bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pepper veinal mottle virus associated with a streak diseaseof tomato in Nigeria
Authors: LADIPO J. L. , ROBERTS I. M. 
Published: February 2008

SUMMARYA destructive streak disease of tomato (Lycopersicon esculentum) was observed on the University of Ife farm. The disease killed many plants and greatly diminished the quantity and quality of fruit produced by the other plants. A virus that is readily transmitted by mechanical inoculation, by the green peach aphid (Myzus persicae) and by grafting was isolated consistently from diseased plants. The virus was propagated in Nicotiana occidentalis and assayed in Physalis angulata. It was infective after dilution to io‐3 but not io‐4; after iomin at 55 but not 60oC; or after 5 days but not 7 days at 20–26oC. Electron microscope examination of sap from infected N. occidentalis leaves revealed flexuous rods with a modal length of about 780 nm. Based on the host range and symptomatology, particle morphology and size, properties in vitro and serology, the virus is shown to be related to, and possibly indistinguishable from, pepper veinal mottle virus.
Interaction between crown rust (Puccinia coronata) and two viruses of ryegrass
Authors: LATCH G. C. M. , POTTER L. R. 
Published: February 2008

SUMMARYIn Lemtal Italian and S.24 perennial ryegrass plants, two isolates of ryegrass mosaic virus (RMV) suppressed the amount of crown rust emerging on leaves inoculated with Puccinia coronata uredospores by up to 75% compared with the amount on virus‐free plants. Severity of rust infection on barley yellow dwarf virus (BYDV) infected plants generally did not differ significantly from that on virus‐free plants. When both RMV and BYDV were present, rust was restricted in Lemtal plants to a level intermediate between those occurring on plants infected by either virus alone, and in S.24 plants to a level below that obtained with either virus alone.The mean water soluble carbohydrate (WSC) content of Lemtal plants was reduced more than 20% by RMV, but was not significantly altered by BYDV. In S.24 plants the WSC content was increased by 10% by RMV and by 60% by BYDV. Rust reduced the WSC content of healthy and virus‐infected plants, the reduction being positively correlated with the level of rust on the sampled leaves. In plants of Lemtal, but not of S.24, the degree of rust infection was positively correlated with the WSC content of leaves from rust‐free control plants.
Studies on host‐plant selection by the cowpea seed moth, Cydia ptychora
Authors: PERRIN R. M. 
Published: February 2008

SUMMARYThe Cowpea seed moth, Cydia ptychora, was able to complete its full life‐cycle on a wide range of tropical grain legumes. In glasshouse tests, the adult moth showed oviposition p references between grain legume species but not between cowpea varieties, although there were differences in larval damage to the seeds of the latter. On cowpea, most eggs were laid on 8–10‐day‐old pods and also in particular micro‐habitats; such behaviour was seemingly influenced by the mode of pod carriage.The moth undergoes no known diapause during the dry season in southern Nigeria and cowpea plants in a suitable condition are infested throughout the year. Wild leguminous hosts were not identified during the present study.
Assessment of methods for testing varietal resistance to aphid s in cereals
Authors: DEWAR A. M. 
Published: February 2008

SUMMARYThe adult weight of three species of cereal aphids on barley was correlated with the number of large embryos and the total number of embryos within newly moulted adults. The relationships between embryo number and weight were constant for each species of aphid on all seven varieties of barley under identical conditions. The weights of aphids of each species on seven varieties of barley were significantly different from each other in each experiment. Pot size and plant age had a significant effect on the weights of Rhopalosiphum padi. The validity of these tests compared with previous methods is discussed.
Effects of C02 enrichment on the rates of photosynthesis and translocation of tomato leaves
Authors: HO L. C. 
Published: February 2008

SUMMARYEffects of C02 enrichment on the rates of net photosynthesis (carbon fixation) and translocation (carbon transport) of tomato leaves were examined on a single mature leaf (seventh basal leaf) of plants grown initially under a light flux density of 40 W m‐2 with 350 (control) or 1000 vpm (enriched) CO2, and then exposed for 6 h to various light flux densities (7, 20, 40 and 130 W m‐2) or CO2 concentrations (350, 500, 700 and 1000 vpm).When measurements were made in the conditions in which plants were grown, the rates of carbon fixation and carbon transport were 20 and 40% respectively higher in enriched plants than in the control ones. Under conditions different from the growing conditions, the rates of carbon transport in the enriched plants were generally higher than those of the controls with a similar rate of carbon fixation.Leaves grown under a C02 enriched environment have a greater constant supply of mobile leaf assimilate than those under atmospheric C02. The higher efficiency of carbon transport in enriched plants was apparently retained even when the leaf was temporarily exposed to lower levels of light or CO2.
The identification of growth stages in winter wheat with reference to the application of growth‐regulator herbicides
Authors: TOTTMAN D. R. 
Published: February 2008

SUMMARYThe development of several varieties of winter wheat {Triticum aestivum) in early spring was studied in order to relate the progress of apical differentiation to easily measured external characters and so provide a guide to the correct timing of herbicide applications. Leaf sheath lengths were more closely related to apical development than were tiller or leaf numbers. Spikelet differentiation occurred when the longest sheaths were c. 5 cm tall. Application of a growth regulator herbicide before this stage of development caused ear deformities in the crop at harvest. A measure of leaf sheath length might, therefore, replace the ambiguous criteria presently used to judge the stages of winter wheat most tolerant of herbicides.
Control of potato cyst‐nematode, Globodera rostochiensis Rol, by picrolonic acid and potato trap crops
Authors: WHITEHEAD A. G. 
Published: February 2008

SUMMARYSmall, sprouted tubers of potatoes (cv. Pentland Crown) grown for 6 wk and then pulled out of soil infested with potato cyst‐nematode, Globodera rostochiensis Roi, increased the hatch of larvae, so that 100 days after planting the top 20 cm of the soil contained only one third of the original number of eggs. The artificial hatching agent picrolonic acid alone at 8‐6, 17*2 or 34‐4 kg/ha rotavated into the soil did not increase hatch but 17*2 kg, incorporated in the soil after potatoes grown for 4 wk, did.
Eradication of the perithecial stage of apple scab with surfactants
Authors: BURCHILL R. T. , SWAIT A. A. J. 
Published: February 2008

SUMMARYClone M3 apple leaves infected with scab (Venturia inaequalis) were dipped in one of a series of surface‐active compounds or mixtures tested at a concentration of 5% a.i. Seven of these reduced the concentration of scab ascopores released in the spring by more than 99%.
Multiplication and morphology of Spiroplasma citri in the leafhopper Euscelis plebejus
Authors: TOWNSEND R. , MARKHAM P. G. , PLASKITT KITTY A. 
Published: February 2008

SUMMARY Spiroplasma citri multiplied in all Euscelis plebejus leaf hoppers injected and sometimes reached titres of over 1 × 107 colony forming units per insect. Spiroplasmas could be isolated from the haemolymph at all times although helices were only apparent for a few days after injection. The salivary glands of injected insects contained membrane bound pockets densely packed with mycoplasma‐like bodies. These bodies were frequently infected with virus‐like particles similar to those found in cultures of S. citri. Spiroplasmas had little effect on the longevity of the leafhoppers.
Methods for testing chemical additives to'prevent moulding of hay
Authors: LACEY J. , LORD K. A. 
Published: February 2008

SUMMARYThree methods for testing additives for their ability to prevent moulding of hay are described. Storage of 25 g samples of hay in glass jars at 25 oC was useful for screening many chemicals rapidly. Dewar flasks (4–5 1) allowed testing on 500 g hay samples with sufficient insulation to allow any effects of chemicals on spontaneous heating as well as on moulding to be measured. Large drums containing 20 kg hay were used for larger scale tests with partially dried fresh, or rewetted old hay. Proprietary additives were unsuccessful at their recommended application rates and some even failed to show antifungal activity with very much larger doses. Volatile fatty acids, particularly propionic acid, and ammonium propionate were the most effective chemicals tested. The amount of propionic acid needed to prevent moulding and spontaneous heating could be defined in terms of the amount of water in the hay. Where the ratio of propionic acid to water was greater than 1–25:100 heating was rare. Ammonium propionate was slightly less effective than propionic acid against moulding. However, it lacks a pungent odour, is less volatile, less corrosive and is more pleasant and safer to handle.
Some hosts and properties of narcissus latent virus, a carlavirus commonly infecting narcissus and bulbous iris
Authors: BRUNT A. A. 
Published: February 2008

SUMMARYNarcissus latent virus (NLV) is common in many cultivars of narcissus and bulbous iris, but was detected in only one of nineteen cultivars of nerine. It induced symptoms in some narcissus cultivars, but inconspicuous infection in bulbous iris and nerine.NLV was not seed‐borne in narcissus or Nicotiana clevelandii but was transmitted readily by aphids (Acyrthosiphon pisum, Aphis gossypii and Myzus persicae) in the non‐persistent manner and by sap‐inoculation to twelve of fifty‐three species from three of sixteen families. Sap from N. clevelandii was infective after dilution to io‐3 but not io*, after 10 min at 65 but not 70 oC or after 3–4 days at 20 oC or 16–32 days at 2 oC.Purified virus preparations were obtained from infected N. clevelandii by clarification of buffered leaf extracts with diethyl ether and carbon tetrachloride, followed by one or two cycles of differential centrifugation and molecular permeation chromatography. NLV has filamentous particles c. i3times65onm which sediment as a single component (io20, w= 156S). They contain c. 5% nucleic acid and a single polypeptide of mol. wt 32·6 × 103. The biological and physical properties of NLV place it in the carlavirus group; it is serologically related to lily symptomless virus, but not to fourteen other authentic carlaviruses. NLV has the cryptogram */*:*/(5):E/E:S/Ve/Ap.
Inactivation of cucumber mosaic virus in cultured tissues of Nicotiana rustica by diurnal alternating periods of high and low temperature
Authors: WALKEY D. G. A. , FREEMAN G. H. 
Published: February 2008

SUMMARYCucumber mosaic virus (CMV) was inactivated in infected tissue cultures of Nicotiana rustica after periods of alternating high (32–40 oC) and low (22 CC) temperature. An increase in the incubation period at high temperatures resulted in greater virus inactivation but more rapid deterioration of the tissue cultures. Optimal programmes for virus inactivation and culture survival were 40 oC (8 h) +22 oC (16 h) per day for 12 or 18 days, 40 oC (16 h) + 22 oC (8 h) per day for 12 days or 36 oC (20 h) + 22 oC (4 h) per day for 12 days.Diurnal treatment periods of variable length and different high temperatures were related by using a concept of hour‐degrees above a base temperature. Taking this base temperature as 25 oC a linear relation was found between the logarithm of virus infectivity and the number of hour degrees.
The effect of ryegrass mosaic virus on carbon assimilation and growth of ryegrasses
Authors: JONES M. B. , HEARD A. J. , WOLEDGE JANE , LEAFE E. L. , PLUMB R. T. 
Published: February 2008

SUMMARYThe growth of simulated swards of Italian and perennial ryegrass, artificially infected with ryegrass mosaic virus (RMV) or RMV‐free, was investigated. During the build up of RMV infection, dry‐matter yield was usually decreased in infected swards, and the effect was confirmed when single vegetative regrowths of swards were investigated in detail.The primary cause of lower yields in RMV‐infected swards appears to be a decrease in net canopy photosynthesis (maximum decrease about 50%) and an associated increase in dark respiration (maximum increase about 50%). The decrease in net canopy photosynthesis is due primarily to a lowered rate of net photosynthesis of constituent leaves within the canopy.A secondary effect of RMV infection is to decrease tillering (maximum decrease about 30%) which results in a change in canopy structure and in particular a lower leaf area index. In the present experiments, lower light utilization by the swards is less important than the decrease in leaf photo‐synthetic efficiency in lowering yield.
Studies on plant growth‐regulating substances XLVIII. The effects of3,5‐diiodo‐4‐hydroxybenzoic acid on seedling growth in compact and loose soils
Authors: WILKINS HENRY , WILKINS SHEENA M. , WAIN R. L. 
Published: February 2008

SUMMARYInvestigations were carried out under growth room conditions to assess the effect on seedling growth of incorporating3,5‐diiodo‐4‐hydroxybenzoic acid (DIHB) in a silt loam soil.In ‘compact soil’ (bulk density 1–5 g/cm3) at 20% moisture content, DIHB significantly increased elongation of the roots of Hordeum and Pisum seedlings, the optimum concentrations being 0–005 [ig and 0–005‐0‐507 fig DIHB/g dry soil respectively. Shoot height and root and shoot dry weights were also improved in barley seedlings. Treated pea seedlings had smaller root diameters 1 mm and 5 mm behind the apices and the roots were less bent than those of seedlings grown in soil in the absence of DIHB. The efficacy of DIHB treatment on pea seedling growth in compact soil decreased in soils at 24 and 28 % moisture contents.In ‘loose soil’ (bulk density i‐i g/cm3) at 20% moisture content, DIHB significantly promoted the growth of barley seedlings but the only effects on pea seedlings were small changes in root diameter.
Response of squash to ethylene and chilling
Authors: OLORUNDA A. O. , LOONEY N. E. 
Published: February 2008

SUMMARYFreshly harvested but already cured Acorn squash (Cucurbita pepo cv. Acorn) were stored for 4 wk in storage environments of20, 15, 10, 5 and o oC, with or without 5 μl 1‐1‐1 ethylene. Ethylene had no significant effect on overall acceptability, weight loss, dry matter, and ion leakage, but did enhance respiration at 15 and 20 oC. Temperature had a significant effect on weight loss, dry matter and overall acceptability. Squash stored at 15 and 20 oC had better flavour and texture than those stored at 0–10 oC, when cooked. Quality attributes such as flavour and texture may be more useful than physiological parameters in detecting insipient chilling injury in squash.
An investigation into the relations between some growth parameters and yield of barley
Authors: DYSON P. W. 
Published: February 2008

SUMMARYTwenty‐five field experiments on barley were done at four sites from 1970 to 1975, with an additional site in 1975, comparing five rates of nitrogen application. The crops were sampled at c. 14‐day intervals from about the four‐leaf stage to maturity to follow changes with time in the dry weights of the constituent plant parts and to measure fertile tiller number, grain number per ear and grain weight. Some data have been selected from this body of information and regression analysis has been used to assess the possible importance of pre‐ and post‐anthesis growth in determining the yield of barley. Ear emergence was taken as an approximate indicator of anthesis. Yield was closely related (r=+0–96) and almost equal to the amount of dry matter accumulated before ear emergence for twenty‐one of the experiments, with a regression coefficient of 0–95. In two of the remaining experiments the regression coefficient was greater, 1–14; and smaller in the other two, o‐8i. Plant population is also shown to affect the regression coefficient. Despite these anomalies grain yield was more closely related to plant dry weight at ear emergence than to the increase in weight after ear emergence (r =+0–79). The increase in plant dry weight after ear emergence was frequently less than the yield of grain, suggesting that the plant can compensate for inadequate photosynthesis during grain filling. The result of this compensation is a reduction in straw dry weight. This implies that previously assimilated dry matter is transported to the grain, or that respiratory losses from the straw are not replaced by current photosynthesis. These observations suggest that yield may be limited by sink capacity rather than by photosynthesis after ear emergence. The main component of sink capacity, grain number per m2 was closely related to yield (r =+0–95) and is known to be determined at or before anthesis. Grain size was shown to be related to grain number per ear (r= 4‐ 0–99), suggesting that grain size is also, at least partially, determined at ear emergence. Therefore, all the yield components are determined, wholly or partly before ear emergence.
Factors affecting the seasonal distribution of red deer (Cervus elaphus) at Glen Dye, north‐east Scotland
Authors: STAINES BRIAN W. 
Published: February 2008

SUMMARYPart of a red deer herd found on an estate in north‐east Scotland in summer spent more time on neighbouring ground during the winter where they damaged farms and woods. Factors associated with the deer's seasonal distribution were studied to help understand how to keep more deer on the estate in winter. There were no indications that food species or food quality were responsible for the observed changes in deer distribution, or that other animals or disturbance influenced distribution over a long period. Deer sought shelter from chilling winds, and areas occupied by deer in winter had more sheltered ground from wind, and the quality of this shelter was higher than on the areas little used. Home‐range behaviour and tradition appeared to determine which areas particular deer occupied in winter. The main recommendation for management was to re‐open mature woodland to provide more and better shelter on the estate in order to get more control over the deer stock and to reduce marauding.
Observations on the life cycle and pathogenicity of Paralongidorus maximus in a forest nursery in Scotland
Authors: BOAG B. , RASCHKE I. E. , BROWN D. J. F. 
Published: February 2008

SUMMARYSoil samples from a forest nursery growing Scots pine were collected at monthly intervals at five different depths during 1975 and examined for Paralongidorus maximus: 49% occurred at the 10–19 cm depth. The fluctuation in the numbers of the larval stages suggested that a complete life cycle from egg to adult probably took more than 1 yr.Growth in the second year after planting and overall height of Scots pine seedlings was inversely related to the numbers of P. maximus. In a glasshouse experiment using varying numbers of P. maximus the growth of Scots pine and European larch but not of Sitka spruce were decreased by increasing numbers of nematodes. A possible relationship between P. maximus, Cylindro‐carpon destructans and the death of small numbers of Scots pine is discussed.
Virus‐like particles in phloem tissue of chervil (Anthriscus cerefolium) infected with anthriscus yellows virus
Authors: MURANT A. F. , ROBERTS I. M. 
Published: February 2008

SUMMARYClusters of isometric virus‐like particles c. 22 nm in diameter, embedded in amorphous electron‐dense material, were found in the phloem tissue of Anthriscus cerefolium (chervil) plants infected with the semi‐persistent aphid‐borne virus, anthriscus yellows (AYV). The particles resembled those seen previously in thin sections of AYV‐transmitting aphids (Cavariella aegopodii). The particles were found only in the central vascular bundle of the petiole and its continuation in the leaf midrib. They were also found in extracts made by grinding petiole and midrib tissue in 10 % sucrose using Carborundum. These results confirm earlier studies which suggest that AYV is confined to deeper‐lying tissues.
Use of oviposition trays to estimate numbers of wheat bulb fly Leptohylemyia coarctata eggs
Authors: OAKLEY J. N. , UNCLES J. J. 
Published: February 2008

SUMMARYTo obtain reliable estimates of wheat bulb fly populations in time to provide advice on seed treatment of the following crop a method of collecting eggs in trays of soil placed in fields has been devised. The trays are examined by 20 August when half of the eggs have been laid.
Effects of photoperiod on some vegetable species
Authors: SOFFE R. W. , LENTON J. R. , MILFORD G. F. J. 
Published: February 2008

SUMMARYSeven vegetable species grown in controlled environments were given similar daily amounts of visible radiation (500 J cm‐2) during three different photoperiod treatments. Plants were given (A) 12 h of visible irradiance (115 W m‐2) from fluorescent and tungsten lamps, (B) 16 h of the same light at 88 W m‐2 or (C) Treatment A extended to 16 h with 4 h of low‐intensity incandescent light (3 W m˜2) from tungsten lamps only. All seven species grew faster when daylength was extended with light of photosynthetic intensity (B), probably through increased net assimilation rates, and leaf area of these plants increased in proportion to change in plant dry weight. Daylength extension with a mixture of red and far‐red light (C) induced photomorphogenic changes in specific leaf area in all species examined and increased leaf area and plant dry weight of lettuce, celery, beetroot and spinach beet but not of three members of the Cruciferae (radish, cabbage and oilseed rape).
Cane blight (Leptosphaeria coniothyrium) in mechanically harvested red raspberry (Rubus idaeus)
Authors: WILLIAMSON B. , HARGREAVES A. J. 
Published: February 2008

SUMMARY Leptosphaeria coniothyrium, the cane blight pathogen, was the fungus most commonly isolated from vascular lesions developing from mechanical harvester wounds on first‐year red raspberry canes. When inoculated to scalpel wounds, it induced similar lesions which were later associated with bud failure and cane death as were infected wounds on machine damaged canes. Cane resistance increased from May until August, inoculations later than July inducing only small lesions and rarely causing bud failure.
The occurrence of benomyl tolerance in Penicillium spp., Botrytis cinerea and a Gliocladium sp. on virus‐tested narcissus twin‐scales
Authors: LYON G. D. 
Published: February 2008

SUMMARYAll isolates of PeniciUium simplicissimum, P. verrucosum var. cyclopium, P. brevicompactum, P. multicolor, P. oxalicum, P. paxilli, Botrytis cinerea, and of a Gliocladium sp. obtained from necrotic virus‐tested narcissus twin‐scales previously dtoped in benomyl were tolerant to 1000 μg/ml of this fungicide in agar. Every necrotic twin‐scale examined was infected with at least one of these species. The first two species were the most frequently isolated and a similar range of species infected different narcissus clones or different cultivars. It is argued that the use of benomyl during the twin‐scaling programme should be discontinued as soon as a suitable alternative fungicide is found.