bluuebunny/crossref_metadata_2025_split huggingface dataset:
Leaf photosynthesis in pure swards of two grasses (Lolium perenne and Lolium multiflorum) subjected to contrasting intensities of defoliation
Authors: OLLERENSHAW J. H. , INCOLL L. D. 
Published: February 2008

SUMMARYPhotosynthetic rates were measured on light saturated, fully‐expanded leaves in pure swards of Lolium perenne and Lolium multiflorum during late summer using 14‐carbon dioxide. These swards were defoliated by cutting at three heights of 3, 6 and 9 cm above the ground. The photosynthetic rates of leaves on tillers in swards cut constantly 3 cm above ground level were higher than those of leaves in swards cut constantly 9 cm above ground level. Additional treatments with various sequences of cuts 3, 6 and 9 cm above ground level were designed to reduce damage to the growing points of tillers whilst ensuring satisfactory harvesting of the shoots. The photosynthetic rates of leaves on tillers cut to various heights above ground level at successive harvests were intermediate between those of similar leaves in the constantly low and high cut swards.The rates of photosynthesis of Italian ryegrass leaves were higher than those of perennial ryegrass leaves for a short time after defoliation of the constantly high cut swards. However, these perennial ryegrass leaves quickly adapted their rates of photosynthesis to the higher irradiances they received after cutting. Thus grass species differing in morphology adjust to management practices by the use of different photosynthetic strategies.
Populations of the phorid fly Megaselia halterata on an experimental mushroom unit over four years
Authors: BINNS E. S. , GURNEY BARBARA , WYATT I. J. , WHITE P. F. 
Published: February 2008

SUMMARYPopulations of phorid flies on an experimental mushroom unit were sampled simultaneously in both spawn‐running and mushroom cropping‐houses by sticky traps. Comparison between these populations showed that each reached a maximum about August and that the rate of increase, as measured by the ratio between them, varied from 22 × (at the beginning of February and in mid‐August to 115 × (at the beginning of June and the end of December). Population growth within a crop was assessed from the peaks plotted from weekly catches. Three such peaks could be seen, starting from initial numbers which were high, on average, at casing but with little increase after the seventh week of cropping. However, population growth within crops, found by pooling data for different seasons, showed logistic increases though slopes varied from low, for May to June‐spawned crops, to high for October spawning. Wide variations occurred in the proportion of the total flies represented in the initial catches in the first wk after casing.Partial regressions were examined for the numbers caught in cropping‐houses on those taken in spawn‐running rooms throughout the year. Catches for crops spawned during June to September gave lower slopes for high cropping‐house populations. Spawn‐running room catches showed a linear relation with outdoor 9.00 a.m. B.S.T. temperature and cropping‐house numbers a logistic relation, a better fit obtaining with temperatures at spawning rather than 5 wk later during cropping. Catches during spawn‐running were correlated with those during subsequent cropping and these with catches made during the previous crop on the unit, irrespective of site. Since it was bimodal, rate of increase between spawn‐running and cropping‐houses did not correlate with outdoor temperature but revealed some very high catches in winter. Many flies were trapped in the cropping‐houses early in the year when flies were absent from spawn‐running rooms. Evidence for movements within farms is discussed, especially with respect to overwintering of the phorid, which validates routine trapping of both populations.
Influence of formulation on chlorfenvinphos uptake and cabbage root fly control on radish
Authors: SUETT D. L. 
Published: February 2008

SUMMARYGranular and liquid formulations of chlorfenvinphos were applied to a sandy‐loam as continuous logarithmically‐changing doses of approximately 0.2 to 4.0 kg a.i./ha and radish were sown immediately and 23 days after treatment. After 62 days, insecticide concentrations in the soil had not diminished detectably in the granule treatment but had declined by about 20% in the liquid treatment. In both sowings, residues in the harvested radish were higher, dose‐for‐dose, from the granule than from the liquid treatment and with both formulations were lower in the second than in the first sowing. Within treatments there were log‐log relationships between the dose of insecticide and residue concentrations in the soil and radish. In both sowings the residues were most variable between replicate soil and crop samples from the granule treatment. In the first sowing, cabbage root fly damage was reduced most by the liquid treatment but in the second sowing equivalent doses of the two formulations gave similar protection.At 2.0, 2.24 or 3.0 kg a.i./ha, chlorfenvinphos incorporated before sowing protected radish better than pre‐sowing or pre‐emergence applications to the soil surface. When applied before sowing, the liquid formulation gave better protection and lower residue concentrations in the radish than the granules. As a post‐emergence spray, chlorfenvinphos was much more effective than fonofos, diazinon or triazophos but it was often phytotoxic, decreased yield significantly, left large residues in the radish in two of the four experiments and, in common with other surface treatments, substantially decreased the Z:E chlorfenvinphos isomer ratio. Although a single application of granules protected two successive radish crops, it was concluded that third and subsequent sowings on the same land should probably be treated with smaller doses to limit terminal residues.
The characteristics of isolates of Erysiphe graminis f. sp. hordei varying in response to tridemorph and ethirimol
Authors: WALMSLEY‐WOODWARD DIANNE J. , LAWS F. A. , WHITTINGTON W. J. 
Published: February 2008

SUMMARYSingle pustule isolates of E. graminis f. sp. hordei were collected from fungicide treated and untreated barley in the field and glasshouse. The isolates were maintained in culture on leaf segments of a mildew susceptible barley cultivar. Each isolate was assayed at least five times in 10 months for tolerance to tridemorph and ethirimol.Variation was found among the isolates both in pathogenicity and in the level of tolerance to tridemorph and ethirimol. Tolerance to either fungicide tended to be stable during the 10 months of culturing, although a small number of isolates lost their tolerance in this time. No evidence of cross tolerance was found, although some isolates were tolerant to varying levels of both fungicides, perhaps due to a fortuitous combination of tolerance genes.
Transmission and differentiation of six viruses infecting hogweed (Heracleum sphondylium) in Scotland
Authors: BEM F. , MURANT A. F. 
Published: February 2008

SUMMARYSix viruses, code‐named HV1‐HV6, were transmitted manually and/or by aphids (Cavariella spp. from symptomless wild plants of hogweed (Heracleum sphondylium) in Scotland. HV1 was identified as parsnip yellow fleck virus (PYFV); anthriscus yellows virus, on which it depends for transmission by aphids, was presumably also present in the hogweed plants. HV2 was transmitted manually and by aphids and had very flexuous filamentous particles c. 700–750 nm long; it has affinities with the closteroviruses, and the name heracleum latent virus is proposed. HV3, HV4 and HV5 were transmitted manually, HV3 and HV5 also by aphids, but their particle morphology is unknown. HV6 was transmitted only by aphids and has very flexuous particles up to 1400 nm long; it is presumably a closterovirus distinct from HV2. All the viruses infected cultivated umbelliferous species experimentally but only PYFV is known to infect umbelliferous crops.
Migratory plant parasitic nematodes as pests of cereals
Authors: JONES R. K. 
Published: February 2008

SUMMARYTwo field trials showed that initial populations of Tylenchus Bastian, Paratylenchus Micoletzky, Pratylenchus minyus Sher and Allen, P. crenatus Loof, P. penetrans Chitwood and Oteifa, Helicotylenchus pseudorobustus Golden and H. digonicus Perry did not decrease yield of cereals whereas a significant inverse relationship existed between populations of Tylenchorhynchus dubius Filipjev and yield of wheat. T. dubius and Longidorus spp. Filipjev were associated with early leaf‐yellowing of barley, though difficulty in controlling nematodes failed to firmly link yield reduction with nematode populations. The possible variability in tolerance of cereals to nematodes is discussed.
In situ bait plants as a method for detecting red core in strawberry fields
Authors: DUNCAN JAMES M. 
Published: February 2008

SUMMARYThe spread of strawberry red core root disease (Phytophthora fragariae) from a heavily infested field with a history of 40 yr continuous strawberry growing, to and across an adjacent field where strawberries had never before been grown, was charted by growing bait plants of the highly susceptible alpine strawberry ‘Baron Solemacher’ at the intersections of an 8 m grid. Initially the fungus could not be detected by a soil sampling/glasshouse baiting test or in field grown baits, but after a very wet winter it was detected in the field grown bait plants. Most infections occurred in plants growing in a shallow depression running the length of the field, receiving drainage water from the higher infested site and where there had been standing water for much of the winter. The importance of topography was further demonstrated when baits were planted at commercial densities in two small areas of the field, one adjacent to and the other 18 m distant from the central depression. In the former many plants were infected within 2 months of planting whilst in the latter bait plants remained free of the disease for at least 18 months.The highly susceptible bait plants may be suitable for monitoring the health of commercial propagation stocks; they are easily propagated from seed and as they do not runner there is little hazard to stock purity.
Methyl bromide fumigation for the control of Aspergilli and Penicillia in stored grains
Authors: PASTER N. , BARKAI‐GOLAN R. , CALDERON M. 
Published: February 2008

SUMMARYFumigation with methyl bromide (MeBr) at a concentration of 120 mg/1 maintained for 4 h at 25°C caused 100% mortality of spores of Aspergillus ochraceus, A. flavus, Penicillium citrinum, P. chrysogenum and P. cyclopium. However, 40% of an A. niger spore population retained its viability after this treatment. Increasing the duration of fumigation to 24 h at a concentration of 40 mg/1 MeBr caused 100% spore mortality of all fungi tested. Total growth inhibition of 24 h‐old mycelia was achieved with 40 mg/1 for 24 h or 120 mg/1 for 4 h. These concentrations for the same period of exposure were not inhibitory for 7‐day‐old mycelia of any of the fungi tested. In A. niger‐inoculated wheat grains fumigated with 100 mg/1 MeBr for 24 h, 20% yielded fungal contaminants after 16 days of storage and 100% after 29 days. There was a marked drop in the percent germination of the grains after fumigation, whereas the free fatty acids level was higher than in unfumigated grain.The results of the in vivo study suggest that MeBr given at a commercial dosage for 24 h is not only ineffective in destroying the internal inocula of wheat grains but also enables their subsequent development by weakening the resistance of grains to fungal attack.
Virus‐like particles in phloem tissue of chervil (Anthriscus cerefolium) infected with carrot red leaf virus
Authors: MURANT A. F. , ROBERTS I. M. 
Published: February 2008

SUMMARYIsometric virus‐like particles c. 22–25 nm in diameter were found in ultrathin sections of chervil leaves infected with carrot red leaf virus (CRLV). The particles were confined to the phloem and occurred in less than 5% of the cells in the vascular bundles. They were commonest in companion cells, occurred frequently in sieve elements and were also found in phloem parenchyma cells. The observations support other evidence that CRLV should be classified in the luteovirus group.
Effects of crop thinning and reduced grain numbers per ear on grain size in two winter wheat varieties given different amounts of nitrogen
Authors: MARTINEZ‐CARRASCO R. , THORNE GILLIAN N. 
Published: February 2008

SUMMARYTo study the importance for final grain size in wheat (Triticum aestivum, L.) of assimilate supply and the storage capacity of the grain, two field experiments were done. In 1976 nitrogen was applied in the range from none to 180 kg ha‐1, part of the crop was thinned, and the top halves of some ears of the short variety Hobbit and of the tall variety Maris Huntsman were removed soon after anthesis. In 1977 ears of Maris Huntsman were halved 5 days after anthesis or at 30 days after anthesis when grain volume was maximum. Thinning the crop from 360 to 180 ear‐bearing shoots m‐2 30 days before anthesis increased the number of grains per ear, except in the absence of nitrogen fertiliser, but did not increase grain size, grain dry weight per ear or total dry weight per culm.Removing the upper half of ears of Hobbit 5 days after anthesis increased dry weight per grain, but when this treatment was applied to Maris Huntsman either 5 days after anthesis in 1976 and 1977, or when grain volume was maximal in 1977, the grains failed to increase in dry weight. Non‐grain dry weight of both varieties was increased by halving the ear. In both varieties the maximum volume of grains in halved ears was larger than in intact ears. Grain dry weight increased relatively less than volume after halving the ear of Hobbit, and the decrease in volume up to maturity was greater in halved than intact ears of both varieties. The larger grain volume in halved ears of Maris Huntsman in 1977 was associated with more endosperm cells.
Phorid fly(Phoridae: Megaselia halterate) longevity and the disemination of nematodes (Allantonematidae: Howardula husseyi) by parasitised females
Authors: RICHARDSON P.N. , CHANTER D.O. 
Published: February 2008

SUMMARYThe longevity of male and female Megaselia haltherata, 75% of parasitised by the nematode Howardula husseyi, was studied for 16 days at 20‐ 21.5 OC. A statistical model fitted to the data indicated that parasitism reduced fly longevity significantly; predicted times to 50% mortality were about 6 days shorter for parasitised males, but only 2 days shorter for parasitised females.An investigation of the number of nematode larvae liberated by female flies at intervals throughout the experiment showed that many had been liberated in the first 4 days, and that the rate of release then gradually declined. A statistical model for nematode dissemination rate was used to estimate the mean number of nematodes released at 4‐day intervals by surviving flies containing 1–5 adult H. husseyi.Mass release of laboratory‐reared parasitised flies on mushroom farms has been suggested as a possible method of boosting the incidence of parasitism in farm fly populations. The results of the present study indicate that if such a measure were taken in spawn‐running rooms then the best effect might be attained by releasing the flies in two batches with one release occurring in the middle of each week of the spawn‐run.
Arracacha virus B, a second isometric virus infecting arracacha (Arracacia xanthorrhiza; Umbelliferae) in the Peruvian Andes
Authors: KENTEN R. H. , JONES R. A. C. 
Published: February 2008

SUMMARYArracacha virus B (AVB), a previously undescribed virus, was found together with arracacha virus A or with a 750 nm flexous filamentous virus in arracacha (Arracacia Xanthorrhiza; Umbelliferae) growing in the Huanuco region of the Peruvian Andes. AVB was transmitted by inoculation of sap to 30 species from eight families out of 45 species from 10 families tested. It was transmitted through seed of Chenopodium quinoa but not by Myzus persicae. AVB was best propagated in C. Quinoa or Tetragonia expansa and assayed in C. quinoa, C. murale or C. amaranticolor. Sap from infeted <C. Quinoa was occasionally infective after dilution to 10‐4 but not 10‐5, after 10 min at 65 d̀ C but not 70 d̀ C, and after 12 but not 14 days at 20 d̀ C.In neutral phosphotungstate, AVB has isometric partilces c. 26 nm in diameter with a hexagonal profile. About 50‐ 150 A1 cm260 units of purified virus were obtained from 1 kg infected C. quinoa leaf by extraction in 0.5 M phosphate buffer at pH 7.5, containing 0.05 M ethylene‐daiminetetra‐acetate (EDTA) and 0.2% mercaptoethanol, and clarificatin with chloroform, followed by two precipitations with polyethylene glycol and three cylces of differential centrifugation. Purified virus coefficent (Sd̀20 w,) of 126 S and A260/A280 ratio of 1.80, bnut formed two isopycnic bands in CsC1 of buoyant density 1.481 and 1.492 g/cm3 with estimated nucleic acid contents of 40 and 41% respectively. AVB particles contained two proteins of mol.wt 26 000 (major component) and 20 000. AVB was not serologically related to any of 20 other morphologically similar viruses. Its properties suggest that it does not fall into any recognised group of viruses.the cryptogram of AVB is */*:*/40–41:S/S:S/*
The effects of application of distillery pot ale to hill vegetation and lowland crops
Authors: BUCKNALL SALLY A. , McKELVIE A. D. , NAYLOR ROBERT E. L. 
Published: February 2008

SUMMARYPot ale is a waste product of malt whisky distilling. Experiments were performed to establish the effects of its disposal on hill land and whether it could be used as a liquid fertiliser on rotational grass and on barley. Heather cover was drastically reduced by frequent low doses of pot ale, but infrequent heavy doses left heather moorland relatively unchanged. Total annual applications of pot ale of over 100 m3/ha to lowland grass swards increased yields of dry matter. Yield of barley was also increased by applications exceeding 100 m3/ha application. Other aspects of disposal of pot ale are considered.
Cavity spot of carrots.
Authors: PERRY D. A. , HARRISON J. G. 
Published: February 2008

SUMMARYCavity spot was induced after compacted carrot beds were watered to excess in July or August, but not after treatment in October. Roots grown in pots containingfield soil from the site of a cavity spot outbreak had fewer lesions when supplied witha minimal amount of water than when waterlogged, and when the soil was mixed withpeat instead of sand.Soft rot lesions developed on roots which had been inoculated with the field soiland sealed in pots with wax and stood in water. Anaerobic pectolytic bacteriabelonging to the genus Clostridium were isolated from the lesions and were proven tobe pathogenic to carrot roots. The lesions later resembled cavity spot after the rootswere returned to dry, aerobic conditions.
Monitoring codling and tortrix moths in United Kingdom apple orchards using pheromone traps
Authors: ALFORD D. V. , CARDEN P. W. , DENNIS E. B. , GOULD H. J. , VERNON J. D. R. 
Published: February 2008

SUMMARYStudies of pheromone traps for Cydia pomonella, A rchips podana and A doxophyes or ana (Lepidoptera: Tortricidae) were made in United Kingdom apple orchards from 1974 to 1976. Compared with light traps, they proved easier to operate and, with the exception of those set for Adoxophyes orana, were more effective monitors. There was considerable site‐to‐site variation in the pattern of weekly catches, and in total catches for each season, such variability often masking inter‐regional differences. The data proved useful for deciding if and when sprays should be applied in individual orchards, and were also used as a basis for district spray warnings. Thresholds below which treatment was generally unnecessary were five moths/trap/ wk for C. pomonella and 20 moths/trap/wk for Archips podana, but results for Adoxophyes orana were inconclusive. Fruit damage in monitored orchards sprayed as advised was generally low.
Dispersal of Erysiphe graminis and Lycopodium clavatum spores near to the source in a barley crop
Authors: BAINBRIDGE A. , STEDMAN O. J. 
Published: February 2008

SUMMARYIn experiments to study dispersal of spores in a crop of barley, a 4‐m wide strip of the cultivar Zephyr (a mildew‐susceptible variety) was a source of mildew (Eyrsiphe graminis) conidia. Small suction traps, previously calibrated in a wind tunnel, were used to measure spore concentration within and above the crop. Large concentrations of conidia were measured in the crop at the downwind edge of the Zephyr strip but these decreased rapidly with distance downwind. At 1 m concentrations were halved and by 4 m they were no greater than the background concentration measured in the crop upwind of the source. Next to the source, concentrations were much greater within than above the crop and net spore movement (flux) was upwards out of the crop; by 4 m downwind concentrations were greater above the crop and spore flux was reversed. Lycopodium clavatum spores were released in the same crop from a line of point sources. Concentrations also decreased rapidly downwind but, with no background of spores, numbers remained greater within than above the crop further from the source than for E. graminis. Even so by 7 m downwind concentrations in the crop had declined to less than those above.Deposition of L. clavatum spores onto horizontal glass slides in the crop agreed with that expected by settling. However, impaction onto vertical cylinders among plants was much greater than predicted. The reason is not known although turbulent air‐flow around plants may, in some way, enhance impaction. Many E. graminis conidia near the source were deposited in clumps. This prevented any accurate prediction of deposition rates as fall speeds of clumps (necessary for prediction) were not known. Not surprisingly, deposition on horizontal slides often exceeded that expected from settling of single spores although it was not always greatest where clumps predominated.The proportion of spores deposited on vertical cylinders and horizontal slides located among plants ranged from 0–02 to 0–27 and from 0–019 to 0–127 of the area dose, respectively. Although these may seem to be small trapping efficiencies, the same deposition rates in a crop with many leaves and stems would rapidly filter most spores from air in the crop and can explain why concentrations were observed to decline so rapidly.
Investigations on fungicides. XXI. The fungitoxicity and systemic antifungal activity of some aromatic quaternary ammonium salts
Authors: CARTER G. A. , HEYNS A. J. , KNIGHT B. E. , WAIN R. A. 
Published: February 2008

SUMMARYRoot application of certain quaternary ammonium salts, most notably tri‐n‐butyl‐and tri‐n‐pentyl‐4‐chlorobenzylammonium bromides, to wheat seedings grown in water culture enhanced their resistance to powdery mildew (Erysiphe graminis) but not to brown rust (Puccinia recondita). Anti‐mildew activity was much less apparent if the compounds were applied to sand‐ or soil‐grown seedlings. Systemic activity is considered in relation to the fungitoxicity, phytotoxicity and growth‐retardant activity of these compounds.