bluuebunny/crossref_metadata_2025_split huggingface dataset:
Initial incidence and development of red core of strawberry
Authors: MONTGOMERIE ISABEL G. , KENNEDY DIANA M. 
Published: February 2008

SUMMARYThe initial incidence of the disease caused by Phytophthora fragariae in healthy stock of strawberry, cv. Merton Princess, was not affected by different systems of cultivation or by no cultivation for several months before preparing infested soil for planting.In disease development studies, healthy plants which were planted in infested soil in April and sampled at 35‐day intervals showed symptoms of red core on 1 September. Disease severity (mean % number of diseased roots) increased with time and, when averaged over intervals of 70 days, the greatest increases occurred between the end of July and the beginning of October and between December and February. Whereas the former was due to infection of plants in which the total numbers of new roots were low, the latter was due to an increase in the numbers of diseased roots. Most primary roots were produced in October and early November and 75% of the final total were formed by 15 December.Healthy plants of the cvs Cambridge Favourite and Redgauntlet, dug from the field at monthly intervals and challenged with zoospores, were less susceptible in May and June than in other months.It is suggested that a fungicide applied in late September or October would protect the maximum number of new roots and achieve the optimum effect for a single application.
Effects of fungicide treatments and variety on development, grain growth and yield of spring barley
Authors: WRIGHT D. , HUGHES LI. G. 
Published: February 2008

SUMMARYThe effects of four fungicide treatments for the control of mildew on spring barley were assessed in three field experiments, one in each of the years 1981, 1982, 1983. The fungicide treatments (+/ ‐ triadimenol seed treatment and +/ ‐ triadimefon foliar spray applied during early booting) were chosen to control mildew, and hence affect yield determining processes, at different times in the life of the crop. Two of the experiments also tested different nitrogen amounts and the third tested four varieties differing in their degree of mildew resistance. Mildew appeared too late to affect the production and survival of spikelets and shoots, but reduced average grain weight by reducing the rate of grain growth. Grains in the upper part of the ear had a considerably lower growth rate and final weight than grains in central and basal positions but there was no evidence that the effects of mildew on grain size depended upon grain position within the ear. Mildew incidence increased with increasing nitrogen and varietal susceptibility but there were few significant interactions between these factors and fungicide treatment for grain yield. The degree of mildew control achieved by the seed treatment varied with barley variety. Use of the two successive fungicide treatments did not yield more barley than use of either alone. Amongst varieties, grain positions within the ear and fungicide treatments there was a close correlation between rate of grain growth and final grain weight. Duration of grain growth was not related to rate of grain growth or final grain weight but was inversely correlated with mean temperature during the period of rapid grain growth. The temperature sums during the period of rapid grain growth were similar for the three years and it is suggested that a more precise knowledge of the relationships between mildew incidence, varietal susceptibility and rate of grain growth may enable more accurate predictions to be made about likely yield responses to fungicide treatments.
Effects of potato genotype, oxamyl and the numbers of potato cyst‐nematodes, Globodera rostochiensis or G. pallida on tuber yields and nematode increase
Authors: WHITEHEAD A. G. , TITE D. J. , FRASER JANET E. , NICHOLS A. J. F. 
Published: February 2008

SUMMARYA new technique is described for establishing different numbers of the potato cyst‐nematode Globodera rostochiensis in field soil, which leaves the soil homogeneous in nutrient status. Field plots established in this way were used to compare yield losses in four potato cultivars (Maris Piper, Pentland Crown, Pentland Dell and Désirée) associated with different numbers of G. rostochiensis. Over the range of 7.4 to 148.4 eggs g‐1 soil at planting, yield losses were 18.7% (Maris Piper), 53.2% (Désirée), 55.7% (Pentland Crown) and 63.5% (Pentland Dell). Similar results were obtained in another experiment on the same field in a different year using only lightly and heavily infested plots. Treating the seedbed soil with oxamyl before planting prevented significant injury to potatoes by G. rostochiensis but increased the yield of Pentland Dell and perhaps Désirée (but not Maris Piper or Pentland Crown) more than expected from nematode control alone. Treating heavily infested soil with such a nematicide cannot therefore be recommended as part of a valid procedure for establishing lightly and heavily infested plots for comparing tolerances of attack by potato cyst‐nematodes in a range of potato genotypes.In peaty loam soils moderately or heavily infested with G. pallida, oxamyl at 5.6 kg a.i. ha‐1 incorporated into the seedbed before potatoes were planted generally increased tuber yields, though the effects varied considerably with the cultivar grown. Increase of G. pallida in these soils was controlled better by growing potatoes bred for resistance to it (ZB 35 – 29, Caxton, Santé, Morag, 11233 ab 22, Fingal, A27/23, Cromwell). Increase of G. pallida on susceptible cultivars varied greatly and Romano increased G. pallida no more than the resistant Morag. G. pallida is probably controlled best in peaty loam by growing a resistant cultivar in soil treated with a granular (non‐fumigant) nematicide.
The relationship between the entry of isoproturon into Alopecurus myosuroides and its effect on growth and CO2 fixation
Authors: BLAIR A. M. 
Published: February 2008

SUMMARY Alopecurus myosuroides (blackgrass) was grown in nutrient and with isoproturon added to the solution when plants had three leaves. The transpiration stream coefficient factor was calculated over a period of 96h after treatment to be approximately 1. On this basis isoproturon entry into A. myosuroides was estimated using data for water loss through plants and there was a linear relationship between herbicide entry and plant weight 14 days after treatment. Treatment for at least 7 days with isoproturon at a dose of 1 μg a.i./15 ml nutrient solution (≡ 0.32 × 10‐6M) before returning plants to fresh nutrient was necessary for damage to be still evident after 14 days. This time period corresponded with the reduction of CO2 exchange to zero as measured by infra‐red gas analysis. Some recovery occurred from 6 h treatment with 120 μg a.i. isoproturon/15 ml nutrient solution when assessed after returning plants to untreated nutrient for 14 days. A quicker depletion in CO2 uptake by blackgrass occurred when both the primary and secondary roots were treated compared with secondary alone but eventually the levels reached were similar. The ‘CALF’ model predicted much higher concentrations of isoproturon than appeared necessary to damage A. myosuroides. This suggests a major influence of climate on the plant and this and other interactions are discussed.
Assessment of horizontal resistance to late blight of potatoes
Authors: SIMMONDS N. W. , WASTIE R. L. 
Published: February 2008

SUMMARYTen potato clones were assessed for horizontal resistance to late blight in the foliage, in replicated plots for 4 years. Plots were scored on several occasions each year and this paper explores the most reliable ways of using the data to detect differences between clones. Using the genetic component of variance (heritability in the broad sense, h2) as criterion, mean resistance over all scoring dates was found to be the best measure out of several tried. Though good discrimination was achieved within years (mean h2 > 90%), there were large clones × years interactions and changes of rank order such that h2 fell to about 65% over seasons, and many years of testing would be required to discriminate between similar clones. There was no reason to think that the interactions were caused by the erratic expression of R genes, though one case of vertical resistance was detected. Some results from parallel testing of diverse potato breeding materials are described, and implications for breeding methods and objectives are briefly discussed.
Etiology and control of durian foliar blight and dieback caused by Rhizoctonia solani
Authors: KWEE LIM TONG , CHONG NG CHING , LAN CHIN CHIEW 
Published: February 2008

SUMMARYFoliar blight and dieback of durian seedlings and trees in Peninsular Malaysia was found to be caused by Rhizoctonia solani (teleomorph ‐ Thanatephoms cucumeris) The fungus grew well and produced abundant sclerotia at temperatures higher than 24°C with an optimum at 28°C. It grew poorly at 35°C and did not grow at 10°C. The strains studied were found to belong to the anastomosis group AG‐1. They were pathogenic on durian, papaya, cucumber, long bean, Mikania weed, padi, musk melon, mung bean, Zoysia grass, Bermuda grass, and St Augustine grass. They were mildly pathogenic on groundnut, and non‐pathogenic on maize, guava and Brassica‘pak choy’. The disease was effectively controlled by foliar sprays of pencycuron and benomyl; triadimefon and an antagonistic bacterium suspension treatment were less effective and quintozene‐etridiazole mixture gave poor disease control.
Variation in pathogenicity among field isolates of Phoma exigua var. foveata
Authors: BAIN R. A. , LENNARD J. H. , WASTIE R. L. 
Published: February 2008

SUMMARYExperiments carried out using a point inoculation method to infect potato tubers with Phoma exigua var. foveata demonstrated considerable variation in pathogenicity among field isolates. This variation was unlikely to be due to differential reductions in isolate pathogenicities during axenic culture. However, fresh field isolates generally produced larger lesions than stored isolates. An investigation of the distribution of pathogenicity variation in the fungus revealed that differences among isolates from different lesions taken from the same potato stock were greater than those between stocks, but pathogenicity variation within each lesion isolate was small relative to that between isolates. The importance of using isolates with a high level of pathogenicity, hence recent field isolates, in studies of this pathogen is stressed.
Long‐range aphid transport hypothesis for maize dwarf mosaic virus: history and distribution in Minnesota, USA
Authors: ZEYEN R. J. , STROMBERG E. L. , KUEHNAST E. L. 
Published: February 2008

SUMMARYIn 1977 a sudden and dramatic epidemic of maize dwarf mosaic virus (MDMV) struck commercial fields of sweet corn in Minnesota causing multi‐million dollar losses. The epidemic was unusual in that MDMV historically had been confined to the southern United States and Ohio River Valley with only occasional occurrences reported from states bordering Canada. An extensive 5‐yr study of MDMV in Minnesota revealed a low incidence of MDMV from 1978 ‐ 81, and commercial fields badly infected in 1977 were not again infected. No evidence of wild host plants was found, neither was seed transmission in maize considered to be important, and MDMV strain ratios changed from year to year as did the distribution of infected fields. Concomitant studies on aphid retention revealed that MDMV could be retained by aphid vectors for more than 19 h, and that the 1977 epidemic was associated with a weather pattern that could be linked to potential aphid transport from the southern Great Plains of North America. All circumstantial evidence led to a long‐distance aphid transport hypothesis. This may be worth considering whenever unexpected epidemics of aphid‐transmitted non‐persistent viruses occur in regions where the particular virus is not endemic, and may also explain the widespread distribution of certain aphid‐transmitted non‐persistent viruses.
Use of monoclonal antibody to potato leafroll virus for detecting groundnut rosette assistor virus by ELISA*
Authors: RAJESHWARI R. , MURANT A. F. , MASSALSKI THE LATE P. R. 
Published: February 2008

SUMMARYThree of 10 monoclonal antibodies (MAbs) produced to potato leafroll luteovirus (PLRV) were found to react in triple antibody sandwich ELISA (TAS‐ELISA) with groundnut rosette assistor luteovirus (GRAV), though none reacted with four other luteoviruses (barley yellow dwarf, bean leaf roll, beet western yellows or carrot red leaf)‐ The most effective PLRV MAb, SCR 6, was used in TAS‐ELISA to detect isolates of GRAV from groundnut plants with chlorotic, green and mosaic forms of rosette from Nigeria and Malawi. The test also detected GRAV in extracts of single Aphis craccivora.
Oxidising activity in root extracts from plants inoculated with virus or buffer that interferes with ELISA when using the substrate 3,3‘, 5,5’‐tetramethylbenzidine
Authors: JONES A. T. , MITCHELL MARGARET J. 
Published: February 2008

SUMMARYIn indirect ELISA using protein A‐horseradish peroxidase (HRP) as enzyme conjugate and 3,3′, 5,5′‐tetramethylbenzidine (TMB) as substrate, extracts of roots of all cucumber, Chenopodium quinoa and Petunia hybrida plants previously inoculated with virus or buffer produced A450 values up to seven‐fold greater than those for comparable shoots or for extracts of roots from undisturbed, uninoculated plants, irrespective of the virus antiserum used for detection. This effect was also produced in tests in which no HRP conjugate was used, indicating that root extracts from virus‐infected or physically injured plants, but not healthy uninjured plants, contain high levels of a factor able to oxidise TMB. The HRP conjugate/TMB substrate version of ELISA is therefore not reliable for detecting viruses in root extracts of herbaceous plants. In contrast, non‐specific reactions were not obtained with root extracts, and viruses were reliably detected, when protein A‐alkaline phosphatase was used as conjugate and p‐nitrophenyl phosphate as substrate.
Variation in the development of stem nematodes, Ditylenchus dipsaci, in susceptible and resistant crop plants
Authors: WHITEHEAD A. G. , FRASER JANET E. , NICHOLS A. J. F. 
Published: February 2008

SUMMARYDicotyledonous plants were reliably inoculated with stem nematodes by placing drops of 1.3% carboxymethylcellulose containing the surface sterilised worms between the cotyledons or in the leaf axils of recently emerged seedlings raised in pots of cool, moist soil. Inoculating onion leaves, bean stems and potato tubers or potato leaves gave variable results and inoculating onion, tulip and narcissus bulbs and lucerne and red clover stems was usually unsuccessful. An attempt to characterise 67 stem nematode populations by the reactions of a number of different plants failed for lack of useful differential hosts. Lucerne was, however, resistant to all but lucerne populations.Multiplication of stem nematode populations varied greatly between cultivars of lucerne or red clover. Some cultivars were resistant to some populations of lucerne or red clover stem nematodes and susceptible to others. These differences could not be ascribed to differences in viability of the nematodes or to differences in success of the inoculations. They indicate the presence of different pathotypes or biotypes in different populations of a so‐called ‘host race’ and indicate the need for new resistant cultivars to be tested against a range of populations before they are released for general use. Amongst lucerne cultivars tested, Vertus was resistant to some lucerne stem nematode populations and susceptible to others. The supposedly resistant lucerne cultivars Euver and Lifeuil were as susceptible as was Europe. Amongst red clover cultivars tested, Redhead, Kühn, Changins and Mt Calme were susceptible, Britta, Lucrum and Temara were the least resistant, Renova, Rittinova and Quin were intermediate and susceptible to one or more of the populations tested but Norseman and especially Sabtoron were very resistant.
Transfer of polygenic resistance to ryegrass mosaic virus from perennial to Italian ryegrass by backcrossing
Authors: WILKINS P. W. 
Published: February 2008

SUMMARYPolygenic resistance to ryegrass mosaic virus (RMV) was transferred from perennial to Italian ryegrass cv. Tribune by repeated cycles of backcrossing, polycrossing and selection. The resulting synthetic variety (Bb 2113) was highly resistant to infection by RMV whereas the Italian ryegrass cultivars Tribune, RvP, Bartolini, Augusta, Wilo and Dalita all were highly susceptible. Leaf width and length of Bb 2113 was similar to that of cv. Tribune and, like Tribune, Bb 2113 had awned florets. In a field trial, Bb 2113 had a similar persistency rating and number of inflorescences in the regrowth to cv. Tribune but produced 11% less dry matter. The results emphasise the need for a more efficient means of transferring small numbers of genes from one species of Lolium to another than backcrossing provides.
Susceptibility of mushroom pests to the insect‐parasitic nematodes Steinernema feltiae and Heterorhabditis heliothidis
Authors: RICHARDSON P. N. 
Published: February 2008

SUMMARYThe potential of two species of insect‐parasitic rhabditid nematodes (Steinernema feltiae, Heterorhabditis heliothidis) for biological control of mushroom flies was studied in pot trials. Three Diptera that commonly infest mushroom crops were used; the larvae of Megaselia halterata (Phoridae), Heteropeza pygmaea (Cecidomyiidae) and Lycoriella auripila (Sciaridae) were all susceptible to parasitism by both nematode species. Fewer adult phorids and sciarids emerged when compost was nematode‐treated and, for L. auripila, the effects of nematode applications at spawning, casing or on both occasions were compared. Casing treatments were more effective than spawning treatments; little extra benefit was gained from applying the nematodes twice. Populations of paedogenetic larvae of H. pygmaea built up rapidly in untreated compost, but were reduced when S. feltiae was applied, and were eradicated by H. heliothidis. Because they can penetrate insect cuticle, as well as natural body openings, Heterorhabditis spp. may be more suitable than Steinernema spp. for the control of mushroom fly larvae.
Resistances to oat mosaic virus in autumn‐sown oats
Authors: CATHERALL P. L. , VALENTINE J. 
Published: February 2008

SUMMARYA total of 100 varieties and advanced lines of autumn‐sown oats were assessed for reaction to soil‐borne oat mosaic virus. Two apparently distinct types of resistance, resistance to becoming infected and post‐infection resistance, were detected. Of the named varieties tested, cv. Lustre was outstanding, possessing the highest level of resistance to infection. Several breeding lines, but no named variety, possessed outstanding post‐infection resistance. A few varieties such as cv. Solva, which lacked either type of resistance, were tolerant of the virus.
Short‐term forecasting of wheat yield loss caused by the grain aphid (Sitobion avenae) in summer
Authors: ENTWISTLE J. C. , DIXON A. F. G. 
Published: February 2008

SUMMARYA damage model was used to take into account the effect on winter wheat yield of the size, duration and timing of Sitobion avenae infestation in summer, and the influence of insecticide applications. It was validated as far as possible using available data, and appeared to be sufficiently accurate to be useful. The model was applied to a total of 32 winter wheat fields over the period 1975 to 1983 in eastern England and the Netherlands, to obtain estimates of yield losses associated with not applying insecticides at the end of ear emergence (G.S. 59), mid‐anthesis (G.S. 65) or the end of anthesis (G.S. 69). These estimates of future yield losses were related in multiple regressions to the number of S. avenae per tiller at the time the insecticide was applied, and the rate of population increase over the previous few days.Basing the decision about whether to apply insecticide on forecasts from the multiple regression equations appeared to be slightly more profitable than prophylactic spraying when the chemical cost alone was considered, but substantially more profitable when the application cost and wheeling loss were also taken into account. The strategy minimising losses involved forecasts at all three crop growth stages. It was validated using a further 21 fields studied in 1984 and 1985, and gave better results than the EPIPRE system, which over‐estimated the number of fields requiring spraying, and the economic threshold of George & Gair (1979), which under‐estimated the number requiring spraying. However, the accuracy of the damage model needs to be checked against measured yield losses in order to establish the success of the multiple regression strategy conclusively.
The effect of frit fly Oscinella frit on the yield and persistence of Italian and hybrid ryegrasses in the laboratory
Authors: MOWAT D. J. , JESS S. 
Published: February 2008

SUMMARYThree cultivars of Italian or hybrid ryegrass were exposed to frit fly attack at varying frequency in the laboratory. Initially a Westerwolds and a hybrid cultivar showed greater yield reductions than an Italian ryegrass cultivar, although they did not usually suffer a higher proportion of damaged tillers. The differing effect on yield appeared to be due mainly to greater impact of first or infrequent attacks on cultivars producing fewer tillers. After two to six attacks in approximately 7 months the Westerwolds and hybrid cultivars appeared to become tolerant to attack and were subsequently the least affected, although continuing to suffer tiller damage at a rate at least as high as the Italian ryegrass. All cultivars recovered fully when attack ceased, and their exclusion from attack did not improve their persistence.
Uptake and movement of the fungicide imazalil following trunk injection into apple and plum trees by a novel, rapid technique
Authors: CLIFFORD D. R. , GENDLE P. , HOLGATE M. E. 
Published: February 2008

SUMMARYA hand‐held apparatus, produced by modifying a veterinary multiple dosing gun, was used to pressure‐inject aqueous solutions of imazalil into the trunks of plum or apple trees after harvest, before bud burst or during flowering. Bioassay showed that post harvest injection led to movement of imazalil up and down the trunk and into branches of both apple and plum trees. Movement in the trunk after injection before bud burst also occurred in plums but was limited in apples and fungicide was detected in branches only in apples and only at the end of the season. Injection at flowering time resulted in movement of imazalil into branches of apple, but not plum, trees. Imazalil was detected in twigs of apple, but not plum, trees but only after flowering time injections.The technique could be useful for control of tree diseases provided due attention is paid to dose, to the number and siting of injection holes and to the linking of injection time with the epidemiology of the target disease.
Comparison of bioassay and chemical determination of the activity of the fungicide guazatine as used in post‐harvest citrus dips
Authors: WILD B. L. 
Published: February 2008

SUMMARYA bioassay procedure was developed as a means of assessing the fungicidal efficacy of post‐harvest citrus dips containing the fungicide guazatine. The method is designed to overcome certain inaccuracies associated with the existing method of chemical analysis. The technique involves assessment of actual fungicidal activity by the inhibition of growth of a Geotrichum candidum culture. Comparisons are made between results of chemical analysis and this method, and the usefulness of the procedure is demonstrated.