bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activity of triadimefon vapour against Erysiphe graminis f. sp. hordei
Authors: JENKYN J. F. , WHITE N. 
Published: February 2008

SUMMARYA series of experiments from 1978 to 1983 investigated the activity of triadimefon vapour against barley powdery mildew (Erysiphe graminis f. sp. hordei). In early experiments there was a pronounced protectant action when the dry product was used as the vapour source, and this protection persisted after test seedlings had been removed from the vicinity of the vapour source. In a glasshouse, sprayed seedlings remained sources of active vapour for at least 6 wk after spraying. In later experiments, effects of triadimefon vapour were much smaller, probably because the pathogen had become less sensitive to the fungicide. The dry product was no longer an effective vapour source but infection of test seedlings was still decreased if they were exposed to vapour emanating from impregnated absorbent paper or sprayed seedlings, presumably because the effective surface areas were much greater. Possible benefits and problems that arise from vapour action in glasshouse and field experiments are discussed.
The transmission of potato virus Y by aphids of different vectoring abilities
Authors: GIBSON R. W. , PAYNE R. W. , KATIS N. 
Published: February 2008

SUMMARYAdult apterae of Myzus persicae and Macrosiphum euphorbiae that did not transmit potato virus YN (PVYN) in a first test were as likely to transmit the virus in a subsequent test as those that did transmit on the first occasion. Only 16% of M. persicae that were allowed a single acquisition probe into a leaf infected with both PVYO and PVYN transmitted both strains, 37% transmitted either PVYO or PVYN and 47% did not transmit. There was no difference in the duration of probes that did or did not result in virus transmission. Statistical models were fitted to data on the frequency of transmission of PVYO, PVYN or both PVYO and PVYN by M. persicae and by aphids of poorer vector species, M. euphorbiae and Rhopalosiphum padi. Transmission of the two viruses ocurred independently of each other and consequently transmission of both was rare with M. euphorbiae and R. padi. Mineral oil applied to leaves infected with both strains diminished the frequency of transmission by M. persicae. Fitted models suggested that the aphids that probed through the oil droplets on leaves treated 30 min previously did not transmit virus, and that 24 h later, when the droplets had spread, aphids probing through them could transmit but with a decreased ability.
The effect of the weight of the seedling‐derived tuber on subsequent clonal generations in a potato breeding programme
Authors: BROWN J. 
Published: February 2008

SUMMARYTwo experiments are reported. In the first, the weight of seed tuber planted in the first clonal year was examined in relation to clonal performance in the first three clonal generations. The weight of seed tuber planted in first clonal year influenced breeders' preference scores and yield characteristics in the first, second and third clonal generations thus suggesting that size of tuber produced by seedlings is in part genetically controlled. The relationship between weight of seed tuber produced by seedlings and clonal performance was, however, reduced with increasing generations from true seed. In the second experiment, the size of seed tubers produced was manipulated by growing seedlings in different sized pots. When seedlings were grown in small pots (2.5 cm) first‐clonal‐year plants produced low yields of small tubers. In contrast, when larger pots were used to raise seedlings, first‐clonal‐year genotypes gave higher yields and were given greater preference scores. Hence, performance of genotypes in the first clonal year was dependent on the size of pot used to raise seedlings. After the first clonal generation however, clonal performance was not influenced by the size of pot used at the seedling stage. The overall conclusion was that, although the size of tuber produced by seedlings had a genetic component, the largest effect of seed tuber size used in the first clonal year was non‐genetic and would adversely influence efficiency of selection for yield, yield components and breeders' preference in the early generations of a potato breeding programme.
Field and glasshouse studies on components of resistance to root fly attack in swedes
Authors: BIRCH A. N. E. 
Published: February 2008

SUMMARYField trials in two years indicated that egg‐laying antixenosis was the major component of resistance in swede cvs Angus and Melfort against root flies (Delia floralis and D. radicum). Between four and eight times as many D. floralis eggs were laid on the susceptible cv. Doon Major as on the resistant cv. Angus. The degree of antixenosis effective against D. radicum was more variable in 1985, due to low numbers of adult flies, but in 1986, when adult fly numbers were higher, D. radicum laid 34 times as many eggs on susceptible cv. Sator Øtofte as on Angus.Root antibiosis against larval feeding is a second but less important component of resistance against D. floralis. In egg inoculation tests, 1.3‐2.0 times more D. floralis pupae developed on Doon Major than on Angus or Melfort. Larval feeding on resistant cultivars was restricted to surface root tissue only, compared with deeper tunnelling on susceptible cultivars. Tolerance to root damage may also occur under certain conditions. Although increased dry matter content was significantly correlated with root antibiosis, its effect on larval feeding was apparently not due to increased tissue hardness. It seems likely that chemical differences in the outer root tissues influence larval feeding and development.
Aerial application of mixed virus formulations to control joint infestations of Panolis flammea and Neodiprion sertifer on lodgepole pine
Authors: DOYLE C. J. , ENTWISTLE P. F. 
Published: February 2008

SUMMARYAn aerial spray using mixed formulations of two viruses, Panolis flammea nuclear polyhedrosis virus (NPV) and Neodiprion sertifer NPV was conducted against mixed populations of the two pests, P. flammea and N. sertifer on lodgepole pine. These were compared with single virus formulations sprayed against their respective host pests and an unsprayed control. One hectare plots of 14 yr old pine were sprayed by helicopter using ultra low volume techniques. Larvae from each plot were assessed weekly for virus and this showed that the mixed formulations gave the same level of control as separate applications of each NPV. Levels of infection in P. flammea reached 95 – 100% 9 wk post‐spray, and in N. sertifer reached 100% 6 wk post‐spray. Later P. flammea pupal sampling showed no viral infection in the control but significant levels in sprayed plots, which ranged from 37–9% in the plot sprayed with the high dose of N. sertifer NPV to 75% in the plot sprayed with the low dose of NsNPV.
Promotion and inhibition by ethylene of chlorophyll degradation in orange fruits
Authors: KNEE M. , TSANTILI ELENI , HATFIELD S. G. S. 
Published: February 2008

SUMMARYThe effect of ethylene concentration on chlorophyll destruction in orange (Citrus sinensis cV. Washington Navel) fruits was examined at 15 °C and 25 °C. The reflectance of the fruits at 680 nm was measured, and the results converted to chlorophyll concentrations through an empirically derived formula based on the Kubelka‐Munk equation. In all ethylene treatments chlorophyll destruction was faster at 25 °C than at 15 °C and all ethylene concentrations tested increased the rate of loss at 25 °C. At 15 °C the highest rate of chlorophyll destruction was observed at 1 μl litre‐1 ethylene, while chlorophyll loss at 1250 μl litre‐1 was slower than in untreated fruits.
Enhancing the performance of ethephon with mepiquat chloride on barley (Hordeum distichon cV. Panda) using an adjuvant comprising acidified soyal phospholipid
Authors: GREEN C. F. , CHALMERS I. F. , PACKE‐DRURY‐LOWE J. 
Published: February 2008

SUMMARYRates of ethephon with mepiquat chloride (as ‘Terpal’) were foliar applied to winter barley during early flag leaf emergence with or without soyal lecithin acidified with proprionic acid included as an adjuvant (‘LI700’). In both the glasshouse and field increasing the rate of ‘Terpal’ decreased the rate of stem extension exponentially, which in turn led to progressively shorter stands.As crop height extended above 0.9 m both the proportion of crop area lodged and the severity of lodging (mean angle of culms to the vertical) increased. As lodging progressed, mean grain weight was depressed and therefore ethephon with mepiquat chloride had the potential to increase yield. However, in the absence of lodging, applications of ‘Terpal’ reduced yield in direct proportion to increasing the dose rate. The influence of ‘Terpal’ on yield becomes a complex interaction between phytotoxicity, probably resulting from exogenous ethylene applications and benefits accruing from the control of lodging.Adding ‘LI700’ as an adjuvant enhanced the performance of ‘Terpal’ in reducing both rate of stem extension and mean grain weight in the absence of lodging.
The response of field‐grown lucerne to a manipulated range of insect‐induced nitrogen stresses
Authors: GOLDSON S. L. , JAMIESON P. D. 
Published: February 2008

G. W. BOURDOT*SUMMARYThe growth of a 1‐yr‐old lucerne (Medicago sativa) stand subjected to nitrogen stress was analysed using a simple model that related growth to intercepted photosynthetically active radiation (PAR). Nitrogen stress was systematically induced by establishing a range of populations of Sitona discoideus (Coleoptera: Curculionidae) larvae in the stand. The direct influence of their feeding on the plants' nitrogen‐fixing root rhizobial nodules was confirmed by the strong linear relationship found between larval density and herbage nitrogen concentration (N%). The negative effect of nitrogen stress on herbage production was found to become abruptly apparent at an N% level of 4–7%. Eighty‐seven percent of the loss in dry matter production in the nitrogen‐stressed plants was associated with a decline in the ability of the canopy to use PAR, rather than a reduction in the amount of PAR intercepted.From the results obtained it was concluded that the damage effects of S. discoideus larvae were less drought‐related than initially thought. It is speculated that the abrupt onset of damage occurred when the re‐establishing rhizobial root nodule population demanded more nitrogen than it fixed.
The relationship between fruit retention force at harvest and quality of feijoa after storage
Authors: DOWNS CHRISTOPHER G. , PICKERING ANA E. , REIHANA MAKARETA , O'DONOGHUE ERIN M. , MARTIN WILHELMINA 
Published: February 2008

SUMMARYFeijoa (Feijoa sellowiana, cvs Apollo and Gemini) fruits were removed from the tree and grouped into treatments according to retention force (RF) at harvest. Fruits with greater RF at harvest had higher titratable acidity and flesh firmness, lower soluble solids content and less locule clarity at harvest than fruits with lower RF. After 4 wk storage at 4 °C and 5 days shelflife at 20 °C titratable acidity, soluble solids and firmness in these fruits were similar across RF grades except that after shelflife the incidence of flesh and locule browning was greater in fruits harvested with low RF when compared with fruits picked with greater force. At harvest the total sugar and organic acids, and the sugar: acid ratio were similar irrespective of RF, whereas after storage and shelflife no consistent effect of RF existed.Taste panellists could not detect differences in the eating appeal of fruit harvested with high or with low retention force after storage and shelflife. Soluble solids, acidity and flesh firmness declined markedly over storage and shelflife irrespective of retention force at harvest and although these fruits were still acceptable for eating, they no longer had the characteristic flavour and texture of unstored feijoas.
Review of recent research on navy beans (Phaseolus vulgaris) in the United Kingdom
Authors: HARDWICK R. C. 
Published: February 2008

SUMMARYNavy beans are the raw material for ‘baked beans’. Since the 1960's a number of workers have attempted to introduce the crop to the United Kingdom. The paper reviews the results of research to date.In favoured areas of the United Kingdom yields of 300 g seed/m2may be expected in small‐plot trials. The optimum plant spacing is between 20 and 30 plants/m2and dressings of about 150 kg/ha of N fertiliser are required for maximal yield. The nitrogen fertiliser may be dispensed with, at the cost of a small reduction in yield, if the seed is inoculated with an elite strain ofRhizobium phaseoli.In the United Kingdom the potential diseases of the crop include halo‐blight (Pseudomonas syringaepV.phaseolicola), bean common mosaic virus, and anthracnose (Colletotrichum lindemuthianum).Genetic sources of resistance have been identified, and they are incorporated in some of the UK‐bred material.It seems likely that the varieties with improved adaptation and disease resistance that are now available from the UK work will be useful to farmers in continental Europe. For the UK itself, some improvements in cold‐tolerance and yield stability may still be required.The paper concludes with a discussion of the lessons to be learned from the project.
Occurrence, growth and survival of Aphis craccivora (Homoptera: Aphididae) on some weeds in a rain forest area of Nigeria
Authors: OFUYA T. I. 
Published: February 2008

SUMMARYTwenty‐five weed species that commonly infest farmlands in Ondo, Nigeria were sampled monthly in 1985 for Aphis craccivora. The aphid was found on Euphorbia hirta, E. glomifera and Boerhaavia diffusa, mainly during the off‐seasons of the principal host plants.In the laboratory, A. craccivora reared on Vigna unguiculata showed lower progeny mortality, and produced heavier and more fecund females than those reared on any of the three alternative weed hosts. Progeny mortality was also lower, and adult weight higher, on B. diffusa than on the Euphorbia weeds.
Chemical control of frit fly on winter cereals sown after grass
Authors: FRENCH N. , NICHOLS D. B. R. , WRIGHT A. J. , GREEN D. I. , GREEN D. B. , FENLON J. S. 
Published: February 2008

SUMMARYFrom 1978 ‐ 1985, 14 trials were conducted, mainly in Northern England, to assess the efficacy of different insecticides, formulations and application times for the control of frit fly (Oscinella frit) on winter cereals (13 on winter wheat and one on winter barley). Treatments were compared by assessing shoot damage in December‐January, numbers of healthy tillers in April and harvested yield. A chlorpyrifos spray to the grass before ploughing or at crop emergence gave the most consistently good results, significantly reducing damage and increasing yield by 0·61 and 0·31 t/ha respectively when taken over all trials. Sprays or granules of other insecticides applied from before drilling to 8 wk after emergence gave variable but sometimes good control and enhanced yield. Chlorpyrifos applied from crop emergence to 8 wk after emergence was generally more effective than other insecticides. Cypermethrin at emergence or 2wk later gave promising results in the two trials where it was used. Of the seed treatments fonofos was the most effective though it did not match the spray treatments.In additional trials, where insecticides were applied after damage occurred, sprays of chlorpyrifos and pirimphos‐methyl reduced damage and increased yield.
Control of apple canker using fungicidal paints and gels
Authors: COOKE LOUISE R. , McCRACKEN A. R. 
Published: February 2008

SUMMARYPaints containing mercuric oxide or thiophanate‐methyl were applied to either scraped or unscraped cankers caused by Nectria galligena on apple trees at two sites. Three gel formulations (carbendazim/triadimefon in alginate or xanthan and carbendazim/imazalil in xanthan) and a solvent‐based PP969 formulation were applied to unscraped cankers only. Assessments were made 9 and 21 months after treatment. Mercuric oxide was more effective than thiophanate‐methyl after 21 months on both scraped and unscraped cankers. All gel formulations reduced spore production and fungitoxicant could still be detected in bark and wood after 21 months. The solvent‐based PP969 formulation did not perform as well as the gels.
Effects of potato leafroll virus on the crop processes leading to tuber yield in potato cultivars which differ in tolerance of infection
Authors: MARSHALL B. , BARKER H. , VERRALL SUSAN R. 
Published: February 2008

SUMMARYThe effects of infection with potato leafroll virus (PLRV) on the four crop processes leading to tuber fresh weight yield were examined in field plots of four cultivars (Montana, Pentland Crown, Maris Piper and King Edward) differing in tolerance to infection. Averaged across cultivars, infection decreased yield by 50%. This decrease was equally due to less light (total solar radiation) being intercepted, a lower efficiency with which intercepted light was converted into dry weight, and a smaller proportion of dry weight being partitioned to tubers. Dry matter content of the tubers was also diminished but to a lesser extent. The main difference between the cultivars in their response to infection was in the partitioning of dry weight. In Montana and Pentland Crown, harvest index was decreased by 15% in infected plants, whereas in the less tolerant cultivars, Maris Piper and King Edward, it was decreased by 25%. The decline in photosynthetic performance of Montana, a cultivar with slightly earlier maturity than the other three, was delayed in PLRV‐infected plants. Effects on number of daughter tubers essentially reflected those on yield to the extent that average tuber weight did not change in Maris Piper, was one third less in King Edward, and the change was intermediate in Montana and Pentland Crown.
Laboratory evaluation of a toxicant‐sterilant, alpha‐chlorohydrin, for the control of Indian mole rat Bandicota bengalensis
Authors: SAINI MANJIT S. , PARSHAD V. R. 
Published: February 2008

SUMMARYA toxicant‐sterilant, alpha‐chlorohydrin, was evaluated against the Indian mole rat Bandicota bengalensis and the ship or house rat Rattus rattus. It caused 100% mortality of B. bengalensis at 100 mg/kg but no mortality was observed in R. rattus even at 300 mg/kg. The acute oral LD50 for B. bengalensis was found to be 82 mg/kg. The survivors of B. bengalensis, which received 60 ‐ 90 mg/kg of alpha‐chlorohydrin by oral intubation, showed dose‐dependent decreases in testicular weight, and cauda epididymal sperm concentration, live sperm count and sperm motility. The values of these parameters indicated that mole rats receiving the above doses would be sterile. In contrast, these changes were observed in R. rattus only at doses of 200 and 300 mg/kg. The toxic and antifertility effects of alpha‐chlorohydrin observed on B. bengalensis suggest that it should be evaluated for the management of this species under held conditions.
A census of seedling establishment in sugar‐beet crops
Authors: DURRANT M. J. , DUNNING R. A. , JAGGARD K. W. , BUGG R. B. , SCOTT R. K. 
Published: February 2008

SUMMARYAnalysis of seedling establishment in 254 experiments from 1970 to 1977 showed that the target of 70%, needed for an adequate plant population and maximum yield, was achieved in only 19% of fields. However, because the plants were only counted once, when they had about six leaves, the cause and timing of the losses could not be identified. This, therefore, gave no sound basis for seeking improvements. Eight studies of all phases of establishment, from sowing to the 6‐leaf stage, were then made at Broom's Barn from 1978 to 1981. The studies were on sandy loam or clay loam soils with seedbeds prepared by standard, recommended methods and sown either early or late in spring. These standard treatments were supplemented by plots which tested irrigation or protection from rain, fine or coarse tilths, and the use of a soil applied insecticide or a sterilant. Despite the widely differing weather experienced by these crops, 70% establishment was achieved in seven studies; in the eighth, seedlings emerged at 75% of seed stations, but 31% were then killed, mainly by birds.On average, the drill failed to place seeds at 2·8% of target positions, dead seed was sown at 6%, seedlings died after germination but before emergence at 12·4% and plants died thereafter at 6·5%. Almost every viable seed sown in the field germinated eventually; waterlogging seemed to be the cause of failure in a few small areas where this was not so. In most studies the first 50% of seeds germinated as expected on the basis of the thermal time required in the laboratory test. The remainder sometimes took longer, mainly because they experienced periods when the water supply was inadequate.Seedlings failed to emerge for several reasons; of which the principal ones were dehydration, restriction under a soil crust or stone, and pest damage. It seemed that waterlogging and herbicide damage were important causes in a few cases. After emergence bird grazing was the major cause of death, preferentially of the seedlings which emerged first and had the greatest yield potential.Because losses occurred at every stage and from many causes the solution to the problem of poor establishment requires a multidisciplinary approach.
A survey of seedling establishment in sugar‐beet crops in 1980 and 1981
Authors: DURRANT M. J. 
Published: February 2008

SUMMARYOne hundred and twenty five crops distributed throughout the UK sugar‐beet growing area were examined to identify the growth stage at which failures occurred during the seedling establishment phase. Establishment varied between 15 and 90% and averaged 64 and 67% in 1980 and 1981 respectively. It exceeded 70% in 46% of fields.Overall, the actual seed spacing was only 0·15cm wider than the 17·0cm intended but the number of seed stations in individual fields varied from 27% less to 19% more than the target. On average the drill failed to place a seed at 5% of seed stations but up to 14% misses were recorded. Germination in the field was 92% ‐ only 1% less than in the standard laboratory germination test. However, on average, 16% (range 2 ‐ 42%) of seeds which germinated failed to develop much further; the cause of only a quarter of these losses was identified as due to soil pests, diseases or being caught under stones or clods. There was a tendency for more seeds to fail between germination and emergence as the proportion of empty seed stations increased.Rapid emergence usually resulted in greater final emergence. There were post‐emergence losses in 122 of the 125 fields. These losses averaged 6% and exceeded 14% on five fields. Birds were considered to have killed plants in 49 fields, soil pests caused losses in 20 fields and herbicides, fungal disease or grazing by rabbits or hares decreased plant stands in about 10 fields.
The relationship between leaf canopy development and yield of barley
Authors: RUSSELL G. , ELLIS R. P. 
Published: February 2008

SUMMARYA study was carried out into the relationship between sowing date, canopy development and yield of four barley genotypes sown in autumn and spring. Yield was considered as the product of PAR absorbed by the crop canopy up till anthesis, the dry matter: radiation quotient, the ratio of grains m2at maturity to the weight of the crop at anthesis and the mean grain weight.Equations were derived to predict the time course of the proportion of PAR absorbed in relation to date of sowing using thermal time as predictor. In crops that were not short of water and were fully vernalised, genotypic differences were detected in plant population density, date of anthesis, and the four yield components identified above. All attributes except plant population density were affected by shortage of water but genotypes differed in their response.