bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Heat Treatment of Potato Tubers on Oospora pustulans
Authors: HIDE G. A.
Published: April 2007

Treating potato tubers in warm water or warm air tilled infections caused by Oospora pustulans. Control was better on tubers lifted and treated in August than in September, but some early‐lifted tubers were damaged or killed. Infections on progeny tubers after lifting were also fewer from treated seed.

Heating also decreased Helminthosporium solani on treated tubers and Rhizoctonia solani on progeny tubers.
Observations on Mildew Development in Winter Cereals: 1968–73
Authors: JENKYN J. F.
Published: April 2007

Mildew on winter cereals in autumn was increased by early sowing and proximity to infected plots sown earlier but, in all years, very little could be detected during late winter and early spring, even where there had been much in autumn. Differences in amounts of autumn mildew between plots, whether due to different sowing dates or proximity to areas of differently treated stubble, did not persist beyond spring, and in summer there was usually most mildew on, those crops sown late which had earlier been least infected.
Protection of Pruning Wounds on Apple Trees from Nectria galligena Bres. using Modified Priming Shears
Authors: SEABY D. A. , SWINBURNE T. R.
Published: April 2007

A device is described which, fitted to conventional pruning shears, applied a small quantity of fungicide to the surfaces of pruning wounds on apple trees. Of a number of fungicides tested in conjunction with the shears plienylmercuric nitrate (PMN) was found to be the most effective protectant against subsequent infections by Nectria galligena.

The data presented showed that both pruning early in the season and well above the bud reduced infection.

Wounds became increasingly resistant to infection with age and very few lesions developed from inoculation of wounds 30 days old. The protestant action of PMN remained effective throughout this period.
Observations on the Epidemiology and Effect on Grain Yield of Brown Rust in Spring Barley
Authors: KING J. E. , POLLEY R. W.
Published: April 2007

In observations made over four seasons, counts of brown rust spores trapped above barley crops and infections of healthy plants placed within crops, indicated that there was a high risk of infection on days when at least 5 far of dew were recorded following a day on which the maximum temperature was greater than 15°C. In spray‐timing trials, the fungicidal sprays applied between the first appearance of brown rust in the crop and the beginning of the exponential phase of the epidemic usually were associated with the highest yields. The relationships between levels of brown rust and yields in these trials is discussed in connection with their relevance to the estimation of losses caused by the disease.
Key for the Identification of the Instars of the Cabbage Aphid (Brevicoryne brassicae (L.))
Authors: DODD G. D.
Published: April 2007

A key is given for the identification of the instars of the cabbage aphid (Brevicoryne brassicae (L.)) based upon the characteristics of the antennae and cauda.
Routine Spraying of Potatoes to Control Aphids and Potato Blight daring 1969–73
Authors: SOUTHALL D. R. , SLY J. M. A.
Published: April 2007

Organophosphorus sprays applied to crops of potatoes in eastern England in 1969–73 inclusive controlled aphid numbers and increased yield by at least 10 per cent when populations of aphids reached 500 or more per 100 leaves on untreated plants. They also tended to reduce the severity of potato blight at sites heavily infected before mid‐September.

Fungicide sprays (mostly mancozeb or maneb) were extremely successful in controlling blight on the foliage and increased yield of ware tubers by 12–24 per cent at sites where blight became severe, the larger increase occurring when blight became severe by the end of August. Blight sprays also appeared to increase the number of aphids present in mid and late July on plots receiving aphicides.
Methods Used in Western Europe and the U.S.A. for Testing Brssica Seedling Resistance to Club Root (Plasmodiophora brassicae)
Authors: DIXON G. R.
Published: April 2007

Details of the techniques used by 12 workers in western Europe and the U.S.A. to test Brassica seedlings for resistance to Plasmodiophora brassicae are compared. Some of the details are common to all workers and would therefore need particular attention by anyone beginning such tests for the first time. In some other respects the techniques differed widely.
An Isolate of Cucumber Mosaic Virus from Rubus phoenicolasius Maxim.
Authors: JONES A. T.
Published: April 2007

Cucumber mosaic virus (CMV) was obtained from five stunted American wineberry (Rubus phoenicolasius Maxim.) plants with leaves showing yellow blotching and line pattern symptoms but not from seven symptomless plants. The virus was readily transmitted to other wineberry plants by grafting, but not to several cultivars of R. idaeus L. either by grafting, mechanical inoculation with, purified preparations, or by aphids (Macrosiphum euphorbiae (Thos.)). The isolate was indistinguishable serologically and in its behaviour in vitro from strain W, originally obtained from lettuce in England.
Diagnosis of Potato Leaf Roll Virus in Post‐harvest Glasshouse Tests
Authors: RICHARDSON D. E.
Published: April 2007

The absence of normal leaf abscission is a reliable criterion for the diagnosis of potato leaf roll virus in potato plants grown from single eye pieces under glass in winter, when typical symptoms of the virus are often indistinct or absent.
Surrey of Diseases of Glasshouse Tomato Crops in Yorkshire and Lancashire in 1974 and 1975
Authors: FLETCHER J. T. , HARRIS PATRICIA A. , BANT J. H. , COLLINS B.
Published: April 2007

Eighty‐one tomato crops were assessed for diseases in 1974 and 50 in 1975. The commonest fungus disease was Botrytis cinerea, which caused stem lesions in 90 and 66 per cent of the crops, leaf lesions in 84 and 98 per cent and fruit ghost spot in 94 and 94 per cent in the two years respectively. Benomyl tolerance was widespread in isolates of this pathogen, showing little decline in the two years in spite of the reduced use of benomyl and other similar fungicides in 1975. Fulvia fulva was severe in one crop in 1974 and in three in 1975; Didymella lycopersici was found in only one crop in 1974 and three in 1975. Tomato mosaic symptoms were seen in 73 and 66 per cent of crops in each year respectively. The use of an avirulent strain of tobacco mosaic virus (TMV) for the purpose of cross‐protection decreased from 53 per cent in 1974 to 34 per cent in 1975. Nurseries with at least some TMV‐resistant cultivars increased from 51 per cent in 1974 to 64 per cent in 1975. TMV tomato Strain 1 was the most commonly identified strain. No new strains or tobacco forms were recorded.

Root rots were extremely common and their severity was closely connected with pre‐planting soil treatment. Steam treatment gave the best control followed by methyl bromide and dazomet. The use of methyl bromide increased and the use of steam decreased in 1975. Verticillium wilt was found in 16 and 15 crops and fusarium wilt in two and three crops respectively in 1974 and 1975.

Fungicides were used on 74 and 56 per cent of crops in 1974 and 1975 respectively, the decrease in 1975 being largely attributable to the decline in the use of benomyl.
Peach‐potato Aphid, Myzus persicae (Sulz.), Resistant to Organophosphorus and Carbamate Insecticides on Potatoes in Scotland
Authors: DEVONSHIRE A. L. , FOSTER G. N. , SAWICKI R. M.
Published: April 2007

Peach‐potato apbids, Myzus persicae (Sulz.), collected from six potato fields in western and central Scotland in 1976 were tested for aphicide resistance biochemically and by bioassay. Most aphids were resistant to organophosphorus insecticides. At five of the sites, some aphids were both highly resistant to organophosphorus compounds and moderately resistant to pirimicarb.
Vertical Distribution of Potato, Beet and Pea Cyst Nematodes in some Heavily Infested Soils
Authors: WHITEHEAD A. G.
Published: April 2007

In a study of heavily infested soils in England from 1972 to 1975, potato cyst nematodes (Globodera rostochiensis (Woll.) Mulvey & Stone and G. pallida (Stone) Mulvey & Stone) were often as numerous in soil 20–40 cm deep as in soil 0–20 cm deep. Below 40 cm the nematodes were uncommon. Beet cyst nematode (Heterodera schachtii Schm.) was also as numerous or more numerous 20–40 or 40–60 cm deep as 0–20 cm deep. Pea cyst nematode (H. goettingiana Liebs.) was uncommon below a depth of about 20 cm.
Resistance in the Peach‐potato Aphid (Myzus persicae (Sulz.)) to Organophosphorus Insecticides in Yorkshire and Lancashire
Authors: SYKES G. B.
Published: April 2007

Field populations of Myzus persicae (Sulz.) collected from 30 sites in Yorkshire and Lancashire were tested by total esterase or bioassay techniques for resistance to Organophosphorus insecticides. All the populations examined included some resistant aphids and some populations contained individuals with esterase activity characteristic of very resistant aphids.
The Susceptibility of Eighteen Chrysanthemum Cultivars to the Chrysanthemum Leaf Miner, Phytomyza syngenesiae (Hardy)
Authors: IBRAHIM A. G. , MADGE D. S.
Published: April 2007

Eighteen cultivars of indoor chrysanthemums were tested in the laboratory for susceptibility to adult female Phytomyza syngenesiae (Hardy). Host susceptibility was assessed by the density of feeding punctures, the density of eggs laid, and the amount of leaf damaged by the mining larvae. Eight of the cultivars were also tested in the field for their susceptibility to leaf damage. Cv. Mary Poppins, a ‘Mini‐mum’, was the most susceptible, for it had most feeding punctures and most eggs per unit area, the largest percentage of mined leaves and a large percentage of damaged leaf area. Cv. Thumbelina, also a ‘Mini‐mum’, was the least susceptible to leaf damage, for it had the smallest percentage of damaged leaf area, although a large number of the leaves were mined. Feeding puncture/egg ratios were not found to be a consistently reliable indicator of susceptibility.
Effect of Paraquat on the Number of Spores of Rhynchosporium secalis on Barley Stubble and Volunteers
Authors: STEDMAN O. J.
Published: April 2007

The number of spores of Rhynchosporium secalis on barley stubble and on volunteers sprayed with paraquat was compared with that on stubble and volunteers left unsprayed in experiments during 1975–76 in Hertfordshire. Paraquat had no significant effect on the number of spores on stubble. The number of spores on sprayed volunteers was greater than on unsprayed volunteers for up to three weeks after spraying but then declined. Spores were present on dead plants 10 weeks after spraying. Approximately one per cent of spores washed from plants during December had germinated but numbers did not differ significantly between treatments. Spores from volunteers from three treatments were tested by inoculation to barley plants in early January, but very few were apparently viable. Spores from treated plants were as viable as from untreated plants five weeks after spraying but less viable eight weeks after spraying.
Field Trials with Attractant Traps for Timing Sprays to Control Pea Moth
Authors: MACAULAY E. D. M.
Published: April 2007

Traps containing a sex attractant of the pea moth (Cydia nigricana (F.)) and placed in pea fields at 16 sites in south‐eastern and eastern England provided records of male moths caught every two or three days from the end of May to the beginning of July, 1976. These traps indicated the arrival of pea moths in the crop considerably earlier than did the traditional egg counts. No advantage was gained by siting traps at emergence sites. The number of moths caught was correlated (P= 0·05) with final damage on unsprayed areas of the crop. Single sprays of azinphos‐methyl with demeton‐S‐methyl sulphone had little effect on damage, irrespective of spray date, so it was not possible from the 1976 data to derive an optimum spray date based on trap catches.
Effect of Timed Fungicide Sprays on Yield of Winter Wheat in Relation to Septoria Infection Periods
Authors: COOK R. J.
Published: April 2007

In field experiments in south‐east England during 1973–75, single sprays of benomyl, or benomyl with maneb, applied between flag leaf emergence and ear emergence increased yield by 0·36 t/ha when the spray followed a postulated Septoria infection period but by only 0·14 t/ha when no infection period was recorded between these growth stages. The full programme of two or more sprays resulted in a mean yield increase of 0·38 t/ha.
Effect of Non‐mercurial Fungicidal Seed Treatments on the Emergence of Sugar Beet Seedlings
Authors: BYFORD W. J.
Published: April 2007

In field trials in England from 1972 to 1975, sugar beet seed sprayed with maneb, captafol or 2‐(thiocyanomethylthio) benzothiazole produced fewer seedlings in the field than seed steeped in ethyl mercuric phosphate. The number of seedlings that emerged from 100 seeds varied greatly between fields, but differences in fungal attack are unlikely to have been an important cause.
Control of Take‐all Disease of Wheat by Grasses and Legumes
Authors: SPEAKMAN J. B. , LEWIS B. G. , COWAN M. C.
Published: April 2007

In pots containing sand or sand‐soil mixtures the commonly used ley grasses Dactylis glomerata, Festuca pratensis, Lolium multiflorum, L. perenne and Phleum pratense were equally effective in decreasing infections of wheat seedlings by Gaeumannomyces graminis var. tritici on wheat seedlings sown after the ley species had been grown. This effect could be attributed only partly to their ability to increase the incidence of the antagonist Phialophora radicicola var. graminicola which was either a natural inhabitant of the soil used, or added as an artificial culture. Other, unidentified, soil factors were equally important. Trifolium repens, and to a lesser degree Medicago sativa, also decreased infections by G. graminis var. tritici but without involvement of P. radicicola var. graminicola.
Distribution of Eggs of the Black Bean Aphid, Aphis fabae Scop., on the Spindle Bush, Euonymus europaeus L., with Reference to Forecasting Infestations of the Aphid on Field Beans
Authors: CAMMELL M. E. , WAY M. J. , HEATHCOTE G. D.
Published: April 2007

Eggs of Aphis fabae were laid on the spindle bush, Euonymus europaeus, in the bud and twig axils, on leaf or twig scars and in cracks on the rough bark which formed after about three years. The numbers of eggs laid on individual first‐year twigs on a particular bush increased with the numbers of buds that it bore, which were directly related to twig length. Very few eggs were laid on weak first‐year twigs. On cut bushes in a hedgerow, the length of first‐year twigs was inversely related to the age of the bush since cutting. Eggs laid in bud and twig axils on first‐year twigs provided an effective measure of numbers on the whole bush for, although some were laid elsewhere, the proportion on first‐year twigs was not significantly affected by the changes in the overall egg density except on very poorly growing bushes. The estimate of egg numbers was improved by excluding poorly growing bushes and by not sampling individual twigs shorter than 5 cm or those with only a single bud. Variability, particularly between sampled bushes of differing vigour, was also decreased if numbers were expressed as ‘eggs/bud’ instead of ‘eggs/twig’.
Virus‐like Symptoms in Red Raspberry Leaves caused by Fenitrothion
Authors: WOODFORD J. A. T. , GORDON S. C.
Published: April 2007

In 1977 in eastern Scotland primocane leaves of the raspberry cultivars Mailing Admiral and Mailing Delight developed numerous yellow blotches after they had been sprayed in June with fenitrothion to control raspberry cane midge (Resseliella theobaldi (Barnes)). The symptoms resembled those caused by the raspberry leaf and bud mite (Phyllocoptes gracilis (Nal.)) and by some viruses. In glasshouse‐pot trials fenitrothion produced similar, virus‐like, symptoms on cvs Mailing Admiral and Mailing Delight and slight symptoms on cv. Glen Clova, but no symptoms developed on cv. Mailing Jewel. Such spray damage could be mistaken for, or mask, genuine virus‐induced symptoms in spawn beds of susceptible cultivars.
Survey of Pests of Glasshouse Tomato Crops in Lanarkshire, 1974–77, with Special Reference to the Biological Control of Glasshouse Whitefly
Authors: FOSTER G. N. , KELLY AILEEN
Published: April 2007

Tomato crops in Lanarkshire, Scotland, were surveyed in 1974–77 to assess the incidence of glasshouse whitefly (Trialeurodes vaporariorum (Westw.)), glasshouse red spider mite (Tetranychus urticae (Koch)) and tomato moth (Lacanobia oleracea (L.)). Glasshouse red spider mite infested 65–76 per cent of the cropped area but glasshouse white‐fly, which affected 62–65 per cent of the cropped area, was the most damaging pest. The survey indicated the success of biological control of whitefly by its parasite, Encarsia formosa Gahan, in 1977 and demonstrated the potential for biological control by contract operators. The percentage of holdings with fruit damaged by tomato moth increased from 4 in 1974 to 23 in 1977.
Tolerance of Tomatoes to Pyrenochaeta lycopersici: Comparison of a Tolerant Line with a Susceptible Cultivar in Infested Soils
Authors: EBBEN MARION H. , SMITH J. W. MAXON , TURNER ENID A.
Published: April 2007

Root rot symptoms and yields of an advanced breeding line of tomato (J513) tolerant to brown root rot (BRR) were compared with those of the susceptible cultivar Ailsa Craig when both were grown in glasshouse soils having different amounts of inoculum of Pyrenochaeta lycopersici Schneider & Gerlach. Less BRR was found on J513 than on Ailsa Craig in both 1972 and 1973 and the decline in yield with increasing soil inoculum was less on J513 than on Ailsa Craig. However, the yield of J513 on freshly sterilised soils was less than that of Ailsa Craig, so that overall the yields of J513 were no heavier than Ailsa Craig on the soils used. Thus, whilst the BRR tolerance was demonstrably effective, further improvements in the agronomic potential of tolerant lines are necessary to exploit this tolerance where BRR is not severe.
Pathogenicity of Fusarium spp. Associated with Foot‐rots of Peas and Beans
Authors: CLARKSON J. D. S.
Published: April 2007

Isolates of Fusarium solani, F. solani var, coeruleum, F. oxysporum, F. oxysporum var. redolens, F. avenaceum, F. graminearum, F. sambucinum var. coeruleum and F. equiseti were obtained from field samples of Pisum sativum, Phaseolus vulgar is, P. coccineus and Vicia faba with foot‐rot symptoms. Their pathogenicity was tested in the glasshouse using artificially infested soiJ. All isolates originally identified as F. solani var. coeruleum and F. oxysporum var. redolens were later regarded as strains of F. solani on the evidence of their pathogenicity.

Virulent isolates of F. solani from Pisum sativwn were also pathogenic to Phaseolus vulgar is but usually not to V. faba, although an isolate from V. faba was strongly pathogenic to Pisum sativum. Less virulent isolates from P. sativum, Phaseolus vulgar is and P. coccineus were generally equally pathogenic to both Pisum sativum and Phaseolus vulgar is. Isolates from Pisum sativum infected other legumes, particularly Trifolium pratense and Medicago sativa and an isolate from Trifolium sp. caused severe foot‐rot of P. sativum.

Isolates of F. avenaceum, F. graminearum and F. sambucinum var. coeruleum showed non‐specific pathogenicity to P. sativum, Phaseolus vulgar is and V. faba, generally causing seedling death. F. avenaceum and F. sambucinum var. coeruleum were also pathogenic to other legumes, particularly M. sativa.
Prediction of Yield Loss due to Eyespot in Winter Wheat
Authors: SCOTT P. R. , HOLLINS T. W.
Published: April 2007

Field plots inoculated and uninoculated with Pseudocercosporella herpotrichoides (Fron) Deighton were compared in trials over a period of nine years. Regression analysis showed that percentage yield loss due to inoculation was related to the incidence of severe eyespot lesions, but was more closely related to the amount of lodging due to eyespot. Disease incidence in spring was not a reliable indicator of the subsequent rate of disease development, or of its effect on yield, but loss in yield sufficient to justify fungicide application was not observed when less than 10 per cent of shoots showed eyespot symptoms in spring.
Biological Control of Tetranychus urticae (Koch) on Protected Strawberries Using Phytoseiulus persimilis Athias‐Henriot
Authors: GOULD H. J. , VERNON J. D. R.
Published: April 2007

A series of trials in 1972–74 in the strawberry‐growing area of Cheddar in SW. England showed that introductions of the predaceous mite Phytoseiulus persimilis in March at a rate of 5–10 adults/plant gave a good control of Tetranychus urticae on protected strawberries where average populations of 0·8–15 ex‐diapause female mites per lower leaf were present at the time of introduction. The cost of the technique was not economically acceptable at the price currently charged by commercial producers of the predator for use on glasshouse crops.
Control of Didymella lycopersici on Tomato Stems with Fungicidal Paints
Authors: FLETCHER J. T. , SHARPE KAY
Published: April 2007

Slurries made from mixtures of wettable powder formulations of fungicides in water or the mineral oil Actipron were applied to Didymella lycopersici Kleb. stem lesions on glasshouse tomatoes. Benomyl/Actipron completely arrested lesion development, but the other treatments, thiram/Actipron, Actipron, and water with captan, captofol, benomyl, benomyl and maneb, an iodophor, maneb, or thiram did not prevent lesion development. Benomyl/Actipron in the ratio of 1:1·5 of commercial products (wt/vol) gave the most satisfactory control of D. lycopersici stem lesions while minimising phytotoxicity.

A fungitoxicant was recovered from tomato stems following application of the benomyl/Actipron mixture. With Actipron/benomyl the uptake of the fungitoxicant by the plants was greater than with the benomyl/water mixture, which was not as effective: it dried to a hard shell and lack of moisture may have impeded uptake of the fungitoxicant.
Control of stem nematode (Ditylenchus dipsaci) in strawberry by granular nematicides
Authors: LEWIS SERFIAH
Published: April 2007

In an attempt to find a control for stem nematode (Ditylenchus dipsaci (Kühn) Filipjev) on strawberry crops in south‐west England, aldicarb, ethoprophos, oxamyl, terbufos, thionazin and Tirpate were tested on severely damaged plants in pots. All treatments, except terbufos, decreased the number of infested plants; aldicarb and thionazin gave the best control. Fewer infested runner plants were found when the mother plant was grown in soil treated with aldicarb or thionazin. Soil treatment with ethoprophos, oxamyl or Tirpate was less effective or inconsistent in reducing spread of nematodes to the runners. Leaf treatment of the mother plants with ethoprophos or oxamyl reduced the number of infested runners.

In a field trial in 1973/74, aldicarb, oxamyl and thionazin were compared with soil fumigation with dichloropropane‐dichloropropene mixture (D‐D). Aldicarb applied at planting decreased the number of plants damaged by stem nematode and increased the number and yield of fruits. Oxamyl granules at planting followed by a spray in February also increased the number and weight of fruits harvested compared with D‐D treated plots. A single application of oxamyl at planting, with or without previous D‐D soil fumigation, or a thionazin drench in February did not reduce damage.

In three subsequent field trials in 1974–76, amounts and methods of application of aldicarb were compared with D‐D treatment. Spot applications of aldicarb to plants in heavily infested soil 15 weeks after planting reduced the rate of spread of stem nematode damage but treatment at 30 weeks had little effect. In a less severely infested plot, spot and band treatments of aldicarb, applied 10 and 21 days, respectively after planting, gave good control. Treatment with aldicarb 21 days after planting decreased the number of plants with severe symptoms, whereas serious damage was not prevented by treatment with D‐D in October or May.
Carnation rust and its control by systemic fungicides
Authors: SPENCER D. M.
Published: April 2007

Urediniospores of carnation rust remained viable for up to six months depending on the conditions of storage. Carnation plants became infected when urediniospores were kept in free water on the leaf for 24 h and uredinia appeared about two weeks after inoculation. Sprays of the fungicides benodanil, oxycarboxin, pyracarbolid or triadimefon did not eradicate established infection but root drenches of benodanil or oxycarboxin decreased rust symptoms when applied before or after inoculation of potted plants.

Oxycarboxin, applied as a drench to carnation plants growing under commercial conditions, effectively halted the progress of rust infection whereas the disease became severe in plants which did not receive the fungicide.
Observations on Pythium root rot of wheat and barley
Authors: WALLER J. M.
Published: April 2007

Pythium arrhenomanes Drechsler and P. graminicola Subramanian cause a pale brown soft rot of the young roots of wheat and barley but other fungi, including other Pythium species, can cause similar lesions. In surveys in 1967, 1970 and 1971, Pythium root rot was prevalent on wheat and barley at Rothamsted, Hertfordshire, Woburn, Bedfordshire, and Saxmundham, Suffolk. Incidence was greatest on barley, particularly on light soils, soils deficient in phosphate and in cool wet conditions. The greater susceptibility of barley to both P. arrhenomanes and P. graminicola was confirmed by inoculation experiments in the laboratory and glasshouse in which the disease severely restricted root growth.
Frost damage to winter barley
Authors: COX A. E.
Published: April 2007

Widespread damage attributed to frost lift was seen in winter barley crops in Devon and Cornwall during late spring 1978. A break in the crown root system of plants had occurred. An affected crop of cv. Astrix in Devon yielded 3.5 t/ha; this was 1.8 t/ha less than an adjacent unaffected crop of the same cultivar.
The effectiveness of soil sampling for virus‐vector nematodes in MAFF certification schemes for fruit and hops
Authors: COTTEN J.
Published: April 2007

In fruit and hop certification schemes of the Ministry of Agriculture, Fisheries and Food, sites used for the propagation of high‐grade virus‐tested stocks are soil sampled to detect vector nematodes before planting. Of 326 sites in England and Wales sampled for Foundation and Elite strawberry certification between 1963 and 1976, vector nematodes were detected in 22 per cent of sites, and most of these sites were rejected. Consideration of the theoretical aspects of sampling for vector nematodes, and of virus acquisition and transmission shows that, although soil sampling will reduce the risk of re‐infection by nematode‐borne viruses, it cannot prevent re‐infection. However, nematode‐transmitted virus infections are seldom detected during growing‐season inspections of strawberry runners entered for certification, which suggests that in practice the risks are small, probably because few vector populations are transmitting virus.
Susceptibility of plants to fungal pathogens when grown by the nutrient–film technique (NFT)
Authors: EVANS S. G.
Published: April 2007

Plants grown by the nutrient‐film technique (NFT) in a glasshouse became infected when fungal pathogens were introduced into the nutrient solution. Isolates of Pythium ultimum infected cucumber. Phytophthora cryptogea, Didymella lycopersici, Verticillium dahliae and Fusarium oxyspomm f. sp. lycopersici infected tomato, but Phytophthora nicotianae var. parasitica did not. Carnations were systemically infected by Fusarium oxyspomm f. sp. dianthi, but Phytophthora cryptogea was recovered only from the roots and caused no aerial symptoms.
Mushroom virus diagnosis: the relationship between mycelial growth rate and infection with mushroom virus four
Authors: HILL S. A. , WRIGHT DAPHNE M.
Published: April 2007

There was an inverse relationship between mycelial growth rate in culture and the numbers of particles of mushroom virus four found by electron microscopy in sporophores submitted for disease diagnosis during 1974–76. Mycelial isolates from sporophores in which few virus particles were detected often showed no decrease in growth rate. Electron microscopy alone is considered to be a satisfactory method of detecting infection by mushroom viruses.
Long‐term survival of sclerotia of Rhizoctonia tuliparum
Authors: COLEY‐SMITH J. R. , HUMPHREYS‐JONES D. R. , GLADDERS P.
Published: April 2007

In 1974 a severe outbreak of grey bulb rot (Rhizoctonia tuliparum Whetzel & Arthur) occurred on tulips in Lincolnshire in a field not planted with a highly susceptible crop for six years. A long‐term experiment on the survival of R. tuliparum showed that about 10 per cent of sclerotia can remain viable for at least 10 years. Where severe outbreaks of disease have occurred, longer intervals between susceptible crops are suggested.
Effect of four crops on the reprodnction and development of Xiphinema diversicaudatum and on the pore space, moisture content and temperature of the soil
Authors: COTTEN J. , ROBERTS HELEN
Published: April 2007

In a two‐year experiment from 1977 to 1979 in microplots growing strawberry, perennial ryegrass, spring barley or sugar beet, Xiphinema diversicaudatum(Micol.) Thorne reproduced and developed best under strawberry and least well under sugar beet. Total numbers of X. diversicaudatum were similar under spring barley and perennial ryegrass but nematode development beyond first‐stage juveniles was less under barley, probably because of the early season senescence of this crop. Differences in the host status of strawberry, barley and sugar beet could not be attributed to changes, caused by cropping, in the pore space or moisture content of the soil. It was not possible to assess the effect of pore space or soil moisture under ryegrass. During the summer and autumn of 1977 and 1978, under strawberry, barley and sugar beet, soil pores with necks large enough to admit X. diversicaudatum and even those that would admit only the first‐stage juveniles were frequently drained. The small differences in the soil temperatures recorded under the four crops had little effect on nematode reproduction and development.
A simple kit for detection of plant viruses by the latex serological test
Authors: TALLEY JANINE , WARREN FRANCES H. J. B. , TORRANCE L. , JONES R. A. C.
Published: April 2007

Serological tests were made using a simple kit consisting of dropper bottles filled with latex sera or buffer, a plastic mixing plate, plastic pipettes, wooden cocktail sticks, a black glass reaction plate and polythene bags, packed in a plastic sandwich box. Potato viruses X, S and Y were readily detected in infected potato leaves in tests done both in the laboratory and in the field. Results were obtained in 4–10 min.
Factors aflfecting the development of silver scurf (Helminthosporium solani) on potato tubers
Authors: LENNARD J. H.
Published: April 2007

When potato tubers with small amounts of silver scurf at lifting (less than 10 per cent of surface cover) were stored over periods of about five months in a dry condition, very little silver scurf developed irrespective of storage temperature. At high humidity, there was little disease after storage at 5°C and very little at temperatures below 4°C: moderate to severe infection (20 per cent or more of surface area covered) occurred at storage temperatures of about 6°C or above. Weight losses of tubers with severe silver scurf (50 per cent surface area affected) stored in a dry atmosphere for 27 weeks were greater than those of tubers with moderate (25 per cent area cover) and slight infection (5 per cent area cover), 8·5, 5·9 and 4·5 per cent respectively. However, tubers stored iti a dry atmosphere showed greater weight losses than tubers stored in a humid atmosphere, despite having less silver scurf infection. Low storage temperatures aggravated symptoms of skin spot.

Slightly affected seed tubers gave rise to more silver scurf in the subsequent crop than tubers with over 75 per cent surface affected, and crops from light sandy soils showed more infection at lifting than crops from heavier soils. These differences persisted during storage, but were largely masked if storage conditions favoured disease development, indicating that in normal stocks there is always an adequate inoculum, at lifting to produce severe symptoms. Very small amounts of inoculum giving little silver scurf after storage, resulted from using seed from stem‐cutting material or by treating seed with benomyl.
The effect of seed and stem‐base treatments with thiophanate‐methyl on the control of white rot disease (Sclerotium cepivorum) of autumn‐sown salad onions
Authors: ENTWISTLE A. R. , MUNASINGHE H. L.
Published: April 2007

In 1976/77, effective control of white rot (Sclerotium cepivorum Berk.) in autumn‐sown salad onions on field plots was obtained by seed treatment with thiophanate‐methyl at 250 g/kg followed by either three stem‐base applications of the same fungicide at 0.3 g/m row/application (equivalent to 34 kg/ha) or by four stem‐base applications at 0.15 g/m row/application (equivalent to 26 kg/ha). Seed treatment alone with thiophanate‐methyl at 125 or 250 g/kg controlled the disease in the autumn but was ineffective by harvest in June the following year.
Chemical control of onion fly, Delia antiqua (Meig.)
Authors: EMMETT B. J. , SAVAGE M. J.
Published: April 2007

In eight field plot trials in Cambridgeshire and Bedfordshire in 1977–79, insecticidal seed treatments and granules were tested against onion fly larvae. Carbophenothion, chlorfenvinphos, dieldrin, fonofos, iodo‐fenphos, permethrin and pirimiphos‐ethyl were tested as seed treatments in soil. Chlorpyrifos, dieldrin and pirimiphos‐ethyl were tested as seed treatments in peat blocks. Chlorfenvinphos and pirimiphosethyl were also tested as granules incorporated in soil and in peat blocks.

Pirimiphos‐ethyl at 5 or 10 g a.i.†/kg seed and chlorfenvinphos, carbophenothion or fonofos each at 10 g a.i./kg seed gave good control of onion fly: all seed had been treated in the laboratory. Chlorpyrifos and pirimiphos‐ethyl seed treatments at 10 g a.i./kg seed were effective but severely phytotoxic to plants grown in peat blocks. Iodofenphos at 5 or 10 g a.i./kg seed was unsatisfactory when the seed was treated in the laboratory, but commercial treatment of seed gave adequate protection from attack. Permethrin at 2.5 g a.i./kg seed gave poor control and dieldrin at 30 g a.i./kg seed provided good control only where flies were not resistant. Granules of pirimiphos‐ethyl at 1.1 kg a.i./ha or chlorfenvinphos at 2.3 kg a.i./ha generally gave satisfactory control when incorporated in the top 2 cm soil at sowing, but the chlorfenvinphos treatment reduced seedling emergence. Chlorfenvinphos granules incorporated in peat blocks at 22.0 mg a.i./peat block (0.45 g a.i./kg peat) and pirimiphos‐ethyl granules at 2.5 mg a.i./peat block (0.05 g a.i./kg peat) gave only moderate control of onion fly attack, but pirimiphos‐ethyl granules at 5.0 or 10.0 mg a.i./peat block (0.1 or 0.2 g a.i./kg peat) were effective without apparent phytotoxicity. None of the seed treatments or granules entirely prevented egg laying by onion fly females. Following seed treatment, residues of chlorpyrifos, fonofos, iodofenphos and pirimiphos‐ethyl in harvested onions were <0.3 mg/kg.
Recent developments in serological methods suited for use in routine testing for plant viruses
Authors: TORRANCE L. , JONES R. A. C.
Published: April 2007

Since the mid 1950s, there have been many developments in serological techniques for testing for plant viruses. Certain of these can provide great savings in time, labour and cost in routine testing situations and are well suited for use by advisory services, certification schemes and healthy stock programmes, statutory and quarantine authorities, and plant breeders. The recent developments are described under the headings flocculation in liquid media, gel diffusion, labelled antibodies and electron microscope serology, Flocculation tests depend on observation of aggregates formed in a liquid medium. The microprecipitin and chloropiast agglutination tests are simple forms which are still widely employed routinely. However, sensitivity is greatly improved by using flocculation tests in which antibodies are adsorbed to the surface of larger inert carrier particles, such as polystyrene latex spheres, tanned red blood cells or bentonite. Latex particles are the most widely used of these because they are easy to sensitise with antibodies, little antiserum is required and the sensitised latex can be stored for years without loss of activity. The latex test is also very simple to do, is well suited for routine checks on either small or large numbers of samples which can be grouped and can be used with many virus–crop combinations.

Gel diffusion tests depend on observation of precipitin lines formed in an agar gel medium. They are of two main types, single (= simple) diffusion and double diffusion. Both can be used effectively with viruses which have isometric or ‘near isometric’ particles but not with those which have elongated particles because these do not diffuse readily through agar. Recent developments which involve breaking elongated particles into sub‐units or fragments which can diffuse through agar now permit gel diffusion to be applied with almost all viruses. Various treatments are useful in breaking particles, the most effective of which employ detergents or other disruptive chemicals such as pyridine, pyrrolidine and ethanolamine, However, although gel diffusion tests which incorporate one or other of these treatments have been employed routinely for testing for viruses in several different crops, such tests are relatively insensitive, require much antiserum and conditions must be carefully controlled to avoid formation of nonspecific precipitin lines.

Antibodies can be labelled to make virus—antibody aggregates readily observable, or to obtain increased sensitivity in testing, or both. The only form of labelled antibody test widely employed in routine screening for plant viruses is enzyme‐linked immunosorbent assay (ELISA), in which antibody is labelled with an enzyme and positive results are observed as an enzyme‐mediated colour reaction. Since its introduction to plant virology in 1976, ELISA has been very widely applied in situations where large numbers of either individual or grouped
Rapid spread by mites of ryegrass mosaic virus from old sward to seedling ryegrass and its prevention by aldicarb
Authors: GIBSON R. W.
Published: April 2007

In experiments in 1979 and 1980 in eastern England, the spread of eriophyid mites and ryegrass mosaic virus (RMV) from transplanted old sward through plots of newly sown Italian ryegrass greatly exceeded spread by windborne mites from outside the plots. During the summer and autumn of each year, mites and RMV spread at least one metre through the ryegrass (6/7 rows) from the old sward. Applying aldicarb (10 kg/ha equivalent) to the seedbed before sowing the Italian ryegrass prevented colonisation by mites and greatly decreased spread of RMV from old sward. It is concluded that old diseased swards should be completely killed before reseeding and that RMV is likely to spread quickly to plants slot‐seeded into old pastures. The use of acaricides might prevent this spread but would be costly.
Control of the mushroom phorid Megaselia halterata (Wood) with dichlorvos applied by an automatic atomiser
Authors: WHITE P. F.
Published: April 2007

As a protection against invading Megaselia halterata adults, a newly spawned mushroom crop was treated for four weeks with intermittent sprays of small volumes of dichlorvos from an automatic atomiser. Efficient control of adults was obtained in small‐ and large‐scale tests by spraying 0.3 mg/m3 of air every 24 min. Automatic spraying of dichlorvos achieved better and cheaper control than that obtained by the incorporation of diazinon in the compost (30 mg/kg).
An effective lure for use in pheromone traps for monitoring pea moth, Cydia nigricana (F.)
Authors: WALL C. , GREENWAY A. R.
Published: April 2007

Lures containing different doses of (E)‐10‐dodecen‐l‐yl acetate (E 10–12: Ac), a sex atfractant for the pea moth, Cydia nigricana (F.), were evaluated for use in monitoring traps at sites in eastern England in 1977 and 1979.

A natural‐rubber serum stopper impregnated with 3 mg E10–12: Ac was shown to be an effective and long‐lasting lure; it was equally effective at different population densities and remained constantly attractive for at least the whole flight season of the male moth. Such lures, which are being used by growers in the United Kingdom to monitor moth populations in dried pea crops, do not need to be renewed during the season nor allowances made for reduced attractiveness.
Aetiology of barley net blotch caused by Pyrenophom teres and some effects on yield
Authors: JORDAN V.W.L.
Published: April 2007

Laboratory and glasshouse tests showed that seed from barley crops in south‐west England with much net blotch was often infected with Pyrenophora teres Drecksler. After sowing, mycelium in the caryopsis grew to infect the developing coleoptile and hence was carried above ground. On the growing foliage the fungus multiplied by conidial infection and also formed perithecia in late summer. The perithecia persisted in debris and released many ascospores in autumn which may infect volunteer plants and newly emerging barley seedlings. Pycnidia also developed on debris but the pycnidiospores were non‐infective.

Mycelial infection from seed often produced streaks on the coleoptile that quickly penetrated to the underlying leaves. This symptom was therefore often distinguishable from those resulting from air‐ or splash‐ dispersed conidia or from ascospores. In optimum weather (20°C, 100 per cent r.h.) net blotch lesions developed and sporulated within five days from inoculation and if suitably positioned could kill a leaf within 15 days.

Severe leaf infection during tillering of winter barley (cv. Sonja) grown in pots outdoors significantly decreased yield both by decreasing the number of grains per ear and the thousand grain weight. In a fungicide trial on winter barley (cv. Hoppel) field plots sprayed with propiconazole yielded 23 per cent more than untreated plots, mostly because individual grains were larger.
Differential sensitivity of Pyrenophom teres to organomercury formulations
Authors: LOCKE T. , THORPE I. G. , CARTER MARGARET A. , GAY CAROLINE E.
Published: April 2007

In agar plate tests, all 45 isolates ol Pyrenophora teres Drechsler tested were less sensitive to methoxyethyl mercury acetate (MEMA) as ‘Panogen M’ than to phenyl mercury acetate (PMA) as‘Agrosan D’, In further tests with eight isolates selected at random, mean ED50 values (p.p.m. Hg) for inhibition of mycelial growth at 17°C were 0.620 for MEMA, 0.098 for PMA, 0.070 for ethyl mercury phosphate and 0.060 for phenyl mercury chloride.

In field trials on spring barley in 1980 at seven different sites throughout England and one in Scotland, mean seedling infection of 5.8 percent was reduced to 1.2 per cent by PMA and to 1.9 per cent by MEMA.
Root‐lesion nematodes (Pratylenchus spp.) in raspberry‐cane beds entered for certification in England
Authors: GOTTEN J. , ROBERTS HELEN
Published: April 2007

Between 1978 and 1980 a total of 33 raspberry‐cane beds at eight nurseries in England were sampled to detect root‐lesion nematodes in the roots of the canes and in the soil. Pratylenchus crenatus Loof was found in 20 cane beds (five nurseries) and was the most abundant species in the roots. P. thomei Sher & Allen was found in nine cane beds and P. neglectus (Rensch) Chitwood & Oteifa in eight (four and three nurseries respectively). P. fallax Seinhorst was found in four cane beds at one nursery only and P. penetrans (Cobb) CMtwood & Oteifa in one cane bed only. At each nursery, different cultivars tended to be uniformly infested with the same species or mixture of species. There was no association between the occurrence of the different species of root‐lesion nematodes and the mineral matter content or the particle size distribution of the soil.
Relationship between eyespot severity and yield loss in winter wheat
Authors: CLARKSON J. D. S.
Published: April 2007

Between 500 and 1000 winter wheat plants were taken at random immediately before harvest from crops with naturally or artificially created attacks of eyespot (Pseudocercosporella herpotrichoides (Fron) Deighton) at eight sites in eastern England from 1975 to 1979. The individual shoots of each plant were placed in one of four categories: healthy, or slightly, moderately or severely infected with eyespot. Healthy shoots were sub‐divided into those from plants with all shoots healthy and those from plants with at least one infected shoot. Ears were threshed individually and average dry weight of grain per ear, grain number per ear and 1000‐grain dry weight were computed for each infection category and both healthy shoot categories.

Slight eyespot had no effect on yield. Moderate eyespot reduced yield per ear, grain number per ear and 1000‐grain weight by 10, 8 and 5 per cent respectively; severe eyespot caused corresponding losses of 36, 29 and 15 per cent.

Healthy shoots showed no apparent compensation for yield loss in eyespot‐infected shoots on the same plant.

The equation y= O.lX1+ 0.36x2, where y= percentage yield loss, x1= percentage of moderately infected shoots and x2= percentage of severely infected shoots, was applied to the results of ADAS winter wheat disease surveys from 1975 to 1980. National yield losses due to eyespot in these years were estimated tobe 0.9, 0.3, 1.1, 1.2, 0.7 and 0.3 per cent respectively.
Fumigation of soil with methyl bromide to kill diapausing Colorado beetles
Authors: POWELL D. F.
Published: April 2007

Diapausing adult Colorado beetles (Leptinotarsa decenilineata (Say)) were buried at various depths up to 30 cm in the soil of an experimental plot in Hertfordshire in July 1977. The plot was then covered with polythene sheeting and fumigated with methyl bromide at a rate of 1 kg/10 m2. Gas concentrations were measured at the soil surface and at a depth of 23 cm during the four days following application of the gas; leakage of gas along the edges of the plot was also measured. The gas concentrations achieved within the plot during the first eight hours (minimum 37 mg/1.) were more than sufficient to kill Colorado beetle and none of the test insects survived. Plots in Suffolk were fumigated in March 1979 witiiout test insects to determine the gas concentrations and distribution in a soil differing in temperature, moisture content and degree of compaction. Penetration and distribution of the gas were less good in these plots, the soil of which was colder, wetter and more lumpy than that in the Hertfordshire plot, and the concentration of gas was insufficient in some places to guarantee killing Colorado beetles.
The use of metalaxyl to control Phytophthora syringae rot of apple fruits
Authors: EDNEY K. L. , CHAMBERS D. A.
Published: April 2007

In an orchard in Kent, metalaxyl applied to the soil at 0.5 or 1.5 kg/ha on 20 July and to fruit as a 0.03 per cent spray on 3 September 1979 controlled rotting of Cox's Orange Pippin apples by Phytophthora syringae. There was also a residual effect of similar treatments applied in the previous year. Dipping fruits in 0.03 per cent metalaxyl controlled infections which had been developing on zoospore‐inoculated apples for five days at 10°C but not when the incubation period was longer. In post‐harvest dip treatments, the ability of metalaxyl at 0.01 per cent to control the spread of rotting by contact with apples inoculated with P. syringae was not affected if it was mixed with 0.05 per cent benomyl.