bluuebunny/crossref_metadata_2025_split huggingface dataset:
An analysis of responses of resistant and of susceptible tomato plants to Verticillium infection
Authors: SINHA A. K. , WOOD R. K. S. 
Published: February 2008

SUMMARYComparative studies were made of the responses of resistant and of susceptible Gem tomato plants to infection by Verticillium albo‐atrum. When inoculated through roots, there were striking differences in their responses. In susceptible plants, the foliar symptoms and amount of mycelium in the stem increased rapidly for some time. Then the mycelium started to disappear from the stem; this was accompanied by a check to the normal progress of symptoms, and by the formation of tyloses. In resistant plants, a limited invasion of the root and lower stem was accompanied by rapid and extensive tylosis. The mycelium soon disappeared from the stem and the plant then recovered from the initially mild symptoms. There was an inverse relationship between the amount of mycelium and the extent of tylosis in infected plants. The growth of susceptible plants was markedly reduced by infection. Total leaf area was much less because the newly produced leaves did not expand normally. The root system in infected plants was smaller because there were many fewer tertiary roots. In resistant plants infection stimulated growth.Tomato cuttings inoculated with conidia reacted similarly to root‐inoculated plants. Hyphae grew well in the vascular system of susceptible cuttings whereas in resistant cuttings the pathogen started to grow but soon disappeared.Detached leaves of susceptible plants, inoculated through cut ends, wilted more than did leaves from resistant plants. It is suggested that resistance is mainly of the active type that develops after infection.
The nature and causes of annual fluctuations in numbers of Aphis fabae Scop. on field beans (Vicia faba)
Authors: WAY M. J. 
Published: February 2008

SUMMARYExperiments for nine successive years showed that Aphis fabae Scop. populations on mid‐March‐sown field beans were either large with peak densities between late June and mid‐July or very small with peak densities in early August. It is concluded that the largest populations develop when many plants have been colonized by primary migrants from Euonymus europaeus and temperature and radiation are above average during June and early July, as in the year 1957. Cold, dull weather slows multiplication and decreases the size of the peak population even when there is a large initial colonization, as in 1954. The peak population may also be less than predicted from the initial colonization when natural enemies are exceptionally abundant in early June, as in the year 1960. Yield losses of mid‐March‐sown crops in years of large A. fabae populations ranged from 53 % in 1954 (peak population of 1260 aphids per plant) to 100% in 1957 (6920 aphids per plant).Small summer populations with peak densities of about 0·2–85 aphids per plant developed on mid‐March‐sown plots in years when fewer than about 6% of the plants were colonized by primary migrants. Yield losses ranged from 6·3–13·6%.Three years' experiments indicated that crops sown in late April or May are relatively lightly infested in years when large populations develop on mid‐March‐sown crops. Conversely, they may be relatively heavily infested when the populations on these crops are small, as in 1955 when temperatures and sunshine during July and early August were above average.Small and large early summer populations tend to alternate in successive years. The alternation is upset by hot, sunny weather during July and August, and perhaps September and October, which compresses the population cycle Thus the large and small populations expected from this alternation in 1956 and 1960 developed instead during exceptionally fine weather in late summer 1955 and 1959, converting 1956 and 1960 to years of small and large populations respectively.
Factors affecting the toxicity of diazinon to Musca domestica L
Authors: GWIAZDA MARIA , LORD K. A. 
Published: February 2008

SUMMARYProcesses affecting the toxicity of diazinon to a susceptible and a resistant strain of houseflies were examined.More evidence was obtained to show that slower penetration of diazinon through the integument of resistant flies is a cause of resistance.Small amounts of two decomposition products were found in both strains. The decomposition mechanisms, in these strains were differently distributed and, although detoxication of diazinon in the two strains is quantitatively similar and small, it may contribute to resistance.Traces of diazoxon were detected when diazinon was incubated with tissue extracts of either strain.Tissue extracts of resistant, but not of susceptible, flies decomposed significant amounts of diazinon in 1 hr. and the ability to decompose diazoxon seems to be an important cause of resistance.Tissues of both strains sorbed diazinon from aqueous solution similarly; the quantities sorbed were large and suggest that sorption may increase the amount of poison needed inside the insects to kill, by between five and forty times.
The role of water in the spread of Phytophthora infestans in the potato crop
Authors: LACEY J. 
Published: February 2008

SUMMARYDuring falls of rain before 5% of the haulm was destroyed by blight, most rain water was deposited on soil at the bottom of the ridge, and least at the top in crops of King Edward, Majestic, and Up‐to‐Date potatoes. Afterwards less water was trapped half way up the side of the ridge than above or below. Water was also channelled down the stems and, while these were upright, was deposited in the channel often formed around the stem bases by wind movement. Fewer than 500 sporangia per ml. were seen in water collected when blight was present in the crop.Growing tubers of Ulster Ensign and King Edward, inoculated with P. infestans, infected healthy tubers less than 1–3 cm. away, when the soil water content was greater than 20%, and sporulation on the inoculated tubers was maximal. Similarly inoculated Up‐to‐Date and Majestic tubers sporulated less abundantly and failed to infect healthy tubers.Sporulation also occurred on inoculated seed tubers, although infection of the haulm from these tubers could not be confirmed. Water movement from the seed tuber region to the furrows may occur under suitable conditions.
The toxicity of some soil insecticides to carabid predators of the cabbage root fly (Erioischia brassicae (Bouché))
Authors: MOWAT D. J. , COAKER T. H. 
Published: February 2008

SUMMARYIn laboratory tests concentrations of dieldrin in soil, below that required to control cabbage root fly, were found to be toxic to several species of carabid beetles which prey on the immature stages of this pest. These results confirm previous findings from field experiments that dieldrin residues in soil can, by reducing the populations of predaceous beetles, increase the survival of the cabbage root fly and the subsequent crop damage caused. The toxicity of selected organophosphorus insecticides to these beneficial insects was studied in soils of different moisture content. Thionazin was found to be highly toxic at all moisture levels as was diazinon in moist soil. Chlorfenvinphos and azinphos‐methyl and, in dry soil diazinon, were very much less toxic.
A comparison of cereal root eelworm resistant and susceptible spring barley genotypes at two sites
Authors: COTTEN JOHN 
Published: February 2008

SUMMARYA comparison between otherwise identical cereal root eelworm resistant and susceptible spring barley lines was made on two sites, one lightly infested the other heavily infested with the nematode. On the lightly infested site, the grain yields of the resistant and susceptible lines did not differ, but on the heavily infested site, the resistant lines out‐yielded the susceptible lines by 20%.A similar comparison was also made between five reputedly eelworm‐resistant spring‐barley genotypes and three cultivars known to be susceptible. On the lightly infested site, the three susceptible cultivars out‐yielded all other genotypes, while on the heavily infested site they were out‐yielded by all other genotypes except one.Development of the nematode was compared in resistant and susceptible genotypes. Although the nematode was as numerous in resistant genotypes as in susceptible genotypes, either invasion or development of the nematode was retarded in resistant genotypes. Although not conclusive, there was evidence that the male was less retarded in development than the female, which was rarely found in the adult form on resistant plants.
The isolation and identification of rhubarb viruses occurring in Britain
Authors: TOMLINSON J. A. , WALKEY D. G. A. 
Published: February 2008

SUMMARYVirus‐like symptoms were common in British crops of rhubarb. All plants tested of the three main varieties, ‘Timperley Early’, ‘Prince Albert’ and ‘Victoria’, were virus‐infected. Turnip mosaic virus and a severe isolate of arabis mosaic virus (AMV) were obtained from ‘Timperley Early’; and ‘Prince Albert’ contained turnip mosaic virus, cherry leaf roll virus (CLRV), a mild isolate of AMV and, infrequently, cucumber mosaic virus (CMV). The main commercial variety ‘Victoria’ contained turnip mosaic virus, CLRV, a mild isolate of AMV and, infrequently, strawberry latent ringspot virus (SLRV). All the viruses were identified serologically. The rhubarb isolates did not differ markedly from other isolates of these viruses in herbaceous host reactions, properties in vitro or particle size and shape. A rhubarb isolate of CLRV was distinguished serologically from a cherry isolate of the virus.Turnip mosaic virus, CLRV and SLRV, were transmitted with difficulty, but AMV isolates were readily transmitted by mechanical inoculation. Turnip mosaic virus was also transmitted to rhubarb by Myzus persicae and Aphis fabae. CLRV was transmitted in 6–8% of the seed of infected ‘Prince Albert’ and ‘Victoria’ rhubarb and in 72% of the seed of infected Chenopodium amaranticolor. Mild isolates of AMV were also transmitted in 10–24% of the seed of infected ‘Prince Albert’ and ‘Victoria’ plants.
The production of virus‐free clones of some British potato varieties
Authors: KASSANIS B. , VARMA ANUPAM 
Published: February 2008

SUMMARYVirus‐free clones of some British potato varieties, of which all commercial stocks are infected, were obtained by culturing apical meristems of sprouts on tubers. The variety Golden Wonder was freed from potato virus A, Arran Comet from potato virus X, and Epicure, Orion and Sharpe's Express from potato virus S. Of the 196 meristems cultured, forty‐one (21%) grew and of these twenty developed into plants, of which nineteen were virus‐free. More of the excised meristems grew when the first leaf primordium was included than when not, and its inclusion seemed not to increase the chances of the progeny being infected.
Studies with 3,5‐diiodo‐4‐hydroxybenzonitrile (ioxynil) and related compounds in soils and plants
Authors: ZAKI M. A. , TAYLOR H. F. , WAIN R. L. 
Published: February 2008

SUMMARYThe inactivation of the herbicide ioxynil by contact with soil has been investigated. Shaking solutions of the sodium salt with acid soils led to a precipitation of the herbicide. With alkaline soils, a small amount of ioxynil became adsorbed on the soil particles. With unsterilized soils, hydrolysis to 3,5‐diiodo‐4‐hydroxybenzoic acid occurred, with 3,5‐diiodo‐4‐hydroxy‐benzamide as an intermediate product. Liberation of iodide ion in this system was also demonstrated.The phytotoxicity of ioxynil is enhanced by exposure of treated plants to light. The reduction in chlorophyll level of bean leaf tissue treated with ioxynil and other dihalogenohydroxybenzonitriles when exposed to light has been determined. Evidence is presented showing that although ioxynil is poorly translocated in the dwarf bean plant, its degradation products appear in the shoots of these plants after the herbicide has been supplied through the roots.
Factors affecting male probing activity of the red bollworm Diparopsis castanea (Hmps.) in relation to sterility induced by tris(1 ‐aziridinyl) phosphine oxide (tepa)
Authors: CAMPION D. G. , OUTRAM I. 
Published: February 2008

SUMMARYAssuming that the sex attractant of the female red bollworm, Diparopsis castanea (Hmps.), can be isolated, it might be used at bait stations in combination with chemosterilants for the control of this insect. To ensure success, it is essential that male moths attracted to the bait station should pick up an effective dose of chemosterilant either by brief contact with, or by momentary probing on, chemosterilant‐treated surfaces.In Rhodesia, during the dry season, up to 90 % of the moths tested probed on water after 3 days, while 80% probed on 10 %‐D‐glucose after 2 days. In a laboratory with controlled humidity, 70 % of the moths probed after 18 h at 0–10% R.H.; and 10% probed after 18 h at 40% R.H. The average amount of liquid imbibed by individual moths varied from 15·5 μl after 18 h at 0% R.H. to 7·2 μl after 18 h at 40% R.H. It was estimated, and later confirmed, that thirsted moths probing on a 0·1 % aqueous solution of tris (1‐aziridinyl) phosphine oxide (tepa) would take up the equivalent of a sterilizing dose. The treated moths were consistently sterilized with no adverse effects on mating frequency, longevity or competitiveness.As both sexes were found to be sexually mature on emergence, it is probable that little dispersion of the newly emerged adult population occurs before the first mating.
The adaptation of tomato mosaic virus to resistant tomato plants
Authors: DAWSON J. R. O. 
Published: February 2008

SUMMARYTomato mosaic virus derived from susceptible tomato plants (the standard virus) was cultured in resistant plants. Sap from non‐inoculated leaves of resistant tomato plants infected with virus from the resistant host was more infective and contained more virus particles than leaf sap of resistant plants infected with the standard virus. Leaves of resistant tomatoes infected with virus from the resistant host also showed more obvious symptoms. Susceptible plants infected with virus from resistant plants not only showed fewer symptoms than when infected with standard virus, but samples were less infective and contained less virus up to 26 weeks, when values for infectivity were similar.This modification in activity was not reversible and was obtained with two lines of tomato having different types of resistance. Passage of virus from resistant plants through susceptible plants did not impair its ability to infect resistant plants.
Epidemiology of stamen blight of raspberry
Authors: DICKENS J. S. W. 
Published: February 2008

SUMMARYStamen blight, caused by Hapalosphaeria deformans Syd., is a disease of a number of Rubus species. It is widespread on commercial raspberries in Angus and east Perthshire. Evidence indicates that spread is from diseased flowers to the axillary buds of young canes during the summer and entry into these buds is complete by autumn, after which it is unlikely that the pathogen can be reached even by an eradicant fungicide. Attempts to infect young canes artificially, however, have failed. Rain splash appears to be of considerable importance in dispersal, but some spread by wind and pollinating insects could occur. Possible control measures are discussed and the importance of planting canes from spawn beds, where no flowering canes are kept, is emphasized.
Emergence and phytopathological properties of a new strain of Claviceps purpurea (Fr.) Tul. on rye
Authors: MANTLE P. G. 
Published: February 2008

SUMMARYThe emergence of a new stable strain of Claviceps purpurea is described. The strain formed the sphacelial stage very weakly on rye, and was unlikely therefore to be able to initiate an epidemic under field conditions, but the sclerotia contained chanoclavine as the major alkaloid in contrast to the ergotamine component of the parent strain. Isolates of C. purpurea derived from ryegrass ergots were also shown to parasitize rye.
The development of Botrytis cinerea on cut flowers of carnation
Authors: EDNEY K. L. 
Published: February 2008

SUMMARYEnclosing carnation blooms in polythene increased rotting associated with naturally occurring Botrytis infections and accelerated the rate of conidia development when flowers were artificially inoculated before being stored at 1·7 °C. Petal infections were observed 16 and 48 h after inoculation and incubation at 18·3 and 1·7 °C respectively. The products of exosmosis from petals kept at 18·3 °C for 7 days stimulated germination of B. cinerea conidia. Slight pectic enzyme activity was detected in a liquid medium, derived from carnation petals, after incubating B. cinerea cultures at 18·3 °C for 6 days. Although cultures of Botrytis evolved virtually no ethylene, the surge of ethylene produced by uncontaminated ageing flowers occurred sooner after inoculation. A spray containing 1·2% a.i. of 2‐aminobutane controlled rotting but damaged flowers.
The role of wounds in the infection of oranges by Penicillium digitatum Sacc
Authors: KAVANAGH J. A. , WOOD R. K. S. 
Published: February 2008

SUMMARYInocula of spores of Penicillium digitatum in water applied to apparently uninjured skin of oranges do not cause lesions to develop. Addition of citric acid, orange juice, or various extracts of rind had little effect on susceptibility to infection.When spores in water are applied to wounds made between oil vesicles, lesions develop only from wounds that penetrate deeply into the albedo. The flavedo of most oranges seems to be resistant to infection even when damaged, but in a few consignments it showed much less resistance. Increasing the number of conidia in the inoculum caused more lesions to develop but some fruits developed lesions from inocula containing very few spores. The method and timing of spore application to wounds had a considerable effect on the incidence of lesions; emanations from infected fruit had no effect.Lesions developed more rapidly and readily when suspensions of spores in water were applied to wounds in the skin that damaged oil vesicles; wounds as shallow as 0–25 mm allowed lesions to develop.
Host range and variation in virulence of Mycosphaerella ligulicola
Authors: CHESTERS C. G. C. , BLAKEMAN J. P. 
Published: February 2008

SUMMARYA soil‐borne inoculum of Mycosphaerella ligulicola was found to be mildly pathogenic to leaves or stems of globe artichoke, rudbeckia, zinnia, sunflower and dahlia, but severely pathogenic to lettuce. This is the first report of an infection by this fungus of plants other than chrysanthemum or pyrethrum. It was found that, with successive passages of the fungus through lettuce and chrysanthemum respectively, an increase in virulence to these hosts occurred. After a single passage through lettuce a reduction in virulence to chrysanthemum resulted, but with further passages through lettuce there was no further reduction in virulence to chrysanthemum.
Effect of the timing of insecticide applications on infestation by Cavariella aegopodii Scop, on carrots*
Authors: DUNN J. A. , KEMPTON D. P. H. 
Published: February 2008

SUMMARYThe residual effectiveness of demeton‐methyl and menazon sprays applied to carrot plants was compared in the laboratory using Cavariella aegopodii Scop, and more observations were made in the field, where applications of both insecticides were timed in relation to the observed immigration period of the aphid. The relative field performances confirmed those found in the laboratory and, as the aphid population control exercised was inversely proportional to the amount of alate immigration occurring after the sprays had become ineffective, the more persistent menazon was progressively superior to demeton‐methyl the nearer they were applied to the beginning of immigration.A single spray application of either material towards the end of immigration gave a similar overall control of aphid numbers to that given by disulfoton granules applied at sowing time.To minimize colonization, two spray applications spanning the immigration peak were required and, with 2 weeks between the demeton‐methyl sprays and 3 between those of menazon, the highest degree of control was obtained when the first application was made 7–10 days after the beginning of immigration.
Studies on a virus causing stem grooving and graft‐union abnormalities in Virginia Crab apple*
Authors: de SEQUEIRA O. AMARO 
Published: February 2008

SUMMARYA virus was transmitted from apple trees to Nicotiana glutinosa and Chenopodium spp. and back to a range of woody indicators in which it affected only Virginia Crab; symptoms were grooves in the xylem, and swelling and necrosis of the scion immediately above the union with the stock. The virus was distinct from that causing stem pitting in Virginia Crab, because although easily detectable in several apple varieties, it was not found in many trees infected with stem pitting virus.The stem grooving virus has flexous particles 600–700 m/μ long, a heat inactivation point of 67 °C, a dilution end‐point of 10‐3 in N. glutinosa sap and remains infective for at least 2 days at 20 °C.
A relationship between leaf structure and growth potential in apple
Authors: BEAKBANE A. BERYL 
Published: February 2008

SUMMARYThe number of palisade mesophyll cells per unit area leaf lamina was related to the growth potential of apple rootstocks covering a wide range of vigour. The number of these cells per unit leaf surface depends on cell diameter, the number of layers of palisade, and the amount of intercellular airspace. In composite, grafted trees rootstock influence was observed on the leaf structure of scions of low, or intermediate, growth potential.
Germination of sclerotia of Sclerotium cepivorum Berk. under aseptic conditions
Authors: COLEY‐SMITH J. R. , KING J. E. , DICKINSON D. J. , HOLT R. W. 
Published: February 2008

SUMMARYThe response of sclerotia of Sclerotium cepivorum to a number of plant extracts and nutrient solutions was tested, aseptically, on agars, silica gels, filter paper discs, and on columns of soil. There was no specific response of sclerotia to extracts of Allium species in any of these experiments, whereas in unsterile soil consistently high levels of germination were obtained only with Allium extracts. It was shown that sclerotia are subject to the mycostatic influence of unsterile soil. With S. cepivorum soil mycostasis appears to be specifically reversed by Allium species or by water extracts made from them.
The effect of growth substances on Verticillium wilt of tomato plants
Authors: SINHA A. K. , WOOD R. K. S. 
Published: February 2008

SUMMARYThis paper describes the effects of a number of growth‐regulating substances on the development of disease in tomato plants caused by Verticillium albo‐atrum. Indole‐acetic acid usually reduced disease and also reduced the number of hyphae in the stem but it increased tylosis; low concentrations slightly stimulated disease development. Some control of disease was obtained by removing apical buds, and axillary shoots as they developed. When the apical bud alone was removed, developing axillary shoots sometimes wilted; this did not occur in plants with intact buds.Gibberellic acid increased disease in susceptible plants and also induced symptoms in resistant plants. Maleic hydrazide greatly reduced growth of plants, made them more diseased and stimulated growth of the parasite in the vessels.Of other growth‐regulating substances tested, 2,4,6‐trichlorophenoxy‐acetic acid, 2,3,5‐triiodobenzoic acid and 2,4‐dichlorophenoxyacetic acid increased disease at some concentrations and reduced it at others. Cycocel (2‐chloroethyl) trimethyl ammonium chloride and naphthaleneacetamide, gave good control of disease over a range of concentrations when applied to the soil in which plants were growing. Treatments which reduced disease also reduced the growth of the parasite in the shoot and stimulated the formation of tyloses.Indole and 2,4‐dichloroanisole had some effect on disease development but this was much less than that induced by the other substances.