bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimation of cold hardiness of Douglas‐fir and Engelmann spruce seedlings by differential thermal analysis of buds*
Authors: TINUS R. W. , BOURQUE J. E. , WALLNER S. J. 
Published: February 2008

SUMMARYLow temperature freezing points of conifer buds were determined by differential thermal analysis and were compared to results obtained in whole plant freezing tests of the same seedlings. To obtain well‐defined, meaningful exotherms, it was necessary to nucleate buds externally. The low temperature exotherms for buds occurred at temperatures very close to the lowest which seedlings tolerate with no visible injury. Thus, for Engelmann spruce and Douglas‐fir, differential thermal analysis may provide a convenient prediction of containerised tree seedling hardiness.
A selective medium for isolating Rhizoctonia solani from soil
Authors: GANGOPADHYAY SAMIRAN , GROVER R. K. 
Published: February 2008

SUMMARYKo & Hora's (1971) selective medium (FM) for counting Rhizoctonia solani propagules from soil has been modified. FM medium minus gallic acid and fenaminosulf i.e. mineral antibiotic (MA) medium, was amended with inhibitors and fungicides at different concentrations. The modified medium consisting of MA + gallic acid (400 μg ml‐1) + fosetyl‐Al (250μgml‐1) was found most efficient in selective isolation of R. solani from soil even in the presence of Macrophomina phaseolina (Rhizoctonia bataticold) and other soil mycoflora.This amended medium was effective in isolating R. solani from soil even when the number of propagules of M. phaseolina present was 10 times greater. The sensitivity of this medium was five times better than Ko & Hora's medium.
Stem canker (Rhizoctonia solani) of maincrop potatoes.
Authors: HIDE G. A. , READ P. J. , SANDISON JANET P. 
Published: February 2008

SUMMARYIn two years, potato plants were sampled at 1‐ or 2‐ weekly intervals from plots planted with seed tubers bearing sclerotia of Rhizoctonia solani (black scurf) and with seed without sclerotia either infested or not with cultures of R. solani at planting. Sprouted King Edward seed was used in 1981 and sprouted and non‐sprouted King Edward and Pentland Crown seed in 1982.In both years 60–80% of shoots from seed with sclerotia and 90% of shoots from seed inoculated at planting were affected with stem canker. Most disease developed before shoots emerged although it gradually increased later when new shoots arising both from seed tubers or as branches on shoots with damaged apices (pruned shoots) became infected before they emerged. Sprouting seed tubers bearing sclerotia decreased the disease on both cultivars but with soil‐applied inoculum the disease was more severe on plants from sprouted than non‐sprouted seed.Some stolons were infected by R. solani soon after they developed and incidence of infection later increased. Thirty to 50% of stolons were infected on plants from infected seed tubers and 60% on plants with soil‐applied inoculum. With both cultivars and sources of inoculum about 70% of the infected stolons had their apices killed (pruned).
Factors affecting the uptake of chlormequat into cereal leaves
Authors: BAKER E. A. , HUNT GRACE M. 
Published: February 2008

SUMMARYThe effects of site of application, growth environment, droplet size, and formulation adjuvants on the retention and uptake of 14C‐chlormequat by wheat cv. Avalon and barley cv. Sonja have been examined using solutions applied by a micro‐sprayer. Wheat plants retained a higher proportion of droplets on initial impaction than barley irrespective of growth stage, site of application or formulation. Leaf retention increased approximately two‐fold with increase in surfactant concentration (0·03·0–3% w/v) or decrease in droplet size (200‐125 μm) but declined markedly with age of leaf. Uptake, which was greater into wheat than barley, increased with increase in surfactant concentration, growth temperature and droplet size, with a combination of decrease in irradiance plus a rise in soil moisture, and after exposure to simulated dew. Droplet reflection increased and chlormequat uptake declined when the fungicide preparations Bavistin and Radar replaced Agral 90 in the spray mixtures. Droplets impacted more readily and spread more extensively over the damaged surfaces of field grown leaves. Both tissue combustion and autoradiography showed that chlormequat translocated readily only in immature tissues.
Grain aphid infestations of winter wheat variety trials, 1984
Authors: LOWE H. J. B. , ANGUS W. J. 
Published: February 2008

SUMMARYAphid infestations of wheat yield trials near Cambridge were assessed by shoot sampling and by breeder's scores. Both resistant and extremely susceptible cultivars were identified. Results from the two methods of assessing infestation were well correlated, indicating that the simpler scores could be used effectively for making selections.
The persistence of infectivity of conidia of the aphid pathogen Erynia neophidis on leaves in the field
Authors: BROBYN PATRICIA J. , WILDING N. , CLARK SUZANNE J. 
Published: February 2008

SUMMARYConidia of the aphid pathogen Erynia neophidis inoculated on to bean leaves in the field in 1980, 1981 and 1982, retained some infectivity for pea aphids for at least 14 days. Decline in infectivity occurred linearly with time. Inocula on leaves near the base of plants remained infective longer than those on leaves near the top and those on the abaxial surface remained infective for longer than those on the adaxial surface. Infectivity persisted longest in 1981 when conditions were coolest with least sun.
Spread of barley yellow dwarf virus and relative importance of local aphid vectors in central Washington
Authors: HALBERT SUSAN E. , PIKE K. S. 
Published: February 2008

SUMMARYData from bioassays of field collected aphids, barley indicator plants exposed to natural conditions, and various types of aphid traps were used to describe the spread of barley yellow dwarf virus (BYDV) in wheat and barley near Prosser, Washington. Bioassays were also used to assess the relative importance of local vector species.Of alate aphids collected from grain in the 1982 and 1983 fall migration seasons, 3.4–14–5% transmitted BYDV. Data from concurrent and post‐migration assays of resident aphids (apterae and nymphs) reflected an increase in the proportion of infected plants in the field. Maximum increase in the percentage of viruliferous aphids occurred in late November and December of 1982 and November of 1983. The 1982 increase occurred after aphid flights had ceased for the year, suggesting active secondary spread. Collections in pitfall traps and infected trap plants from November to February confirmed aphid activity and virus spread. Rhopalosiphum padi was the most important vector in central Washington in 1982 and 1983 because of its abundance and relative BYDV transmission efficiency. Metopolophium dirhodum was more winter‐hardy than R. padi and equal to R. padi in its efficiency as a vector; however, it was not as abundant as R. padi except during the mild winter of 1982–83, when it was a major contributor to secondary spread. Sitobion avenae may be important in years when it is abundant, but it was only a quarter as efficient as R. padi. Rhopalosiphum maidis was a much less efficient vector than R. padi and it only reached high populations in late autumn barley.
Deoxyradicinin and 3‐epideoxyradicinol production by the sunflower pathogen Alternaria helianthi
Authors: ROBESON DAVID J. , STROBEL GARY A. 
Published: February 2008

SUMMARYThe phytotoxic compound deoxyradicinin, a metabolite of Alternaria helianthi, was isolated from naturally infected leaves of sunflower (Helianthus annuus). The production of this toxin in liquid culture together with 3‐epideoxyradicinol is discussed. Production of deoxyradicinin by liquid cultures was observed to decrease after successive sub‐culture of the fungus on solid medium. All 10 accessions of Helianthus tested were sensitive to deoxyradicinin although some quantitative differences between lines were noted. Evidence is presented for the metabolism of deoxyradicinin by host leaf tissue.
A distinct strain of lucerne Australian latent virus in white clover in New Zealand
Authors: FORSTER R. L. S. , MORRIS‐KRSINICH B. A. M. 
Published: February 2008

SUMMARYA strain of lucerne Australian latent virus (LALV) was widespread in Trifolium repens (white clover) in Northland, New Zealand, occurring in 20–100% of plants tested on 23 of 26 farms. Infected plants showed chlorotic line patterns or were symptomless. In agar gel double diffusion serological tests, white clover isolates of LALV differed from lucerne isolates by two or three twofold dilution steps of antisera. In mechanical inoculation tests, white clover isolates did not infect lucerne and lucerne isolates did not systemically infect white clover. White clover and lucerne isolates also differed in their reactions in some other hosts. Six LALV isolates from white clover were indistinguishable in double diffusion serological tests and by enzyme‐linked immunosorbent assay, although the isolates could be differentiated by some reactions in test plants. Purified LALV particles of lucerne and white clover isolates contained two nucleoprotein components and two RNA species of molecular weight 2.82 × 106 (8150 nucleotides) and 2.46 × 106 (7100 nucleotides) (estimated under denaturing conditions).
Some properties of an isolate of tobacco rattle virus from Northern Ireland
Authors: MILLS P. R. 
Published: February 2008

SUMMARYA virus obtained from soil in which potato plants had shown severe spraing symptoms induced symptoms on indicator plants typical of tobacco rattle virus (TRY).Purified virus preparations of a local‐lesion isolate contained particles of two modal lengths, 192 nm and 94 nm containing RNA molecules of mol. wt 2.4 × 106 and 1.23 × 106. Virus coat protein had a mol. wt of c. 21 500.The virus was serologically distantly related to TRY (SYM) and pea early browning virus (PEBV) SP5, but did not react with TRY (CAM) or TRY (PRN) antisera. However, cDNA hybridisation indicated that the virus was more closely related to TRY (PRN) than either TRY (SYM) or PEBV (SP5).The virus isolate has been designated TRY (NI).
Detection of maize rough dwarf virus by enzyme‐linked immunosorbent assay in plant hosts and in the planthopper vector
Authors: CACIAGLI P. , ROGGERO P. , LUISONI E. 
Published: February 2008

SUMMARYSVPs were efficiently detected by ELISA in individual male and female insects. Females carried more virus per insect and per unit fresh weight, but no significant difference was detected between males and females in vector efficiency. Of insects positive in ELISA, 15–20% were unable to transmit the virus to host plants. Storage of viruliferous hoppers at‐20°C decreased the level of viral antigen detected by half in about 240 days.Subviral particles (SVPs) of maize rough dwarf virus were detected in the planthopper vector Laodelphax striatellus and in maize and barley plants using double antibody sandwich ELISA. In purified preparations diluted in buffer, as little as 36 ng/ml of SVPs was detectable whereas after dilution in extracts of healthy frozen planthoppers the sensitivity was reduced to 50 ng/ml. Freezing the hoppers prior to extraction lowered to one third the background reading due to normal components. Neither the dissociated proteins of the SVP nor the viral double‐stranded RNA contributed to the ELISA readings.
Selection for Fusarium root rot resistance in red clover
Authors: RUFELT S. 
Published: February 2008

SUMMARYIntercrossing red clover plants, selected for reaction to Fusarium root rot (F. avenaceum), produced progenies with lower root rot scores than the parental cultivar Hermes II. Eleven percent of the progenies had less than 2 mm root rot after two cycles of selection, compared to less than 1% in the parental cultivar. Root rot severity in two old local strains of red clover, as well as in two populations of wild red clover, was lower than in cv. Hermes II. This could indicate that a natural selection for root rot resistance can occur in red clover.
The influence of harvest maturity, calcium concentration and storage conditions on the keeping quality of Spartan apples grown in England
Authors: STOW J. , PERRING M. A. , JOHNSON D. S. 
Published: February 2008

SUMMARYSpartan apples from several commercial orchards were stored in three successive years. The principal physiological disorders that developed were scald and core rowning. These disorders were minimised by picking at the end of September and storing in either 2% O2 or 2% CO2+ 2% O2 at 1.5°C. Fruit calcium concentrations were usually high enough to avoid flesh breakdown but could be increased without risk of skin damage by dipping in a 2% solution of calcium chloride.It was concluded that storage of Spartan for up to 9 months is possible provided that fruit calcium concentrations are adequate and that picking date and storage conditions are optimised.
Variation in embryo size of inbred lines of carrot
Authors: DOWKER B. D. , GRAY D. 
Published: February 2008

SUMMARYMean embryo lengths and coefficients of variation (CVs) of embryo length of inbred carrot lines differed between years but not between the two sets of inbreds tested nor between male‐sterile and maintainer lines. Estimates of CVs were of similar magnitude to those previously obtained for experimental and commercial open‐pollinated seed lots, but estimates of mean embryo length were lower. Thus greater genetic uniformity did not lead to lower CVs of embryo size of the inbreds.
Genetic control of green curd colour in cauliflower
Authors: CRISP P. , ANGELL S. M. 
Published: February 2008

SUMMARYA genetic model was fitted to observed curd colours in a segregating cauliflower population derived from crosses between white and green curded types. The model was of a gene (Wi wi) giving white dominant over yellow, and an independent codominant gene (gr1 gr2) for green‐ness.
Effects of bendiocarb and diflubenzuron on mushroom cropping
Authors: WHITE P. F. 
Published: February 2008

SUMMARYWhen mixed into the casing or compost layers of a mushroom bed in the absence of pests, bendiocarb decreased yield and number of mushrooms according to concentration. The most severe effects were on mushroom number at the two highest rates used (100 and 1000 μg/g), and there were large increases in mushroom size. Effects of bendiocarb incorporation in the compost diminished with time, and there was partial compensation in yield and numbers at the fourth flush. The action of bendiocarb persisted when it was mixed into the casing.Diflubenzuron showed some opposite effects at lower concentrations. When either mixed into, or drenched onto the casing at the commercial rate (30 μg/g), yield and size were both increased and the timing of the flushes was unaffected. At the two higher concentrations (180 and 1080 μg/g), reductions in yield and number and an increase in mushroom size were shown. However, these effects became more severe with time, especially those on mushroom number, possibly due to the accumulation of a toxic breakdown product.
Effects of permethrin sprays on the mite fauna of apple orchards
Authors: KAPETANAKIS E. G. , WARMAN T. M. , CRANHAM J. E. 
Published: February 2008

SUMMARYIn two apple orchard trials, single high volume sprays of 25–50 mg permethrin/ litre greatly reduced numbers of the phytosend predatory mite Typhlodromus pyri whether the spray was timed pre‐bloom at growth stages from ‘bud‐burst’ to ‘late green cluster’ or post‐bloom in June. At ‘bud‐burst’T. pyri were partially protected in hibernating sites on the bark, but the lethal effect of the spray was only delayed; no appreciable selectivity could be obtained by this early timing. Bioassays showed that the persistent toxicity of permethrin residues on bark or on leaves declined to a low level within 20 days, and was related to the decline in residue levels determined by G.C. analyses. Residues were detectable for 3 months or longer. Resurgence of spider mites, Panonychus ulmi, occurred within 2 months after all spray timings, and effective predation by T. pyri was only fully re‐establised after several months. In one trial, apple rust mite, Aculus schlechtendali also increased when T. pyri was reduced by spraying. Tydeid mites were killed by permethrin.
Transmission characteristics and some other properties of bean yellow vein‐banding virus, and its association with pea enation
Authors: Virus Mosaic , COCKBAIN A. J. , JONES P. , WOODS R. D. 
Published: February 2008

SUMMARYBean yellow vein‐banding virus (BYVBV) has been found occasionally in mixed infection with pea enation mosaic virus (PEMV) in spring‐sown field beans (Vicia faba minor) in southern England. Glasshouse tests confirmed that, like PEMV, BYVBV is transmissible by manual inoculation and by aphids in the persistent manner. However, BYVBV can be transmitted by aphids only from plants that are also infected with a helper virus, usually PEMV. Thus after separation from PEMV by passage through Phaseolus vulgaris it was no longer aphid‐transmissible. It became aphid‐transmissible again only after re‐mixing in plants with PEMV or with a substitute helper, bean leaf roll virus (BLRV). It was not transmitted by aphids that fed sequentially on plants singly infected with PEMV and BYVBV. Thus the interaction between BYVBV and PEMV (or BLRV) that enables BYVBV to be transmitted by aphids seems to occur only in doubly infected plants. However, it was not transmitted by aphids from plants doubly infected with BYVBV and broad bean wilt virus (BBWV). BYVBV and PEMV were transmitted more readily by Acyrthosiphon pisum than by Myzus persicae; neither virus was transmitted by Aphis fabae.Phenol extracts of BYVBV‐infected leaves were more infective than phosphate buffer or bentonite‐clarified extracts and were sometimes infective when diluted to 1/1000. The infectivity of BYVBV in phosphate buffer extracts of leaves singly infected with BYVBV, unlike that in extracts of leaves doubly infected with BYVBV and PEMV (or BLRV), was destroyed by treatment with organic solvents. BYVBV infected 11 of 28 plant species that were inoculated with phenol extracts; seven of the infected species were legumes. No transmission of BYVBV was detected through seed harvested from infected field bean plants. Isometric particles c. 30 nm in diameter were seen in extracts of plants doubly infected with BYVBV and PEMV but not in extracts of plants infected with BYVBV alone. Leaves of plants infected with BYVBV, alone or with PEMV, contained membrane‐bound structures c. 50–90 nm in diameter associated with the tonoplast in cell vacuoles. These structures were not found in healthy leaves.BYVBV has several properties in common with other known aphid‐borne viruses that are helper‐dependent and transmitted in a persistent manner. Possibly, as suggested for some of them, aphid transmission of BYVBV depends on the coating of its nucleic acid with helper virus coat protein.
Studies on melon necrotic spot virus disease of cucumber and on the control of the fungus vector (Olpidium radicale)
Authors: TOMLINSON J. A. , THOMAS B. J. 
Published: February 2008

SUMMARYMelon necrotic leaf spot virus (MNSV) caused a major outbreak of a leaf necrosis disease of hydroponically‐grown cucumber plants at Humberside in 1983. The virus had c. 33 nm diam. particles which reacted serologically with MNSV antiserum of Dutch or American origin. Virus particles, which contained a single polypeptide (mol. wt 45 × 103) and a presumed RNA species (mol. wt 1.5 × 106), had a sedimentation coefficient (s20.w) of 134 S and a buoyant density in caesium chloride of 1.35 g/cm3. The virus was mechanically transmissible, confined to species of Cucurbitaceae, transmitted by zoospores of Olpidium radicale and retained in the resting spores of the fungus. MNSV is thus both water‐borne and soil‐borne. O. radicale zoospores were killed in <5 min in suspensions containing 20 μg/ml of the surfactant Agral (alkyl phenol ethylene oxide). The disease did not reappear in 1984 when the cucumber crops were fed with nutrients containing 20μg/ml Agral.
The effect of resistant potato cultivars on a field population of Globodera pallida Pa2 over three years of cropping
Authors: ANDERSON J. A. D. 
Published: February 2008

SUMMARYSix potato cultivars with different levels of resistance to the white potato cyst nematode (PCN) Globodera pallida Pa2 were grown for three seasons in field plots to which G. pallida Pa2 cysts had been introduced earlier. There were two planting times, corresponding to early and maincrop commercial planting times, and two initial PCN population densities, high and low.The effect of cultivar on PCN population density was far greater than the effect of planting time or initial nematode population. The final PCN populations for the cultivars Ilam Hardy, Wha, 4696A(2), Sovereign, D40/6 and V390 were 151, 74, 27, 1.4, 0.2 and 0.06 eggs per g of soil respectively.It is concluded that resistant potato cultivars can be very effective in controlling G. pallida Pa2 in the field.
The effect of Heterodera avenae, on the root system of susceptible and resistant oat seedlings
Authors: RAWSTHORNE DENISE , HAGUE N. G. M. 
Published: February 2008

SUMMARYThe effects of invasion by the cereal cyst nematode, Heterodera avenae, on the root growth of susceptible and resistant oat seedlings were similar. Nematode invasion directly inhibited root extension and lateral root production, which was dependent upon the developmental status of the invaded root tissue and the nematode density cm‐1 root. Both responses are caused by mechanical damage due to nematode invasion leading to decreased top growth in the host. Reduced root development, decreased efficiency of water and nutrient uptake in invaded plants being indirect effects of nematode invasion.
Superoxide dismutase polymorphism in field populations of the potato cyst nematodes Globodera rostochiensis and G. pallida
Authors: FOX P. C. , FINNEMORE T. W. , ATKINSON H. J. 
Published: February 2008

SUMMARYSuperoxide dismutase (SoDase) polymorphism in reference populations of potato cyst nematodes (PCN) was studied by isoelectric focusing and compared with the banding pattern obtained from 26 English field populations of PCN. Qualitative and quantitative differences were found between the reference populations: a band detected only in the G. rostochiensis Ro4 and Ro5 reference populations was found in four field populations of varying pathotype composition and two field populations of G. rostochiensis Rol possessed extra bands that were not detected in the other field populations. Analysis of the band differences showed little correlation between pathotype and banding pattern in the field populations.
The relationship between the rate of entry of ioxynil and effects on photosynthesis in normal and drought‐stressed Stellaria media
Authors: MERRITT C. R. 
Published: February 2008

SUMMARYThe entry of 14C‐labelled ioxynil octanoate into leaves of Stellaria media has been measured for plants grown in dry or moist soil. Of the total herbicide applied, 1–3% entered the leaf by 24 h and 2–5% by 72 h after treatment. Entry into moist‐grown plants proceeded at about twice the rate of that into drought‐stressed plants. Despite the limited rate of entry, the inhibitory action of ioxynil octanoate on photosynthetic carbon dioxide exchange was rapid, inhibition within 24 h reaching 70–90% in moist‐grown plants, and 30–70% in dry‐grown plants. Plants grown under moisture stress contained greater concentrations of the pigments chlorophyll a, carotene and lutein (a xanthophyll) than did moist‐grown plants, and ioxynil‐induced breakdown of these pigments was more rapid in moist‐grown plants. It is suggested that these factors contribute to the greater tolerance of drought‐stressed S. media to applications of ioxynil octanoate.The importance of continuous measurements of herbicide action is discussed in relation to the value and interpretation of 14C uptake data.