bluuebunny/crossref_metadata_2025_split huggingface dataset:
The significance of tuber damage and inoculum concentration of Phoma exigua var. foveata in the development of gangrene in stored potato tubers
Authors: ADAMS M. J. 
Published: February 2008

SUMMARYThe susceptibility to gangrene infection of wounds of various shapes and depths on potato tubers was studied by inflicting wounds using differently‐shaped brass teeth and rods of different diameters. Inoculating wounds with spore suspensions or damaging tubers which had been previously contaminated with Phoma exigua var. foveata or which had been recently lifted from plots of field experiments showed that wounds in which tissue was crushed were most susceptible to infection. Over a wide range of inoculum concentrations and in experiments using several different cultivars the incidence of infection of any wound type was compared to that of the standard severe cut and crush wound. Using a probit transformation a linear relationship was established, the slope of the line indicating the relative susceptibility of the wound.In 1977 and 1978, crops of cv. Pentland Dell were surveyed for damage incidence, inoculum and inoculum potential on arrival at a commercial bulk store. Nets of tubers buried among the tuber bulk were recovered after storage and gangrene incidence compared with damage and inoculum assessments. Inoculum potential and incidence of severe damage both influenced disease development but damage incidence was of greater importance, showing that priority should be given to decreasing damage and to curing to promote rapid wound healing in endeavours to control the disease.
Observations on the prevalence and incidence of ergot disease in Great Britain with special reference to open‐flowering male‐sterile cereals
Authors: WOOD G. , COLEY‐SMITH J. R. 
Published: February 2008

SUMMARYErgot (Claviceps purpurea) of grasses is prevalent throughout Britain. The disease also occurs regularly in most cereal varieties but generally is of low incidence. Incidence is much greater in open‐flowering and male‐sterile cereals, with the infection seeming to come, initially, from the large reservoir of inoculum amongst grasses. The production of F1‐hybrid cereal seed, which necessitates the use of male‐sterile lines, could therefore be jeopardised.
Effects of environmental factors on growth of lesions on field bean leaves infected by Botrytis fabae
Authors: HARRISON J. G. 
Published: February 2008

SUMMARYChocolate spot lesions increased in size only slowly when the relative humidity of the air was below 66%. Following a lag phase immediately after infection the rate of increase was linear and proportional to humidity between c. 70% and 100% r.h. Lesions on leaflets kept at 70% r.h. for 8 h and at 100% r.h. for 16 h/day increased in size at only 27% of the rate of those at continuous 100% r.h. The optimum temperature for lesion growth was between 15 and 22 °C, the minimum <4 °C and the maximum c. 30 °C. Humidity did not interact with temperature between 10 and 20 °C. Neither light intensity nor a film of water over the leaves affected lesion growth. These findings are discussed in relation to meteorological data and field observations.The possible mechanisms whereby humidity affects lesion growth did not appear to be related to CO2 and O2 concentrations nor to the overall water potential of the leaf.Preliminary evidence is presented for the production of phytotoxins within lesions.
Effects of aldicarb persistence on field populations of Heterodera schachtii
Authors: BATTERBY S. , PATOUREL G. N. J. LE , WRIGHT D. J. 
Published: February 2008

In field trials in 1976 and 1977 various granular formulations of aldicarb (2–8 to 12.8 kg a.i. ha‐1) were applied to sugar‐beet fields infested with Heterodera schachtii. The levels of toxic residues of aldicarb and of H. schachtii populations in the soil were monitored at intervals throughout the sugar‐beet season.A severe drought in 1976 seriously affected the field trials and although aldicarb levels were maintained in the soil no aldicarb treatment proved effective in controlling H. schachtii; this was probably due to lack of mobility of the pesticide in the soil. In 1977, the final nematode populations in plots treated with 2.8 or 11.2 kg a.i. ha‐1 added incrementally through the growing season to simulate the effect of a controlled release formulation were not significantly different from those of untreated plots. In contrast treatment at drilling with fast‐releasing formulations at all application rates did promote control of H. schachtii populations. No significant increase in yield was found on any trial after treatment with aldicarb.The value of controlled release formulations of aldicarb for the control of H. schachtii populations over the growing season has not been proven.
Resistance to aphids in immature wheat and barley*
Authors: LOWE H. J. B. 
Published: February 2008

SUMMARYResistance to Sitobion avenue and Metopolophium dirhodum was assessed in the glasshouse by releasing immature aphids on uncovered wheat and barley plants at the tillering stage. Six cultivars of winter wheat were tested with S. avenue and of these cv. Kador was resistant and cv. Maris Huntsman susceptible. Among seven cultivars of barley, cv. CI16145 was more resistant to S. avenue than any other whilst cvs Tyra and Nirakei 10 were the most susceptible, but the cultivars did not differ significantly in the numbers of M. dirhodum on them, although there were ranking differences similar to those observed with S. avenue.
Observations on the production and dispersal of spores, and infection by Rhynchosporium secalis
Authors: STEDMAN O. J. 
Published: February 2008

SUMMARYThe numbers of spores of Rhynchosporium secalis washed from samples of barley plants taken weekly, varied markedly. No consistent association with amount of previous rainfall or length of the preceding dry period was detected. On potted seedlings exposed within a crop most infection occurred during long rain periods or when rain fell late in the evening; fewest lesions usually developed on seedlings prevented from touching adjacent plants.Rotorod traps fitted with a 13 mm diameter disc at the apex of each arm were operated under 24 cm diameter covers. Spores were collected on circular cover slips fixed to each disc with glycerine jelly. At all stages of crop growth more spores were trapped at ground level than at other heights tested up to 1 m. The number of spores trapped was not related to the quantity of or duration of rainfall but was related to the mean rate of fall during brief showers only. Efficiency of droplet retention was assessed in a wind tunnel. It declined rapidly when more than c. 5 pl was presented to the disc surface and was less at a wind speed of 1.0 than 0.5 m s‐l. Spore distribution on discs indicated that spores were washed from the surface during long rain periods.
Characterisation of rhizobia isolated from nodules on locally‐adapted Glycine max grown in Nigeria
Authors: BROMFIELD E. S. P. , ROUGHLEY R. J. 
Published: February 2008

SUMMARYStrains of Rhizobium spp. (cowpea miscellany) and R. japonicum are characterised by their symbiotic performance on two hosts, Vigna unguiculata cv. Ife Brown and Glycine rnax cv. Bossier. The results indicate that isolates from G. max cv. Malayan, a promiscuously nodulating cultivar adapted to Nigerian conditions, form a group intermediate between R. japonicum and R. spp. but are more closely related to the latter. We tentatively suggest on the evidence of symbiotic performance that R. japonicum is a specialised group within R. spp.
Some effects of differently‐acting nematicides on the cereal cyst‐nematode (Heterodera avenae) and on the appearance of ‘scorch’ in spring wheat on light loamy sand
Authors: WILLIAMS T. D. , BEANE J. 
Published: February 2008

SUMMARYIn a field trial on light loamy sand, aldicarb was more effective than formalin or dazomet in controlling cereal cyst‐nematode on spring wheat.In the second year of the trial severe ‘scorch’ symptoms appeared and yield losses were greatest in aldicarb treated plots that received most nitrogen even though invasion of plants by juveniles of Heterodera avenae was greatly reduced. Before a dry spell in early summer, crop growth was best in those plots which had received most nitrogen but which finally yielded least; crop growth‐stage and the timing of dry periods are critical in the development of ‘scorch’ symptoms (early shrivelling, browning, and failure of ear emergence) on a light soil given a high rate of nitrogen. ‘Scorch’ occurred at the very luwest H. avenae population levels; the effects of fungal pathogens and NO3 nitrogen content of the crop remain uncertain. The rôle of copper in the ‘scorch’ condition could not be assessed since it was applied in a wetter year, in which ‘scorch’ failed to appear.
Selection for cold tolerance in Phaseolus vulgaris— yields of selected lines grown in warm and cool environments
Authors: HARDWICK R. C. , ANDREWS D. J. 
Published: February 2008

SUMMARYForty‐eight F4 families of a cross between two cultivars of Phaseolus vulgaris were grown in ‘warm’ and ‘cool’ environments in the field. The F2 and F3 generations had been assessed for cold tolerance using the test described by Hardwick & Andrews (1980). The mean seed yields of the F4's were 333 and 167 g m‐2 in the ‘warm’ environment (blackened soil surface, clear polyethylene mulch, windbreaks) and ‘cool’ environment (whitened soil surface, no mulch or windbreaks) respectively. The ratio of yields in the two environments was larger in families selected for cold sensitivity than in those selected for cold tolerance (values of ratio 2.28 to 1 and 1.76 to 1 respectively).The ‘warm’ treatment decreased the number of days between sowing and emergence from 15.6 to 8.6, increased the estimated weight per seedling axis at emergence from 544 to 904 mg/plant, and increased the weight/plant at flowering from 3.75 to 4.7 g. Plants from the ‘warm’ treatment had bigger leaf weights, smaller stem weights, more branches and bigger specific leaf areas than plants of the same weight from the ‘cool’ treatment. Differences in yield were due mainly to differences in the number of seeds produced/plant.Eleven F, families were grown in a simple yield trial the following year. The season was cooler and yields were reduced. The reduction in yield was greater in the cold sensitive than in the cold tolerant families.
Influence of host plant Brassica species) and temperature on population increase of the cabbage whitefly Aleyrodes brassicae
Authors: IHEAGWAM EMMANUEL UCHE 
Published: February 2008

SUMMARYLaboratory studies on the influence of host plant species on population growth of the cabbage whitefly Aleyrodes brassicae Walk. showed that greatest longevity occurred on mustard and lowest on turnip. Leaf age did not affect survival. At 20 or 25 °C the survival curves from mustard plants were shortened Slobodkin's type I whereas those from purple sprouts and turnip were typical of Slobodkin's type II. At 15 °C the survival curves from young leaves of all host plants were of Slobodkin's type I but those from mature leaves were of Slobodkin's type III except that of mustard which was of type I. Young leaves induced higher fecundities than mature leaves. Fecundity was highest on mustard followed by purple sprouts and turnip. This affected population rate such that, for example, daily rm values on young leaves of mustard, purple sprouts, and turnip at 25 °C were 0.206, O.172, and 0.147, respectively.
A comparison of a corer and a shovel for sampling populations of wheat bulb fly Delia coarctata eggs
Authors: McKINLAY R. G. , FRANKLINT M. F. 
Published: February 2008

SUMMARYThe most commonly used tool for sampling soil for eggs of the wheat bulb fly Delia coarctata Fall.) is a corer, but in Scotland samples are taken with a modified shovel. The sampling properties of a corer and shovel were compared in two exercises in which soil samples were taken from the ridge, sides and furrow of drills of maincrop potatoes at several sites in east Scotland. Although each tool sampled approximately the same surface area of soil, the corer sampled three times as much soil as the shovel. The numbers of wheat bulb fly eggs estimated by the corer and shovel were similar in both sampling exercises and there were no indications that the comparison of the two tools was affected by the sampling position on the potato ridge. The results of the two exercises gave no reason to believe that in similar conditions the shovel is an inferior sampling tool or that population estimates obtained with a shovel in Scotland are not comparable with those obtained with a corer. Evidence from some sites suggested that wheat bulb flies lay more eggs on the potato ridge than in the furrow.
The relationship between cabbage root fly egg laying and volatile hydrolysis products of radish
Authors: ELLIS P. R. , COLE ROSEMARY A. , CRISP P. , HARDMAN J. A. 
Published: February 2008

SUMMARYRadish populations selected from the cvs Asmer Tip Top and Sparkler on the basis of high or low preference by the cabbage root fly for egg laying were tested at different ages by exposing them to the pest in a laboratory test chamber. Results confirmed the existence of a cycle of changing attractiveness of radish for egg laying, the peak occurring as plants reached a marketable age. Selection within radish cvs for different levels of preference resulted in a shift in the cycle of attraction such that ‘high‐preference’ plants reached a peak in attractiveness earlier than ‘low‐preference’ ones. Egg laying was correlated with the total amounts of two volatile glucosinolate hydrolysis products (4–methylthio‐3–butenyl isothiocyanate and 1–cyano‐4–methyl‐thio‐3–butene) detected in ether extracts of macerated radishes. The relationship between chemicals and egg laying suggested a possible chemical assay to complement biological techniques for identifying cabbage root fly‐resistant radish for breeding work.
Development of potato blight Phytophthora infestans after planting infected seed tubers
Authors: BOYD A. E. W. 
Published: February 2008

SUMMARYAbout 1000 blight‐infected seed potato tubers, usually of the cultivar King Edward, were planted for 9 yr and the subsequent plants examined until the disease had developed in the plots. Haulm infection originated each year from the seed tubers and occurred first on basal leaves. When tubers were inoculated with a complex race of P. infestans this race was recovered from the leaves and from the soil near the seed tuber.Transmission of infection from soil to leaves was demonstrated by splash of artificially contaminated soil to leaves suspended above the soil.In 4 yr, plants were grown on flat rows as well as on ridges. In 2 yr, when emergence was almost complete, infected stems were observed on otherwise normal plants. In the first year 0.6% grew on ridges and 3.0% on the flat and in the second all grew on the flat (5.3%). Only seven of the 43 plants had more than one infected stem. Flat plots had a significantly higher number of stemdplant than ridge plots, but this bore no relation to numbers of infected stems. When flat plots which had developed affected plants had soil replaced as ridge plots, no further infected stems were observed. Such stems continued to develop on flat plots.No prematurely dead stems were observed below soil level when all plants were dug.Underground portions of most infected stems showed little evidence of P. infestans which was found only at about soil level. Infection appeared to occur first in this area.
Studies on the seed‐borne phases of dark leaf spot Alternaria brassicicola and grey leaf spot Alternaria brassicaeof brassicas
Authors: MAUDE R. B. , HUMPHERSON‐JONES F. M. 
Published: February 2008

SUMMARYTests in Britain on samples of basic and commercial Brassica oleracea seed between 1976 and 1978 showed that many lots were infected with Alternaria brassicicola. A. brassicae was uncommon in basic seed in these years and in commercial seed harvested in 1976 and 1977 but was frequent in seed harvested in 1978. Most affected seeds were contaminated by surface‐borne spores and mycelium of A. brassicicola but many were internally infected by the fungus situated within the seed‐coat and in some seeds in the embryo tissues. Superficial contamination by the fungus declined rapidly after 2 yr in cabbage seeds stored at 10 °C, 50% r.h. but internal infection persisted for up to 12 yr. In some samples, internal infection was commonly associated with small shrivelled seeds. Surface contaminated and internally infected seeds transmitted the disease but seedling infection was more closely correlated with the latter.
The effect of iprodione on the seed‐borne phase of Alternaria brassicicola
Authors: MAUDE R. B. , HUMPHERSON‐JONES F. M. 
Published: February 2008

SUMMARY Alternaria brassicicola infection of Brassica oleracea seeds was effectively controlled by a dust application of iprodione (Rovral 50% w.P.). At 2.5 g a.i./kg the seed‐borne fungus was usually eliminated from samples with up to 61.5% affected seeds (35.5% internally diseased) but higher levels of infection required increased doses for complete eradication of the fungus. The germination of healthy seeds, including samples from 7–yr‐old stocks, on filter paper was unaffected by the treatment. However, the germination of diseased samples, particularly those internally infected with A. brassicicola, was improved. More seedlings emerged from iprodione treated than from untreated seeds in glasshouse soil but the differences were not significant. The application of gamma‐hexachlorocyclohexane to iprodione treated seeds sown in soil did not adversely affect subsequent emergence or disease control. Disease control was maintained and germination was not affected by the treatment when treated infected seeds were stored for 2 yr at 10 °C, 50% r.h. In a field trial iprodione seed treatment reduced seedling infection in a cabbage crop grown from naturally diseased seeds (100% contaminated, 45.5% internally infected) from 5.6 to 0.04%.
The relative importance of some yield components in East of Scotland strawberry plantations
Authors: MASON D. T. , RATH N. 
Published: February 2008

SUMMARYYield components were measured in 69 plantations of the strawberry cv. Cambridge Favourite located in eastern Scotland. Yield of fruit/ha was positively correlated with number of crowndha. Number of berries/truss (inflorescence), mean berry weight and weight of fruithuss were negatively correlated with number of emerged trusses/crown. Weight of fruit/truss was positively correlated with both number of berries/truss and mean berry weight.Since crown number accounted for more than 50% of the yield variance it is suggested that the potential yields of strawberry plantations can be predicted from crown counts made during the dormant period.
Effect of abscisic and gibberellic acid on grain set in wheat
Authors: RADLEY MARGARET 
Published: February 2008

SUMMARYWhen abscisic acid was applied to wheat ears at or just before anthesis, it prevented grain set in the third floret of each spikelet but not in the lower florets. It had no effect on semi‐dwarf cultivars in pot experiments, but there was a small response in a field experiment. Gibberellic acid inhibited anthesis in all florets of all cultivars.
Use of protein A to improve sensitisation of latex particles with antibodies to plant viruses
Authors: TORRANCE L. 
Published: February 2008

SUMMARYProtein A‐coated latex (PAL) was compared with uncoated latex (L) for sensitisation with antibodies to five plant viruses: apple mosaic virus (ApMV), arabis mosaic virus (AMV), plum pox virus (PPV), potato virus Y ordinary strain (PVY°) and prunus necrotic ringspot virus (NRS V). A range of globulin concentrations was used with each antiserum and detection end points determined in serial dilutions of infective sap. When sensitised with antibodies to ApMV, PAL detected ApMV readily, whereas L did not. When sensitized with antibodies to PVY° and AMV, PAL gave higher detection end points than L. However, PAL gave little increase in sensitivity with the antisera to PPV and NRSV. Non‐specific aggregation of latex, which sometimes occurred in very dilute sap with PAL, could be dispersed by adding 0.02% Tween‐20 to the extraction buffer. Globulins of PVY° and AMV could be used at higher dilutions with PAL than with L, giving a saving in antiserum. Both types of latex sensitised with PVY° antibody globulins readily detected the tobacco veinal necrosis and C strains of this virus.
Barley yellow dwarf virus infectivity of alate aphid vectors in west Wales
Authors: A'BROOK JOHN , DEWAR A. M. 
Published: February 2008

SUMMARYLive trapping at 0.9 m of alate aphid vectors of barley yellow dwarf virus (BYDV) at Aberystwyth from 1970 to 1979 showed that ten species transmitted the virus to oat test plants. Conversion of percentage infective at 0.9 m to numbers infective based on continuous trapping at 1.2 m showed Rhopalosiphum padi and R. insertum to be the main vector species in most years, whilst Metopolophium dirhodum and Sitobion auenae were normally of minor importance. The data obtained suggest that epiphytotics of BYDV in autumn‐sown cereals were caused by numerous infective vectors flying late in the year and transmitting severe strains of the virus. Evidence is presented that gynoparae and males of R. padi are involved in the autumn spread of BYDV and that three further aphid species, Anoecia corni, Metopolophium albidum and M. frisicum are BYDV vectors. The use of live and continuous trapping techniques in forecasting BYDV epiphytotics is discussed.
Genetic control of the reactions of raspberry to black raspberry necrosis, raspberry leaf mottle and raspberry leaf spot viruses
Authors: JONES A. T. , JENNINGS D.L. 
Published: February 2008

SUMMARYBlack raspberry necrosis virus (BRNV) induces a severe apical necrosis in black raspberry (Rubus occidentalis) but fails to induce diagnostic symptoms in red raspberry. However, BRNV infection of F1, F2 and F3 hybrids from the cross black raspberry × red raspberry induced mosaic symptoms of varying intensity but no typical apical necrosis.In a survey of 28 red raspberry cultivars, a few developed severe angular chlorotic leaf spots when infected with raspberry leaf mottle virus and a few others did so when infected with raspberry leaf spot virus. These reactions were determined by single dominant genes designated Lm and Ls respectively.The value of the different host reactions for controlling the effects and spread of these viruses is discussed.