bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water stress in field‐grown perennial ryegrass.
Authors: JONES M. B. , LEAFE E. L. , STILES W. 
Published: February 2008

SUMMARYSwards of perennial ryegrass (Lolium perenne) were grown in the field and in boxes with low water‐holding capacity (simulated swards). Water stress was allowed to build up in half the swards by using rain covers and withholding irrigation. Stress developed slowly in the field swards (over a period of 4 wk) but rapidly in the simulated swards (over a period of 5 days). Comparisons of leaf water potential, osmotic potential and stomatal resistance were made between these stressed swards and field and simulated swards whose soil water content were kept within 20 mm of field capacity. Measurements were made on the youngest fully expanded leaves. In the field swards the leaves on which measurements were made had grown during the development of stress, whereas in the simulated swards they were fully developed before the imposition of stress.Daily minimum values of leaf water potential fell to —12 bars (‐1.2 M Fa) in both field and simulated irrigated swards, to —16 bars in the stressed field swards and to —20 bars in the stressed simulated swards. Osmotic potential declined in the stressed leaves; in the field swards this ensured that turgor was maintained under stress but in the rapidly stressed simulated swards turgor fell to zero for a significant part of the day.In all swards, leaf resistance measurements indicated that stomata began to close at leaf water potentials below —13 bars. There was no clear difference between slowly and rapidly stressed swards in the sensitivity of stomata to the decrease in leaf water potential.Leaves which grew under slowly developing stress were morphologically different from leaves from non‐stressed swards. The leaves were smaller, had a higher stomatal density, smaller epidermal cells and showed deeper ridging on their adaxial surface.
Effect of simulated rain on retention, distribution, uptake, movement and activity of difenzoquat applied to Avena fatua
Authors: CASELEY J. C. , COUPLAND D. 
Published: February 2008

SUMMARYIn glasshouse studies the degree of control of A vena fatua increased as the period between application of difenzoquat and the onset of simulated rain was prolonged. 0.5 mm of ‘rain’ removed 29% of the herbicide deposit without adversely affecting performance at the recommended dose of 1 kg/ha. A further 30% was removed by 2.0 mm of ‘rain’, resulting in a marked reduction in acrivity. With lower amounts of ‘rain’ (0.16 mm), some of the spray deposit was redistributed from the leaf lamina to the leaf base/ligule area. The rate of penetration of 14C‐difenzoquat was much greater when applied to the inner surface of the leaf sheath than when the leaf blade and outer sheath areas were treated. Translocation from the ‘inner sheath’ to other parts of the plant was up to 100 times greater than from other areas. It is suggested that the performance of difenzoquat is not reduced by low amounts of rain because: (1) the spray deposit is removed principally from the leaf blade, whilst in the more responsive ligule/leaf sheath area the herbicide remains in solution, (2) the recommended dose of 1 kg/ha allows for some loss of active ingredient without reduction in performance. The practical implications of the work are discussed and further topics for research are outlined.
Evidence for a calcium‐binding site on the eggshell of Globodera rostochiensis with a role in hatching
Authors: ATKINSON H. J. , TAYLOR JILL D. 
Published: February 2008

SUMMARYTwo inhibitors of hatching in Globodera rostochiensis, ruthenium red and lanthanum, have been shown to bind to the eggshell using the techniques of microdensitometry for ruthenium red and X‐ray microanalysis for lanthanum. Neither inhibitor penetrated or adhered to unhatched or hatched viable juveniles. Scatchard analysis for binding of lanthanum and ruthenium red to eggshells gave dissociation constants (K) of KLa 32.5 ± 14.0 μM and KRured 33.5 ± 5.0 μM respectively. Both values are within the 95% fiducial limits of those shown to cause 50% inhibition of hatch in previous work. Pretreatment with sodium hypochlorite separated an outer part of the eggshell from an inner region which exclusively bound ruthenium red. It is the inner lipoprotein layer that is believed to include the membranes controlling the permeability of the tylenchid eggshell. The rate of binding of ruthenium red was similar for intact and isolated eggshells with 50% binding occurring after 6.11 ± 0.91 min and 4.95 ± 2.38 min but the latter gave a significantly higher maximum binding suggesting that rupture of the eggshells made available additional binding sites on their inner surface. The binding of ruthenium red to the eggshells was pH dependant over most of the range pH 2.8–8.5 with 50% binding, given with its standard deviation, occurring at pH 5.75 ± 0.85.Competitive binding of lanthanum influenced the binding of ruthenium red to the eggshells from which Scatchard analysis gave Kla of 176 ± 79 μM. Similarly, calcium influenced the binding but this caused a biphasic plot with high and low affinity binding sites of K“ca of 0.423 ± 1.16 μm and K‘ca of 1078 ± 462 μM. The existence of a high affinity site for calcium that also binds ruthenium red, suggests that the eggshell membrane includes a calcium binding glycoprotein as found in some other receptor mechanisms.
Screening for resistance to potato cyst nematode using closed containers
Authors: PHILLIPS M. S. , FORREST J. M. S. , WILSON LINDA A. 
Published: February 2008

SUMMARYA screening method is described whereby potato plants are grown in soil in closed plastic containers in the dark, producing root systems upon which potato cyst nematodes can reproduce. Tubers are planted in John Innes No. 2 compost at 30% moisture and inoculated with an egg suspension. The canisters are held at 20°C for 7 wk after which, visible developing females are counted. This method of screening is more rapid, economical and produces data as reproducible as those from conventional pot tests. The value of the test for detecting resistance early in a potato breeding programme is discussed.
The herbicidal activity of bromoxyside (3,5–dibromo‐4–hydroxyphenyl methyl sulphide), its esters and related compounds
Authors: WILCOX E. J. , WAIN R. L. , WAIN ROSEMARY J. 
Published: February 2008

SUMMARYStudies on the herbicidal activity of 3,5–dibromo‐4–hydroxybenzonitrile (bromoxynil) and 3,5–dibromo‐4‐hydroxyphenyl methyl sulphone (bromoxysone) have been extended to include 3,5–dibromo‐4‐hydroxyphenyl methyl sulphide (bromoxyside), its esters and other related compounds.Bromoxyside produced chlorotic effects in barley and wild oat seedlings, the herbicidal activity being similar to that of bromoxysone but quite different to that of bromoxynil. A range of aliphatic and aromatic esters of bromoxyside were prepared and examined as herbicides using barley and wild oat seedlings as test plants. The acetate and propionate were the most active against both species. No compound tested was more herbicidal to wild oat than to barley. Introduction of a further bromo or methyl ring‐substituent into bromoxyside removed herbicidal activity.Spraying plants of differing age showed that the herbicidal effect was greater when the plants were small.
Methods for detection of resistance to woolly aphid (Eriosoma lanigerum) in apple
Authors: LYTH M. , WATKINS R. 
Published: February 2008

SUMMARYTwo ways of examining resistance in apple to Eriosoma lanigerum were assessed. The first method involved a single mass inoculation of young seedlings with first‐instar nymphs. This failed to identify many susceptible seedlings and also produced inconsistent results which strongly suggested an uneven distribution of aphids at inoculation. Repeated inoculations were far more efficient in identifying known susceptibles than single inoculations, but they did not discriminate between susceptible and some resistant seedlings. However, the technique would be very useful where the major objective was the identification of higher levels of resistance. To overcome the destructive nature of mass inoculation and the inefficiency in classifying individual seedlings, a second method was devised using clonal material which allowed replication of genotypes. Calibrated inoculations made direct comparisons with controls possible and aphid numbers could be estimated with acceptable accuracy with a volumetric technique. However, comparisons based on approximate colony lengths were adequate, and faster, for routine screening.
Effects of pesticide treatments on the yield of swedes
Authors: FRENCH N. , COLLINGWOOD C. A. , SAYNOR M. , BROCK A. MURIEL 
Published: February 2008

SUMMARYThe effects of insecticide and fungicide applications to swedes (Brassica napus var. napobrassica) were examined at 15 sites in England from 1974 to 1978. Several different pesticide combinations were applied including carbofuran granules at drilling (63 mg a. i./m of row), demeton‐S‐methyl sprays (0·24 kg a. i./ha) and fluotrimazole sprays (0·18 kg a. i./ha). The best treatments, which varied in different years, gave significantly higher yields than no treatment in 12 out of a total of 15 trials, with varying levels of damage attributable to cabbage root fly (Delia brassicae), aphids (Myzus persicae) and powdery mildew (Erysiphe cruciferarum) in each of the 4 years. In 10 of 12 trials, plots receiving a complete insecticide and fungicide programme yielded on average 40% (range 21–61%) more than untreated plots, mainly through control of root fly and aphids in 1975 and of aphids and mildew in 1976. Aphid damage to swedes was exceptionally severe in both years. Granular formulations of aldicarb, carbofuran, chlorfenvinphos or fonofos used alone to prevent cabbage root fly damage gave significant yield benefits in only 8 of the 15 trials, with least effect in 1977 and 1978 when growing conditions for swedes were good and damage relatively light.
Control by imazalil of fruit storage rots caused by Alternaria alternata
Authors: PRUSKY D. , BEN‐ARIE RUTH 
Published: February 2008

SUMMARYThe fungicide imazalil has potential value for controlling post‐harvest diseases caused by Alternaria alternata in pears, apples and persimmons. Imazalil was active in vitro on germination and hyphal growth (ED50) at 1.4 and 0.5 μg/ml, respectively. Protectant action of the fungicide lasted only 1 day after treatment. At 1000 μg/ml the fungicide inhibited development of Alternaria rot in inoculated apples at 0 °C and in naturally infected pears and persimmons at–1 °C.
The distribution and persistence of iprodione applied by thermal fogging in a glasshouse tomato crop
Authors: MORGAN WALTER M. 
Published: February 2008

SUMMARYDeposits collected on filter paper after application of a ready‐to‐fog formulation of iprodione and the residues of iprodione washed from tomato leaves after fog and HV spray application were analysed by gas‐liquid‐chromatography. Relatively heavy deposits were found close to the fogging machine but the deposit became lighter with increasing distance from the machine and in positions lateral to the stream of fog. The deposit collected within the leaf canopy was considerably lighter than that collected above the plants. Residues of iprodione on plants treated with HV sprays were always considerably higher than on fogged plants given a comparable rate of application. After repeated treatment, a substantial build‐up of residue was found, but the amount on fogged plants was approximately half that on plants treated with HV sprays. There was a good correlation between the residue found on plants at six positions within the glasshouses and the incidence of infection from artificial inoculations of Botrytis cinerea on petioles.
Natural distribution, spread, and variation, in the tobacco mosaic virus infecting Nicotiana glauca in Australia
Authors: RANDLES J. W. , PALUKAITIS PETER , DAVIES C. 
Published: February 2008

SUMMARY Nicotiana glauca is a naturalised introduced species widely distributed in Australia. A survey of stands in the central zone of its recorded distribution has shown that a type of tobacco mosaic virus which characteristically induces a bright yellow mosaic symptom (TMV‐Y) is commonly associated with N. glauca throughout this zone. Surveys of a natural community of N. glauca less than 5 yr old, and in an experimental block, showed that TMV‐Y could spread at a rate, and in a pattern, which could not be explained by contact transmission alone, and which indicated that an airborne vector was probably involved in transmission. These results together have led to the conclusion that the common association of TMV‐Y with N. glauca is due to spread of the virus by an unknown vector(s). Seed transmission of TMV‐Y in N. glauca has not been detected.Molecular hybridisation analysis has shown that all but one of the TMV‐Y isolates studied were related to TMV‐U2, and that the isolate which was unrelated to U2, was partially related to TMV‐U1, TMV‐U5, and tomato mosaic virus. Selected isolates which showed a close relationship to TMV‐U2, also showed a close relationship to TMV‐U5, a distant relationship to TMV‐U1, and tomato mosaic, and very little or no relationship with three other tobamoviruses (sunn‐hemp mosaic virus, odontoglossum ringspot virus, and cucumber virus 4). These results show that the Australian TMV‐Y isolates are similar to the TMV isolated from N. glauca in California.
Effects of decreasing the number of grains in ears of cvs Hobbit and Maris Huntsman winter wheat
Authors: RADLEY M. E. , THORNE G. N. 
Published: February 2008

SUMMARYAt 6 days after anthesis, grain numbers in ears of Maris Huntsman and Hobbit winter wheat growing in the field were decreased either by removing the two lower grains in each spikelet (degraining) or by removing the top half of the ear (halving). At maturity, degraining increased the dry weight of the third grains in each spikelet of Maris Huntsman by 11% and of Hobbit by 40%, compared with third grains in intact ears. Halving increased the mean dry weight of all the grains in the lower six spikelets of the ear slightly less; it increased the number of grains in Hobbit but not in Maris Huntsman. The responses to halving in Hobbit were greater with additional nitrogen fertiliser.At 28 days after anthesis in both varieties, degraining increased grain dry weight and the amount of water, reducing sugar, amino acids and total nitrogen in third grains. Effects of halving on these properties of the two lower grains of each spikelet were much less or nil. The increases in nitrogen content of grains at 28 days and at maturity caused by degraining or halving were relatively greater than the increases in dry weight and were similar in the two varieties.
Experimental studies on the responses of European siricid woodwasps to host trees
Authors: SPRADBERY J. P. , KIRK A. A. 
Published: February 2008

SUMMARYA study was made of the oviposition responses of the siricid woodwasps, Sirex noctilio, S. juvencus, S. cyaneus and Urocerus gigas to experimentally debilitated spruce and pine trees. Treatments included felled, fire‐burned, logged and girdled trees which were treated at intervals before bioassay with cages siricid females. In comparable treatments, S. noctilio showed a distinct preference for pines although it was quite successful on spruce while the other siricid species displayed a preference for spruce. The Sirex species successfully attacked more recently treated material although U. gigas showed a preference for timber in a more advanced state of debility. All species showed preferences for girdled trees although other treatments were also favoured by the different siricid species. Overall, the siricids preferred the area above the girdle irrespective of tree species and there was a higher rate of eggs above the girdle in treated spruce trees. A wide range of moisture content in the timber appeared to have no effect on drilling activity or the successful development of eggs. The response of a wild population of S. juvencus to the treated spruce is also described. The results are discussed in relation to the ecology of Siricidae in Europe and the establishment of S. noctilio in Australia. It is suggested that of the species studied, only S. noctilio poses a serious threat to the living pine stands of Australia.
Disease progress of non‐specialised fungal pathogens in intraspecific mixed stands of cereal cultivars. I. Models
Authors: JEGER M. J. , GRIFFITHS ELLIS , JONES D. GARETH 
Published: February 2008

SUMMARYTwo mathematical models are presented which describe progress of disease, caused by an unspecialised pathogen, in pure and mixed stands of cereal cultivars. One is a simple, discrete model utilising the parameters infection frequency (lesions/spore) and sporulation rate (spores/lesion/event) on each cultivar. The model predicts that, in most circumstances, the amount of disease in mixtures will be equal to or less than the arithmetic mean of the component pure stands. An increase in disease is only predicted in situations where the ranking of cultivars with respect to infection frequency and sporulation rate is opposed. In the other model differential equations are proposed. Solutions of these equations indicate that disease amelioration can usually be expected in such mixtures, confirming the conclusions of the discrete model and that disease levels will deviate around the geometric, rather than arithmetic, mean of the pure stands. However the advantages of this model lie in wider generality and conceptual, rather than practical, utility.
Disease progress of non‐specialised fungal pathogens in intraspecific mixed stands of cereal cultivars. II. Field experiments
Authors: JEGER M. J. , JONES D. GARETH , GRIFFITHS ELLIS 
Published: February 2008

SUMMARYEpidemic development of Septoria nodorum was examined in pure stands and mixtures of two spring wheat cultivars, Kolibri and Maris Butler. In mixtures, disease development was reduced almost to that of the more resistant pure stand (Maris Butler). Disease levels, however, were low and no significant differences in grain yield per head were demonstrated. Disease development was further investigated for the host‐pathogen combinations winter wheat/S. nodorum and winter barley/Rhynchosporium secalis. With both combinations the mixed stands again reduced disease levels to almost that of the more resistant pure stands. In general, mixed stands were more effective against R. secalis, although, with S. nodorum, disease levels were low. The yield response in mixed stands differed for the host cultivars and was not significantly changed by the presence of disease. The complexity of analysing such situations and the implications of these findings for mixtures of cultivars differing in resistance to non‐specialised pathogens are discussed.
The effect of minimum cultivation on the incidence of take‐all down the root profile of winter wheat
Authors: PREW R. D. 
Published: February 2008

SUMMARYThe effects of direct drilling, shallow cultivation and ploughing on the infection of winter wheat roots by the take‐all fungus (Gaeumannomyces graminis var. tritici) were studied on three field sites over a number of years. All three soil types were categorised by Cannell, Davies, Mackney & Pidgeon (1978) as suitable for sequential direct drilling. The results show that a smaller proportion of roots was infected at depth in the direct‐drilled plots in May/June. However by July these differences had all but disappeared and an estimate of infection in the top 7 cm of the roots (approximately equivalent to traditional hand sampling for take‐all) gave a reliable comparison of the total take‐all on plants grown under these different cultivation systems.
Epidemiology of vascular‐streak dieback of cocoa
Authors: KEANE P. J. 
Published: February 2008

SUMMARYInoculation studies provided further evidence that Oncobasidium theobromae is the cause of vascular‐streak dieback of cocoa and that the fungus can penetrate undamaged, soft leaves. Spores are forcibly ejected from basidia at night and dispersed by wind. They are rapidly killed by exposure to normal day‐time conditions and require free water for germination. Spore dispersal is probably very limited under plantation conditions and disease spread occurs along a steep gradient into new plantings. Disease increase in young plantations was found to occur at a rate of 0.31 per unit per month; in one block 100% of seedlings were infected and 55% were killed within 33 months of planting. The disease was most damaging in seedlings younger than 18 months old, although there was evidence that it also caused substantial yield loss in mature susceptible cocoa. Sporophore production and infection rate were correlated with rainfall incidence. The unusual grographical distribution of the disease and aspects of its control are discussed.
Properties of spinach yellow mottle, a distinctive strain of tobacco rattle virus
Authors: KURPPA A. , JONES A. T. , HARRISON B. D. , BAILISS K. W. 
Published: February 2008

SUMMARYA virus (isolate SYM) obtained from spinach plants in England with a severe yellow mottle disease induced symptoms resembling those of tobacco rattle virus (TRV) in several indicator species but caused systemic necrosis in Chenopodium amaranticolor and C. quinoa. It was transmitted to bait plants grown in soil containing the nematode Trichodorus primitivus.Purified virus preparations contained rod‐shaped particles that were predominantly of four modal lengths: 188 nm (L particles), 101 nm (S particles), 57 nm and 48 nm (together called VS particles), containing RNA with mol. wts of 2.4, 1.5, 0.7 and 0.6 million, respectively. L particles (s°20= 300 S) and S particles (230 S) greatly outnumbered VS particles (c. 150 S). All particles contained a single polypeptide species with estimated mol wt of 24 700, slightly larger than those previously reported for tobraviruses. Purified L particles were infective but both L and S particles were needed to induce the production of virus nucleoprotein particles. VS particles were not infective and apparently had no qualitative or quantitative effect on infection by L or by L plus S particles. S particles carried determinants for serological specificity and ability to invade C. amaranticolor systemically.Isolate SYM produced pseudo‐recombinants with isolate PRN of TRV. Also, isolates CAM, OR and PRN of TRV, and isolate SYM, were found to be distantly related by three kinds of serological test. No relationship was detected between these isolates and pea early‐browning virus in gel‐diffusion precipitin tests or electron microscope serological tests, but a distant relationship between isolate SYM and pea early‐browning virus was found by micro‐precipitin tests. Isolate SYM therefore has closer affinities with TRV than with pea early‐browning virus and is considered to be a distinctive strain of TRV.
The expression of resistance to powdery mildew infection in winter wheat cultivars. I. Seedling resistance
Authors: BENNETT FIONA G. A. 
Published: February 2008

SUMMARYDetached seedling leaf tests were used to assign 18 winter wheat cultivars to three wheat mildew resistance (WMR) groups on the basis of identified race‐specific resistance characters. The same cultivars were exposed in mobile seedling nurseries from 1976 to 1979. Infection by mildew populations containing matching pathogenicity characters was used to recognise background seedling resistance in three cultivars: Maris Freeman, Maris Huntsman and Sentry. The value of background seedling resistance is discussed.