bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of aldicarb on the control of red spider mite, Tetranychus urticae (Koch), by the predator Phytoseiulus persimilis Athias‐Henriot on year‐round chrysanthemums
Authors: CROSS J. V. 
Published: April 2007

SUMMARYIn the summer of 1979 a study was made of the effect of aldicarb application to glasshouse chrysanthetnums on the interaction between Phytoseiulus persimilis and aldicarb‐resistant Tetranychus urticae. Different rates of aldicarb were applied to chrysanthemums three weeks after planting and predators were introduced three weeks later. Whilst exceptionally large numbers of red spider mite were controlled in a mean of 25 days on untreated beds, control took 42 days where aldicarb had been applied at the rate of 11 kg active ingredient per hectare. The delay in control when intermediate rates of aldicarb were used was roughly proportional to the dose of aldicarb.
Pirimicarb resistance in the melon and cotton aphid, Aphis gossypii Glover
Authors: FURK C. , POWELL D. F. , HEYD S. 
Published: April 2007

SUMMARYThe resistance to pirimicarb of populations of Aphis gossypii Glover from several glasshouses in England was studied in the laboratory by topical applications of insecticide and by electrophoresis and isoelectric focusing of aphid esterases. When compared with a known susceptible population, the aphids were found to be resistant to pirimicarb. Esterase patterns produced from resistant populations by poly‐acrylamide gel and starch gel electrophoresis and by isoelectric focusing consistently differed in both numbers of bands and migration rates from the susceptible type. Resistant A. gossypii were found infesting only chrysanthemums and would not transfer to cucumber, the host of the susceptible population.
Forecasting egg populations of wheat bulb fly, Delia coarctata (Fall.), from catches of adult females in water‐traps
Authors: COOPER D. A. 
Published: April 2007

SUMMARYBetween mid‐July and the end of August in 1977 and 1978, wheat bulb flies were caught in white water‐traps at 16 oviposition sites in eastern Scotland. The numbers of females caught per site and the subsequent egg populations, estimated from soil‐cores from each site, were linearly related. Water‐trapping may therefore provide a reliable and early forecast of egg numbers, independent of soil‐sampling, and so enable seed treatment to be limited to years when the risk of damage is great.
An analysis of the variability in yield of pea crops attacked by Heterodem goettingiana, Helicotylenchus vulgaris and Pratylenchm thomei
Authors: GREEN C. D. , DENNIS E.B. 
Published: April 2007

SUMMARYIn 1977 and 1978 the effect of nematodes and oxamyl treatment on the growth of a pea crop was examined at a site known to be ‘pea sick’ in an area of heavy clay loam soil in Worcestershire, In 1977, Heterodera goettingiana lieb., Helicotylenchus vulgaris Yuen and Pratylenchus thornei Sher & Allen were associated with decreased pea plant growth. The losses caused by each were additive but complicated by an inverse relationship between numbers of Het. goettingiana and Hel. vulgaris. Crop losses and the benefits of nematicide application could be predicted by using multiple regiession coefficients to account for the effects of all species. In 1978, when numbers of Het. goettingiana were great, crop loss in nematicide‐treated plots was correlated with numbers of the nematode.
Biological control by predatory mites (Phytoseiulus persimilis Athias‐Henriot) of red spider mite (Tetranychus urticae Koch) infesting strawberries grown in walk‐in' plastic tunnels
Authors: PORT C.M. , SCOPES N.E.A. 
Published: April 2007

SUMMARYDuring 1 978 and 1979, the control of red spider mite on strawberries by the predacious mite Phytoseiulus persimilis was studied at two sites in Hampshire where crops were grown in ‘walk‐in’ plastic tunnels.An introduction of at least two predators per plant in March was required to control red spider mite in one experiment. In the second experiment, introductions of small numbers of predators (fewer than two per plant) in August controlled mites on newly planted runners before diapause. Similar numbers of predators introduced in the following March, 10 days after red spider mite eggs were seen, controlled mite infestations throughout the growing season. Controlling mites in the autumn before diapause was considered important.
The influence of soil pH on the severity of swede powdery mildew infection
Authors: BRAIN P. J. , WHITTINGTON W. J. 
Published: April 2007

SUMMARYField and pot experiments at Nottingham during 1976–78 confirmed previous evidence that swede powdery mildew infection was greater on plants grown in soils of high rather than low pH. This effect appears to be related to the manganese content of the leaves because there was more manganese in leaves grown at low pH and progressively less mildew infection on plants supplied with increasing quantities of manganese.
Chocolate spot of field beaes in Scotland
Authors: HARRISON J. G. 
Published: April 2007

SUMMARYAlthough Botrytis fabae Sard, was frequently isolated from spring‐sown Scottish field bean crops in 1976–80, chocolate spot is not regarded as such a serious problem in Scotland as it is in England and Wales, where a large proportion of the crop is autumn‐sown. Pieces of leaf (with lesions) from bean crops grown on two farms at different sites in Scotland were plated on agar during the five seasons 1976–80. The calculated date on which B. fabae was recovered from 50 per cent of the pieces each year was consistently earher on one farm than on the other, despite apparently similar climates. There was a highly significant correlation (coefficient of 0.90) between the severity of chocolate spot disease in different regions of England and Wales and temperatures during May. This, however, may merely reflect regional differences in the proportions of autumn‐ and spring‐sown crops.
The distribution and importance of cabbage stem flea beetle (Psylliodes chrysocephala (L.)) on winter oilseed rape in England
Authors: GRAHAM C. W. , ALFORD D. V. 
Published: April 2007

SUMMARYFollowing several cases of serious damage to winter oilseed rape by cabbage stem flea beetle in eastern and south‐eastern England, surveys and obsei‐vations throughout England from 1974 to 1979 showed that infestations occurred mainly in Buckinghamshire, Cambridgeshire, Huntingdonshire and Northamptonshire; the heaviesl attacks also occurred in these areas. Minor infestations were recorded locally in 13 other counties. No attacks occurred elsewhere in England.
Post‐harvest tuber indexing in the seed potato certification schemes of England and Wales, 1978
Authors: WOOSTER P. 
Published: April 2007

SUMMARYIn a voluntary scheme in autumn 1978, 100‐tuber samples of certified and basic category seed potatoes were tested for infection with severe viruses (potato virus Y and potato leafroll virus). One sprouted eye was removed from each tuber and grown on in the glasshouse for visual assessment of symptoms. Breaking dormancy of the samples was difficult, possibly because of the young physiological age of the mother crops and the interval between haulm destruction and treatment to break dormancy. Correlation between results from the glasshouse tests and assessments on plants grown from the same tubers in the field at Cambridge the following season was within three per cent for the majority of samples. Some results were less accurate owing to difficulties with certain cultivars under glasshouse conditions. Statistically, the sampling method was unsuitable for detecting small amounts of virus infection in seed stocks. Also, the results were obtained too late to influence seed tuber sales from the crops tested.
Introduction of American serpentine leaf miner, Liriomyza trifolii, into England and Wales and its eradication from commercial nurseries, 1977–81
Authors: BARTLETT P. W. , POWELL D. F. 
Published: April 2007

SUMMARYThe American serpentine leaf miner, Liriomyza trifolii (Burgess), was first seen in England in 1977, at a nursery where chrysanthemums were being grown from cuttings imported from Kenya and Malta. Eradicatory action was taken at this and 14 other nurseries where infestations were found during that year. In 1978, 12 infestations were found, originating on chrysanthemum cuttings from Kenya and the Canary Islands and on Gerbera from the Netherlands. In 1979, 132 infestations were found; by then the sources also included Denmark and the USA. Following the withdrawal of the licence permitting imports of chrysanthemum cuttings from Kenya, 63 infestations were found in 1980 and 48 in 1981.Eradication measures rarely required the destruction of infested crops hut frequently required the selective destruction of infested imported plants, together with the application of various insecticidal treatments. To kill adults, fogs and smokes were used; to kill larvae, foliar sprays were applied and persistent systemic insecticides were incorporated in the planting beds; to kill pupae, soil drenches and sterilants were necessary.By the adoption of this control programme and the vigilance of the plant health authorities, eradication of L. trifolii has been, achieved wherever it has been found in England and Wales.
The eradication campaign against American serpentine leaf miner, Liriomyza trifolii, at Efford Experimental Horticulture Station
Authors: POWELL D. F. 
Published: April 2007

SUMMARYIn May 1979 an outbreak of Liriomyza trifolii (Burgess) was detected on glasshouse chrysanthemums, at Efford Experimental Horticulture Station in Hampshire, England. The pest spread to glasshouse tomatoes and then to cultivated and wild hosts outside. An intensive eradication campaign included pest and weed control, monitoring adults with yellow sticky traps, and extensive surveys of potential host plants to determine the spread of the pest. Eleven new hosts of the pest were recorded. In November 1980, following a series of surveys, the pest was deemed not to have survived in the area.
Crown rot (Phytophthora cactorum) in glasshouse‐grown strawberries at East Mailing Research Station
Authors: HARRIS D. C. , STICKELS J. E. 
Published: April 2007

SUMMARYFrom 1973 to 1977 the spread of crown rot (Phytophthora cactorum(Leb. & Cohn) Schroet.) in glasshouse‐grown strawberries at East Malling Research Station (EMRS) threatened to disrupt the production of virus‐tested stocks. An eradication programme involving trickle irrigation of plants, rooting ranners above the level of mother plants, regular inspection for disease and routine tests for latent infection, special precautions at repotting and annual renewal of mother plants eliminated the disease in two years, except in a quarantine house containing new importations.Isolates of P. cactorum from strawberry plants and apple trees were moderately or highly virulent to their original hosts but caused only latent infection or limited necrosis in reciprocal inoculations. This supports the separation of the strains commonly attacking these hosts as distinct pathotypes. The evidence suggests that crown rot entered the strawberry stocks at EMRS with infected introduced plants and not from local field sources.
Use of forced buds to extend the period of serological testing in surveys for fruit tree viruses
Authors: TORRANCE L. 
Published: April 2007

SUMMARYForced buds were investigated as, a source of test material to determine whether they could be used to extend the period of reliable serological testing in routine surveys for some fruit‐tree viruses. Dormant bud‐sticks of cherry, plum and apple were cut in midwinter and either stored at 4°C or used immediately. Buds were forced in one to three weeks by keeping the budsticks at about 18°C. The emergent flower and leaf tissues were tested by enzyme‐linked immunosorbent assay for the presence of cherry leaf roll (CLRV), prune dwarf (PDV), strains of prunus necrotic ringspot (NRSV) and plum pox (PPV) viruses. PDV and the cherry serotype of NRSV (NRSV‐C) were detected in cherry and plum, CLRV in cherry, PPV in plum and the apple serotype of NRSV in plum and apple. Virus detection was not affected when cherry and plum budsticks were stored for 10 weeks at 4°C before testing. PDV, NRSV‐C and CLRV were still detected in cherry leaf and flower tissue wliich was forced and then stored at either 4 or ‐ 18°C for one to two months.
Observations on Globodera pallida and G. rostochiensis on early potatoes
Authors: WEBLEY D. P. , JONES F. G. W. 
Published: April 2007

SUMMARYObservations in south Wales during 1971–78 on population changes in the cyst nematodes G. pallida (Stone)‐Behrens Pal and G. rostochiensis(Woil.) Behrens Rol on early potatoes grown in concrete‐bounded microplots confirmed that populations can be controlled by early harvesting. When potatoes were planted on 11 Match, harvesting 83 days later led to a decline in the population density of G. pallida in every year except 1976, which was exceptionally warm. The best estimate of the rate of decline was 55 per cent per annum. Harvesting after 91 days resulted in population densities otily slightly less than harvesting after 103 or 120 days, when population densities fluctuated around an equilibrium of 120 eggs/g soil. Sitnilarly, when plots infested with G. rostochiensis were harvested after 83 days, population densities declined. Harvesting after 91 days resulted in fluctuations about an equilibrium of 7 eggs/g soil and after 103 and 120 days around an equilibrium of 120 eggs/g.Females of G. pallida developed faster and produced eggs sooner than those of G. rostochiensis over the spring temperature range. Therefore, early harvesting would favour G. pallida and, if done routinely, would lead to the selection of this species and the replacetnent of G. rostochiensis. Harvesting a fixed number of days after planting would probably give satisfactory population control in most years, but harvesting on the basis of accumulated temperature above a known basal development temperature would probably be better, especially in years in which, the temperature departs appreciably from the average.
Use of continuous light to improve diagnosis of potato leaf roll virus in tuber indexing tests
Authors: JONES R. A. C. 
Published: April 2007

SUMMARYControlled environment cabinets were used to determine light.and temperature conditions needed for full expression of potato leaf roll virus (PERV) symptoms in potato plants grown from eyeplugs taken from tubers of cv. Désirée. PLRV symptom development was poor under conditions in which growth was etiolated. In general, typical rolling of lower leaves developed faster and was more distinct at 18 than at 22°C, and when light intensity was increased, but the two continuous light regimes used gave better results than any of those involving 10‐or 18‐h photoperiods. At 18°C, distinct symptoms suitable for scoring during tuber indexing developed in all infected plants after four to five weeks or five to six weeks with continuous light at 7000 or 4000 lux respectively, but only after six to eight weeks with 18 h/day at 7000 lux, which was the best of the 10‐ and 18‐h regimes. Yellowing and shedding of lower leaves developed faster in healthy plants kept under either of the continuous light regimes than in healthy plants kept for 18 h/day at 7000 lux or in infected plants kept in any of these three regimes, and was very obvious after only six weeks. In terms of symptom appearance in infected plants and defoliation m. healthy ones, a regime of 23 h/day at 7000 lux gave similar results to those obtained with continuous light at 7000 lux. In trials done in winter in a heated glasshouse illuminatcd by mercury vapour lights, continuous illumination had the same effects: distinct PLRV symptoms and obvious loss of lower leaves devefoped after only five weeks in all the infected and healthy plants respectively.
Effects of covering potato crops with clear polyethylene film on spread of potato virus Y
Authors: GIBSON R. W. , GUNENC YILDIZ 
Published: April 2007

SUMMARYPlots of potatoes in eastern England were covered at planting with finely slit, clear polyethylene film which remained over the foliage until harvest. Spread of potato virus Y and the numbers of aphids on the leaves in these plots were compared with those in uncovered plots. In two years fewer tubers of covered plants were infected with potato virus Y and in the first year the covered plants had fewer Myzus persicae(Sulz.) and Macrosiphum euphorbiae (Thos.).
Procedures for the generation of formaldehyde vapour to fumigate structures
Authors: CONNOLLY G. P. , FLETCHER J. T. 
Published: April 2007

SUMMARYFormaldehyde gas concentrations were measured following the mixing of potassium permanganate and formalin within a 1 ‐m3 chamber. Similar concentrations of gas were measured irrespective of the order of mixing of the reactants at the lower ratios used (1 KMnO4:4–8 formalin), but at the higher ratio (1:2–4) more gas was produced when the KMnO4was added to the formalin than when the reverse sequence was followed. Spores of Botrytis cinerea were all killed at the dosages tested (0.18–0.30 mg formaldehyde per litre).
Response of wheat and barley isolates of Septoria nodorum to passage through barley and wheat cultivars
Authors: FITZGERALD W. , COOKE B. M. 
Published: April 2007

A single‐spore wheat isolate of S. nodorum was passaged once through barley and a barley isolate passaged once through wheat. Reisolations from barley leaves were designated as either ‘original‐type wheat’ (OTW) and resembled the wheat isolate used for inoculations in morphology, or ‘sector‐type barley’ (STB) resembling the known morphology of barley isolates. Reisolations from wheat were similarly designated either OTB or STW. Sub‐cultures of STB were significantly more pathogenic to barley in a glasshouse experiment than OTW, and vice versa. Similarly STW was significantly more pathogenic to wheat than OTB, and vice versa.A single‐spore wheat isolate was also passaged 0, 1, 2, 3 or 4 times through barley and a barley isolate passaged similarly through wheat. Disease assessment and yield data from a field experiment showed that the pathogenicity of the passaged wheat isolate remained largely unaltered from that of the original isolate. However, the barley isolate responded after the third wheat passage by causing significantly less disease and significantly higher yields in barley than the unpassaged isolate; conversely, on wheat, disease levels significantly increased and yield slgnficantly decreased after the second wheat passage.Data obtained are discussed in the context of cultural observations made on colony morphology during host passage sequences and possible genetic mechanisms responsible.
Residual effects of triadimefon in soil on powdery mildew and yield of spring barley
Authors: RAWLINSON C. J. , MUTHYALU G. , CAYLEY G. R. 
Published: April 2007

Residual triadimefon (or a breakdown product), from a spray application (2 kg/ha) to field soil in 1978, significantly decreased powdery mildew on spring barley throughout two subsequent growing seasons, with consequent yield increases of 42% in 1980 and 18% in 1981.In other field experiments triadimefon applied to soil at rates >0.06 kg/ha decreased mildew in barley growing in the soil 11 months later. In these experiments triadimefon, but not benomyl, imazalil or prochloraz (all at 0.5 kg/ha) significantly decreased mildew up to harvest and increased yield by 22%.Triadimefon incorporated into a loam soil and a peat‐based compost at rates >0.1 ng/g significantly decreased mildew on barley grown in pots under glasshouse conditions. Plants grown in the treated compost at the same time but in isolated pots supplied with filtered moistened air and capillary watering required more triadimefon (>100 ng/g) in soil for significant mildew control.Despite strong adsorption of triadimefon to soil (Kd 19.4), an active substance appears to remain available for uptake and translocation by barley plants over long periods. The sensitivity of barley mildew to extremely small residues of triadimefon is discussed in relation to the siting of field experiments on mildew control. The implications for widespread commercial use of formulations containing triadimefon are discussed in relation to disease control practice in cereal growing systems.
Subterranean clover mottle virus: another virus from Australia with encapsidated viroid‐like RNA
Authors: FRANCKI R. I. B. , RANDLES J. W. , HATTA T. , DAVIES C. , CHU P. W. G. , McLEAN G. D. 
Published: April 2007

A new virus, subterranean clover mottle virus (SCMoV) was found at several locations in Western Australia in Trifolium subterraneum L. (subterranean clover) with severe disease symptoms. Paiticles of the virus were shown to share many physical properties with members of the sobemo‐virus group. However, in addition to the single‐stranded RNA of MJ about 1.5 × 106 which is characteristic of sobemoviruses, SCMoV particles also contained circular and linear viroid‐like RNAs of two size classes, one about 400 and the other about 300 nucleotides long. At present it is not clear if the two types of viroid‐like RNAs are components of the same SCMoV strain or of closely related strains of the virus which are able to confect subterranean clover.SCMoV was shown to be serologically related to lucerne transient streak virus (LTSV). However, the relationship was remote and whereas most high‐titred antisera to LTSV reacted with SCMoV particles, antisera to SCMoV failed to recogaize those of LTSV. Neither SCMoV nor LTSV are serologically related to velvet tobacco mottle virus (VTMoV) or Solanum nodiflorum mottle virus (SNMV). However, particles of all four viruses have many physical and chemical properties in common, including RNA complements consisting of both virus‐like and viroid‐like RNAs. Because of their affinities and unique RNA complements, we suggest that SCMoV, LTSV, VTMoV and SNMV may warrant inclusion in a new taxonomic group.
Studies of crop loss in potato blight caused by Phytophthora infestans
Authors: ROTEM J. , BASHI ESTHER , KRANZ J. 
Published: April 2007

Relationships between healthy haulm area (HHA) and yield, and between losses of HHA and yield in the potato late blight system, were evaluated in several seasons and fields variously affected by the disease in Israel. The results showed that because of the different yield potential of potatoes cultivated in different conditions, evaluation of crop losses cannot be separated from evaluation of yield potentials of the crop as influenced by environmental and cultural factors.In one calculation the yield and the HHA in the healthiest plot in each field were equated to 100% and losses in other plots were derived from comparisons with this plot. In such a calculation the relationships of yield loss to HHA loss in all fields and seasons fitted one regression equation, and a high correlation was obtained between both parameters. However, the actual haulm areas and yield weights differed widely from one field to another, even in the healthiest plots. Also, a similar percentage of destroyed haulms sometimes corresponded to different areas of the remaining haulms and to different yields. So no correlation was found between HHA and yields over all fields and seasons. Such a correlation was found only for several plots, variously affected by late blight, in the same field and season and in different fields and seasons yields responded in a different way to increases in HHA.