bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ecological characteristics of nematode ‐trapping Hyphomycetes
Authors: COOKE RODERIC C. 
Published: February 2008

SUMMARYA study of thirteen species of nematode‐trapping Hyphomycetes demonstrated wide differences in their growth rate, competitive saprophytic ability, effect on free‐living nematode populations and ability to produce traps spontaneously.The species producing adhesive reticulate traps tended to have the most rapid growth rates and the highest saprophytic ability ratings. In the soil they appeared to be pre‐daceously inefficient and did not form traps in pure culture. In contrast the ring‐formers had slow growth rates and lower saprophytic ability ratings. They tended to be predaceously efficient and two of the four species studied formed traps spontaneously. The adhesive branch or knob‐forming fungi resembled the ring‐formers in their growth rates, predaceous efficiency and spontaneous trap formation.Thus it appears that the development of predaceous efficiency has been accompanied by a tendency to lose those characters associated with an efficient saprophytic existence in the soil; namely rapid growth rate and good competitive saprophytic ability.
Studies on the chemical control of Phytophthora palmivora (Butl.) Butl. on Theobroma cacao L. in Nigeria
Authors: HISLOP E. C. 
Published: February 2008

SUMMARYIn laboratory trials, phenyl mercury nitrate at 0·02 p.p.m. and fentin acetate at 0·2 p.p.m. severely retarded growth of four isolates of Phytophthora palmivora on cassava agar. These two chemicals, with captan, maneb and a dithiocarbamate‐copper chelate, were also highly toxic to encysted zoospores of a ‘rubber’ group isolate of P. palmivora.Deposits of captan on pods were readily removed by artificial rain, but some improvement in tenacity was obtained by the addition of a sticker. In other laboratory trials, the deposit from low‐volume sprays of cuprous oxide dried more quickly on pods than that from high‐volume sprays but showed no advantage in subsequent resistance to weathering.In a field trial in 1961, seven fungicide treatments were applied three‐weekly and compared with an unsprayed control. The lowest percentage black‐pod infection followed treatment with fentin acetate: Bordeaux mixture and carbide Bordeaux both gave good control. The captan treatments were completely ineffective. More black pods were harvested from close‐spaced trees than from those wide‐spaced.Weekly applications of 0·15% fentin acetate to seedlings induced no significant damage.In a field trial made in 1962 very heavy rainfall provided a severe test of the fungicides, the most effective being Bordeaux mixture and carbide Bordeaux mixture applied three‐weekly, carbide Bordeaux mixture applied four‐weekly and fentin acetate applied two‐weekly. Captan with added sticker was again no better than the control. There was no marked effect of spacing.Comparisons of Bordeaux and carbide Bordeaux mixtures made at two other sites in 1962 showed no difference in disease control. It is suggested that carbide Bordeaux mixture could be replaced by the cheaper preparation made with lime.
Dressed cereal seed as a hazard to wood‐pigeons
Authors: MURTON R. K. , VIZOSO MONICA 
Published: February 2008

SUMMARYThe dynamics of a wood‐pigeon population in Cambridgeshire are described and the potential risk of dressed grain considered in relation to the feeding behaviour of the birds and the use of the dressings seasonally and annually. Wood‐pigeons use autumn sowings as a source of food only in the absence of better grain supplies on stubbles; it is unusual for more than 50% of the population to feed on them, and the conditions leading to high exploitation of autumn sowings are discussed. In contrast, spring sowings coincide with a period of poor alternative food supplies and are fed upon by over 80% of the population.In the spring of 1961 about one‐quarter of the acreage of cereals planted in the study area had been treated with aldrin or heptachlor insecticides and most of the remainder with γ‐BHC or organo‐mercury dressings. In autumn 1961 only 3·3% of the total acreage was treated with heptachlor and no aldrin or dieldrin was used, while in spring 1962 only γ‐BHC or plain organo‐mercury dressings were used.In 1961 there were no differences between the distribution of pigeons on fields containing grain treated with aldrin or heptachlor and that on fields planted with BHC‐treated grain; also there was no field evidence that pigeons found dressed grain unpalatable. Counts in 1962 showed no difference in the distribution of feeding wood‐pigeons in fields containing cereals treated with plain organo‐mercury dressings and in fields sown with grain treated with mercury plus γ‐BHC.Many dead pigeons were found in the spring of 1961: population counts in one roost indicated that at least 8% of the birds had been killed. However, in the spring of 1962 wood‐pigeon mortality was too low to measure. It is concluded that the voluntary agreement from I January 1962, after which aldrin, dieldrin and heptachlor dressings were not to be used on spring‐sown cereals, virtually abolished direct wood‐pigeon mortality resulting from the consumption of treated grain. The general significance of such bird mortality on population size is briefly discussed.
The use of insecticides to find when leaf roll and Y viruses spread within potato crops
Authors: BURT P. E. , HEATHCOTE G. D. , BROADBENT L. 
Published: February 2008

SUMMARYAttempts to find when leaf roll and Y viruses spread within Majestic potato crops, made during 4 years at Harpenden by spraying with aphicides to restrict virus spread during four different periods per season, succeeded with leaf roll but not with virus Y.I n 1957, 1958 and 1961 leaf‐roll virus spread mostly before mid‐July, very little between mid‐ July and early August, but a little more from early August to the season's end. In 1959, when the summer was exceptionally fine, more virus spread during July. Four sprays with persistent aphicides: (I) when 50 yo of the crop has emerged from the ground; (2) 10 days later; and (3) and (4) at fortnightly intervals, will prevent leaf‐roll virus spreading within a potato crop until the end of July and in most seasons will therefore prevent almost all spread; the earliest sprays are usually the most important. Systemic soil insecticides applied to prevent leaf roll virus spreading should make the plants lethal to aphids as early as possible.Little was learned about the time of spread of virus Y because in the experimental conditions the insecticides did not prevent its spread.Further evidence was obtained that leaf roll virus is spread within crops mostly by alatae colonizing the potatoes in spring and early summer.
The epidemiology of tomato mosaic V. The effect on TMV‐infected plants of nutrient foliar sprays and of steaming the soil
Authors: BROADBENT L. , WINSOR G. W. 
Published: February 2008

SUMMARYSpraying tomato plants infected with tomato mosaic virus (a strain of tobacco mosaic virus) and uninfected ones at weekly intervals with a 0·3% aqueous solution of urea, or this solution with 0·1% mono‐ammonium phosphate and 0·1% potassium sulphate, had little effect on the yield or quality of the fruits, although there was a slight increase in mean weight per fruit in sprayed, early‐infected plants. Steaming the soil did not affect total yield of fruits (weight) but increased fruit number by nearly 6% and also the proportion of good quality fruits. Some severe fruit‐quality disorders were prevalent only on late‐infected plants. A mild tobacco strain of mosaic virus failed to protect inoculated plants from late infection with the tomato strain of the virus.
Studies on parsnip canker
Authors: CHANNON A. G. 
Published: February 2008

SUMMARYIn field experiments at Wellesbourne, reductions in both black and orange‐brown canker of parsnips were obtained either by late sowing (in May or June), or by singling the plants to a narrow interval (3 in.), or by a combination of both treatments. The treatments reduced mean root size, and small roots had less canker than large ones.It seemed that much of the disease reduction obtained was a consequence of the reduction in mean root weight caused by the treatments. There was evidence, however, that the reductions in black canker obtained by late sowing were also dependent to some extent upon the shorter period that the roots were in the ground.Marketing assessments were made on four occasions in an experiment in which crops were grown from seed sown in March and May and were singled to 3 in. or 6 in. in rows 15 in. apart. They showed that the highest total and highest marketable yields were generally obtained from the earlier‐sown crop at the narrower spacing.
Hypersensitivity of monogenic resistant tomato scions to toxins produced in Bonny Best rootstocks invaded by Fusarium oxysporum f. lycopersici
Authors: KEYWORTH W. G. 
Published: February 2008

SUMMARYPrevious experiments made by the writer showed that scions of tomato varieties that were monogenically resistant to wilt caused by Fusarium oxysporum f. lycopersici were apparently hypersensitive to toxins produced in infected Bonny Best (susceptible) rootstocks on to which they were grafted. The experiments did not prove conclusively, however, that the toxins were generated in the rootstocks, since they might have arisen from an interaction between the invading fungus and the resistant scion or by the generation of toxic materials when non‐toxic metabolites from the invaded root‐stock entered the resistant scion.In the present study it was demonstrated that the symptoms on the resistant scions arose when the fungus was still confined to the susceptible rootstocks. By double grafts, using resistant or susceptible intermediate stem pieces, it was also shown that the translocation of metabolites from invaded susceptible rootstocks through such stem pieces caused no change in their toxicity.It was concluded that resistant scions were highly sensitive to the direct action of toxins formed in invaded susceptible rootstocks, at concentrations which had no apparent effect on susceptible scions.
Investigations on fungicides
Authors: CARTER G. A. , GARRAWAY J. L. , SPENCER D. M. , WAIN R. L. 
Published: February 2008

SUMMARYA series of β‐(thiocarbamoylthio)‐aldehydes and ‐ketones, N‐methyl analogues and 2,3‐dihydro‐2‐thio‐1,3‐thiazines derived therefrom were examined in laboratory tests for fungitoxicity against seven fungi and in greenhouse tests against four plant diseases. The most active compounds were the phenyl‐ or trichloromethyl‐substituted β‐(N‐methylthiocarbamoylthio)‐ketones. The corresponding thiazines were less fungitoxic. Structure/fungitoxicity relationships are discussed with special reference to the influence of water solubility and water/oil partition coefficients.
Investigations on the use of dichlorvos in the control of the mushroom phorid, Megaselia halterata (Wood)
Authors: HUSSEY N. W. , HUGHES J. T. 
Published: February 2008

SUMMARYConcentrations of dichlorvos (2,2‐dichlorovinyl dimethyl phosphate), lethal to mushroom flies, were produced in cropping houses by automatic aerosols, application of emulsion to the floors and by slow vaporization from a solid formulation in a plastic resin. Techniques used to measure these aerial concentrations and determine any residues in mushrooms are described.A concentration–time product of 0·7 μg./1./hr. was found completely effective. No residues were found in mushrooms grown in houses treated with dichlorvos aerosols at rates up to 600 mg./100 cu.ft. but in laboratory tests residues of the order of 1 p.p.m. persisted for 24 hours when the mushrooms were directly exposed to the aerosol. The aerial concentrations of dichlorvos used were well below the mammalian safety level of 1·0 μg./1.
The life history and behaviour of the willow weevil Cryptorrhynchus lapathi L
Authors: SMITH B. D. , STOTT K. G. 
Published: February 2008

SUMMARY Cryptorrhynchus lapathi L. is a serious pest of basket willows in Somerset, feeding as both larva and adult on the rods and stools. Adults reared in outdoor cages at Long Ashton completed their life history in 12 months in a cycle similar to that found in Southern France, Italy and North America. However, part of the population on reaching the adult stage in late summer did not emerge before the following May and so had a 2‐year life cycle. In contrast, willow bed sampling indicated that the population showed only the 2‐year cycle generally similar to that found in Northern and Eastern Europe. Maximum damage to rods occurred in May and June when adults emerged and in 1959, when there was a serious infestation, 62% of the rods were damaged. The maximum density recorded at one time was one adult per six stools or 138 shoots but surveys in which marked weevils were recaptured showed that only part of the total adult population was visible at any one time and hence over a 5‐day period a density of one adult per four stools was found. Soon after emergence adults showed a preference for evening activity. There appeared to be very little lateral movement of adults across the rows in willow beds and flight has been observed only in the laboratory. There was no evidence of alternate host plants being used at any stage in the life history or for the hypothesis of alternating light and heavy infestation years between 1958 and 1963.
Strawberry latent ringspot: a new nematode‐borne virus
Authors: LISTER R. M. 
Published: February 2008

SUMMARYThe properties and mode of transmission of strawberry latent ringspot virus (SLRV) are described. Natural infections have been found, in several widely separated localities, on cultivated and wild rosaceous species—strawberry, raspberry, cherry, plum, black currant—and on elder (Caprifoliaceae), but so far no diseases in these plants have definitely been associated with SLRV. Similarly, SLRV was transmitted mechanically to a wide range of hosts, many of which it infected symptom‐lessly. SLRV is transmitted by Xiphinema diversicaudatum (Micoletsky), has polyhedral‐shaped particles of about 26 mμ diameter, and has other features that suggest it should be classified along with a group of other similar soil‐borne viruses.
Studies on a strain of raspberry ringspot virus occurring in England
Authors: DEBROT E. A. 
Published: February 2008

SUMMARYA strain of raspberry ringspot virus (RRV‐E) infecting blackberry in Essex was transmitted by inoculation of sap to twenty‐six herbaceous species, and caused symptoms in Nicandra physaloides, Datura metel and Gomphrena globosa that differentiated it from the Scottish strain of the virus (RRV‐S). In sap, with an infection end‐point of 10‐5, it was inactivated in 10 min. at 74° C, and in 5 weeks at 23° C. It was precipitated without inactivation by a 30% acetone or 30%‐saturated ammonium sulphate solution, but was inactivated when acidified to less than pH 4. Partially purified preparations of RRV‐E contained approximately equal amounts of three components with sedimentation rates of 50, 90 and 127S; electron micrographs of preparations mounted in neutral sodium phosphotungstate showed three kinds of particles with diameters about 30 mμ but with different internal structure. A preparation of RRV‐S contained a main component with a sedimentation rate of 129s, and a minor one with 50S. Petunia hybrida, cucumber and French bean seemed equally susceptible to infection with RRV‐E when grown in soil containing the nematode vector Longidorus macrosoma, but inoculation of sap infected the roots of P. hybrida much more readily than roots of the other two species. Cucumber seedlings became infected when exposed for 1 day to infective L. macrosoma, and virus‐free L. macrosoma acquired the virus from plants in 4 days. Infective L. macrosoma transmitted readily at 20° C, occasionally at 25° C, and not at 30° C; feeding seems inhibited at 30° C. RRV‐E was transmitted to seedlings grown in soil containing L. macrosoma that had been kept free from plants for 34 days. Of sixty‐eight extracts of infective L. macrosoma inoculated to Chenopodium quinoa plants, only one caused infection.
Studies on the physiology of cocoa (Theobroma cacao L.)
Authors: ASOMANING E. J. A. , LOCKARD R. G. 
Published: February 2008

SUMMARYShading retarded the growth of cocoa seedlings infected with cocoa swollen‐shoot virus proportionately more than the growth of uninfected seedlings. Infected seedlings grown in bright light did not produce the swellings on stems and roots which were consistent symptoms of infection on plants grown under shade. The type of leaf symptoms also differed in shaded and unshaded seedlings.Attention is drawn to the possible implications of shade in the severity of swollen‐shoot outbreaks in farmers' cocoa.
Factors influencing seedling infection of barley by Ustilago nuda (Jens.) Rostr
Authors: KAVANAGH T. 
Published: February 2008

SUMMARYIn the seedling method of inoculation of barley with Ustilago nuda, a chlamydospore suspension is introduced into decapitated coleoptiles held under partial vacuum. The optimum conditions for infection were provided by the use of a partial vacuum of 25 in. of mercury for 2 min. on coleoptiles 1‐1·5 cm. long: lower infection percentages resulted when the coleoptiles were over 1·5 cm. No benefit was obtained by suspending the spores in dextrose or peptone solutions.The variety Jet remained immune to infection.
The effect of potassium chloride on the infestation of sugar beet by beet eelworm, Heterodera schachtii Schmidt
Authors: CURTIS GODFREY J. 
Published: February 2008

SUMMARYA high‐potassium compound fertilizer (N, 9 parts; P, 4 parts; K, 15 parts) increased sugar‐beet size and reduced the number of cysts of Heterodera schachtii on the roots: the same effects were induced by potassium chloride, and a smaller reduction in cyst number occurred after application of a standard compound fertilizer (N, 7; P, 3; K, 5·8 parts).Application of 0·1M potassium chloride solution 2 weeks before inoculation brought about the greatest reduction in infestation; the optimum invasion by eelworm occurred after KCl application at strengths between 0·01 and 0·001M.Larvae stimulated to emerge by leachates from potassium‐treated plants were more infective than those stimulated by control leachates. Leachates from potassium‐deficient plants induced quicker and cumulatively greater hatching of cysts than did leachates from plants receiving potassium. Where only part of the root system was grown in 0·1 m KCl solution, larval invasion in the untreated portion was lower than in controls. No indication of a relationship between potassium content and infestation was observed among lines of beet selected for high and low potassium content of ‘roots’ for processing, although there was a significantly reduced population of cysts in the high‐potassium plants. In the field, large doses of potassium chloride applied as top dressings reduced the reproduction of the eelworm to below the maintenance level: sugar content and yield of the marketable ‘roots’ were unaffected: potassium content was increased.
Purple blotch (Alternaria porri) of onion in Kenya
Authors: BOCK K. R. 
Published: February 2008

SUMMARYIn 1961 an epidemic attack by Alternaria porri occurred on irrigated onions at Baringo in the Rift Valley, Kenya. Two distinct lesion types appeared: (1) typical purple or brown blotches; (2) white, irregular spots or flecks. These were present in varying proportion, depending on the duration of conditions favourable to infection, and subsequent relative humidity. High R.H. favoured the development of purple blotches; low R.H. for prolonged periods after infection usually resulted in white flecking only. These flecks were often sterile, making diagnosis difficult.Germination, appressorial and lesion formation displayed a broad optimum temperature (21–30° C). Resistance to the disease shown by a number of American hybrid onions was governed by cuticle thickness; this resistance was reduced by wounding—such as is associated with sand‐storm blast—or by incubation after infection for prolonged periods at high R.H.Two fungicides, mancozeb and dicloran, effectively controlled the disease in the field.
The effect of the composition of the storage atmosphere on the development of rotting of Cox's Orange Pippin apples and the production of pectolytic enzymes by Gloeosporium spp
Authors: EDNEY K. L. 
Published: February 2008

SUMMARYStorage of Cox's Orange Pippin apples in 5% CO2+ 3% O2 or 0% CO2+ 3% O2 at 3·3° C. reduced rotting by Gloeosporium spp., as compared with storage in air. 5% CO2+ 16% O2 was less effective and reduced rotting on fewer occasions. In some years no reduction of rotting was obtained by storage in these gas mixtures. Retardation of rotting was sometimes achieved during the early part of the storage period by treatments which did not control rotting over the whole period. Production of pectolytic enzymes was reduced by incubation in these atmospheric conditions; the effect on G. album was greater than on G. perennans.
The effects of D‐D treatments applied during a five‐course rotation on the soil population of Heterodera rostochiensis Woll
Authors: DONCASTER C. C. 
Published: February 2008

SUMMARYA field cropped with potatoes in the 1st and 6th years and with non‐host crops in the 2nd to the 5th years was divided into plots for D‐D injection, each at 400 lb./acre. Before the final potato crop, untreated plots showed a 50% mean annual decline of the population of potato‐root eelworm. Single injections in different years left populations not materially different. With repeated injections there was a progressive decrease in the proportion of nematodes killed. However, injections for 4 or 5 consecutive years decreased the populations by spring of the 6th year enough to affect them after the final host crop was grown. Under this crop, all populations increased to about the same extent.
The effect of temperature in a sack‐drier on survival of insects (Oryzaephilus surinamensis (L.) (Col., Silvanidae)) and weed seeds (Avenafafua L. and A. ludoviciana Dur.)
Authors: WILLIAMS GWYNETH C. , THURSTON JOAN M. 
Published: February 2008

SUMMARYThree kinds of damp sacks, taking 10 min. to pass through a drying plant, the heating panels of which averaged approximately 200°C., were heated to temperatures ranging from 46 to 95°C. and remained above 60°C. for not more than 5·5 min. All insects (Oryxaephilus surinamensis) attached to the sacks were killed. Seeds of Avena fatua and A. ludoviciana were more heat‐resistant than insects. Even when similar dry sacks with Avenu seeds attached were passed through the drier at its slowest rate (18 min.) with the heaters set as hot as possible without damaging the sacks, not more than 40% of the seeds were killed, although temperatures reached 81–135°C., and 105°C. was maintained or exceeded for 4–7°5 min. on the sides and faces of the sacks.
Purification and properties of lettuce mosaic virus
Authors: TOMLINSON J. A. 
Published: February 2008

SUMMARYLettuce mosaic virus (LMV) was partially purified from homogenates of infected lettuce leaves in 0·5 M sodium borate buffer (pH 7·5) containing 0·1% thioglycollic acid. The filtered homogenate was clarified by adding butanol and the virus was concentrated and partially purified by differential centrifugation. Such preparations were infective at dilution up to 10‐3. Comparable preparations made in potassium phosphate buffer were not infective.Electron‐micrographs showed the virus preparations to contain long, flexuoiis particles with a mean length of 746 and width of 13 mμ. Antisera made by injecting such preparations intravenously into rabbits precipitated specifically with the preparations and with extracts from infected leaves.