken from host roots. Overall, some 14% of full cysts taken from soil were diseased, although much variation was found. About half of the cysts were substantially and half partially diseased. Where beet monoculture had long been practised, overall disease was approximately doubled. Less than 50% of diseased cysts were parasitised by recognised egg pathogens and nearly the same proportion showed symptoms of lysis, coagulation or decay, the causes of which could not be ascertained. The remainder contained unexamined or miscellaneous fungi and a few showed oily degeneration. Disease in 10 populations of cysts from roots was higher than in cysts from soil. In females from roots it was especially variable, for most diseased females were invaded by one or two specific fungal pathogens in whose absence all were healthy. Examination of six populations of Heterodera avenae indicated the extent and nature of disease was not dissimilar from that in H. schachtii.

The pathogens, which were all fungi, and the disease symptoms of uncertain origin found in cysts and females of H. schachtii are briefly summarised.
Preliminary observations on variation in susceptibility to clubroot among collections of some wild crucifers
Authors: BUCZACKI S. T. , OCKENDON J. G.
Published: February 2008

Collections of Capsella bursa‐pastoris and other common cruciferous weeds showed significant differences in susceptibility to populations of Plasmodiophora brassicae as defined on the European Clubroot Differential (ECD) set. Some evidence was obtained that selection for tolerance may occur within natural populations of C. bursa‐pastoris. Overall virulence of P. brassicae collections on the ECD set was not correlated with virulence to the weeds tested. The significance of wild hosts in studies of resistance to P. brassicae is discussed.
Feral pigeon damage to field beans
Authors: LAWSON H. M.
Published: February 2008

Feral pigeon (Columba livia) feeding behaviour and its effect on crop growth and yield of field bean (Viciafaba) sown at three depths is described. By digging up seeds and destroying seedlings, pigeons reduced plant populations by over 95% on plots sown at 1–6 cm depth and by over 50% on plots with seeds at 2–2 cm in comparison with plant populations on plots sown at 2–9 cm. The pigeons returned at harvest time and caused varying levels of crop loss depending on plant density and especially on the degree of lodging of the crop. The results are used to illustrate the need to consider potential bird damage as a factor when changes in husbandry systems are being developed.
Studies on the tolerance of Erysiphe graminis f. sp. hordei to systemic fungicides
Authors: WALMSLEY‐WOODWARD DIANNE J. , LAWS F. A. , WHITTINGTON W. J.
Published: February 2008

Successive sowings of glasshouse‐grown barley plants were treated with either tridemorph, ethirimol or both fungicides, and inoculated with an initially fungicide‐sensitive isolate of Erysiphe graminis f. sp. hordei. The time taken for symptoms to appear, compared with that for untreated plants, decreased with successive sowings. This was interpreted as evidence for the increase in the frequency of fungicide‐tolerant propagules in the pathogen population.

Effective mildew control was obtained by the use of either or both fungicides in trial plot and field crops. Seedling assays for tolerance to tridemorph and ethirimol showed that tolerance was more evident in treated than in untreated crops in June. Some mildew populations partially tolerant to one fungicide also showed reduced sensitivity to the other. By July a response intermediate between tolerant and sensitive was recorded on all the plots, probably indicating the mixing of fungal populations from adjacent plots. Larger numbers of tolerant isolates were found in random samples from treated than from untreated crops.
Effect of temperature on competition amongst strains of Rhizobium trifolii for nodulation of two white clover varieties
Authors: HARDARSON G. , JONES D. GARETH
Published: February 2008

The effect of temperature and soil type on the relative success in nodulating cultivars of white clover (Trifolium repens) by mixtures of antibiotic‐resistant mutants of Rhizobium trifolii was studied.

Under aseptic test‐tube culture, 75 str nodulated the plants 5 days earlier than 33 spc at the lowest temperature, but the temperature ×Rhizobium strain interaction was not significant. 33 spc was more effective than 75 str at 25°C and, although no significant difference was found between the two mutant strains at the lower temperatures, die temperature ×Rhizobium strain interaction was highly significant.

In soil, when inoculated with mixed inoculum, cv. S100 was more uniformly nodulated by 75 str (81%) than S184 (49%). Success in nodulation could be altered by temperature and the temperature × bacterial strain interaction was significant. In the mixed inoculum treatments, 75 str was most compatible with S100 at 12°C, whereas 33 spc was most compatible with SI84 at 25°C; the bacterial strain × variety × temperature interaction was highly significant.

The results are discussed from the point of view of improving symbiotic nitrogen fixation by selecting effective strains of Rhizobium which are compatible with the particular host cultivar, which are competitive with the indigenous population and whose optimum temperatures for nodulation and competitiveness are similar to the soil temperature at the times of inoculation.
The dispersal of Ditylenchus dipsaci with vegetable seeds
Authors: GREEN C. D. , SIME S.
Published: February 2008

Ditylenchus dipsaci was found in 36–45% of seed stocks of broad beans, red beet and carrots examined, in 14–17% of those of shallots and runner beans, and in less than 3% of those of peas, onions and leeks. None was found in any samples of chive and dwarf (French) bean seed. There was a tendency for seed stocks to be very lightly or very heavily infested so that small samples would be adequate to identify the stocks most likely to introduce stem eelworm. Seed from all sources whether merchant or farmer was equally likely to be infested and a difference in infestation between varieties was found only for broad bean. Judging by samples tested for export the risk of distributing D. dipsaci with onion seed seems to have decreased since 1968 so that there is more risk of introducing it with other crops grown before onions.
Aggregated distribution of Ditylenchus dipsaci on broad bean seeds
Authors: GREEN C. D.
Published: February 2008

The distribution of Ditylenchus dipsaci (Kühn) Filipjev between seeds in infested samples of broad bean seed was skewed so that the nematodes were concentrated on a few seeds. Such aggregation increases the likelihood of reproduction by the nematodes in infested plants and the consequent establishment of foci of infestation in the soil. These foci will be small and scattered giving the nematode the best chance of a finding a favourable environment in the field. The numbers of foci of infestation introduced by seed tend to be nearly constant, independent of the numbers of nematodes on the seed and therefore provide a stable unit of population.
The origins of weed beet
Authors: HORNSEY K. G. , ARNOLD M. H.
Published: February 2008

Samples of weed beet were collected from two fields in Norfolk, one in which they had been present for several years and could have evolved from normal sugar beet varieties, and another in which the weed beet were thought to have arisen more recently, through contamination of a monogerm variety. The samples were grown to maturity and used as mother plants in test crosses with monogerm O‐type (non‐restorer lines. Observations on the mother plants and on the progenies of the test crosses, with respect to the occurrence of the monogerm gene and of cytoplasmic male sterility, were consistent with the hypothesis that weed beet can arise by evolution from bolting plants in uncontaminated seet lots, as well as from seed lots that have been contaminated with annual forms of Beta vulgaris. This conclusion is important in relation to the need for implementing agronomic control measures for weed beet, as well as for eliminating the risk of releasing contaminated seed lots.
Efficacy of carboxin and heat treatment for controlling the growth of Sclerotium rolfsii during culture of the mushroom Pleurotus flabellatus
Authors: RAJARATHNAM S. , SINGH N. S. , BANO ZAKIA
Published: February 2008

Soaking paddy straw for 18 h in a carboxin suspension in water (5 mg a.i./l) effectively controlled the growth of Sclerotium rolfsii occurring as a natural contaminant in paddy straw, during culture of the mushroom Pleurotus flabellatus. Carboxin at this concentration delayed sporophore formation by 2–3 days, but did not affect total yield. No detectable carboxin residues were found in the mushrooms grown on the treated paddy straw. Treatment of the paddy straw with hot water at 60°C for 10 min completely controlled the contaminant without affecting mushroom growth and yield; but 20 mm treatments with hot air at 60°C or heating with the steam to 75–80°C did not control S. rolfsii.
The inheritance of preference for strains of Rhizobium trifolii by white clover (Trifolium repents)
Authors: HARDARSON G. , JONES D. GARETH
Published: February 2008

The preference or selection of Rhizobium strains by both parental and F1 white clover plants was studied using antibiotic resistant mutants of Rhizobium trifolii.

Highly significant differences were found between crosses in their preference for 75 str. Progenies from crosses between plants in which the preference for 75 str was 90–100% had 85% of the nodules inhabited by that strain. Progenies of crosses between plants in which the preference for 75 str was less than 50% had only 13% of their nodules inhabited by 75 str. Intermediate values were found for progenies from other crosses. The inheritance for this particular character was clearly additive and without any dominance or maternal effect.

The results are discussed from the point of view of improving symbiotic nitrogen fixation by breeding white clover for uniform preference for effective strains of R. trifolii.
Vigour control, an integrated approach to cane, pest and disease management in red raspberry (Rubus idaeus)
Authors: WILLIAMSON B. , LAWSON H. M. , WOODFORD J. A. T. , HARGREAVES A. J. , WISEMAN J. S. , GORDON S. C.
Published: February 2008

The first flush of young canes of red raspberry (Rubus idaeus) was removed at different dates in spring, using the contact herbicide dinoseb. In comparison with untreated plots, cane removal increased fruit yield, controlled excessive cane vigour, and improved the health status of vegetative canes in a plantation infested by raspberry cane midge (Resseliella theobaldi). At the end of the growing season vegetative canes on treated plots were shorter and thinner, and sustained less physical injury than those on untreated plots. Access to the fruit at harvest was also improved. Reduced competition between fruiting and vegetative canes increased yield in the year of treatment by an average of 35%. Yield was not affected by date of cane removal, but growth of replacement cane was reduced below optimum when first flush cane was removed after mid‐May.

The later the canes were removed, the less was the incidence of pest and diseases. Cankers and lobate vascular lesions (‘patches’) resulting, respectively, from the feeding of first and second generation midge larvae (with associated fungi) affected fewer canes in treated than in untreated plots. Significantly fewer live larvae of R. theobaldi were recovered in the following winter from soil in plots treated on or after 11 May than from untreated plots. The main effect of vigour control on R. theobaldi and midge blight was that replacement canes provided fewer egg‐laying sites (natural splits) than did the first flush canes on untreated plots. The incidence of spreading vascular lesions (‘stripes’) attributed to Leptosphaeria coniothyrium infecting either physical wounds (cane blight) or midge feeding wounds (midge blight) was substantially less in treated than untreated plots. Cane botrytis (Botrytis cinerea) and spur blight (Didymella applanata) were also less common in treated plots.

Interactions between vigour control and pest and disease incidence are discussed in relation to the efficient management of cv. Glen Clova in eastern Scotland.
Effects of fungicides and surfactants on the zoospores of Olpidium brassicae
Authors: TOMLINSON J. A. , FAITHFULL ELIZABETH M.
Published: February 2008

Lettuce big‐vein disease is transmitted from diseased to healthy plants by zoospores of the lettuce root‐infecting fungus Olpidium brassicae. A laboratory technique based on microscopical examination of Olpidium Zoospores is described for assaying the toxicity of chemicals to zoospores.

Chemcials found to kill zoospores in <1 h included copper (4 μ/ml), zinc (10μ/ml), diluted preparations of carbendazim (methyl‐2‐yl‐benzimidazole carbamate) as Bavistinand a formulation of Bavisitin containing no carbendazim. Bavistn controlled the disease when introduced at a concentration of 0.6 g/litre into a lettuce crop grown in a re‐circulated film of nutrient.

Various surfactants inlcuding Agral, Cetrimide, Deciquam, Ethylan CPX, Hyamine 1622, Manoxol/OT and sodium lauryl sulphate were toxic to zoospores at concentrations of 1–10 μ/ml.
Application of iprodione by thermal fogging for the control of grey mould of tomato
Authors: MORGAN W. M.
Published: February 2008

A ready‐to‐fog' formulation of iprodione applied with themal foging equipment was a satisfactory alternative to high‐volume (HV) sparys of iprodione for the control ofnatural infecton with grey mould (Botrytis cinerea) in an unheated tomato crop. There were no significant differences in numbers of droped fruit nor in the control of naturally‐occurring lesions in stems or leaves, nor of ghost‐spotting on fruit, between the HV sprays and fogs applied every fortnight. Except for ghost‐spotting, control by fogs applied weekly was better than by eihter for nightly treatment. In contrast, the control of infection from B.cinerea inoculations on peitoles was significantly better by the fortnightly HV treatment than by either frequency of foging. Control of infection imporved with increase in the number of fungicide applications to the peitole before inoculation; two HV sprays gave complete control but six fog applications did not. The variation in the conrrol of infection by fogs and presumbly therefore in the distribution of fungicide within the 61 m2 glasshouse compartments was small. Application of the iprodione fogging formulation significantly reduced the number of fruits see by about 5% compared with the HV treatment.
A strain of guniea grass mosaic virus naturally occurring on maize in the Ivory Coast
Authors: LAMY D. , THOUVENEL J.C. , FAUQUET C.
Published: February 2008

During a survey of cereal crops in Ivory Coast, a virus wiht flexuous filamentaous paricles c. 825 nm long was isolated from diseased maize. Its host range, biological properties, morphology and aphid transmission place it in the potyvirus group. Antigenically it is closely related to guinea grass mosaci virus, from which it differs in hos range, aphid transmissibility and behaviouir on isoelectric focusing. It is named guinea grass mosaic virus strain B.
The control of voulunteer potatoes in the autumn in cereal stubbles.
Authors: LUTMAN P. J. W.
Published: February 2008

The emergence of volunteer potatoes and their regrowth after the cereal harvest were studied in four barley crops. Cutting the shoots of the potato plants before or during cereal harvest did not prevent regrowtth of many of them afer harevet. There was more regrowth (i) after winter barley, (ii) after barley grown at above normal seed rates and (iii) when the early growth of the potatoes in May an June ws suppesed by dry conditions. In one experiment the number of emerged plants on 12 May was negatively correlated with the number of emerged plants on 12 May was negatiely correlated with the number regrowing in September. These studies suggest that control of volunteer potatoes may be possible with foliar applied herbicides after cereal harvest.
The Control of volunteer potatoes in the autumn in cereal stubbles.
Authors: LUTMAN P. J. W.
Published: February 2008

Many of the volunteer potato plants present in two winter barley crops continued to grow after the cereal harvest. Aminotriazole applied to this regrowth resulted in 50–69% fewer potato plants emerging in the year following treatment. Glyphosate gave better control, averaging 72% in one experiment and 88% in the other. Few of the potato plants regrew after harvest of two spring barley crops and with the same two herbicides over 70% of the tubers survived. Herbicide response was not affected by dose (glyphosate 0.5‐3.0 kg/ha and aminotriazole 1.5‐4.0 kg/ha). With adequate time for the potatoes to start regrowing after harvest (3–4 wk), there was no improvement in performance from further delay. The potential use of these two herbicides in cereal stubbles for groundkeeper potato control is discussed
Acetylene reduction assay on white clover genotypes and on grass/clover swards
Authors: CONNOLLY V. , O'KEEFFE M.
Published: February 2008

Acetylene reduction assay was used to measure the nitrogenase activity of white clover genotypes in pots and of grass/clover swards in situ. Much of the variation in nitrogenase activity of single genotypes and hybrid populations was associated with plant dry weight. After adjustment for plant dry weight it was concluded that there was limited scope for selection for increased nitrogenase activity. In plant breeding this technique would seem to have greatest application in the selection for continued nitrogen fixation activity in the presence of inhibitory factors such as high levels of mineral nitrogen.

The in situ studies revealed differences in nitrogenase activity of grass/clover swards based on contrasting cultivars of white clover. These differences were due to variation in clover density and also to variation in activity per unit clover dry weight. It was concluded that the variation in nitrogenase activity per unit dry weight reflected differences in growth pattern of the cultivars in the autumn when these assays were made.

The in situ studies offer a means whereby the nitrogenase activity of cultivars and selected families can be monitored under varying levels of mineral nitrogen and other husbandry treatments without disruption of the sward.
Doubling of onion bulbs as affected by size and planting date of sets
Authors: RABINOWITCH H. D.
Published: February 2008

The effect of size of sets and planting dates on the frequency of double bulbs was investigated with two early onion cultivars. The two cultivars varied significantly in their performance, with the cv. Beit‐Alfa being more prone to doubling than the cv. Ori. Bulbs developing from large sets produced more shoots per bulb and showed a higher percentage of doubling in the field. Environmental conditions changing with planting dates significantly affected the tendency for axillary shoot development. The effect of genotype and environmental conditions on doubling is discussed.
The effect of partial flower removal on the relation betwen root, shootand fruti growth in the indeterminate tomato
Authors: HURD R. G. , GAY A. P. , MOUNTIFIELD A. C.
Published: February 2008

The root, vegetative shoot and fruit growth of November and January sown glasshouse tomato plants grown in flowing water culture was followed over 6–7 months. The relationship between vegetative and reproductive growth was examined after two‐thirds of the flowers were removed from half the experimental plants. This resulted in larger plants which had fewer, larger fruits and eventually a fruit yield almost as large as the controls.

In the control plants, fruit growth increased steadily until it reached 90% of the total incremental fresh weight of the plant 50–60 days after first anthesis. Leaf growth was markedly depressed at this stage and root growth ceased 4 wk after anthesis. Some root death was observed from anthesis onwards. When fruit growth subsequently diminished, vegetative growth recovered but to a lower rate than before fruiting commenced. Following partial flower removal, only 64% or less of the total increment of fresh weight went into the fruit. Although vegetative growth at this stage was thus greater than in the control plants, both shoot and root growth followed the same qualitative pattern with time.

The ratio of vegetative shoot to root fresh weight remained essentially constant throughout the fruiting phase in plants of both sowings whether flowers were removed or not. This suggests that the fruit grew in competition with the vegetative organs as a whole, although, for a short period at early fruiting, root growth was more seriously affected.

The pattern and amount of fruiting in this indeterminate plant was influenced by the size of the vegetative organs at fruiting, and by the effect of the existing developing fruit on further vegetative and reproductive growth.
Cavity spot of carrots.
Authors: A PERRY D. , HARRISON J. G.
Published: February 2008

Cavity spot is initiated anywhere on the carrot storage organ, when cells of the outermost layers of the secondary phloem collapse progressively, leading eventually to rupture of the periderm. A wound periderm forms around the lesion and suberin and lignin are deposited in the cell walls. Polyphenols accumulate in tissue around the lesion.

Neither Ca or K concentrations in the soil or their ratios were related to cavity spot in surveys of crops in E. Scotland. Of the many characteristics recorded, only soil bulk density was related to the incidence of the disorder.

No consistent responses to high concentrations of Ca or K were obtained in field and pot experiments. A response to Ca as gypsum was possibly due to its effect on soil structure.
Electrophoretic studies on populations of Myzus persicae in Scotland from October to December, 1976
Authors: BAKER J. P.
Published: February 2008

Myzus persicae populations in Scotland were sampled during the last three months of 1976 and the individuals collected were classified into clones or groups of clones by electrophoretic analysis at three polymorphic loci. Samples from rape or mustard had a different range of clone compositions from samples from swede, cabbage or calabrese. The data provide further evidence in support of the oligogeneous population structure of this species during the period of the investigation.
Phytotoxicity and fungitoxicity tests for tree wound paints
Authors: MERCER P. C.
Published: February 2008

To assess quickly the wide range of potential treatments for pruning wounds phytotoxicity and fungitoxicity tests were devised. The phytotoxicity test was based on the growth of poplar callus and the fungitoxicity test on the inhibition of fungal growth on wood strips. Results of field tests were in broad agreement with the laboratory phytotoxicity tests.
Biological control of crown gall in cherry rootstock propagation
Authors: GARRETT CONSTANCE M. E.
Published: February 2008

English isolates of Agrobacterium tumefaciens from cherry were sensitive to the bacteriocin produced by A. radiobacter strain 84 in vitro, and simultaneous inoculation of the two organisms into tomato stems or cherry leaf scars completely inhibited the gall formation that occurred in the absence of strain 84. However, attempts to achieve biological control of crown gall of cherry in the field were successful only when the antagonist was applied as a preplanting treatment to cuttings. Disease on infected cherry layers was not reduced even after three sprays of the antagonist. A. radiobacter strain 84 was also ineffective as a preplanting dip, or both preplanting and post‐harvest dips for symptomless, but latently infected, rootstocks harvested from an infected layer bed.
The occurrence and effects of red clover necrotic mosaic virus in red clover (Trifolium pratense)
Authors: BOWEN ROBERTA , PLUMB R. T.
Published: February 2008

In 1976, red clover necrotic mosaic virus (RCNMV) was identified in red clover variety trials at the Scottish Colleges of Agriculture and at the trial centres of the National Institute of Agricultural Botany (NIAB) in Northumberland, Dyfed, Devon and Cambridge. In 1977, RCNMV was also found in two commercial crops of red clover in South Wales. The only previous finding of this virus in Britain was in 1971.

In red clover leaves RCNMV causes veinal chlorosis, often followed by severe necrosis and deformation; the plants become stunted. All cultivars tested were infected either in field or glasshouse experiments and three of the four most susceptible cultivars were tetraploids. Yield losses in cv. Hungaropoly averaged 57% over three cuts. RCNMV was transmitted manually but not through seed or by aphids {Acyrthosiphon pisum and Myzus persicae) or weevils (Apion spp. and Sitona lineatus). Seedlings became infected when grown in pots containing RCNMV‐infected plants or soil from infected sites, and the roots of infected test seedlings contained an Olpidium sp. which may be the vector.

White clover mosaic virus (WCMV), also common in red clover at some sites, was less damaging than RCNMV and in a glasshouse experiment decreased yield by only 22%. An unidentified seed‐borne virus with spherical particles c. 33 nm in diameter was the only virus detected in clover seedlings screened for RCNMV.
A technique for scoring midge blight of red raspberry, a disease complex caused by Resseliella theobaldi and associated fungi
Authors: WILLIAMSON B. , HARGREAVES A. J.
Published: February 2008

A scoring technique is described for assessing midge blight using maps representing vascular lesions beneath periderm damaged by second generation larvae of Resseliella theobaldi. Individual canes were scored and some components of yield examined. Yield was not affected until lesions covered more than 20% of the stele surface at the base of canes. Midge blight scores increased with cane girth, probably because splitting of the cortex was most extensive in stout canes.
Factors affecting the sporulation of Gloeosporium perennans and Gloeosporium fructigenum in vitro
Authors: SNEH B. , CORKE A. T. K.
Published: February 2008

An ability to spore predictably and plentifully when grown in darkness at a constant temperature, is a highly desirable attribute for any organism used to test antisporulant chemicals in vitro. The extreme variability of isolates, and their rapid loss of vigour in culture, resulted in erratic sporulation by Gloeosporium perennans: although sporulation could be temporarily improved by various means, it remained too variable for assessing the antisporulant activity of chemicals in vitro. G. fructigenum, on the other hand, grew vigorously throughout a long series of transfers, and spored reliably and plentifully when grown under the same conditions.
Antisporulant activity of chemicals towards fungi causing cankers on apple branches
Authors: CORKE A. T. K. , SNEH B.
Published: February 2008

Six antisporulant compounds, selected from 120 chemicals screened against Gloeosporium fructigenum in vitro, were applied to lesions on Cox apple shoots caused by Nectria galligena or G. perennans. In the following 11 months, 42 and 33% fewer spores were trapped from N. galligena cankers treated with 2,4,5,6‐tetrachlorophenol or benomyl respectively, and 87 and 71% fewer from G. perennans cankers treated with 8‐hydroxyquinoline or benomyl respectively, compared with those caught from untreated cankers. Miscible tar‐petroleum oil had an antisporulant effect equal to that of benomyl on both N. galligena and G. perennans.
The suppression of Phytophthora syringae in orchard soil by furalaxyl as a means of controlling fruit rot of apple and pear
Authors: HARRIS D. C.
Published: February 2008

Apple orchard soil treated with Aaterra (etridiazole), A5430 (furalaxyl), copper sulphate, LS 74–783 (aluminium tris(ethyl phosphonate)) or water in mid‐August 1977 was assayed for Phytophthora syringae by an apple fruit baiting method immediately after fungicide application and at weekly intervals for 8 wk. There was no infection of baits placed in the orchard and this was attributed to low rainfall. When wetted and baited, samples of surface soil caused from 0 to 85% fruit infection depending on the time of sampling and soil treatment. In control soil, fungus activity was low in the first 4 wk, high in the fifth wk and fluctuated widely thereafter. In samples from soils treated with Aaterra, copper sulphate or LS 74–783 activity was first apparent in the fifth wk and then fluctuated roughly in parallel with that of control soil although at generally lower levels. Changing levels of activity were apparently related to air temperature during baiting. No infection of fruits occurred in any samples from soil treated with furalaxyl. Further assays of this soil indicated a complete suppression of P. syringae to at least 10 cm soil depth. Furalaxyl is sufficiently active to be considered as a soil treatment for controlling Phytophthora fruit rot of apple and pear.
The effect of time of sowing on the incidence of subterranean clover red leaf virus infection in broad bean (Vicia faba)
Authors: JOHNSTONE G. R. , RAPLEY P. E. L.
Published: February 2008

Yield losses in broad beans due to subterranean clover red leaf virus (SCRLV) in 1972/73 were 21, 30, 61 and 8% in plots sown in May, July, September and November respectively. The variations in yield loss resulted from differing levels of virus infection during periods in which harvestable pods were set because further pod set virtually ceased after symptoms of infection became apparent. The increases in infection were paralleled by increases in the infestation of Aulacorthum solani the aphid vector of SCRLV. Yield losses were greatest in the September‐sown plots because the plants emerged at the commencement of the spring peak of aphid flight and were least in the November‐sown plots which emerged after the peak of aphid flight had declined. However, potential yields decreased with deferment of sowing time and recorded yields were greatest from May‐sown plots.

Yield losses due to SCRLV in 1973/74 were 79 and 91% for plots sown in May and September respectively. These larger yield losses resulted from an earlier and more rapid colonisation of plants by A. solani than in the previous year.

Choice of May as sowing date would not have controlled the disease satisfactorily in 1973/74 but would have been practical in the previous season when colonisation by A. solani was delayed so that little infection with SCRLV occurred before pod set had ceased.
Lack of correlation between the coat protein composition of tobacco mosaic virus isolates and their ability to infect resistant tomato plants
Authors: DAWSON J. R. O. , REES M. W. , SHORT MARGARET N.
Published: February 2008

The differing responses of a wide range of tobacco mosaic virus (TMV) isolates to various genes controlling resistance in tomato were not correlated with the amino acid composition of their coat proteins. Nor were they necessarily linked with ability to cause necrotic local lesions in White Burley tobacco, which is usually associated with the presence of methionine in the coat protein.
Screening for quantitative resistance to the white potato cyst nematode Globodera pallida
Authors: FORREST J. M. S. , HOLLIDAY J. M.
Published: February 2008

The resistance to Globodera pallida of potatoes bred from Solanum uernei was assessed rapidly in pot tests by counting cysts on the exterior of the root ball. Assessments of resistance made in this way in three consecutive years were reproducible on a ranking basis. There was also a significant agreement in the ranked results of pot and field tests. A more accurate assessment of nematode multiplication rates in the field could be provided by laboratory tests in which temperature, moisture and initial nematode numbers were strictly controlled.
Some expression of heterosis in F1‐hybrid barley
Authors: DONE ANGELA C. , MACER R. C. F.
Published: February 2008

Small and large scale trials of F1 barley hybrids were done in a glasshouse in the United Kingdom and in the field in the United Kingdom and Europe in 1970, 1971 and 1972. The results showed that there were few instances of significant positive heterosis in yield with either the small or field scale experiments. The hybrids studied were all derived from American varieties as male‐sterile parents and therefore the hybrids were not adapted to European countries, thus the case for or against F1‐hybrids cannot be assessed solely on this material.
The influence of soil temperatures as controlled by mulching on growth and development in maize
Authors: IREMIREN G. O. , MILBOURN G. M.
Published: February 2008

An increase in soil temperature (at 5 cm) of between 1.5 and 4.0 d̀C occurred for 84 days after sowing maize with a surface mulch of clear polyvinyl chloride (PVC) sheet compared with a ground chalk mulch. This rise in soil temperature resulted in a 15 day advance in both emergence and the commencement of tassel primordia differentiation, with full tassel differentiation being 24 days earlier. The PVC mulch also led to 13 days earlier silking, with the spread in date of silking being reduced from 19 to 8 days, this effect being similar for both a double‐cross and a single‐cross hybrid. Dry matter yields of whole crop silage and of grain were increased by 11 and 39% respectively with PVC mulch due to the earlier development of a complete canopy with a longer grain fill period.
The effect of time of planting inoculated tubers on the incidence of potato blackleg and gangrene
Authors: LOGAN C. , COPELAND R. B.
Published: February 2008

In a series of trials in the years of 1973‐76 inclusive, chitted seed tubers of potato cvs Ulster Sceptre, Majestic and Pentland Crown were immersed immediately before planting, on three dates in each year, in water, suspensions of Erwinia carotovora var. atroseptica, Phoma exigua var. foveata or a mixture of both. The development of blackleg was greatest in cv. Ulster Sceptre and most rapid after late planting. Its final incidence was not closely related to date of planting except in cv. Pentland Crown which was least affected when planted late.

Combined inoculum of P. exigua var. foveata and E. carotovora var. atroseptica increased five‐fold the number of plants that failed to emerge and often retarded early growth of the remainder. Failure to emerge was more frequent the earlier seed tubers were planted. Yield was affected most by blanking and blackleg in the Erwinia‐inoculated plots and was also reduced by the pre‐plant dip in a P. exigua var. foveata suspension, especially after early planting.

Seed dipped in the mixed suspensions yielded progeny that after wounding and cool storage developed a lower incidence of gangrene than progeny from seed dipped in P. exigua var. foveata alone. There was no evidence that planting time influenced the incidence of gangrene during storage.
A study of the effects of fungitoxic compounds on Phytophthora cinnamomi in water
Authors: SMITH PAULINE M.
Published: February 2008

Copper and chlorine‐releasing compounds were the most fungitoxic of 13 compounds tested in water for inhibition of Phytophthora cinnamomi. Mycelium was killed when immersed for 24 h in suspensions containing copper (13–45 mg/1) or a solution containing free residual chlorine (100 mg/1). Sub‐lethal concentrations of these compounds reduced the numbers of sporangia. Exposing zoospores of P. cinnamomi for 60 s to water containing 2 mg free residual chlorine/1 reduced subsequent colony production on agar plates by 96–100%.

Prothiocarb, etridiazole ex. and furalaxyl killed mycelium immersed in solutions or suspensions for 3–6 days at 1500, 1000 and 600 mg a.i./l respectively and suppressed sporangium production at 1000, 500 and 300 mg/1.

Mycelium survived 3 days' immersion in ethyl hydrogen phosphonate compounds at 4000 mg a.i./l but 1000 mg a.i./l suppressed sporangium formation.

1‐(2‐Cyano‐2‐methoxyiminoacetyl)‐3‐ethyl urea and drazoxolon did not kill mycelium at 2000 and 1500 mg a.i./l respectively with a 6‐day exposure, but reduced numbers of sporangia produced.
The use of cultivar trials records in assessing the incidence of cereal disease in England and Wales. II. Erysiphe graminis in barley, wheat and oats
Authors: ROWE JANET
Published: February 2008

Cereals in cultivar trials at N.I.A.B. regional centres showed significant mildew levels at flowering in most years. Oats were more heavily infected than barley or wheat. Years of peak mildew infection usually coincided in all cereals, and were generally in agreement with the results of national surveys of mildew in commercial crops, although little association with weather conditions could be demonstrated. Regional variation in mildew occurrence was most marked in barley, but the pattern of distribution of mildew infection varied between years. Disease records from cultivar trials can provide useful information on the behaviour of mildew nationally.
The effect of 3,5‐diiodo‐4‐hydroxyphenylmethylsulphone (ioxysone) on Phaseolus vulgaris: absorption and translocation studies
Authors: SARMA R. , WHITFORD P. N. , FLOOD A. E. , WAIN R. L.
Published: February 2008

The herbicide 3,5‐diiodo‐4‐hydroxyphenylmethylsulphone (ioxysone) is shown to be absorbed by the roots of dwarf bean (Phaseolus vulgaris) and readily translocated. No evidence was obtained that iodide becomes released from the herbicide within the plant. This behaviour is discussed and contrasted with that of the corresponding nitrile (ioxynil), a widely used contact herbicide which is not readily translocated in the plant and whose mode of action is different from that of ioxysone.
Resistance to Leptosphaeria coniothyrium in the red raspberry and some related species
Authors: JENNINGS D. L.
Published: February 2008

Useful resistance to Leptosphaeria coniothyrium was found in the red raspberry cv. Latham, but its effectiveness was affected by the stage of growth reached by the canes when they were inoculated and by the kind of inoculum used: it was effective when field‐grown canes were inoculated in mid‐August but less so when they were inoculated in early July, and more effective against a spore inoculum than against a mycelial one. Resistance was inherited as a dominant multigenic character, but there were interactions between parents and two very favourable combinations were found.

The species Rubus pileatus, R. mesogaeus, R. coreanus and R. lasiocarpus showed resistance when inoculated in pot experiments, but F1 hybrids obtained by crossing them with the raspberry were largely susceptible. The problems of using these resistance sources in breeding are discussed.
The response of growth rate to temperature in seedlings of several Allium crop species
Authors: BREWSTER J. L.
Published: February 2008

Relative growth rates (Rw), leaf area ratios (LAR), net assimilation rates (NAR), and leaf weight ratios (LWR) were estimated for seedlings of onion, leek, Japanese bunching onion and chives grown at constant temperatures of 10, 12, 15, 19, 23, 27 and 31 d̀C. Rw was greatest at 19 d̀C in Japanese bunching onion and chives, and at 27 d̀C in onions and leeks. Rw increased approximately linearly between 10 and 19 d̀C in all species; between 19 and 27 d̀C it either increased further, decreased or remained constant depending on species but at 31 d̀C Rw was lower than the maximum in all cases. LAR's were greatest at 27 d̀C in onions and leeks and at 23 d̀C in the other two species. Between 10 and 19 d̀C both LAR and NAR increased in all species. Between 19 and 27 d̀C increases in LAR were compensated for by decreases in NAR with the result that Rw showed little change with temperature. Averaging over all temperatures the species were ranked in order of decreasing Rw, NAR and LWR as onion, leek, Japanese bunching onion and chives. For LAR this ordering was reversed with respect to onions and leeks. Plant to plant variability increased in the order onion, leek, Japanese bunching onion then chives. Although onions were the fastest growing of the Alliums tested their Rw was lower than that of several other vegetable species for which Rw was similarly measured.
Some responses of cabbage root fly (Delia brassicae) to ally I isothiocyanate and other volatile constituents of crucifers
Authors: WALLBANK B. E. , WHEATLEY G. A.
Published: February 2008

Vapour components emanating from disrupted cauliflower, turnip, radish, wallflower and brown mustard tissue were assessed for their effects on the cabbage root fly (Delia brassicae). Of about 20 vapour components detected and separated by gas chromatography, six elicited sufficiently large electroantennal responses to warrant further testing, but of these only allyl isothiocyanate and hexyl acetate markedly affected the behaviour of gravid flies in an olfactometer. In wind‐tunnel tests at a wind speed of 1–2‐1‐7 m/s, the numbers of females caught was increased when allyl isothiocyanate vapour was released at 32–130 mg/h but decreased at higher evaporation rates. The only effect of hexyl acetate vapour released at 40–140 mg/h was a reduction in the numbers caught at the highest concentration.

In a cabbage crop, yellow water traps fitted with allyl isothiocyanate sources, each evaporating 2–3 g/day, caught 11 times as many female and seven times as many male flies as unmodified traps during the early period of the third generation but the improvement in trap efficiency later diminished. Trap efficiency was slightly reduced when the rate of evaporation of allyl isothiocyanate from a trap was decreased from 2–3 to 0–51 g/day. On fallow ground, allyl isothiocyanate improved trap performance in catching female flies by about seven‐fold, but along a hedgerow adjacent to Brussels sprouts the improvement was barely two‐fold. Hexyl acetate did not improve the performance of traps in a cabbage crop.
Hirsutella thompsonii, a fungal pathogen of mites. I. Biology of the fungus in vitro
Authors: KENNETH R. , MUTTATH T. I. , GERSON U.
Published: February 2008

Hirsutella thompsonii, a moniliaceous fungus pathogenic to mites, grew and sporulated on sterilised wheat bran. The effects of environmental factors were studied on the fungus grown on potato‐dextrose‐agar (PDA). The fungus was mesothermophilic. Growth, sporulation and conidial germination were best at 25o‐30 oC. Conidia kept at 37 oC for 5 days on PDA died, but those held at 5 oC germinated upon a subsequent removal to 25 oC. Almost all conidial germ tubes survived an 8 h exposure to 3–5% r.h. and to 60% r.h., but subsequently the former grew poorly at 100% r.h. H. thompsonii sporulated equally well in continuous darkness or light, and produced typical chlorinous to light olive‐green mycelium and conidia under all conditions. A 2 h exposure of naked mycelium and conidia (which have melanised walls) to u.v. irradiation failed to kill the fungus.
A study of the persistence of warfarin on wheat bait used for the control of grey squirrels (Sciurus carolinensis)
Authors: ODAM E. M. , PEPPER H. W. , TOWNSEND M. G.
Published: February 2008

Wheat was treated with 14C‐warfarin sodium (0–02%, w/v. a.i.) using the recommended method for preparing bait for the control of grey squirrels (Sciurus carolinesis L.). The persistence of this anticoagulant on sterilised grain was determined by monitoring the rate of change of radioactivity in five different treatments. The time taken for the initial concentration of warfarin to decrease by half in the samples buried in three forests with different soil types varied between 9 and 60 days, and appeared to be correlated with the soil conditions and rainfall. Wheat kept in a hopper exposed to the weather showed no loss of warfarin during the 12 month study period, although warfarin was lost from a pile of bait left exposed on the soil surface.

A sixth radioactive treatment involved normal wheat (as purchased from a merchant) since most squirrel control work is done with unsterilised wheat. This showed that during the summer months when squirrel control is permitted the buried unsterilised wheat germinated, but there was no detectable radioactivity in the shoots. Warfarin was lost from both sterilised and unsterilised grain at similar rates when buried in the same forest.
Three‐dimensional mapping of stain and decay columns in trees
Authors: MERCER P. C.
Published: February 2008

A visual and a computer method were used to produce three dimensional maps of stain and decay columns within trees. The merits of each method are discussed. Using these methods, tests were made to establish the accuracy of a pulsed‐electric‐current resistance meter (Shigometer) to estimate stain and decay columns in a nondestructive manner.
The effect of bulb size on the storage‐life of onions
Authors: WARD C. M.
Published: February 2008

In 2 years, 1972 and 1973, onion bulbs were harvested on various dates, graded into a range of sizes and stored at ambient temperatures. Periodic assessments showed that the number of bulbs that both rotted and sprouted increased with increasing bulb size. Although rotting can be controlled with benomyl seed dressing the increased tendency of large bulbs to sprout could have commercial implications. The date of commencement of sprouting was not affected by bulb size, but the percentage increase of sprouting was faster in the larger bulbs. Delayed harvesting also led to increased sprouting in store.
Field and laboratory observations on the substrates of the mushroom fungus gnat Lycoriella auripila (Diptera: Sciaridae)
Authors: BINNS E. S.
Published: February 2008

Observations in mushroom houses showed that the number of larvae of L. auripila in the casing was higher than in the compost throughout the post‐casing phase of culture. The intestines of larvae from casing contained both peat and fungal material. Choice of oviposition site was accordingly non‐specific. Females from cropping houses appeared to consist of a mixture of monogenic (predominantly unsexual) and digenic (bisexual) strains. Males matured c. 2 days before females at 20 °C; such protandry appeared to be related to sexual differences in the extent of migration undertaken by the dimorphic sexes.

Sciarids were reared from egg to adult equally effectively on (a) detached sporophores or on portions of (b) pileus, (c) stipe or (d) gills, all placed on moist peat, or on detached sporophores placed on a variety of inert substrates. Development was completed where sporophore material was the only food source and also occurred on peat to which only protein, particularly egg albumin, had been added. Hence, assuming no protein metabolism by a third organism, for development in the casing layer to occur, the mushroom need contribute only such proteins. However, their replacement by amino acids was not successful in limited tests.

Addition of increasing amounts of the fungal metabolites mannitol and calcium oxalate to compost delayed development, and the accumulation of these materials during fungal growth may be responsible for the antagonism between mycelial and sciarid development which results in subsequent migration of emerging adults.
Inhibition of germination of Mycosphaerella brassicicola ascospores on young cabbage and cauliflower leaves
Authors: Hartill W. F. T. , Sutton P. G.
Published: February 2008

Symptoms of ringspot of brassicas, caused by Mycosphaerella brassicicola, rarely appeared on rapidly expanding leaves of cabbages and cauliflowers but were common on fully expanded leaves. M. brassicicola ascospores did not germinate, or germinated poorly, on expanding leaves or on recrystallised wax deposits taken from these young leaves. A high proportion germinated on expanded leaves, on waxes taken from expanded leaves and on various other surfaces in the absence of nutrients.

A volatile metabolite, present in the younger leaves, appears to inhibit ascospore germination.