bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical control of wheat bulb fly (Delia coarctata) attacking winter wheat in Eastern England, 1969–1981
Authors: MASKELL F. E. , GAIR R. 
Published: February 2008

SUMMARYSeveral insecticides were applied to the soil and/or plant foliage as granule or spray treatments to control wheat bulb fly larval damage to late‐sown winter wheat in eastern England between 1969 and 1981. Treatment effects in preventing larvae from entering plants or in killing larvae within attacked shoots and effects on yield were compared with controls and with a standard chlorfenvinphos seed treatment.Granules of chlorfenvinphos, fonofos or terbufos at rates between 1–40 and 2–24 kg a.i./ha were highly effective when applied at sowing in mineral soils, and fonofos granules were also effective in organic soils. Single spray applications of chlorfenvinphos, and especially of fonofos, applied at sowing at rates between 0–84 and 1–40 kg a.i./ha were effective in both soil types.Sprays applied when wheat bulb fly eggs began to hatch were more effective in mineral than in organic soils and gave lower yield increments than the standard chlorfenvinphos seed treatment.Single sprays of chlorpyrifos, formothion, omethoate or pirimiphos‐methyl, applied to the foliage when larval damage was first seen (‘deadheart’ stage) significantly increased yields; dimethoate spray or granule treatments applied at this stage were not significantly better than control and ‘deadheart’ treatments were generally less effective than chlorfenvinphos seed treatment.Multiple treatments involving two or more of the above methods were extremely effective in both soil types; their economic and environmental implications are discussed.
Definition of leaf health in Agrostis palustris at the time of infection and colonisation by Curvularia lunata
Authors: MUCHOVEJ J. J. 
Published: February 2008

SUMMARYThe state of leaf health of intact Penneagle creeping bentgrass leaves into whichCurvularia lunatawas able to ingress was determined by reducing cuticle/wax formation with trichloroacetic acid (TCA) and stressing plants with high air temperatures. Leaf health was estimated throughout the growing period of the plants by extracting chlorophyllaand then regressing the values with respect to time. In this manner, leaves at each nodal position could be classified as either juvenile, mature or senescent. The addition of TCA to plants decreased leaf and plant life. Stressing plants with high air temperatures accelerated leaf senescence as did higher levels of TCA. Inoculation withDrechslera sorokinianaresulted in lesion formation within 2 days. Symptoms commonly attributed to Curvularia blight were present on plants treated with 140 ^M TCA when high‐air‐temperature stressed and inoculated withC. lunata.Histochemical procedures failed to show the presence of mycelium ofC. lunatawithin the cells of Curvularia blight symptom areas. Results demonstrated that C.lunatahad the ability to colonise heat stressed and/or old leaves but did not have the ability to infect and colonise juvenile or mature tissues.
Regional variation of Puccinia coronata avenae in Australia and its implications for oat breeding
Authors: BROUWER J. B. , OATES J. D. 
Published: February 2008

SUMMARYA virulence survey of Puccinia coronata avenae was conducted in Australia from 1977 to 1980 with a chosen series of resistant oat lines as a tester set, viz., Ascencao, Pc‐38, Pc‐39, Pc‐45, Pc‐48, Pc‐50, Pc‐55, Pc‐56 and TAM 0–312. Isolates of the pathogen were classified by using these nine tester lines in combination with the International Differential Set. The survey area was divided into six zones (1) ‐Queensland; (2) ‐ northern New South Wales; (3) ‐ southern New South Wales; (4) ‐ Victoria; (5) ‐ South Australia and (6) ‐ Western Australia.Virulence for Pc‐38 was widespread throughout Australia and virulences or partial virulences for lines Pc‐39, Pc‐45, Pc‐48 and Pc‐55, although not as frequent, were common in Zones 1, 2 and 3. No isolates were found with virulences for oat lines Pc‐56 and TAM 0–312, while virulences for Ascencao or Pc‐50 were rare. The combination of virulences or partial virulences for lines Pc‐39, Pc‐45 and Pc‐48 was relatively common only among samples from Zones 1, 2 and 3.The diversity of the pathogen population varied between zones. Isolates from Zones 1 to 6 comprised 16, 21, 9, 8, 5 and 4 different standard races and mean virulence values were 5‐0, 3–8, 3‐0, 2–7, 2–6, 3‐1 and 3‐0, respectively. The proportion of complex strains (virulence value 5 or higher) decreased from 48‐5% (Zone 1) and 17‐0% (Zone 2) to 1–7% (Zone 3), 6‐3% (Zone 4), 0% (Zone 5) and 13‐9% (Zone 6). Greater diversity of the pathogen population in Zones 1 and 2was indicated by a higher incidence of strains with virulence for one or more of the nine resistant oat tester lines.
Propagation of black raspberry necrosis virus (BRNV) in mixed culture with solanum nodiflorum mottle virus, and the production and use of BRNV antiserum
Authors: JONES A. T. , MITCHELL MARGARET J. 
Published: February 2008

SUMMARYThe concentration of particles of black raspberry necrosis virus (BRNV), which is normally extremely low in herbaceous plants, increased about 1000‐fold when Nicotiana clevelandii plants were inoculated with a mixture of BRNV and an unrelated virus, solanum nodiflorum mottle (SNMV). In sap from N. clevelandii infected with the mixed culture, BRNV infectivity survived dilution to 10˜4 but not 10˜5, and storage for 6 but not 8 days at 20 oC, for 6 but usually not 10 days at 4 oC and for more than 13 days at – 15 oC. When plants were inoculated with the mixed culture, BRNV induced typical symptoms in several Chenopodium species and infected several previously unreported hosts. Purified preparations of particles of the mixed culture contained only a small proportion of BRNV particles, which sedimented in sucrose density gradients as two components, one, probably non‐infective, of c. 505, and the other, infective, of 120‐130S. An antiserum prepared to purified particles of the mixed culture was cross‐absorbed with SNMV particles and used in indirect ELISA to detect BRNV in herbaceous plants infected with the mixed culture, and also in a wide range of Rubus species, cultivars and hybrids infected naturally, by grafting or by inoculation with the aphid Amphorophora idaei. The reliability of ELISA for detecting BRNV in raspberry leaves depended on the cultivar and time of year. Some cultivars, such as Glen Clova, had low concentrations of BRNV, which was detected reliably only in late spring/early summer, whereas other cultivars, such as Lloyd George and Mailing Enterprise, had greater BRNV concentrations.In small‐scale surveys in eastern Scotland, BRNV was detected by ELISA in many raspberry cvs, including some that contain major gene resistance to the vector, A. idaei; in five of nine raspberry stocks entered for the Standard grade certificate but in none of five stocks entered for the Stock Cane certificate; and in 40% of wild raspberry and 14% of wild bramble plants growing near commercial raspberry crops. The significance of these findings for the control of BRNV is discussed.
Maize rough dwarf virus (Reoviridae) in its planthopper vector Laodelphax striatellus in relation to vector infectivity
Authors: CACIAGLI P. , CASETTA ALDA 
Published: February 2008

SUMMARYThe infectivity of females of the planthopper vector Laodelphax striatellus given access to maize rough dwarf virus (MRDV) infected plants was assessed for up to 55 days from the end of the access period. A 3‐day inoculation access period was used, and this avoided intermittent transmission. Maximum infectivity was reached c. 30 days after acquisition access and the proportion of transmitter insects then remained constant.There was no difference in the efficiency of female L. striatellus in acquiring MRDV as third instar nymphs or as adults when compared in transmission tests 24, 30, 35 and 40 days after access to the virus.ELISA tests for MRDV subviral particles (SVPs) discriminated between individual viruliferous and non‐viruliferous insects from the 30th day after access.Of the viruliferous (ELISA positive) insects about 30% did not transmit MRDV and the proportion remained similar from 30 to 55 days after access. None of the non‐transmitter insects tested in serial transfer transmission tests was positive in ELISA.The concentration of SVPs detected by ELISA in the transmitter hoppers continued to increase exponentially, even after maximum infectivity was reached.
Relationship between pectin content of stems of flax cultivars, fungal cell wall‐degrading enzymes and pre‐harvest retting
Authors: BROWN AVERIL E. , SHARMA H. S. S. , BLACK D. L. R. 
Published: February 2008

SUMMARYOf five flax cultivars suitable for fibre production Ariane retted most rapidly and Belinka and Hera were the slowest to ret after treatment with the herbicide glyphosate. Prematurely senescing stems of the different cultivars bore the same populations of saprophytic, filamentous fungi.More polygalacturonase (PG) activity was detected in retting, naturally‐colonised stems of Belinka, Hera and Regina than in stems of Ariane or Natajsa but pectin‐lyase (PL) activities were not significantly different. The pectic substance content of stem cell walls varied between cultivars; Hera and Belinka contained significantly the greatest amount, 34‐0 and 32‐5% w/w respectively and Ariane contained the least, 26‐3% w/w. Significant differences in xylan content of cell walls were not obtained but the highest levels of xylanase activity were detected in colonised stem tissues of Belinka. Fibres of this cultivar were found to be slightly weaker than those of the other cultivars but also the finest.
Ryegrass establishment and yield in relation to pesticide treatment, irrigation and fertiliser level
Authors: SPAULL ALISON M. , CLEMENTS R. O. , RIDOUT M. S. , G. MEWTON P. 
Published: February 2008

SUMMARYThe effects of irrigation, four fertiliser rates, fungicide, insecticide + molluscicide, and nematicide treatments were tested on an Italian ryegrass sward sown in May 1983, in a multi‐factorial experiment that allowed treatment interactions to be examined.Pests and fungal diseases were monitored over a 2‐yr period. No recognised grassland insect pests or slugs were found in the seedbed but there were an estimated 17 300 plant parasitic nematodes/litre soil. Other, non‐pest invertebrate populations, e.g. earthworms, were not assessed.In the first year yields were increased most by irrigation. There were also large yield responses to fertiliser over the range 50–900 kg N/ha/yr. Responses to pesticide application were relatively small. However, there were significant yield responses in the first year to nematicide and to insecticide + molluscicide treatments.Yields in the second year were affected more by increased fertiliser use than by irrigation; increases after pesticide use were similar to the previous year, and there was also a small but significant yield gain over untreated plots at the second harvest from those treated with fungicide.Interactions between main factors occurred in both years, affecting yields and nematode abundance. Nematode numbers were decreased in both years where the larger, compared to the smaller fertiliser applications had been made. In the first year these differences were only apparent on irrigated plots.It was concluded that, in this trial, irrigation had the greatest effect on yields of spring‐sown ryegrass during its establishment year but that increasing fertiliser rates had a greater effect the year after; that fungi had had little effect on ryegrass yields, and that nematodes were more important pests than insects during establishment but insects were more important subsequently.
The effect of pollen irradiation on segregation in spring barley crosses
Authors: ELLIS R. P. 
Published: February 2008

SUMMARYObservations on the Ml, M2 and M3 generations from three barley crosses confirmed that pollen irradiation can cause deviations from expected segregation ratios for certain characters. The reduced fertility observed in the Ml and M2 generations of these crosses could be problematical in breeding programmes. It was of particular interest that at the highest dose rate used for the cross TS117 × Scots Bere there was no expression of the 6‐row character, which is controlled by a recessive paternal factor.
An assessment of genetic variability in somacloned lettuce plants (Lactuca sativa) and their offspring
Authors: BROWN C. , LUCAS J. A. , CRUTE I. R. , WALKEY D. G. A. , POWER J. B. 
Published: February 2008

SUMMARYPlants were regenerated from callus derived from cotyledons and first true‐leaves of the lettuce cultivars Salad Bowl, Lobjoits Cos and Pennlake. Sexual progeny of these regenerants were assessed under glasshouse and field conditions for variation including reaction to lettuce mosaic virus (LMV) and downy mildew (Bremia lactucae). All three cultivars exhibited somaclonal variation. Mutations detected at the seedling stage included reduced vigour, albinism and changes in chlorophyll content, with most being recessive. Variation for leaf shape and vigour was detected in mature plants. One line exhibited increased yield and chlorophyll content together with early flowering. Enhanced and reduced susceptibility to both LMV and B. lactucae were observed. Reduced susceptibility to B. lactucae was indicated by an extended latent period following inoculation in two lines. Reduced susceptibility to LMV in glasshouse trials could not be confirmed in the field although one such line exhibited an improved yield and a second line segregated 1:1 in glasshouse tests for plants which were obviously infected and those without symptoms. All variable lines were diploid.
The effects of nitrogen application on growth and nitrogen distribution within the potato canopy
Authors: MILLARD P. , MACKERRON D. K. L. 
Published: February 2008

SUMMARYThe effect of applying nitrogen (N) fertiliser on the growth and distribution of N within the potato canopy was studied in 1983 and 1984. In both years N was applied either in excess of that required to produce maximum tuber yields, or not at all. The large application of N changed the pattern of canopy growth ‐ stimulating growth of leaves at the top of the stem, particularly lateral branches, for longer during the season, and accelerating the death of (shaded) leaves at the base of the canopy. The pattern of canopy senescence was, therefore, changed from a synchronous to a progressive type.Application of nitrogen fertiliser at supra‐optimal rates increased the N contents of leaves, stems and tubers. The extra N in the leaves of these plants was present as reduced N in all leaf positions, and as nitrate (NO‐3) in the lowermost leaves. In addition, substantial quantities of NO‐3 were also stored in the stems. Part of this extra N in the canopy was redistributed during subsequent growth, especially to the lateral branches as crop N uptake slowed towards the end of the season. In addition, substantial quantities of N were also potentially available for redistribution to the growing tubers. There was little redistribution of N from the leaves of N‐deficient plants.It is suggested that redistribution of N in the canopy of N‐replete plants allowed the growth of lateral branches towards the end of the season, thereby maintaining photosynthetically active leaves for longer than N‐deficient plants.
Field studies on the effects of peanut stunt virus on growth, nodulation and yield of Viciafaba in the Sudan
Authors: AHMED A. H. 
Published: February 2008

SUMMARYThe effects of the Sudanese isolate of peanut stunt virus on the growth, nodulation and yield of two cultivars of broad bean (Viciafaba) were assessed in field trials in the Sudan for two consecutive years. Virus infection reduced both the fresh and dry weights of shoots and roots, reduced nodulation by up to 78% and significantly reduced the number and weight of seed per plant. Seed yield per area was reduced by up to 91% and 93% in the cultivars Silaim and Tarbia respectively. These adverse effects were attributed to the virulence of the virus strain, the time of infection and the susceptibility of the cultivars tested.
Control of cereal aphids in winter wheat by natural enemies: aphid‐specific predators, parasitoids and pathogenic fungi
Authors: CHAMBERS R. J. , SUNDERLAND K. D. , STACEY D. L. , WYATT I. J. 
Published: February 2008

SUMMARYWinter wheat fields on two farms in West Sussex were sampled in 1980 and 1981 for cereal aphids and their natural enemies. The grain aphid, Sitobion avenae was present in all 19 fields examined, but in no case did the populations increase to densities liable to cause economic damage. The observations strongly suggest that aphid population growth was stopped by aphid‐specific predators, hymenopterous parasitoids and fungal pathogens. In two fields in 1980, S. avenae population densities approximately equalled five aphids per ear at flowering, the threshold at which insecticide application is recommended in the UK, but numbers were then reduced by natural enemies, mainly aphid‐specific predators. In three fields in 1981, S. avenae would probably have exceeded the spray threshold had natural enemies not intervened in late May.
Characterisation of the distribution of individual response times in bacterial infection of plants
Authors: ERCOLANI G. L. , VANNELLA S. 
Published: February 2008

SUMMARYThe distribution of time of visible response to infection was followed after inoculation of Pseudomonas syringae pv. syringae onto the flowers of pear cv. Williams, Pseudomonas syringae pv. phaseolicola into the leaves of bean cvs Borlotto di Vigevano and Saluggia, Corynebacterium michiganense subsp. michiganense into the stem of tomato cvs Fiorentina and C 1402 and Agrobacterium sp. biovar 3 into the stem of sunflower cv. Egnazia at a dosage of either 0.5–32 times the median effective dose (ED50) or 1–64 ED50. The distribution contracted and the median response time decreased as the dose of inoculum was increased for each host‐pathogen combination. Modified Weibull regressions with shape parameter 1< c < 2.5 gave a highly significant fit to the observed distributions of individual response times in all dose groups and host‐pathogen combinations.
Melon rugose mosaic virus, the cause of a disease of watermelon and sweet melon
Authors: JONES PHILIP , ANGOOD SAEED BA , CARPENTER JOHN M. 
Published: February 2008

SUMMARYA mechanically transmissible virus with isometric particles c. 32 nm in diameter, was isolated from infected watermelons and sweet melons in the People's Democratic Republic of Yemen. Purified virus preparations contained two major sedimenting components with sedimentation coefficients of 61S and 117S. In isopycn ic centrifugation in CsCl the particles formed a single band of buoyant density 1.39 g cm‐3. Preparations of virus particles comprised of a single polypeptide of mol. wt c. 22 000 and ssRNA of mol. wt 2.1 × 106. The virus was serologically related to three of six subgroups of tymoviruses tested. The name melon rugose mosaic virus is proposed for this newly described virus.
Effect of ethofumesate on the epicuticular waxes of onion leaves, and on the response of plants to foliage‐applied herbicides
Authors: RUBIN B. , ADLER U. , VARSANO RINA , RABINOWITCH H. D. 
Published: February 2008

SUMMARYThe herbicide ethofumesate is commonly used in onion fields in Israel. Experiments with four onion cultivars have shown the combination of a pre‐emergence treatment with ethofumesate and foliar application of a variety of herbicides to cause a marked decrease in plant fresh weight. This effect of ethofumesate was still evident when post‐emergence herbicides were applied as late as the third leaf stage of development. Significantly lower amounts of waxes were extracted with chloroform from the leaves of onion plants treated pre‐emergence with ethofumesate, at the rates of 0.2–0.8 kg/ha. SEM micrographs showed considerable changes in the onion epicuticular fine structure following these ethofumesate treatments. Furthermore, a significant increase in the penetration of 14C‐labelled compounds into the onion leaves was measured. The possible implications of ethofumesate effects on onion leaf surface fine structure, are discussed.
Introducing Erynia neoaphidis into a field population of Aphis fabae: form of the inoculum and effect of irrigation
Authors: WILDING N. , MARDELL SUSAN K. , BROBYN PATRICIA J. 
Published: February 2008

SUMMARYThe effect of treating field populations of Aphis fabae on spring‐sown field beans with different preparations of the entomogenous fungus Erynia neoaphidis, with and without irrigation of the crop, was examined at Rothamsted in 1979. The fungus applied on 21 June as the triturated cadavers of fungus‐killed aphids established infection in the host population as effectively as by distributing living laboratory‐infected aphids. Although the introduced fungus, together with other species present naturally, killed more than 70% of aphids in late July, it failed to multiply fast enough to protect the crop adequately. An application of an homogenate of the fungus grown on agar plates failed to establish infection.From 25 June to 28 July there was little rain and irrigation greatly increased the proportion of aphids killed by E. neoaphidis during late July confirming that the spread of this fungus can be limited by dry conditions.
Effects of changing temperature regimes on resistance to races of Melampsora medusae in a cultivar of poplar
Authors: PRAKASH C. S. , HEATHER W. A. 
Published: February 2008

SUMMARYLeaf discs of Populus deltoides cv. W‐79/307 inoculated with race 4–C of Melampsora medusae, give a compatible reaction when incubated at 16°C (LT), but an incompatible reaction at 26°C (HT). When, over a 12–day period, sets of inoculated leaf discs were reciprocally transferred between the temperature regimes (LT to HT, or HT to LT), incubation for as short as 15 h at HT resulted in incompatibility which was not reversed by subsequent incubation at LT. In contrast, incubation of the inoculated discs at LT for at least 4 days was necessary for the development of a compatible reaction following transfer to HT. Further, incompatibility induced in discs by inoculation with race 4–C and incubation at HT is epistatic to expected compatibility following subsequent inoculation with race 4–M, a temperature non‐sensitive biotype. The rapidity, irreversibility and epistatic nature of the temperature‐induced incompatibility suggests that initial recognition in this pathosystem may be for incompatibility. The significance of these results in this host/pathogen system is discussed.
Genetic studies on resistance to clubroot in Brassica napus
Authors: GUSTAFSSON MATS , FALT ANN‐SOFIE 
Published: February 2008

SUMMARYTen lines of Brassica napus have been tested against four Scandinavian races of clubroot (Plasmodiophora brassicae). The host‐parasite interaction is mainly differential. The genetics of resistance in the host have been investigated. Several major dominant genes have been localised and their distribution in the cultivars is discussed.
Damage to cereal crops by larks in north‐western Iraq
Authors: HALSE S. A. , TREVENEN H. J. 
Published: February 2008

SUMMARYTwo types of lark‐caused damage occurred in cereal crops in north‐western Iraq: grazing by skylarks and digging by calandra larks. The level of damage in large‐scale cereal plantings was low but extensive damage, resulting in lowered grain yields, occurred in some experimental trials and made evaluation of cereal cultivars difficult. The amount of grazing varied amongst cultivars, differences being more pronounced with grazing than digging.