bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tulip chlorotic blotch virus, a second potyvirus causing tulip flower break
Authors: MOWAT W. P. 
Published: February 2008

SUMMARYTulip chlorotic blotch virus (TCBV), an apparently undescribed potyvirus found in field grown tulips in Australia, causes symptoms in tulip leaves and flowers identical to those induced by tulip breaking virus (TBV). TCBV was transmitted mechanically to 14 of 34 species in four of 13 families. Nicotiana clevelandii is a suitable propagation host and Chenopodium amaranticolor a local‐lesion assay host. TCBV was transmitted from tulip to tulip and TV. clevelandii by the aphid Myzus persicae. Unlike TBV it was not transmitted to Lilium formosanum either by M. persicae or by manual inoculation.Leaf extracts from TCBV‐containing TV. clevelandii were infective after dilution to l0‐3 but not 10‐4 and after heating for 10 min at 50°C but not 60°C; infectivity and particle recovery were adversely affected by freezing at ‐20°C. TCBV particles were purified (c. 1 mg/100g g N. clevelandii leaf) from tissue extracts in 0·3 M citrate buffer containing 10 mM EDTA and 0·2% (v/v) 2‐mercaptoethanol at pH 7·4 by clarification with 8·5% (v/v) n‐butanol followed by differential centrifugation and sucrose density gradient centrifugation. Purified particles measured c. 720 × 12 nm. Virus particle antigen was readily detected in leaf and tepal extracts of tulip by enzyme‐linked immunosorbent assay. A distant serological relationship was found between particles of TCBV and those of bean yellow mosaic virus but no serological relationship was found to TBV or four other potyviruses.
The occurrence and distribution of isolates of raspberry bushy dwarf virus in England
Authors: BARBARA D. J. , ASHBY S. C. , KNIGHT V. H. 
Published: February 2008

SUMMARYThe distribution of distinct isolates of raspberry bushy dwarf virus (RBDV) in Rubus in England was studied. Isolates similar in Rubus host range to the Scottish type isolate (D200) were largely confined to the old red raspberry (Rubus idaeus) cv. Norfolk Giant, but were also encountered in a single plant of an unidentified raspberry cultivar and in a clump of wild R. idaeus. Outside East Mailing Research Station (EMRS) RBDV isolates with wider Rubus host ranges than that of the type isolate were found only and exclusively in hybrid berries (Loganberry, clones LY59 and L654, and Tayberry) in which infection ranged from < 1% to 100%. The significance of these findings is discussed.
Inactivation of a nuclear polyhedrosis virus on cotton by the substances produced by the cotton leaf surface glands
Authors: ELLEMAN C. J. , ENTWISTLE P. F. 
Published: February 2008

SUMMARYLoss of viability of a nuclear polyhedrosis virus (NPV) of Spodoptera littoralis was shown to occur on cotton leaves but not on cabbage leaves or on semi‐synthetic insect diet. The inactivation was rapid, occurred in the dark and required contact between the cotton leaf surface and the polyhedral inclusion bodies (PIBs). It was shown that the products of the cotton leaf glands, which exude a crystalline material onto the leaf surface, could account for the rapid inactivation observed. Inactivation did not involve loss of virus polyhedral inclusion bodies. The use of EDTA or a low pH buffer in the NPV suspension reduced the inactivation which suggested that the loss of activity was due to the presence of calcium and magnesium in the cotton gland exudate.
The effect of resistant cultivars of catch crops on the hatching of Heterodera schachtii
Authors: COOKE D. A. 
Published: February 2008

SUMMARYIn laboratory tests with Heterodera schachtii, root leachates of nematode‐resistant and susceptible cruciferous crops stimulated egg hatches of up to 77% and 95% respectively. In these tests very little hatch occurred at 5°C or 10°C, more at 15°C and most at 20°C. In field experiments in which these crops were sown in September 1982 and August 1983 into soil infested with H. schachtii, numbers of viable eggs had decreased only slightly under resistant crops 4–5 months later. This was possibly because the soil was too cold and dry to permit a large proportion to hatch.
DNA stability in the anabiotic fourth‐stage juveniles of Ditylenchus dipsaci (Nematoda)
Authors: BARRETT J. , WORTH PENELOPE E. BUTTER. 
Published: February 2008

SUMMARYWater plays an important role in DNA structure and desiccation of microorganisms has been correlated with breaks in their DNA.The fourth‐stage juveniles of the anabiotic nematode Ditylenchus dipsaci can lose up to 90% of their body water and survive in a dehydrated state for long periods of time; however, there was no increase in the frequency of breaks in DNA isolated from anabiotic as opposed to hydrated juveniles. Desiccation of the non‐anabiotic nematode Panagrellus redivivus similarly did not lead to an increased frequency of DNA breaks, nor did the polyol glycerol significantly effect DNA stability.The stability of DNA during tissue desiccation, like the stability of proteins, seems to be a general feature of biological material and not a unique property of anabiotic organisms.
Seed survival and seasonal pattern of seedling emergence in some Leguminosae
Authors: ROBERTS H. A. , BODDRELL JUNE E. 
Published: February 2008

SUMMARYSeeds of 11 species of Leguminosae were collected, usually in each of 3 years, and mixed with the top 7·5 cm of sterilised soil confined in cylinders sunk in the ground outdoors and cultivated three times yearly. Emergence was recorded for at least 3 yr. Some seedlings of all species emerged soon after sowing but their numbers varied both within and between species, a probable reflection of the percentage of ‘hard’ seeds in the samples. Appreciable numbers of seedlings appeared in the following 3 yr but few seeds remained viable and dormant after 5 yr. The annual weed Vicia hirsuta was an exception, with an average of 11% of the seeds sown still viable at this time. Most seedlings of Lotus corniculatus, Medicago lupulina, Melilotus altissima, Trifolium repens and Vicia cracca emerged in spring, V. cracca rather later than the others. In contrast, maximum emergence of Trifolium arvense, T. campestre and T. dubium took place from June to September. Limited data indicated a similar pattern for T. striatum and Lathyrus pratensis. Seedlings of Vicia hirsuta emerged from October to May but scarcely at all in summer. Although variation in the percentage of hard seeds influenced the extent of immediate germination and seed persistence, the seasonal patterns in seedling emergence of most species were found to be very consistent.
The effects of pH during treatment of lettuce seeds with chlorine‐releasing compounds on germination and seedling development
Authors: DREW R. L. K. , BROCKLEHURST P. A. 
Published: February 2008

SUMMARYHypochlorite seed treatments have been reported in the literature as giving variable results. We report experiments on this topic in which lettuce seeds were used as a model biological system. Seeds were treated for 2 h with solutions of sodium hypochlorite diluted with buffers of pH 9·8, 10·8 and 11·8, or with the buffers alone. Only the seeds treated with hypochlorite diluted with pH 9·8 buffer showed increased numbers of abnormal seedlings when subsequently germinated. In an experiment in which lettuce seeds were treated with sodium dichloroisocyanurate (a chlorine‐releasing triazine compound) and related non‐chlorinated compounds, seedling abnormalities were related to chlorine in solution. Measurements of pH together with the known chemistry of hypochlorite suggest that the damaging agent in these experiments was the biocidal undissociated hypochlorous acid.
Relationship between the concentration of chlorogenic acid in carrot roots and the incidence of carrot fly larval damage
Authors: COLE R. A. 
Published: February 2008

SUMMARYChlorogenic acid (1·24‐3·36 mg/g) was identified as the main phenolic component in the peel of carrots by hplc analysis. The higher the concentration of chlorogenic acid in different cultivars the greater the susceptibility to carrot fly larval damage. Increases in concentration were found both after carrot fly damage and after carrots had overwintered in the field. The presence and location of chlorogenic acid was confirmed in sections of carrot tissues, mounted in 0·05 M ammonia solution by viewing them using a u.v.‐epifluorescent microscope. The importance of phenolic compounds and their function in the production of insect cuticle is discussed in relation to the different concentrations of chlorogenic acid and resistance to carrot fly in carrots.
Occurrence of Cryphonectria canker disease of Eucalyptus in Kerala, India*
Authors: SHARMA J. K. , MOHANAN C. , FLORENCE E. J. MARIA. 
Published: February 2008

SUMMARY Cryphonectria cubensis, recorded for the first time in India, is responsible for causing severe stem cankers in Eucalyptus grandis in Kerala. Disease outbreaks are localised and vary in severity with host species, at times affecting up to 30% of the trees in a stand. Infection usually occurs on the main stem 1 to 1 ·5 m above ground and occasionally near ground level. There is evidence of tree to tree spread of the disease from the primary infection foci. The disease also affects coppicing by stumps after harvest. Details on the incidence and epidemiology of the disease are presented.
The effect of imazalil in the control of decay in yellow yam caused by Penicillium sclerotigenum
Authors: PLUMBLEY R. A. , COX J. , KILMINSTER K. , THOMPSON A. K. , DONEGAN L. 
Published: February 2008

SUMMARYA strain of Penicillium sclerotigenum isolated from decaying yellow yams (Dioscorea cayenensis) was found to have developed resistance to benzimidazole fungicides and the use of imazalil was investigated as an alternative agent for controlling it. Two formulations were tested and proved to be equally effective in controlling decay at a concentration of 50 mg imazalil litre‐1 if the yams were dipped in it for 5 s; concentrations down to 10 mg litre‐1 were effective if the immersion time was increased to 5 min or more. These treatments gave good control of decay when applied up to 24 h after inoculation but were less effective when application was 48 h after inoculation, although at 500 mg litre‐1 there was some indication that levels of decay were decreased when compared with untreated tubers. Fungal penetration was unaffected or increased by increasing delays in the time of the fungicide application depending on the concentration applied. In trial shipments of yams from Jamaica to Britain imazalil alone was less effective in controlling overall decay because of the presence of a Rhizopus species. This could be controlled by the addition of dichloran to the dip. Imazalil residues were highest in the peel; levels in the peeled tuber varied and tended to decrease during storage but were generally in the range of 0·5 ‐ 0·8 mg kg‐1 which is higher than the maximum levels accepted for other produce. A simple cooking test showed that residues in treated yam slices declined by about one third after boiling the slices in water for 45 min.
Field studies on the spread of African cassava mosaic
Authors: FARGETTE D. , FAUQUET C. , THOUVENEL J.‐C. 
Published: February 2008

SUMMARYThe spread of African cassava mosaic disease (ACMV) into healthy cassava fields was recorded at weekly intervals. In addition, 21 yellow water traps were placed in one field and the number of whiteflies caught was recorded twice a week. The number of Bemisia spp. feeding on cassava was also estimated. The results indicate that the pattern of disease spread is related to the pattern of infestation with Bemisia.Airborne whiteflies carried by the south‐west prevailing wind alighted preferentially on cassava plants along the upwind edges (south and west borders) of the plantings. The pattern of incidence of mosaic disease resembled that of whiteflies. Along the SW‐NE diagonal, there was a gradient of disease incidence with a maximum at the SW corner block. Similar gradients occurred in three different fields and they were maintained throughout the 6‐month study, although gradually flattening with time. There were indications that the reservoirs both of the virus and of the vectors were located some distance upwind from the experimental fields.
A comparison of spike and spikelet survival in mainstem and tillers of barley
Authors: COTTRELL JOAN E. , EASTON RUTH H. , DALE J. E. , WADSWORTH ANGELA C. , ADAM JILL S. , CHILD R. D. , HOAD G. V. 
Published: February 2008

SUMMARYInitiation and abortion of spikelet primordia on primary tillers and mainstem were compared for plants of spring barley, Maris Mink, sown on two sowing dates during 1983, in plots at the Scottish Crop Research Institute (SCRI) and at Long Ashton Research Station (LARS). Sowing date had no effect on the number of spikelets initiated on either mainstem or surviving tillers and many more spikelets were initiated on equivalent stems at LARS than at SCRI but more spikelets aborted at the former site. The final number of spikelets produced was eventually similar. Spikelet abortion was complete by anthesis and coincided with the period of rapid stem and rachis elongation and with the time over which tiller death occurred. Despite the fact that plants at SCRI produced fewer fertile tillers they outyielded those at LARS because much heavier grains were produced on the mainstem and tiller 1 of plants at the Scottish site. An interval of 2 wk between sowing had only small effects on the components of yield.
The role of the sheath tube in the development of expanding leaves in perennial ryegrass
Authors: WILSON RUTH E. , LAIDLAW A. S. 
Published: February 2008

SUMMARYA possible morphogenic effect of leaf sheaths on subsequent leaf development was investigated by varying sheath tube (pseudostem) length in plants of perennial ryegrass (Lolium perenne) cv. Talbot by either incising longitudinally or excising the distal portion of the sheath tube, while leaving the basal length of the tube intact. The tube was maintained at predetermined lengths by incising and excising new growth daily. The youngest rapidly expanding leaf was allowed to grow through the tube and was measured when fully expanded. Reducing tube length by excision or by incision from 60 mm to just above the cowl leaf on the apex reduced lamina length by 87% and 77% respectively. Over all tube lengths, laminae in incised treatments were almost twice as long as those in excised treatments. Sheath length followed a similar pattern.The effect on developing leaves of artificially extending sheath tubes (previously excised to 15 mm) to 30 or 45 mm with foil was similar to that of initially excising sheath tubes to 30 or 45 mm.The shorter the sheath tube (reduced by incision) through which the leaves had to grow, the shorter the cells, especially in the laminae. The estimated cell number per row along the length of the laminae ranged from 190 in tillers (shoots) with a very short tube (just above the cowl leaf) to 454 in intact control tillers.It is concluded that the sheath tube has a morphogenic influence on the development of subsequent leaves due to the change in environment of the leaf lamina on appearance, affecting both cell elongation and cell division.
A tobamovirus infecting capsicum in Australia
Authors: PARES R. D. 
Published: February 2008

SUMMARYA tobamovirus infection of Capsicum annuum is recorded for the first time in New South Wales, Australia. The causal virus is described and shown to differ from tobacco (TMV) and tomato (ToMV) mosaic viruses in its host reactions and serology.Seventeen capsicum cultivars were tested for reaction to the Australian isolate and ranked according to symptom severity. Field and glasshouse observations indicated that the virus causes a decrease in height and weight of plants, fruit malformation and leaf mosaic symptoms.It is proposed that the capsicum tobamovirus strains are sufficiently distinctive from TMV and ToMV to be grouped together and designated a separate virus: capsicum mosaic virus (CaMV).
Purification and properties of two Swedish isolates of barley yellow dwarf virus and their serological relationships with American isolates
Authors: EWEIDA M. , OXELFELT P. 
Published: February 2008

SUMMARYTwo Swedish isolates of barley yellow dwarf virus (BYDV), one (39/78) transmitted much more efficiently by Rhopalosiphum padi than by Sitobion avenae and the other (27/77) transmitted specifically by Sitobion avenae, were purified with yields of 200–300 μg/100 g infected oat leaves. Three light scattering zones were obtained when isolate 39/78 was sedimented in 10–40% (w/w) sucrose density gradients but only one zone with the other isolate. The sedimentation coefficients of 39/78 particles were 94,106 and 150 S, respectively, whereas the 27/77 particles sedimented at 110 S. Four protein bands of mol. wts 31 900, 29 700, 28 000 and 15 000 were detected when disrupted 150 5 particles of the 39/78 isolate were electrophoresed in SDS‐polyacrylamide gels. Only one major band of mol. wt 24 500 was detected when 94 or 106 S particles were electrophoresed under the same conditions. The 27/77 isolate yielded one major band of mol. wt 23 500. A weak serological relationship was found between isolates 39/78 and 27/77. In enzyme‐linked immunosorbent assay, isolate 39/78 was serologically closely related to New York isolate PAY, whereas 27/77 was closely related to MAY.
The effects of mixing Italian ryegrass (Lolium multiflorum) with perennial ryegrass (L. perenne) or red clover (Trifolium pratense) on the incidence of viruses
Authors: LEWIS G. C. , HEARD A. J. , GUTTERIDGE R. A. , PLUMB R. T. , GIBSON R. W. 
Published: February 2008

SUMMARYMixing the ryegrass mosaic virus (RMV) resistant perennial ryegrass (Lolium perenne) cv. Endura with the susceptible Italian ryegrass (L. multiflorum) cv. RvP decreased infection of RvP wth RMV from 37% when grown alone to 22% when mixed. However, Endura yielded less than RvP and there was no yield benefit from mixing the two cultivars. Mixing red clover (Trifolium pratense) cv. Hungaropoly with RvP had no detectable effect on RMV incidence in RvP but did decrease the incidence of red clover necrotic mosaic virus in Hungaropoly from 9% to 1% and of white clover mosaic virus from 53‐5% to 41%. The yield of the mixture was equal to that of RvP grown alone but given nitrogen fertiliser.The numbers of eriophyid mites, including Abacarus hystrix the vector of RMV, on ryegrass leaves were similar in pure and mixed swards.It is concluded that with herbage crops, the common practice of sowing mixtures of species may help control virus diseases.
Control of potato cyst‐nematode, Globodera rostochiensis, and root‐knot nematode, Meloidogyne incognita, by organosphosphorus, carbamate, benzimidazole and other compounds
Authors: WHITEHEAD A. G. , BROMILOW R. H. , FRASER J. E. , NICHOLS A. J. F. 
Published: February 2008

SUMMARYControl of potato cyst‐nematode, Globodera rostochiensis, was examined on potato or tomato in pots and on potato in field plots by various chemicals incorporated into the soil at planting. The most effective nematicides were organophosphorus compounds, generally of the type O,O‐diethyl O‐phosphoro‐thioates or O,O‐diethyl phosphorodithioates, carbamates and benzimidazoles. In organic soils, the more lipophilic compounds were less effective, presumably because of sorption onto soil organic matter.Foliar sprays of chemicals, including oxamyl which is known to be translocated to roots, gave poor control of G. rostochiensis.The root‐knot nematode, Meloidogyne incognita, on tomato, widely used in screening for nematicidal activity, was controlled by aldicarb or phoxim incorporated into the soil at planting, but not by benomyl or thiabendazole, in contrast to the moderate effectiveness of these latter two chemicals against G. rostochiensis.
Vertical distribution of Pratylenchus neglectus, P. crenatus and Tylenchorynchus dubius associated with maize roots and the effect of aldicarb residues
Authors: BEANE J. 
Published: February 2008

SUMMARYDepth samples on a field trial on forage maize revealed consistent differences in the numbers of Pratylenchus neglectus, P. crenatus and Tylenchorynchus dubius at different depths after treatment with aldicarb the previous year. Pratylenchus was more numerous lower down in residual‐treated soils but more evenly distributed in untreated soils. T. dubius, although less numerous after aldicarb, was more numerous in the upper layers of the soil. Aldicarb and benomyl applied the previous year had no residual effects on yields.
Non‐glaucousness, a probable aphid‐resistance character of wheat
Authors: LOWE H. J. B. , MURPHY G. J. P. , PARKER MARY L. 
Published: February 2008

SUMMARYCuticular waxes from wheat cultivars that have a bluish‐green waxy bloom under field conditions were compared with those of non‐glaucous (NG) variants that appeared dark green and glossy in the field. Cuticular wax from NG variants was deficient in diketones and hydroxydiketones, and did not form the micro‐spicules of epicuticular wax which were characteristic of the normal bloom.Typically, NG wheats were resistant to Sitobion avenae in the field, but in environments where wax secretion was diminished, resistance was reduced or absent. Possible causes of this resistance, which appears likely to be easy to exploit, are discussed.
Field evaluation of resistance to black bean aphid, Aphis fabae, in close relatives of the Faba bean, Vicia faba
Authors: BIRCH N. 
Published: February 2008

SUMMARYA field assessment of 26 accessions of Vicia narbonensis and three of V. johannis confirmed previous laboratory studies demonstrating higher levels of resistance to Aphis fabae in these two wild species compared to the closely related crop, Vicia faba. Accessions of V. johannis were significantly more resistant than most accessions of V. narbonensis for all resistance indices measured except survival of aphid nymphs. Plant growth stage significantly affected levels of resistance in both Vicia species, resistance being moderate at pre‐bud stage, decreasing on flowering and rising again at pod fill and onset of leaf senescence. Significant intraspecific variability in aphid resistance was found only within the 26 accessions of V. narbonensis, var. serratifolia being more resistant than var. narbonensis. Possible resistance factors and the agronomic potential of these two wild relatives of Faba bean are considered.
Flowering response of pearl millet to water stress during panicle development*
Authors: MAHALAKSHMI V. , BIDINGER F. R. 
Published: February 2008

SUMMARYIn pearl millet, severe water deficit during the period of panicle development delays flowering. The flowering response of both main shoot and tillers to water stress during panicle development was investigated using four hybrids. Panicle initiation of all tillers occurred in the three early genotypes despite water stress. In the late genotype, however, panicle initiation of tillers occurred only after the release of stress. The delay in flowering due to water stress was more pronounced in the tillers than in the main shoot. However, the proportion of tillers producing an inflorescence was increased by water stress. Grain yield losses on the main shoot by water stress were compensated by an increase in tiller grain yields. Delay in flowering and buffering by tillers provide an important adaptive mechanism to overcome a period of drought stress prior to flowering.