bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of plant spacing on the numbers of aphids trapped over the groundnut crop
Authors: A'BROOK JOHN 
Published: February 2008

SUMMARY Aphis craccivora, Aphis gossypii and Longiunguis sacchari were trapped at 3 ft above ground more often over widely‐spaced than over close‐spaced groundnuts. At crop height A. craccivora and A. gossypii showed a similar but greater response to plant spacing. Numbers of Rhopalosiphum maidis and Tetraneura nigriabdominalis caught were not affected by groundnut spacing differences. All aphid species studied except T. nigriabdominalis responded to yellow, but their sensitivity to colour was less during the dry season. It is suggested that the effect of plant spacing on numbers caught was not due to colour alone, but perhaps also to the contrast of plants and soil in widely spaced groundnuts. At crop height, an alighting response was shown only by those species that feed on groundnuts. The control of rosette disease of groundnuts by early planting and close spacing appears to be due to the inhibition of the landing response in A. craccivora by the continuous ground cover resulting from these treatments.
The incidence of virus diseases in English sweet‐cherry orchards and their effect on yield
Authors: POSNETTE A. F. , CROPLEY R. , SWAIT A. A. J. 
Published: February 2008

SUMMARYTwo thousand sweet‐cherry trees (Prunus avium) in English orchards were tested for virus infection by using Lambert and Mazzard F 12/1 as indicators. Most trees of varieties commonly grown before 1920 were infected with more than one virus, usually little cherry (69%) and necrotic ringspot/prune dwarf (56%). Other infection was less prevalent, 35% of these trees having European rusty mottle, 30% ring mottle and 3% necrotic rusty mottle. Most trees of varieties introduced since 1920 were virus‐free (61%) but some had become infected with each of these viruses except necrotic rusty mottle.In a field trial of 12 years duration the yield of three varieties was diminished by infection with necrotic ringspot/prune dwarf, rugose mosaic, rusty mottle, ring mottle and necrotic line pattern. The effect of rusty mottle was due to growth suppression resulting in smaller trees, but that of other viruses was also due to impaired fertility. The yield of one variety (Merton Heart) was greatly enhanced by infection with rugose mosaic, rusty mottle and necrotic ringspot/prune dwarf viruses.The high incidence of virus infection and consequent yield depression has probably diminished the potential yield by at least 30% and contributed to the decline in acreage of sweet cherries in England.
Virus diseases of garden lupin in Great Britain
Authors: HULL R. 
Published: February 2008

SUMMARYTwo viruses occur widely in lupins in Britain. Alfalfa mosaic virus (AMV), of which two strains were isolated, was found mainly in named Russell varieties. Lupin mottle virus (LMV), a previously undescribed strain of the bean yellow mosaic virus (BYMV) common pea mosaic virus (CPMV) complex, was found more commonly in seedling lupins. Cucumber mosaic virus (CMV) was isolated once.The AMV strains were differentiated by their reaction in Phaseolus vulgaris; they were serologically closely related. Both AMV and LMV were aphid transmitted but not transmitted in lupin seed. LMV was distantly serologically related to both BYMV and CPMV. It cross‐protected against BYMV but not against CPMV and it differed from both these viruses in some host reactions. The CMV isolate from lupins was similar to type CMV. It was transmitted both mechanically and by aphid, easily from cucumber to cucumber, but with difficulty from cucumber to lupin.
Effects of volatile products of Allium species and their extracts on germination of sclerotia of Sclerotiutn cepivorum Berk.
Authors: KING J. E. , COLEY‐SMITH J. R. 
Published: February 2008

SUMMARYIt was shown that sclerotia of Sclerotium cepivorum, normally subject to the mycostatic influence of unsterile soil, germinated in response to a volatile principle evolved from growing onion and leek seedlings. Air, which was bubbled through diluted onion and garlic juices, contained vapours which stimulated sclerotia! germination. The vapours evolved at room temperature by garlic juice were collected as a condensate which also induced germination. Stimulatory activity was found in both distillates and distillands of garlic as well as in air bubbled through such a distillate.
Comparative toxicity of the two anti‐coagulants, coumatetralyl and warfarin, to wild house‐mice (Mus musculus L.)
Authors: ROWE F. P. , REDFERN R. 
Published: February 2008

SUMMARYIn comparative tests using individually caged wild house‐mice (Mus musculus L.) coumatetralyl at 0·05 % in an oatmeal bait‐base was found to be as acceptable as plain bait and as acceptable and as toxic as warfarin at 0·025% (the standard dosage). It was less readily accepted at 0·1 or 0·2% in the same bait‐base or at 0·05% in a proprietary bait formulation.In further tests with suspected warfarin‐resistant mice, coumatetralyl at either 0·05, 0·1 or 0·2% proved more toxic than warfarin at either 0·025, 0·1 or 0·2% respectively. However, some individuals survived 21 days feeding on each of these concentrations of coumatetralyl and, in field and laboratory trials, 0·05 and 0·1% coumatetralyl baits failed to control warfarin‐resistant mouse populations after 3–5 weeks.It is concluded that coumatetralyl is a suitable alternative poison to warfarin for use against mice that are susceptible to anti‐coagulants but that it is unlikely to control warfarin‐resistant populations effectively.
Micro‐meteorological studies of coffee berry disease A field investigation into the incidence of the physical conditions favourable for spore germination
Authors: WOODHEAD T. 
Published: February 2008

SUMMARYIn an investigation in a coffee plantation, the frequency and duration of the micro‐meteorological conditions necessary for the germination of conidia of Colletotrichum coffeanum were evaluated on coffee twigs of different ages, aspects and exposures. No consistent relationships between aspect and disease incidence were established, but there were indications that east‐facing branches might be slightly more disease‐prone than west‐facing ones because of more rapid warming of the surface water films by morning insolation.The macro‐climate of the plantation was measured by conventional meteorological instruments. Daytime air temperatures, measured inside a Stevenson screen between the rows of trees, were, on average, about 1 C° and 2·5 C° lower than those recorded on twig surfaces under wet and dry conditions, respectively.
Some factors affecting germination of Peronospora farinosa conidia in water
Authors: RUSSELL G. E. , EVANS GWENLLIAN M. 
Published: February 2008

SUMMARYThe germination of conidia of Peronospora farinosa f. sp. betae, collected from sugar beet and suspended in deionized water, was inhibited by dilution with 10% solutions of glycerol, glucose or sucrose and with sap from sugar‐beet leaves. Germination was stimulated by diluting with deionized water but not with tap water or biological saline. Substances that diffused from excised buds of sugar‐beet plants into deionized water also stimulated germination of conidia but diffusates from leaves did not. This may partly explain why buds are more susceptible to downy mildew than leaves in sugar beet. Germination of conidia was apparently stimulated more by diffusates from buds of seedlings than by those from buds of older plants; this may help to explain why sugar‐beet seedlings are more susceptible to downy mildew than older plants. Diffusates from plants of four sugar‐beet stocks, that differed from each other in susceptibility to downy mildew, had very similar effects on germination of P. farinosa conidia. Stimulation of spore germination on the surfaces of buds and leaves did not seem, therefore, to be an important factor in determining resistance or susceptibility to downy mildew in these stocks.
The effect of inbreeding on potato cyst‐nematode, Heterodera rostochiensis
Authors: HOWARD H. W. 
Published: February 2008

SUMMARYTwo populations, Duddingston and Feltwell, of potato cyst‐nematode were inbred for seven and six generations respectively. The Duddingston population maintained a high fecundity in some lines for three generations, but in subsequent generations the fecundity as measured by cyst production declined in spite of selection for high fecundity. By selecting for fecundity, some lines of the Feltwell population still produced many cysts after five generations of inbreeding. In the Duddingston population it was possible to increase the number of cysts produced by an inbred line of poor fecundity by using paired cysts plus selection for fecundity. A similar change may have been obtained for unprolific lines of the Feltwell population. Selection for production of few cysts quickly produced lines with poor fecundity. One cause of poor fecundity was the small number of larvae in cysts used for inoculations. Yellow eggs were found in large numbers in some cysts but these were not a cause of loss of fecundity following repeated inbreeding.
Effects of sucrose sprays and darkness on aphid colonization of sugar beet and on aphid transmission of yellowing viruses
Authors: Russell G. E. 
Published: February 2008

SUMMARYIn the glasshouse, adult, apterous Myzus persicae (Sulz.) and Aphis fabae Scop, settled better and deposited more larvae on sucrose‐sprayed sugar‐beet plants than on water‐sprayed plants. M. persicae settled badly and deposited few larvae on plants that were kept in the dark before or after infestation. The effects of darkness on aphids were reduced by spraying the host plants with 10% solutions of sucrose before infestation.Viruliferous M. persicae transmitted beet yellows virus (BYV) and beet mild yellowing virus (BMYV) less efficiently to dark‐treated plants than to those grown in normal daylight. Spraying sugar beet with sucrose before inoculation with viruliferous M. persicae increased the proportion of successful BYV transmissions but only when the plants were dark‐treated. The effects of sucrose and darkness on settling and larviposition of aphids and on virus transmission may be related to changes in the concentration of carbohydrates, particularly sugars, in the leaves.
Studies on the bacterial diseases of Sudan crops
Authors: SABET K. A. , ISHAG FARIDA , KHALIL OSMAN 
Published: February 2008

SUMMARYNew records are presented of bacterial diseases affecting the following weed plants: Heliotropium sudanicum, Rhynchosia memnonia, Vigna radiata, V. pubigera, Euphorbia acalyphoides and Phyllanthus niruri. Bacterial leaf blight of pigeon pea (Cajanus cajan) caused by Xanthomonas phaseoli f. cajani is reported for the first time from the Sudan. The causal bacteria, all of which belong to the genus Xanthomonas, are compared with related pathogens. The differences between these bacteria are considered of little diagnostic value. Pathogenically, they can be separated into three groups: (i) the Heliotropium pathogen; (ii) the bacteria affecting leguminous plants; and (iii) the bacteria affecting species of the family Euphorbiaceae. Because of the diversity in opinion on speciation in the genus Xanthomonas, two alternative proposals are put forward. In the first, Xanthomonas is considered a monotypic genus with X. campestris as the sole species. The pathogens reported in this work from previously unrecorded hosts, which proved to differ in pathogenicity from established ones, are considered to be new formae speciales. These are X. campestris f.sp. heliotropii from H. sudanicum, X. campestris f.sp. rhynchosiae from R. memnonia, X. campestris f.sp. vigna‐radiatae from V. radiata, X. campestris f.sp. euphorbiae from E. acalyphoides and X. campestris f.sp. phyllanthii from P. niruri. The organism from V. pubigera is accordingly identified as X. campestris f.sp. vignicola. Other bacteria used for comparison are also reduced to ff.sp. of X. campestris.The other proposal is to lump together pathogens with overlapping host ranges in a single species that comprises a number of ff.sp. differing in pathogenicity. Thus the bacteria from leguminous plants are all considered to belong to X. phaseoli as previously suggested by Sabet. New ff.sp. are created for the pathogens from R. memnonia (X. phaseoli f.sp. rhynchosiae), and V. radiata (X. phaseoli f.sp. vigna‐radiatae). The organism from V. pubigera is identified in this case as X. phaseoli f.sp. vignicola. The bacteria from members of the Euphorbiaceae are considered to belong to X. ricini on priority grounds. X. cassavae and X. poinsettiaecola which have been used for comparison are reduced to the ff.sp. X. ricini f.sp. cassavae and f.sp. poinsettiaecola respectively. Two new ff.sp. are created: for E. acalyphoides pathogen, X. ricini f.sp. euphorbiae and for P. niruri pathogen, X. ricini f.sp. phyllanthii.The creation of a new species (X. heliotropii sp.nov.) is proposed for the Heliotropium pathogen.The present study shows that many weed plants may be affected with new bacterial strains that can also infect cultivated crops.
Studies on Claviceps purpurea (Fr.) Tul. parasitic on Phragmites communis Trin
Authors: Mantle P. G. 
Published: February 2008

SUMMARYIsolates from C. purpurea sclerotia occurring naturally on Phragmites communis usually sporulated vigorously on the culture medium employed, and their failure to produce alkaloid in vitro was associated with a thin white growth form. Such isolates also failed to produce sclerotia on the host plants tested. A variant having a plectenchymatic morphology in vitro and producing a thick pigmented non‐sporulating growth form yielded alkaloid (up to approximately 300μg/ml mainly δ8–9 and δ9–10 lysergic acids and chanoclavine) in surface or submerged culture and developed typical ergot sclerotia (containing 0·2‐0·4% alkaloid, mainly ergotoxine and ergotamine) in vivo.Improved alkaloid yield in vitro was obtained from a strain reselected after passing through a parasitic phase.Aetiological aspects of the P. communis ergot are discussed.
Experiments on integration of chemical and biological control of aphids on brussels sprouts
Authors: WAY M. J. , MURDIE G. , GALLEY D. J. 
Published: February 2008

SUMMARYTwo field experiments were made to test whether natural enemies would take over control of brussels sprouts aphids at the time when protection from a selectively acting, soil‐applied systemic insecticide, menazon, began to fail.The natural enemies, notably Syrphidae, proved ineffective against Brevicoryne brassicae L. despite advantages given by the insecticide and by close planting, which greatly increased the ratio of numbers of syrphid eggs and larvae to aphids. Thus, development of the aphid population was little altered when infested plants were kept free of most natural enemies by hand removal.I lb/acre (1–12 kg/ha) of menazon applied as spot treatments to the soil at planting‐out time decreased the number of overwintering parasite mummies by 70 % but such ‘mortality’ was compensated for by decreased mortality from hyperparasites and other causes, so the numbers of adults of the primary parasite Diaretiella rapae (McIntosh) which emerged in the spring were similar to those from untreated plots. Soil cultivation in winter drastically decreased the numbers of emerging adult primary parasites, hyperparasites and syrphids.The menazon treatment designed for integrated control (1 lb/acre) seemed too unpredictable in action, e.g. less effective in dry than in damp conditions, to provide the hoped‐for chemical control needed until natural enemies became abundant. Menazon at 4 lb/acre (4·48 kg/ha) protected the crop throughout the growing season and bioassays showed that menazon or its toxic derivatives continued to occur in leaves during cool periods in winter and also in the following April‐May nearly 1 year after application. The same amount of menazon per unit area of crop was less effective on 1 ft 6 in (45·6 cm) spaced than on 3 ft (91·2 cm) spaced brussels sprouts plants.
The potentiation between thanite and arprocarb in their action on houseflies
Authors: HEWLETT P. S. 
Published: February 2008

SUMMARYThere was considerable potentiation between thanite and arprocarb in their actions on an insecticide‐susceptible strain of houseflies. The isobole at the LD 50 level was asymmetric, which was to be expected, since thanite probably potentiates arprocarb but not vice versa. The joint action ratio, i.e. the maximum actual potency of the jointly acting insecticides relative to what their joint potency would be if they showed additive action, was about 4·6 (apart from in one aberrant experiment). Thanite appears to potentiate arprocarb less than it potentiates isolan or m‐iso‐propylphenyl N‐methylcarbamate.
The multiplication and spread of sacbrood virus of bees
Authors: BAILEY L. 
Published: February 2008

SUMMARYSacbrood virus multiplied without causing symptoms in adult bees when it was injected into them or when it was fed to young individuals. More virus accumulated in heads of infected bees than elsewhere in their bodies, and much was in their hypopharyngeal glands. The extract of each infected head contained about 102medial lethal doses (LD 50s) of sacbrood virus for larvae when given in their food. The infective dose of sacbrood virus by injection for adults was about 10‐4of the LD 50 in food for larvae. The infective dose by mouth for adults was about 102LD 50s for larvae, but bees older than 4–8 days could not be infected this way. Infection did not spread between adults but is probably transmitted in nature from infected adults to larvae and back to young adults that ingest remains of larvae killed by sacbrood. The youngest adult bees infected with sacbrood ate little pollen and lived only about 3 weeks in the laboratory, as did bees receiving no pollen, whereas bees fed with ample pollen lived 9 weeks.
The control of Aphis fabae Scop, on spring‐sown field beans (Vicia faba L.)
Authors: GOULD H. J. , GRAHAM C. W. 
Published: February 2008

SUMMARYDisulfoton or phorate granules or demeton‐S‐methyl, menazon and vamidothion sprays, applied once in early June as preventive treatments before heavy aphid colonies developed, gave good control of Aphis fabae Scop, on field beans. Phosalone gave relatively poor results and DDT was ineffective. Applications in June to crops sown in February and early March were made with minimal wheel damage to the crop and are known to be less harmful to bees than sprays at flowering time. Eradicant treatments with demeton‐S‐methyl and dimethoate sprays or with disulfoton or phorate granules on heavily infested plants during flowering were also effective, but menazon was less satisfactory. These eradicant sprays are likely to be harmful to bees, and wheel damage in late June reduced yield by 1–2 cwt/acre (125–250 kg/ha).Peak populations of 3000 aphids/plant in early July reduced yield by 6 cwt/acre (750 kg/ha) in one trial.
The insect faunas of pear and apple orchards and the effect of windbreaks on their distribution
Authors: LEWIS T. , SMITH B. D. 
Published: February 2008

SUMMARYTwo coir netting windbreaks, each 7 m tall and 46 m long, were erected in a pear and an apple orchard, to try to increase the number of insect pollinators present at blossom time. The flying insects were sampled with suction traps and insects visiting trees were sampled by examining marked clusters of blossom.The mean aerial density was calculated for each of the forty‐two taxa, mainly families, identified from the aerial population. There were about 50% more insects flying in the pear than in the apple orchard. The distribution of flying insects was greatly affected by the windbreaks, and the sheltered zone contained three times as many of most species, and more than three times as many Chironomidae, Psychodidae and Bibionidae as elsewhere.Small flies were the most abundant insects in the air, in both orchards. In the pear orchard large insects comprised only about 7 % of the total aerial population, of which honeybees constituted 0–7% and wild bees 0–3%.By contrast, large insects accounted for a greater proportion of the population on blossom. The reasons for this are discussed. On apple blossom Syrphidae and honeybees were the insects most often seen, and on pear blossom Bibionidae and Mycetophilidae.
Laboratory and field tests in 1966‐67 on chemical control of wireworms (Agriotes spp.)
Authors: GRIFFITHS D. C. , SCOTT G. C. , LOFTY J. R. , ROBERTS P. F. 
Published: February 2008

SUMMARYOf sixteen compounds applied to soil in laboratory tests, azinphos‐ethyl, P2188 (O,O‐diethyl S‐chloromethyl phosphorothiolothionate), ‘Dursban’ (O,O‐diethyl O‐3,5,6‐trichloro‐2‐pyridyl phosphorothioate), P1973 (S‐(N‐methoxycarbonyl‐N‐methylcarbamoylmethyl) dimethyl phosphorothiolothionate), B77488 (O,O‐diethylphosphorothioate O‐esterwith phenylglyoxylonitrile oxime) and R42211 (O,O‐diethyl O‐(2‐diethylamino‐6‐methyl‐pyrimidin‐4‐yl) phosphorothioate) killed wireworms when first tested, but in second tests with the same soils only ‘Dursban’, P2188 and B77488 did so. Treating seeds with ‘Dyfonate’ (O‐ethyl S‐phenyl ethyl phosphonodithioate) or with ethion/γ‐BHC mixtures killed few wireworms.Three field trials compared the organophosphorus insecticides ‘Dursban’, ‘Dyfonate’ and phorate with organochlorine standards. In trials with barley and potatoes the standard was 3 lb a.i./acre (3·36 kg/ha) of aldrin. The organophosphorus compounds increased plant stands of barley almost as much as aldrin, although they killed fewer wireworms; and they protected fewer potato tubers from wireworm damage. The third trial compared the organophosphorus compounds with 0·5 lb a.i./acre (0·56 kg/ha) γ‐BHC sprayed on a site drilled with sugar beet seed dressed with dieldrin. The γ‐BHC increased plant stands almost as much as did 3 lb a.i./acre of the organophosphorus insecticides, and killed as many wireworms.
Changes in a Heterodera rostochiensis population through the growing season
Authors: EVANS K. 
Published: February 2008

SUMMARYChanges in the numbers of all stages of Heterodera rostochiensis in plants and soil were studied in a potato crop growing on infected land. Hatching and invasion occurred early in the season, when plants were very young and temperatures were below those considered necessary for hatching and invasion in Long Island, U.S.A. More larvae hatched from cysts nearer than away from potato roots. Males were abundant during June and July, when fertilization probably occurs. Many new cysts appeared during late June and early July. In May/June, there were many larvae in the roots of young plants but later there were few; a slight increase during August probably indicated a small second generation. The larvae for this second invasion may have come from the most recently formed cysts, which may have been stimulated to hatch either by root exudates or by substances from other soil organisms.
Transmission of strains of raspberry ringspot and tomato black ring viruses by Longidorus elongatus (de Man)
Authors: TAYLOR C. E. , MURANT A. F. 
Published: February 2008

SUMMARYScottish isolates of raspberry ringspot (RRV) and tomato black ring viruses (TBRV) showing slight serological differences were associated in the field with the nematode Longidorus elongatus and were all transmitted equally efficiently by this species in laboratory experiments. Forms of both viruses from southern England and Germany that are distantly serologically related to the Scottish isolates were also transmitted experimentally by L. elongatus, although in the field they are associated with other Longidorus species. L. elongatus transmitted English isolates of RRV almost as efficiently as the Scottish isolates but it transmitted English and German isolates of TBRV only occasionally. Four isolates each of TBRV and RRV were detected by inoculating plants with extracts of nematodes; the results paralleled those of the vector studies.