bluuebunny/crossref_metadata_2025_split huggingface dataset:
The infection of oranges by Trichoderma viride and mixed infection by Trichoderma viride and Penicillium digitatum
Authors: COLE A. L. J. , WOOD R. K. S. 
Published: February 2008

SUMMARY Trichoderma viride spores applied in water to apparently uninjured skin of oranges do not cause lesions. Adding orange juice, rind extract, citric acid or orange essential oil did not influence infection. Oranges became infected only when the stem‐end cuts or wounds deeper than 6 mm into oil vesicles were inoculated. Sound oranges in contact with decayed oranges did not become infected. Diphenyl‐impregnated wrappers reduced infection. A mixed inoculum of T. viride and Penicillium digitatum caused as fast rotting as P. digitatum, which caused faster rotting than T. viride alone. Lesions infected with P. digitatum could become infected by T. viride but those caused by T. viride did not become infected by P. digitatum. T. viride was antagonistic to P. digitatum in vivo and in vitro, possibly because it produces a heat‐labile diffusible substance toxic to P. digitatum.
Effects of water potential on the infection of potato tubers by Streptomyces scabies in soil
Authors: LEWIS B. G. 
Published: February 2008

SUMMARYWhen soil was maintained at a mean water potential (Slatyer & Taylor, 1960) of the order of ‐80 J kg‐1 at 25 cm depth throughout the growing period, much infection of potato tubers by Streptomyces scabies occurred, but when soil was irrigated to maintain it at potentials greater than ‐ 13 J kg‐1 at 10 cm depth infection was negligible. Until about 5 weeks after initiation, tubers were very susceptible to infection; irrigation during this period reduced scab considerably, but subsequent irrigation reduced it only slightly.At the low water potential, actinomycete populations on lenticels were high and bacterial populations low; these effects were reversed at the high water potential. Since also actinomycetes were more frequently isolated in the absence than in the presence of bacteria it was deduced that there was an interaction between these two groups. It is suggested that irrigation may decrease the population of S. scabies in tuber lenticels by increasing populations of bacteria antagonistic to it.
Distribution patterns of assimilated 14C in vegetative and reproductive shoots of Lolium perenne and L. temulentum
Authors: RYLE G. J. A. 
Published: February 2008

SUMMARYThe movement of 14C‐labelled assimilate to the terminal meristem, stem, mature leaves, tillers and roots was measured in Loliurn perenn and Lolium temulentum after exposure to 14C02 of the youngest fully‐expanded leaf and, on fewer occasions, the oldest healthy leaf on the main shoot.During early vegetative growth, the terminal meristem, tillers and roots received most of the 14C exported from the youngest leaf. As the shoot aged, more 14C was exported to the terminal meristem and tillers and less to roots. When the stem became a sizeable sink for 14C at the six‐leaf (L. temulentum) or eleven‐leaf (L. perenne) stage, less 14C moved to tillers and much less to roots. The terminal meristem continued to receive 14 at a steady rate throughout late vegetative growth.The transition from vegetative to reproductive growth in both species was marked by an abrupt increase in the export of 14C to stem from the upper leaf, but there was little change in the proportion of 14C which moved to the developing leaves and incipient inflorescence at the terminal meristem. At the same time, less 14C moved to tillers and much less to roots. Immediately before ear emergence, the export of 14C from the upper leaf (flag leaf) to the stem declined and the proportion moving to the ear increased, reaching a maximum of 55–75% as the ear emerged.The relative patterns of export of upper and lower leaves showed that while some 14 moved from each leaf to all meristems, the proximity of actively growing meristems appeared to be the main factor which determined the destination of most exported 14C. The distribution of 14C from upper and lower leaves was most alike in young vegetative plants of L. perenne. At later stages of development of both species, the terminal meristem and stem received most 1414C from the upper leaf, while roots and tillers received mos 1414C from the oldest leaf at the base of the shoot.
Resistance of sugar beet to the cyst‐nematode Heterodera schachtii Schm.
Authors: CURTIS GODFREY J. 
Published: February 2008

SUMMARYLines exhibiting heritable resistance and susceptibility to beet cyst nematode were selected from a heterogeneous cultivated variety of beet but no major gene resistance was detected although many hundreds of lines of wild and cultivated varieties were tested. Recurrent selection improved the resistance of one line, selected originally for yield and non‐bolting qualities, when progenies in each generation were compared with susceptible controls and with the original ancestral lines. Resistance was inherited by progenies from selections crossed with susceptible plants, but evidence of some reduction in resistance was detectable where fewer eelworms were available to invade from the soil. There was no evidence of heritable cytoplasmic influence on the resistance. Resistance is probably controlled by a polygene system in sugar beet, although immunity in Beta procumbens and B. webbiana and near‐immunity in B. patellaris suggest that in other species of Beta major gene resistance may occur.
Studies on the seed transmission of cucumber mosaic virus in chickweed (Stellaria media) in relation to the ecology of the virus
Authors: TOMLINSON J. A. , CARTER ANNE L. 
Published: February 2008

SUMMARYCucumber mosaic virus (CMV) was transmitted in the seed of infected Stellaria media plants. The rate of seed transmission varied both in manually infected plants (3–21%) and in plants grown from infected seed (21–40%). In naturally infected plants the rates of transmission found were 4–29%.Seeds recovered from field soil carried 4–5% infection and in infected seed placed in the soil the virus persisted for at least 5 months.Seed transmission of CMV also occurred in infected Lamium purpureum (4%), Cerastium holosteoides (2%) and Spergula arvensis (2%) but it could not be demonstrated in six other more common weed species in five botanical families.Seed transmission in Stellaria media occurred with a British (W) and an American (Y) strain of CMV. The virus was shown to occur in S. media pollen.The importance of CMV‐infected S. media seed in the soil in relation to the epidemiology of the virus is discussed.
Potato coiled sprout in relation to seed tuber storage treatment and to infection by Verticillium nubilum Pethybr
Authors: ALI M. A. , LENNARD J. H. , BOYD A. E. W. 
Published: February 2008

SUMMARYInoculation of seed potato tubes with Verticillium nubilum produced infection on the underground stem bases to subsequent growth in the form of brown lesions, often accompanied by longitudinal or transverse cracking. Some inoculation tests provided further evidence of a causal relationship between infection with V. nubilum and coiled sprout, but it was not possible to define the conditions in which the fungus gave rise to coiling.Seed tubers sprouted in light before planting produced more coiling than unsprouted or desprouted tubers. Sprouting had this effect whether V. numbilum was present or not and coiling induced by sprouting and that induced by V. nubilum occurred independently. The increased coiling of stem bases from sprouted tubers was often accompanied by fasciation, whereas this symptom was not usually associated with the coiling from unsprouted or desprouted seed tubers inoculated with the fungus. Brown lesions associated with V. nubilum were readily distinguishable from those of Rhizoctonia solani but not from those caused by Oospora pustulans. Neither of these fungi was found to cause coiling.Different varieties of potatoes showed differences in the incidence of coiling in response to sprouting treatment. There was no apparent differences in varietal response to infection by V. nubilum.
Air movement near windbreaks and a hypothesis of the mechanism of the accumulation of airborne insects
Authors: LEWIS T. , DIBLEY G. C. 
Published: February 2008

SUMMARYDifferent components of wind were measured to leeward of artificial windbreaks to show which most affected accumulations of airborne insects there. Horizontal motion was the most important. Accumulations of small airborne insects in sheltered places are probably caused when the insects are diffused or convected into the recirculating air behind barriers. The concentrations likely to occur theoretically in this way were compared with concentrations measured in the field.
The control of paedogenetic cecid larvae in mushroom beds by the use of thionazin
Authors: WYATT I. J. 
Published: February 2008

SUMMARYThionazin incorporated in the casing layer of mushroom beds was shown to be highly phytotoxic even at 5 ppm, but when incorporated in compost it caused little phytotoxicity up to 20 ppm. A rate of 8 ppm gave satisfactory control of Heteropeza pygmaea Winnertz (Dipt.: Cecidomyiidae), but was less suitable against Mycophila speyeri (Barnes), for which the use of γ‐BHC in the casing should be retained. A severe infestation of M. speyeri was shown to depress the total yield of mushrooms by 59% and the saleable yield by 87%.
The toxicity of certain herbicides to hens' eggs assessed by the egg‐injection technique
Authors: DUNACHIE J. F. , FLETCHER W. W. 
Published: February 2008

SUMMARYTwenty‐five herbicides have been tested for their toxicity to hen embryos at various concentrations, using an egg‐injection technique. Paraquat was the most toxic, giving a complete kill at a concentration in the egg of 0.3 ppm; two other compounds related to it were almost completely lethal at 10 ppm. Of the other compounds, seventeen had little or no effect at 50 ppm and of these eight had none at 100 ppm. Except for feather blanching, caused by some of the substituted phenoxy‐acids, no teratogenic effects were found.
The effect of small doses of nematicides on migratory root‐parasitic nematodes and on the growth of sugar beet and barley in sandy soils
Authors: WHITEHEAD A. G. , TITE D. J. , FRASER JANET E. 
Published: February 2008

SUMMARYSmaller amounts of D–D (6–12 gal/acre) (68–135 1/ha) or ethylene dibromide (9 gal/acre) (100 1/ha) than are customarily used to disinfest field soils killed many root‐parasitic nematodes (Trichodorus, Pratylenchus, Tylenchorhynchus and Longidorus attenuatus) when injected 6–8 in (15–20 cm) deep during early autumn in rows 10 in (25 cm) apart in well‐drained sandy soils. They also increased the yield of sugar beet grown in fields infested with Trichodorus or Longidorus attenuatus, without affecting sugar percentage or juice purity of the roots, and in some places increased the yield of barley grown after the beet. D–D was much less effective when injected 8–12 in deep during late autumn or winter. Increasing nitrogen dressings to the seedbed from 1·5 to 3 cwt/acre (188 to 376 kg/ha) increased sugar beet yield in one field, decreased it in another and decreased juice purity in both. In two other experiments extra nitrogen did not affect sugar beet yield.Even smaller amounts of the nematicides ‘placed’ in the rows, before or after sowing sugar beet in them, killed many of the nematodes and also increased sugar yield. Phytotoxic nematicides can be placed in the rows during autumn, winter or spring but placement is simpler during spring, when the treated rows are indicated by the position of the marks of the tractor wheels left when the nematicide was applied. When applied during autumn or winter, the rows need to be indicated by drilling wheat or grass.
The effect of light wavelength on the susceptibility of plants to virus infection
Authors: COAST E. M. , CHANT S. R. 
Published: February 2008

SUMMARYPlants exposed for 24–72 h to light of different wavelengths differed in their subsequent susceptibility to virus infection. French bean leaves were less susceptible to infection by tobacco necrosis virus and Nicotiana glutinosa leaves were less susceptible to infection by tobacco mosaic virus when previously exposed to blue or red light than when exposed to green light. These differences were most pronounced at low energy levels. Leaves exposed to each kind of light were less susceptible than those kept in darkness.
Chemical treatment of cereal seed in relation to plant vigour and control of soil fungi
Authors: RAWLINSON C. J. , COLHOUN J. 
Published: February 2008

SUMMARYTreating oat seeds not contaminated with any known pathogen of this crop with an organo‐mercury preparation (Ceresan) increased seedling vigour only when they were grown in natural or simulated winter conditions with periods of frost. This beneficial effect on vigour was largely confined to seedlings and young plants.The fungicide protected the mesocotyls from contamination or invasion by certain soil‐borne fungi normally regarded as saprophytes. Cylindrocarpon radicicola and Fusarium sambucinum were closely associated with discoloured mesocotyls bearing lesions and reduced vigour of untreated plants. Protection from such fungi enabled mesocotyls to grow thicker, and, when seedlings were grown in unsterilised soil and exposed to frost, reduced the number with lesions or discolouration. Thus the ability of the saprophytic soil‐borne fungi to cause damage seems to be influenced by environmental conditions.
Studies on the fate in plants of ethylenebisdithiocarbamate fungicides and their decomposition products
Authors: VONK J. W. , SIJPESTEIJN A. KAARS 
Published: February 2008

SUMMARYA study was made of the fate in plants of ethylenebisdithiocarbamate fungicides and their decomposition products. Nabam (disodium ethylenebisdithiocarbamate) is known to decompose rapidly in aqueous environment, mainly to ethylenethiourea and ethylenethiuram monosulphide. Only ethylenethiourea was taken up by the roots and leaves of cucumber seedlings and by the roots of wheat seedlings. It was converted to a slight extent into an unknown compound.The fate of maneb (manganese ethylenebisdithiocarbamate) and zineb (zinc ethylenebisdithiocarbamate) does not differ essentially from the fate of nabam.
Quantities and qualities of leaf protein concentrates from wild species and crop species grown under controlled conditions
Authors: LEXANDER K. , CARLSSON R. , SCHALÉN V. , SIMONSSON Å. , LUNDBORG T. 
Published: February 2008

SUMMARYThe amount of protein produced per m2 by plants cultivated in soil in a greenhouse at three levels of fertilizer application, for c. 10 weeks, was estimated by Kjeldahl analysis of the TCA‐insoluble fraction of freeze‐dried material. The quantity of protein extractable for production of leaf protein concentrates was determined by Kjeldahl analysis of non‐dried but frozen material after disintegration with a meat mincer and an Ultra‐Turrax homogenizer, hydraulic pressing and filtration, and protein precipitation by heat (in two steps) or by TCA. The precipitability was also studied by Folin‐Ciocalteu determination of protein. The quality of each protein concentrate was studied by determining nitrogen content (Kjeldahl), digestibility by pepsin and by pepsin + pancreatin, nutritive value in Tetrahymena tests, and lysine and methionine content (analysed microbiologically). Twenty‐nine species and varieties were investigated. Large differences between species were found in all the properties studied. Protein extractability varied between 5 and 80%, while the extractable protein produced per m2 ranged between 1 and 140 g. The highest digestibility was two to three times greater than the lowest one. In the most digestible species (Amaranthus caudatus), 82% of the N of the chloroplastic protein concentrate was digested by pepsin + pancreatin. The Tetrahymena value generally ranged between 40 and 98, whereas casein gave values of about 75. The lysine content always exceeded the FAO minimum. The methionine content of most species varied between 2.0 and 2.2% of the hydrolyzed protein. Amaranthus caudatus and the Chenopodiaceae investigated were the most suitable species for large‐scale production of leaf protein concentrates for human consumption because they gave high yield of extractable protein and high‐quality protein concentrates.
Analysis of differences in yield between six sugar‐beet varieties
Authors: LOACH K. 
Published: February 2008

SUMMARYThe basis of differences in yield between six sugar‐beet varieties was studied by measuring the changes in their leaf areas and dry weights throughout the season. Initially, dry‐matter production was determined by the rate at which leaf area developed, but this effect did not persist to final harvest. Varieties that maintained the largest net‐assimilation rates in September produced largest sugar yields. Characteristically, these varieties showed the smallest losses in lamina dry weight through leaf senescence late in the season, and put the largest proportion of their photosynthate into root production.
Relative ability of two strains of Pucccinia graminis tritici to survive when mixed
Authors: OGLE HELEN J. , BROWN J. F. 
Published: February 2008

SUMMARYThe relationship between relative survival ability and the number of genes for virulence in two strains of Puccinia graminis tritici was investigated using a differential variety to determine the proportion of each race in the mixture. The strain with the widest host range (21 Anz‐2,3,7) became predominant after a number of uredial generations, regardless of its proportion in the original inoculum mixture. However, despite the higher relative survival ability of strain 21 Anz‐2,3,7, strain 21 Anz‐2,7 persisted at c. 1% frequency after four successive uredial generations. The longer the period between successive inoculations, the more rapidly strain 21 Anz‐2,3,7 became predominant in the mixture. The variety on which the mixture was cultured did not influence the relative survival ability of the two strains.
Infection periods in relation to the natural development of hop downy mildew (Pseudoperonospora humuli)
Authors: ROYLE D. J. 
Published: February 2008

SUMMARYThe relationships between temperature and surface wetness and subsequent infection of hop tissues by P. humuli were examined on potted plants and detached leaves kept in temperature‐controlled growth rooms. Periods of wetness which would just allow leaf infection ranged from 1 1/2 h at 30d̀ to 24 h at 5d̀. The corresponding ranges for shoots were: light infection, 3 h at 19–23d̀ to 6 h at 8–10d̀; severe infection, 4 h at 19–23d̀ to 8 h at 12–13d̀. These data were used to relate the development of downy mildew in an unsprayed hop garden during 1967 and 1968 to periods with temperature/surface wetness suitable for minimum (minor infection periods) and severe infection (major infection periods).In 1967 a sudden outbreak of infected basal shoots (spikes) was related to an isolated major infection period. By contrast, early in 1968, major shoot infection periods did not arise and spikes appeared gradually in response to a succession of minor infection periods. More spikes were formed in 196 than in 1967; this was not related to the incidence of infection periods but probably reflected the relatively higher concentrations of airborne sporangia early in 1968.In both years outbreaks of leaf and lateral shoot infection could be traced to major infection periods caused by rain; sudden disease increases again originated from isolated infection periods. There was a close similarity between the incubation period for each principal disease outbreak and that expected from growth‐room experiments. Major infection periods occurred more frequently at the end of June 1968, resulting in a higher final concentration of diseased tissue than in 1967. Predicted major infection periods failed to induce large disease increases when dew alone provided wetness or when no airborne sporangia could be detected.
The susceptibility of verieties of carrot to attack by the aphid, Cavariella aegopodii (Scop.)
Authors: DUNN J. A. 
Published: February 2008

SUMMARYRepresentative varieties from the carrot groups, Chantenay, Nantes, Berlikum and Autumn King, together with three Australian varieties, were tested for susceptibility to attack by Cavariella aegopodii (Scop.). Tests were done at different average temperatures in cages in the insectary by inoculating plants with apterous forms of the aphid and frequently checking the extent of colonization over the next 20 or so days. Field sowings of the varieties were also made in each of 3 years, and over the immigration period and the subsequent population development and decline of the aphid, regular counts were made of the alates settling on a standard number of plants of each variety, and of the progeny produced. Some differences in susceptibility to attack were noted but, because the main development of C. aegopodii on field carrots is limited to two generations, these were too small to be of practical value in terms of plant resistance, and on all varieties large numbers of aphids could be found. Although the Australian variety Osborne Park was thought to have some resistance to C. aegopodii in New Zealand, it proved to be of average susceptibility. Autumn King appeared to be the most aphidsusceptible variety but could be tolerant to motley dwarf virus. Nantes was not as tolerant to aphid attack as the other varieties and as it is also intolerant to motley dwarf virus, might suffer much damage in years favouring aphid expansion. Berlikum seemed to be the least susceptible to aphid attack. Temperature differences affected expressions of varietal susceptibility less than they affected aphid fecundity and a few degrees increase in temperature more than halved the number of young born in a generation.
The action of some systemic aphicides on the nymphs of Anthocoris nemorum (L.) and A. confusus Reut
Authors: ELLIOTT W. M. 
Published: February 2008

SUMMARYThe aphicides phorate, dimethoate and menazon were compared to elucidate the different pathways by which they can affect Anthocoris nymphs and their aphid prey.When nymphs were caged in contact with deposits on bean leaves phorate and dimethoate had contact LC 50s of 20 and 3 μg/cm2 respectively to Anthocoris nemorum and 46 and 6 μg/cm2 to A. confusus. When the nymphs were confined on treated leaves on the opposite surface to the deposits, neither phorate nor dimethoate killed them. Menazon did not kill anthocorids at any dosage. All three aphicides killed over 50% of Acyrthosiphon pisum (Kalt.) on bean leaves at 1.6 μg/cm2 whether the aphids were on the treated or untreated surface.Experiments with 35S‐labelled phorate showed that anthocorids confined on phorate‐treated bean plants, with or without insect food, accumulated the insecticide or its labelled derivatives. In field experiments in which A. nemorum were caged on plants treated with phorate, many were killed on young newly treated plants but not on older plants. A. confusus was relatively unaffected.Anthocorids were reared from 2nd‐instar nymphs to adults on aphids killed systemically with phorate, dimethoate or menazon without ill effects, despite evidence that 35S‐labelled phorate was ingested from the aphids and excreted in the faeces.In the field, fewer large A. nemorum nymphs were found in August in plots of tick beans treated with phorate granules at 6 lb/acre (6.7 kg/ha) when sown, than in plots treated at 1.5 lb/acre (1.7 kg/ha) with phorate or menazon or untreated plots.