bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of cereal nematode populations and cereal yields under continuous or intensive culture
Authors: GAIR R. , MATHIAS P. L. , HARVEY P. N. 
Published: February 2008

SUMMARYIn a field experiment on infested sandland from 1955 to 1967, numbers of Heterodera avenae increased only in 1957 and then decreased under both continuous and rotational spring oats (1955‐62) and subsequently under spring barley (1963‐67). Fluctuations in numbers of Pratylenchus neglectus and Trichodorus primitivus were recorded from 1963 to 1967. Cereal grain yields were generally unsatisfactory, but were consistently higher for cereals grown in rotation rather than continuously. Extra nitrogen fertilizer gave slightly improved yields with higher post‐cropping numbers of H. avenae.
The effect of sowing date and plant density on barley
Authors: KIRBY E. J. M. 
Published: February 2008

SUMMARYProctor and Maris Puma barleys were sown in October, early March, and late April at 50, 100, 200, 400 and 800 plants per m2and at low and high fertilizer levels.Shoot dry matter and grain dry matter showed no significant response to density for the first two sowings, but increased with increasing density in the last sowing. In all sowings the ear number per m2rose with increasing density, and grain number per ear fell, and there were only small interactions between density and sowing date, but the effect on weight per grain differed markedly in the last sowing from that in the first two sowings. Nitrogen concentration per cent of dry matter in the grain and in the straw showed little response to density and the values for both grain and straw were highest in the last sowing. Nitrogen content per m2for both shoot and grain at first rose, and then fell with increasing density. The maximum amount of nitrogen per m2was found at about 100 plants per m2in the early sowings, and at 400 plants per m2in the last sowing. The nitrogen data indicated a loss of nitrogen from the plant at high densities.
Seasonal variations in the sporulating capacity of the fungus causing coffee berry disease
Authors: NUTMAN F. J. , ROBERTS F. M. , FREEMAN G. H. 
Published: February 2008

SUMMARYAssessments of the sporulating capacity of Colletotrichum coffeanum Noack in coffee branches (defined as the number of conidia produced per cm2per hour under optimum conditions) have been made for 4 years on a number of different sites in Kenya. An annual rhythm is evident which is essentially similar on all sites and for all years. Early‐season and late‐season peaks are separated by a mid‐season trough. The change in sporulating capacity at any time is negatively correlated with wetness in the immediately preceding period, and daily rainfall can be used as a measure of wetness. The position of the peaks and their duration is defined by the timing of the onset and the duration of the monsoon rains, and is, therefore, subject to considerable variation.It is suggested that the correct timing of control sprays might be related to the form of the annual curve of sporulating capacity, and be predictable from rainfall records.
Effects of spraying plants with suspensions of inert dusts*
Authors: EVELING D. W. 
Published: February 2008

SUMMARYIn an examination of possible harmful effects to plants caused by spraying leaves with inert dust suspensions it was shown that Stockalite (kaolin), talc, silica or Tiona W.D. (titanium oxide), suspended in water and sprayed on excised leaves of three species, significantly (P≯ 0·05) increased water loss and penetration of gaseous ammonia; these increases were not caused by soluble chemicals in the sprays, but depended on intimate contact of the dust particles with the epidermis. With a given dust, epidermal permeability increased with increasing concentration and with decreasing size of particles. The increased permeability persisted for at least 4 weeks and was unaltered by partial removal of deposits; deposits on bean leaves caused more visible damage in dry than in humid air. Water losses from sprayed adaxial and abaxial leaf surfaces were similar, but more was lost when deposits dried on turgid leaves than when they dried on flaccid ones.Spraying potted Coleus plants with a Stockalite suspension increased transpiration and, in one test, decreased the fresh weight of the Coleus shoots.
Hollow heart and poor stands of peas (Pisum sativum L.)
Authors: HEYDECKER W. , KOHISTANI M. R. 
Published: February 2008

SUMMARYLaboratory and field experiments on three seed lots of peas have shown that the incidence of the physiological disorder, hollow heart, depends largely on the seed environment. Seeds subjected to excessive watering showed little hollow heart: insufficient watering favoured hollow heart development.Hollow heart did not directly affect germination and seedling growth but led to rotting of the cotyledons, thus predisposing seedlings to fungus infection.Over‐watering and over‐firming of soil can severely affect pea stands irrespective of the incidence of hollow heart, and a seed lot susceptible to hollow heart is not necessarily the most susceptible to fungus infection and vice versa.
Persistent effects of seedling treatment on growth of sugar beet in pots
Authors: FRENCH S. A. W. , HUMPHRIES E. C. 
Published: February 2008

SUMMARYFurther evidence is provided that the environment of sugar‐beet seedlings, or growth substances applied to seedlings, continues to influence growth when the plants are later in other environments.Sugar‐beet seeds were germinated at 20 °C in 8, 16 or 24 h photoperiods of constant light intensity, i.e. with different amounts of total radiation. When the seedlings had two leaves (15–18 days old) they were transferred to large pots in the glasshouse. Some seedlings were treated with (2‐chloroethyltrimethylammonium chloride) either sprayed on the leaves or applied to the soil, at different times.The treatments affected areas of individual leaves throughout the growing period; plants raised in 24 h photoperiod had the largest leaves, and those in 8 h photoperiod the smallest. Consequently, 24 h plants had most dry matter and 8 h plants least. Plants given most radiation produced leaves fastest and CCC applied early increased the rate, but as the leaves were smaller, except late in 1967, and died sooner, the leaf area duration was less and so yields were less. CCC applied later did not affect leaf production. There was no interaction between amount of radiation and CCC treatment.Twenty‐four hour plants had the greatest net assimilation rate (E) early. CCC decreasedEearly, but increased it later and more when sprayed on the leaves than when applied to the soil.Some factor, possibly pot size, eventually restricted growth and probably diminished the effect of the treatments applied to the seedlings.
Resistance of rape (Brassica napus) to attack by the cabbage aphid (Brevicoryne brassicae L.)
Authors: DUNN J. A. , Kempton D. P. H. 
Published: February 2008

SUMMARYResistance to Brevicoryne brassicae L. attacks in a New Zealand variety of forage rape resulted from a combination of host non–preference and antibiosis. Using clonal plant material obtained from cuttings, only half the numbers of immigrant alate cabbage aphids that settled to reproduce on the susceptible rape were to be found on the resistant rape. The reproduction rate of these alates was about 12 % slower on the resistant plants than on the susceptibles and the young took about 13% longer to mature. Antibiosis then shortened the reproductive life of the apterae by one‐third, reduced their fecundity by nearly 50 % and caused 40% mortality in their progeny. The over‐all effect of this was considerable and under conditions specified in the text could result in the population on the resistant plants being about one‐eighth that on the susceptible plants in under 1 month. The resistant plants lost their resistance on flowering and became normally susceptible to cabbage aphid attack. With maturity, however, the B. brassicae‐resistant plants became slightly resistant to Myzus persicae.
Eggplant mosaic virus, and its relationship to Andean potato latent virus
Authors: GIBBS A. J. , HARRISON B. D. 
Published: February 2008

SUMMARYEggplant mosaic virus (EMV), obtained from Solanum melongena L. from Trinidad, is readily transmitted by inoculation of sap to several solanaceous and a few non‐solanaceous plant species. Purified preparations of EMV contain isometric particles 30 nm in diameter, and with sedimentation co efficients of either 111 or 53 S. The particles have thirty‐two major morphological subunits. EMV is closely serologically related to Andean potato latent virus and has a similar host range, but is more virulent. Also, whereas EMV accumulates fastest in Nicotiana clevelandii leaves at 20–24 °C, Andean potato latent virus accumulates fastest at 15 °C, and fails to attain a serologically detectable concentration at 24 °C. A few symptomatologically or serologically distinguishable strains of EMV were obtained. EMV has properties typical of viruses of the Andean potato latent subgroup of the turnip yellow mosaic group of viruses, and its present cryptogram is */*:*/*:S/S:S/Cl.
The location of raspberry ringspot and tomato black ring viruses in the nematode vector, Longidorus elongatus (de Man)
Authors: TAYLOR C. E. , ROBERTSON W. M. 
Published: February 2008

SUMMARYElectron microscopy of thin sections of Longidorus elongatus (de Man) fed on plants infected with raspberry ringspot and tomato black ring viruses showed virus‐like particles in the lumen of the buccal capsule and in the space between the stylet and the guiding sheath. In sections of L. elongatus fed on plants infected with arabis mosaic virus, which it does not normally transmit, a few virus particles were seen in the buccal capsule but none was associated with the stylet guiding sheath. It is suggested that the association of virus particles with the cuticular guiding sheath is an explanation of the specificity of virus transmission evident in L. elongatus.
The control of fungal seed–borne diseases by means of a thiram seed soak
Authors: MAUDE R. B. , VIZOR ANN S. , SHURING CATRIONA G. 
Published: February 2008

SUMMARYA method of soaking seeds in an 0·2% aqueous suspension of thiram for 24 h at 30 °C, which had previously been shown to eradicate infection by several fungi, was tested against a further thirteen seed‐borne pathogens. Eleven of these were completely controlled, one was almost completely controlled and one was not adequately controlled by the treatment.The thiram soak treatment was much more effective than dust treatments with fungicides for the control of many internal fungal pathogens. It was also generally more effective and less damaging than hot‐water treatment.The ways of applying the method commercially have been investigated and it is being adopted for the treatment of celery, brassicas and red beet.
Production of volatile alkyl sulphides by microbial degradation of synthetic alliin and alliin‐like compounds, in relation to germination of sclerotia of Sclerotium cepivorum Berk
Authors: KING J. E. , COLEY‐SMITH J. R. 
Published: February 2008

SUMMARYOnion distillands proved more stimulatory than distillates towards germination of sclerotia of Sclerotium cepivorum. Synthetic allylcysteine and n‐propylcysteine and their sulphoxides stimulated germination of sclerotia when added to soil. Solutions of these compounds in the presence of unsterile soil produced gaseous alkyl mercaptans, sulphides and disulphides which were detected by gas‐liquid chromatography and which stimulated sclerotial germination when drawn through soil containing sclerotia. No volatile sulphides were detected above autoclaved solutions but the atmosphere over propyl and allylcysteines was slightly stimulatory although the corresponding autoclaved sulphoxides showed no such activity. The gases above all four solutions sterilized by membrane‐filtration were not stimulatory. Six common soil bacteria were shown to be capable of degrading the synthetic precursors, causing the evolution of appropriate volatile alkyl sulphides.
The effects of formalin, nabam, irrigation and nitrogen on Heterodera avenae Woll., Ophiobolus graminis Sacc. and the growth of spring wheat
Authors: WILLIAMS T. D. 
Published: February 2008

SUMMARYIn 1964, nabam (sodium ethylene bisdithiocarbamate), water and three amounts of nitrogen fertilizer were applied to spring wheat on soil treated and untreated with formalin. The experiment lasted for 3 years during which there were eight different formalin, no–formalin sequences. The nabam and irrigation treatments were discontinued when it was found they did not affect the principal pathogens present, the cereal cyst nematode Heterodera avenae and the take–all fungus Ophiobolus graminis. Formalin increased grain and straw yields in the year in which it was applied but led to increased H. avenae populations which adversely affected the succeeding crop. Formalin controlled O. graminis in the year it was applied except on land treated for the first time in 1966. H. avenae seemed to be the main check to growth until about June, and O. graminis later. At the end of the experiment, total grain yields and nematode soil populations were greatest in the plots treated with formalin each year and least in those never treated with formalin. Yield loss from either O. graminis or H. avenae alone could not be assessed because formalin usually controlled both during the season in which it was applied and both were present in untreated plots. However, in 1965, some comparisons of the effects of each pathogen were possible when one occurred in the presence of differing amounts of the other. A doubling of total grain yield over 3 years was accompanied by an eightfold increase in H. avenae in sequences of continuous formalin or formalin 1964 and 1965, whereas yield increases caused by extra nitrogen were not matched by such a big increase in H. avenae. This suggests that formalin might be affecting H. avenae through factors other than increased plant size and vigour, which in themselves would tend to encourage larger nematode populations. In the absence of formalin, H. avenae soil populations either fell or failed to increase.
Effect of seedling treatment on growth and yield of sugar beet in the field
Authors: HUMPHRIES E. C. , FRENCH S. A. W. 
Published: February 2008

SUMMARYSugar‐beet seeds were germinated (1) in a growth cabinet at 20°C lit continuously by fluorescent tubes (L), (2) in a cabinet at 20°C lit by fluorescent tubes for 16 h/day (S), (3) in a cage with glass roof and open sides with natural illumination (N), or (4) in the open ground (D). The seedlings from the cabinets and cage were transplanted to the field when they had two true leaves. Samples were taken on six occasions during growth, and leaf areas and dry weights determined.There were no differences between treatments in total number of leaves produced or leaf area duration. Leaf area per plant increased fastest on L plants at first, but from mid‐June until end of July drilled plants had the largest leaf surface. From August onwards S plants had the largest area. Although treatment had little effect on growth of the tops, roots grew fastest throughout the season on the plants raised in growth cabinets and the final mean root dry weight of L and S plants was 39% greater than of N and D plants. Throughout the season L and S plants had a larger root:top ratio than plants raised in the cage or drilled directly in the field. The larger roots of plants raised in the cabinets evidently provided a larger sink for carbohydrate and increased the mean photosynthetic efficiency of the leaves over the whole season by 11 % and increased yield of roots by 6 tons/acre.
Studies on plant growth‐regulating substances. XXX. The plant growth‐regulating activity of substituted phenols
Authors: HARPER D. B. , WAIN R. L. 
Published: February 2008

SUMMARYThe growth‐regulating activity of a number of substituted monophenols and related compounds has been assessed in the wheat cylinder, pea segment, pea curvature and tomato‐leaf epinasty tests and the effect on activity of position, size and electronic nature of the substituents has been studied. The results indicate that, for high auxin activity, electron‐attracting substituents, having certain steric properties must be substituted in the 2‐ and 6‐positions. Furthermore, at least one of these ortho‐substituents must be capable of intramolecular bonding with the hydrogen of the phenolic hydroxyl group. Any substituent in the para‐position to the hydroxyl group leads to complete loss of activity and activity is reduced by meta‐substitution.This new group of phenolic plant growth regulators is considered in relation to other synthetic auxins from the viewpoints of structural requirements for activity and current theories on mode of action.
Methods of investigating populations of the take‐all fungus(Ophiobolus graminis)in soil
Authors: HORNBY D. 
Published: February 2008

SUMMARYAttempts to isolateOphiobolus graminisdirectly from infested soils failed, so host‐infection techniques were used to study soil‐borne populations of the fungus. Extracting organic debris from soils and grading it by wet sieving through standard meshes concentrated the fungus. Fractions were tested for infectivity either as layers in pots of sand or by packing into short lengths of polyvinyl chloride tubing, through which wheat seedlings were grown. Coarse debris (retained by 420 μ aperture sieves) was most infectious and usually caused lesions within 3 weeks; whole soil and especially fine debris (< 420 μ) caused fewer and less severe infections, which often became apparent only after 3 weeks. Slight infectivity of the sediment fractions was attributed to imperfect separation of debris. Soil sampled in crop or stubble rows caused more infections than soil from between rows.Usually seedling infection was made manifest by root lesions and runner hyphae, but these symptoms were not always plain or conclusive. Many seedling roots that rotted when kept moist and in the light produced perithecia within 6 weeks. Although perithecia formed on some roots where neither lesions nor hyphae were found, they did not form on all diseased roots. More needs to be known about the factors influencing perithecial formation before it can be used as a reliable confirmatory test.
The behaviour of potato mop‐top virus in soil, and evidence for its transmission by Spongospora subterranea (Wallr.) Lagerh.
Authors: JONES R. A. C. , HARRISON B. D. 
Published: February 2008

SUMMARYPotato mop‐top virus (PMTV) was best detected in field soils by air‐drying them for more than a week before remoistening and growing seedlings of Nicotiana tabacum or N. debneyi for a 6–10 week period. Infection of N. tabacum was assessed by inoculating sap from roots and shoots to Chenopodium amaranticolor. Similar inoculations from N. debneyi were far less convenient for detecting PMTV than recording leaf symptoms, but slightly more efficient.Air‐dry soil retained PMTV infectivity for 9 months, when passed through a 50 μ sieve or when diluted with 103 but not 104 parts of steamed soil. Tobacco seedlings were not infected when their roots were steeped in PMTV‐containing tobacco sap. Infective soils contained Spongospora subterranea, spore balls of which resisted air‐drying for more than a year and passed a 50 μ sieve. Roots of susceptible seedlings were infected with PMTV when exposed to spore balls of S. subterranea taken from powdery scabs on PMTV‐infected potato tubers, or to suspensions obtained by steeping, in nutrient solution, roots infected with virus‐carrying cultures of S. subterranea. Plants in several families were hosts of S. subterranea, but probabilities of infection when exposed to spore balls differed greatly between families and only species of Solanaceae were good hosts. The ten species infected with PMTV when grown in infective soil or when exposed to spore balls of S. subterranea taken from PMTV‐infected potato tubers are all members of this family. PMTV seems to be carried internally in S. subterranea spore balls and survived in them for at least a year.PMTV was transmitted by S. subterranea to Arran Pilot potato, causing yellow blotches in some leaves and spraing in many tubers. However, when newly infected with PMTV in the field, not all Arran Pilot tubers developed spraing. Also, although many spraing‐affected or symptomless but PMTV‐infected tubers carried PMTV‐containing spore balls of S. subterranea, powdery scabs were rarely found near the centres of the rings of primary spraing. PMTV became established in virus‐free soil when PMTV‐infected tubers carrying S. subterranea were planted as ‘seed’ but not when virus‐free tubers bearing powdery scabs were used. 5. subterranea seems the main, and possibly the only, vector of PMTV in the soils examined. S. subterranea did not transmit potato aucuba mosaic virus from potato to N. debneyi or Capsicum annuum.
Effects of soil fumigation on disease incidence, growth, and yield of spring wheat
Authors: EBBELS D. L. 
Published: February 2008

SUMMARYPlots were fumigated with various amounts of D‐D or 85% dazomet dust and sown with spring wheat given various amounts of nitrogenous fertilizer. Dazomet increased yield and decreased take‐all disease in the first crop after application, but increased the disease in the second crop. Although D‐D increased take‐all slightly, it increased yield in 1966, but in 1967 it decreased yield and its use was associated with a severe ear deformity. Fumigation had little effect on eyespot, sharp eyespot, root browning (Fusarium spp.), or browning root rot (Pythium spp.), but decreased nematode damage where nematodes were numerous.
Hot‐water treatment of seed as a method for decreasing the incidence of certain cotton and flax seedling diseases
Authors: ABD‐EL‐REHIM M. A. , MICHAIL S. H. , ELAROSI H. , KHAIRY ENAYAT A. 
Published: February 2008

SUMMARYImproved pathogen‐free seed germination and better seedling growth were obtained by hot‐water treatments at 60 °C for 10 min of seed of the cotton varieties Karnak and Ashmouni, and at 45 °C for 5 min of seed of the flax varieties Giza 4 and Baladi.These treatments also reduced pre‐ and post‐emergence losses due to Rhizoctonia solani and Fusarium oxysporum f.sp. vasinfectum in cotton, and to F. oxysporum f.sp. lini in flax, and resulted in better growth of the surviving plants.
Growth of Pseudomonas phaseolicola in susceptible and in resistant bean plants
Authors: OMER M. E. H. , WOOD R. K. S. 
Published: February 2008

SUMMARYRace 1 of Pseudomonas phaseolicola introduced into leaves of susceptible Canadian Wonder bean plants multiplied logarithmically for 3–5 days, reaching final populations about 105–106 times the original. In resistant Red Mexican, Race 1 multiplied less rapidly to give final populations about 102–103 times the original. Race 2 behaved in susceptible Red Mexican as did Race 1 in Canadian Wonder. Macroscopic symptoms appeared in leaves when bacterial numbers reached their maxima.When introduced into the cotyledonary node Race 1 moved more rapidly upwards than downwards, and more rapidly and farther in Canadian Wonder than in Red Mexican. But even in Canadian Wonder the bacterium appeared only sporadically above the node of the first compound leaf. It could be isolated only rarely from chlorotic haloes around necrotic areas in leaves, or from chlorotic leaves not carrying lesions.Fewer lesions developed and the bacteria multiplied less in older than in younger leaves.Addition of glucose and casein hydrolysate to inocula of Race 1, separately or together, had little effect on growth in Canadian Wonder or Red Mexican, and the bacterium grew equally well in extracts of susceptible and of resistant plants.Preinoculation of leaves with an avirulent race reduced the number of lesions caused by a virulent race inoculated later, and also reduced growth of this race in leaves of a susceptible variety.