bluuebunny/crossref_metadata_2025_split huggingface dataset:
The action of some systemic aphicides on the eggs of Anthocoris nemorum (L.) and A. confusus Reut
Authors: ELLIOTT W. M. , WAY M. J. 
Published: February 2008

SUMMARYComparisons were made of the systemic action of phorate, menazon and dimethoate on Aphis fabae Scop, and on the eggs of the aphidophagous Anthocoridae Anthocoris nemorum (L.) and A. confusus Reut., which are laid within plant tissue.Against 4th‐instar apterous A. fabae the order of toxicity of the insecticides taken up by roots of the field bean Vicia faba L. was: menazon > dimethoate > phorate. Phorate concentrations needed to kill all A. fabae (10–15 ppm of wet weight of plant) killed most A. nemorum eggs but did not harm A. confusus eggs. Few A. nemorum eggs were killed by 15 ppm of menazon or 5 ppm of dimethoate.In the field a commercial in‐row treatment of 1·5 lb/acre of phorate applied as granules in the seed drill of field beans sown in late April killed 86 % of eggs laid in June by overwintered A. nemorum and 30% of those laid in late July by second‐generation females. Plants initially treated with 6 lb of in‐row phorate per acre killed 74% of A. nemorum eggs in late July but did not harm A. confusus eggs. A. nemorum eggs laid in early June were unharmed by 1·5 lb/acre of in‐row menazon.Of the A. nemorum eggs, 92–96% were inserted into the stipules and leaf margins of young bean plants, i.e. in the region (peripheral and distal part of the leaf) where most 32P from labelled phorate accumulates after root uptake. The egg‐laying sites of A. nemorum in potatoes and brussels sprouts (edges of the leaves) and in oats (the leaf tips) are also where most of the 32P accumulates. In contrast, 98% of A. confusus eggs were laid in the stems, petioles and leaf midribs of field beans, where there was generally much less 32P from labelled phorate.
Effects of feeding by larvae of Phaedon cochleariae (F.) and Plutella maculipennis (Curt.) on the yield of radish and turnip plants
Authors: TAYLOR W. E. , Bardner R. 
Published: February 2008

SUMMARYDifferent numbers of larvae of the beetle Phaedon cochleariae (F.) and the moth Plutella maculipennis (Curt.) were fed on the leaves of turnip plants (variety Early Milan White) and radish (variety French Breakfast) growing in a constant‐environment room.Turnips grew more slowly than radish, were less affected by insect feeding and were affected more by Phaedon than by Plutella. Phaedon larvae severed leaf veins and rasped the leaf surface, thus killing more leaf tissue by desiccation than they ate. They remained on and greatly damaged the older leaves and their feeding reduced yield. Plutella larvae fed on leaves of all ages, which they ate cleanly, leaving the veins. They pupated sooner than Phaedon and did less damage to older leaves, which grew larger and lived longer than corresponding leaves on intact plants. This compensatory growth by turnip prevented loss of yield and may have increased it, as indicated by dry weight of the roots.Both species of insect decreased the yield of radish similarly. Loss of yield of turnip caused by Phaedon or of radish caused by both species of insects was negatively and linearly proportional to the number of larvae that fed on the leaves.
Field experiments on the chemical control of blackcurrant reversion virus and its gall‐mite vector (Phytoptus ribis Nal.)
Authors: THRESH J. M. 
Published: February 2008

SUMMARYHealthy blackcurrant bushes and others infected with reversion virus were exposed equally to infestation by the gall‐mite vector (Phytoptus ribis Nal.) spreading from unsprayed sources planted nearby. Four applications of 1·0% lime sulphur at fortnightly intervals during the dispersal period were less effective than 0·05% endosulfan in preventing the infestation of healthy bushes, whereas endrin at 0·04% gave almost complete control. All spray treatments were much less effective when applied to the virus‐infected bushes, although endosulfan remained superior to lime sulphur and inferior to endrin. Infected bushes sprayed with lime sulphur developed more galls than unsprayed healthy bushes.In another experiment, four applications of endrin or lime sulphur decreased the spread of mites and reversion virus from infested bushes to adjacent sprayed and unsprayed bushes. Lime sulphur was much less effective than endrin in preventing infestation with mites, but more effective in decreasing the incidence of virus.These results are discussed in relation to commercial spray programmes and to the design of experiments on the effectiveness and mode of action of spray materials against mites and virus.
Field and laboratory studies of the effect of urea on ascospore production of Venturia inaequalis (Cke.) Wint
Authors: BURCHILL R. T. 
Published: February 2008

SUMMARYApplications of urea after harvest but before leaf‐fall restricted perithecial production by Venturia inaequalis. Immersion of detached leaves in urea appeared to be the most effective method of preventing perithecial formation, although spraying attached leaves was equally effective when leaf abscission occurred within a week of treatment.A high nitrogen content within the leaf was one of the major factors contributing to suppression. Urea‐treated leaves decomposed rapidly, thus destroying the overwintering substrate for the fungus.When apple plants (clone M. 111) were sprayed in autumn with 5 % urea, followed by a second (pre‐bud‐burst) application at 2 %, ascospore production in the spring was suppressed. The second treatment appeared to prevent the release of ascospores from mature perithecia.
Factors affecting the occurrence of gangrene (Phoma exigua) in potatoes
Authors: MALCOLMSON JEAN F. , GRAY ELIZABETH G. 
Published: February 2008

SUMMARYThe presence in soil from Scotland and England of Phoma exigua f. sp. exigua and P. exigua f.sp. foveata, which cause gangrene, is confirmed by isolation, and it is established that infection of tubers occurs before lifting, and after lifting from soil adhering to tubers. The distribution of the disease is related to soil moisture, gangrene being most prevalent in tubers from the north‐eastern counties of Scotland where the moisture content of arable soils remains high throughout the growing season. The incidence of the disease may be affected by the haulm, either as a source of infection—though not an important source—or by its effect on the maturity of the tubers. The incidence of gangrene is less where haulm destruction is rapid.The incidence of gangrene in a crop is not related to its incidence in the seed tubers planted and, unless infection is severe, the effect on yield is not serious.Symptoms of skin necrosis were associated with tubers from acid soils, infected with P. exigua f.sp. foveata and stored at low temperature.
The incidence of gangrene of potatoes caused by Photna exigua in relation to handling and storage
Authors: MALCOLMSON JEAN F. , GRAY ELIZABETH G. 
Published: February 2008

SUMMARYDamage to potatoes during harvesting and grading increases the incidence of gangrene. Among the factors involved, the condition of the soil and the type of damage caused by the implements may be of importance. Gangrene is most evident in tubers which have been stored cold or moved when cold; warmer storage at some stage usually reduces its incidence and severity.Seasonal incidence is not directly related to rainfall but is determined by factors affecting ripening and destruction of haulm, moisture status of soils at harvest, susceptibility to damage, and exposure during storage and in transit.
The effect of species of Allium on soil bacteria in relation to germination of sclerotia of Sclerotium cepivorum Berk
Authors: COLEY‐SMITH J. R. , DICKINSON D. J. , KING J. E. , HOLT R. W. 
Published: February 2008

SUMMARYExtracts made from Allium species were shown to exhibit marked antibiotic properties in a variety of tests. However, no evidence was obtained to suggest that intact Allium seedlings exude antibiotic compounds in sufficient quantity to cause inhibition of bacteria in the soil or in assay tests in the laboratory. Germination of sclerotia of Sclerotium cepivorum was induced by Allium extracts which were too dilute to cause antibiotic responses in laboratory tests using a number of bacteria. Synthetic methyl‐methanethiolsulphinate had little effect on germination of sclerotia. The specific reversal, by Allium species and their extracts, of the mycostatic effect of unsterile soil on sclerotia of S. cepivorum does not appear to be due to antibiotic effects.
The use of menazon seed dressing to decrease spread of virus yellows in sugar‐beet root crops
Authors: HEATHCOTE G. D. 
Published: February 2008

SUMMARYMenazon, an organophosphorus insecticide (only slightly toxic to mammals), applied to sugar‐beet seed, decreased the proportion of seedlings infested with aphids during May and early June and the number of aphids per plant during June and early July to one‐third of that in the control plots. It also checked the spread of virus yellows.Of eight field trials in 1965, 1966 and 1967 in which more than 10% of the plants in plots not treated with insecticide had yellows, menazon seed dressing increased sugar yield by about 8 cwt per acre. Spraying with demeton‐methyl when ‘a spray warning’ was issued in the area gave a similar increase, and had no further effect on plots sown with menazon‐treated seed.Menazon‐dressed sugar‐beet seed is recommended in regions where yellows is usually prevalent, or where there is reason to expect a large aphid infestation.
Purification, properties and transmission of parsnip yellow fleck, a semi‐persistent, aphid‐borne virus
Authors: MURANT A. F. , GOOLD R. A. 
Published: February 2008

SUMMARYParsnip yellow fleck virus (PYFV) is the commonest cause of virus‐like symptoms in parsnip plants in Britain: it is sap‐transmissible but systemically infects few species outside the Umbelliferae. It has isometric particles 29–31 mμ in diameter, a sedimentation coefficient of 167s, and loses infectivity in sap after dilution to 10‐3‐10‐4, heating for 10 min at 57·5–65°C, or storage at room temperature for 4–7 days. Two isolates, from parsnip and Anthriscus sylvestris respectively, are only distantly serologically related.The aphid Cavariella aegopodii transmits PYFV in a semi‐persistent manner from A. sylvestris but not from parsnip. Transmission by aphids apparently depends on the presence in A. sylvestris or other source plants of a second virus, anthriscus yellows (AYV), which is persistent in the vector and not manually transmissible. PYFV was therefore not transmitted by aphids from manually inoculated plants or from parsnip or other plants immune to AYV. In controlled experiments, C. aegopodii transmitted PYFV (both A. sylvestris and parsnip isolates) from chervil plants inoculated separately with PYFV and AYV, but not from plants inoculated only with PYFV.
The secretion of the systemic insecticides dimethoate and phorate into nectar
Authors: LORD K. A. , MAY MARGARET A. , STEVENSON J. H. 
Published: February 2008

SUMMARYIn pot experiments, root applications of dimethoate and phorate were made to plants of fuchsia, nasturtium and bean. Twenty‐five mg dimethoate applied to a 5‐in pot made nectar from fuchsia and nasturtium and nectaries of beans toxic to bees and Drosophila melanogaster. Similar amounts of phorate and disulfoton did not cause toxicity.Gas chromatography showed that 4 days after treatment there was at least 100 times more dimethoate than phorate in the nectar of fuchsia and nasturtium.The dimethoate in nectaries taken from bean plants treated at rates between 0·5 and 50 mg dimethoate per pot was assayed by gas chromatography. The concentration of dimethoate in the nectaries depended on the applied dose: it was greatest 4 days after treatment. Loss was more rapid with larger doses than with smaller doses.
Influence of direct‐drilling of winter wheat on incidence of take‐all and eyespot
Authors: BROOKS D. H. , DAWSON M. G. 
Published: February 2008

SUMMARYWinter wheat drilled directly into stubble or pasture treated with paraquat to kill the vegetation has been found to be less severely attacked by take‐all (Ophiobolus graminis (Sacc.) Sacc.) and eyespot (Cercosporella herpotrichoides Fron) than wheat drilled after cultivation. The reduction of take‐all is associated, not with a direct effect of the chemical, but with factors, resulting from the technique, which limit the rate of spread of the fungus in the undisturbed soil.
The effect of 6‐benzylaminopurine (benzyladenine) on senescence and chocolate spot (Botrytis fabae) of winter beans (Viciafaba)
Authors: MOORE K. G. , LEACH R. 
Published: February 2008

SUMMARYIn laboratory trials on detached bean leaves, benzyladenine delayed both senescence and aggressive attack of chocolate spot disease.In field plots, over 80% of the aggressive spots were on senescent leaves and the distribution of aggressively attacked leaves was predictable from the distribution of senescent leaves. The total frequency of aggressively attacked leaves per shoot was apparently related to the frequency of senescent spotted leaves.Although benzyladenine significantly reduced leaf senescence in field plots sprayed in May, the senescent leaves were more frequently attacked aggressively. Wider plant spacing (14 in instead of 8 in) similarly increased the ratio of aggressive attack to senescence, and the individual fields retained until June the differences in infection earlier established by frost damage.
Studies on the influence of leaf washings on infection by Mycosphaerella ligulicola
Authors: BLAKEMAN J. P. 
Published: February 2008

SUMMARYInfection of chrysanthemum leaf discs by spores of Mycosphaerella ligulicola was increased in the presence of concentrated leaf washings obtained from five plant species tested. On separation of leaf washings by dialysis the residue stimulated infection and caused aggregation of hyphae on leaf and cellophane surfaces. In the presence of the diffusible fraction an extensive branching network of hyphae developed but there was no increase in infection except in the presence of the chrysanthemum diffusate.Infection of leaf discs of certain plants normally resistant to M. ligulicola occurred in the presence of concentrated leaf washings.Leaf washings from a resistant variety of chrysanthemum had the same effects as those from a susceptible variety. An extract of chrysanthemum leaves was less effective in stimulating infection than was a leaf washing.Defined nutrient media and potato extract stimulated infection but caused the development of different growth habits on leaf surfaces.The active components of the dialysis residue of chrysanthemum leaf washings were heat‐stable but apparently volatile. Eluates from strips of certain regions of paper chromatographs of leaf washings and potato extract caused increased infection together with development of characteristic growth habits of the fungus on the leaf.
Studies on plant growth‐regulating substances XXV. The plant growth‐regulating activity of cinnamic acids
Authors: UGOCHUKWU E. N. , WAIN R. L. 
Published: February 2008

SUMMARYEffects of ring substitution on the plant growth‐regulating activities of trans‐ and cis‐cinnamic acids have been investigated in the wheat cylinder, pea segment and pea curvature tests. Most of the cis‐ acids were shown to be active. Substitution of fluorine, chlorine or bromine into the ring of cis‐cinnamic acid in most cases increased the activity. The results are discussed in relation to mode of action and chemical structure/biological activity relationships: 4‐chlorobenzoic acid is shown to act as a competitive antagonist towards 4‐chloro‐cis‐cinnamic acid.
Resistance to the potato cyst‐nematode, Heterodera rostochiensis, in the plant genus Lycopersicon
Authors: ELLIS P. R. 
Published: February 2008

SUMMARYForty‐eight lines of Lycopersicon and four lines of Solanum were screened for resistance to twelve Heterodera rostochiensis populations of known patho‐type(s). Plant lines were assessed for resistance first by examining the outside of the root ball for cysts and later by washing the root ball to extract all cysts. Possible resistant plant selections were re‐tested against three eelworm populations, including the one to which they were first shown resistant. Resistance was discovered in two lines of Lycopersicon pimpinelli‐folium, two L. esculentum L. pimpinellifolium crosses, L. esculentum var. cerasiforme, six lines of L. peruvianum, in L. peruvianum var. humifusum, L. hirsutum var. glabratum, and in Solanum indicum. Because resistance was found most commonly in L. peruvianum and because it has already been used as a resistant parent in breeding programmes to incorporate resistance to root‐knot nematode (Meloidogyne spp.) in tomato, L. peruvianum seems to be the best source of resistance among plants tested so far.The host‐parasite relationships of resistant L. hirsutum var. glabratum (B 6013) were compared with those of a commercial, susceptible tomato, L. esculentum‘Ailsa Craig’. Plants were inoculated with three eelworm isolates; the extent of eelworm invasion, plant reaction and eelworm development were studied. Larvae invaded and penetrated roots of the resistant plant as freely and in as large numbers as they penetrated roots of the susceptible tomato. In the latter, numerous larvae matured while, in contrast, few larvae matured in the roots of L. hirsutum var. glabratum. L. hirsutum var. glabratum was shown to possess a root diffusate as active in hatching larvae of Heterodera rostochiensis as that of L. esculentum‘Ailsa Craig’.The existence of pathotypes of H. rostochiensis, identifiable by their differing abilities to increase on resistant tomato lines, was not clearly revealed in the experiments.
Some effects of the nematodes Ditylenchus myceliophagus and Aphelenchoides composticola on the yield of the cultivated mushroom
Authors: ARROLD N. P. , BLAKE C. D. 
Published: February 2008

SUMMARYThe addition of one, ten and fifty Aphelenchoides composticola per ioo g compost at spawning reduced the total yield of sporophores by 26%, 30% and 42% respectively (P= 0·01), demonstrating a significant regression (P= 0·05) of yield on inoculum concentration.In pots inoculated at spawning with ten and fifty A. composticola per 100 g compost, cropping ceased after 12 weeks. The addition of twenty, 100 and 300 Ditylenchus myceliophagus at casing reduced the total yield of sporophores by 50%, 68% and 75 % respectively (P= 0·01). Cropping did not occur in pots inoculated at spawning, but continued for 9 weeks in pots inoculated at casing. The yield from pots inoculated at casing with either nematode was significantly greater (P= 0·05) than that from pots inoculated at spawning.When inoculated at spawning, peak populations of D. myceliophagus and A. composticola were reached 7 and 13 weeks, respectively, after spawning. Then the numbers present were unrelated to the number in the inocula.
Properties, relationships and transmission of a strain of raspberry ringspot virus infecting raspberry cultivars immune to the common Scottish strain*
Authors: MURANT A. F. , TAYLOR C. E. , CHAMBERS J. 
Published: February 2008

SUMMARYPlants of Lloyd George and Seedling M raspberry (Rubus idaeus L.) were found in eastern Scotland infected with raspberry ringspot (RRV), a virus to which these varieties were previously considered immune. Most RRV isolates from affected plants caused milder symptoms in herbaceous test plants than did the type isolates of the common Scottish and English strains. In graft‐transmission tests the Lloyd George strain of RRV infected all the raspberry cultivars tested, including those immune to the common Scottish strain. No consistent differences were found between isolates of the two strains in in vitro properties or serological behaviour. Both strains were transmitted in seed of Stellaria media and in soil containing Longidorus elongatus. Possible reasons why the new strain is uncommon in Scotland are discussed.
A biochemical difference between healthy bean leaves resistant and susceptible to the halo‐blight disease caused by Pseudomonas phaseolicola
Authors: EPTON H. A. S. , DEVERALL B. J. 
Published: February 2008

SUMMARYSubstrate for an endogenous oxidation in homogenates of leaves of bean (Phaseolus vulgaris) was traced to two fractions of lipids, each representing less than 2% of the dry weight of leaves. The substrate lipids, tentatively identified as galactosyl diglycerides, yielded linolenic and linoleic acids on acid hydrolysis. Amounts of linolenic acid in total lipids in resistant and susceptible leaves were similar. Amounts of free linolenic acid in resistant leaves increased eightfold to 408.6 μg and in susceptible leaves fourfold to 130.6 μg/g fresh leaf after homogenization and incubation for 16 min at 4 °C. These quantities are sufficient to account during their lipoxidation for the previously reported oxygen uptakes in homogenates. Differences between resistant and susceptible leaves were traced to the activities of lipase systems which liberate linolenic acid from substrate lipids.
Effects of infestation with fruit tree red spider mite, Panonychus ulmi (Koch), on the growth and cropping of young fruit trees
Authors: BRIGGS J. B. , AVERY D. J. 
Published: February 2008

SUMMARYWhen Brompton plum, and M. IV and Crab C apple rootstocks grown in pots were inoculated with fruit tree red spider mites (Panonychus ulmi (Koch)), shoot extension was decreased by 7–17%, the dry weight of the new shoot by 21–32%, and the dry weight increments of old stem and roots by 12–30%, and 7–50%, respectively, compared with control plants sprayed with the acaricide tetradifon. Some of these effects were found in a field experiment with Brompton plum, but not with potted M. I apple rootstocks. Infestation of fruiting Lord Lambourne apple trees, also in pots, had little effect on vegetative growth but in one experiment modified fruit setting, and decreased the dry‐matter content, but increased the seed content of harvested fruit. Lighter inoculation caused no damage to Brompton plum. Spraying inoculated Brompton plum rootstocks with tetradifon + TEPP in mid‐June and mid‐July prevented damage, and though August sprays did not prevent damage to the new shoot, the decreases in dry weight increments of old stem and roots were only 9–13% and 11–19%, respectively, compared with 21–25% and 45–50% in infested, unsprayed plants.
The aetiology and development of damage in young fruit trees infested with fruit tree red spider mite, Panonychus ulmi (Koch)
Authors: AVERY D. J. , BRIGGS J. B. 
Published: February 2008

SUMMARYInfestations of fruit tree red spider mite, Panonychus ulmi (Koch) altered the growth of young plants of plum and apple. At first, damage to the leaves from mite feeding did not affect their photosynthetic rates. The effects on other processes depended on the density of the infestation. Densities of 1–2 mites/cm2 of leaf decreased the rate of shoot extension of Brompton plum, but about 0.5 mite/cm2 increased it. Less dense infestations apparently caused no damage. The rate of growth of the leaf area of a plant relative to that of the mite population on it determined changes in the mite density, and therefore the effects of infestation. The growth of the root system was decreased before that of the shoots.Later, when some leaves were severely damaged photosynthesis was decreased. The onset and severity of this phase probably depended on the number of mites and days of feeding on individual leaves. The later‐formed leaves were smaller, and sometimes fewer on infested plants. Some plants were infested with too low a density of mites to decrease shoot extension, but grew less in dry weight because of decreased photosynthesis later in the season.The initial effects are ascribed to an imbalance in the growth controlling substances caused by feeding. Radioactivity was detected in the growing regions of plants remote from mature leaves on which 14C‐labelled mites were confined.