bluuebunny/crossref_metadata_2025 huggingface dataset:
Cool Storage of Some Parasites Used for Pest Control in Glasshouses
Authors: Scopes N. E. A. , Biggerstaff S. M. , Goodall D. E.
Published: April 2007

The effect on adult emergence of storing the pupae of Encarsia formosa Gahan, Aphidius matricariae Haliday and Aphelinus fiavipes Kurdjumov at various temperatures has been investigated.

Some E. formosa pupae survived storage at 10°C for periods of 41–50 days but survival was, at best, 30 per cent. Storage at lower temperatures is impracticable. After storing pupae at 13°C for 20 days before transferring them to 22°C, adult emergence was 68 per cent.

Lower temperature storage of pupae of Aphidius matricariae was possible. Following the return of the pupae to 22°C after 30 days’ storage at 4 or 7°C, adult emergence was 80 and 92 per cent respectively. When the pupae were kept continuously at 4°C, 41 per cent survived and produced adults after 42–52 days.

Storage of Aphelinus fiavipes pupae was tested down to 7°C. After 30 days at this temperature, adult emergence was 75 per cent when the pupae were transferred to 22°C. However, only 4 per cent survived storage when the pupae were transferred to 22°C after 83 days.

Humidity did not affect the survival or emergence of the parasites. Prehminary tests with E. formosa and Aphidius matricariae showed no adverse effects on fecundity.
The Reaction of Eleven Genotypes of Lolium perenne to British and New Zealand Strains of Gloeotinia temulenta
Authors: SPROULE T. R. M. , FAULKNER J. S.
Published: April 2007

A method involving induced infections is being used to breed for resistance to Gloeotinia temulenta in Lolium pererme. Resistance has been found to vary in a quantitative manner which is repeatable from year to year, but is not specific to strains of the pathogen from particular geographical areas, although these strains differ in their overall aggressiveness.

Any cultivar of L. perenne selected by this method is likely to be resistant throughout the world.
Colorado Beetles Reported in England and Wales, 1973
Authors: SEYMOUR P. R.
Published: April 2007

In 1973, 103–108 adults of the Colorado beetle, Leptinotarsa decemlineata (Say), were found, of which 51 were alive. This is the largest annual total for 20 years. Details of these finds are presented. The outstanding feature is the large number (74–79) associated with French wheat.
Effect of Nitrogen Nutrition of the Host on Barley Powdery Mildew
Authors: BAINBRIDGE A.
Published: April 2007

The number of mildew infections, pustule growtk ard conidia production were all increased by giving more nitrogen to barley plants in pots. Thus, independent of any effect of increased plakt growth on atmospheric humidity in a crop, nitrogen supply could directly influence the speed of disease development.
Chlorotic Streaking in Italian Ryegrass
Authors: CATHERALL P. L.
Published: April 2007

A virus apparently indistinguishable from the ryegrass.chlorotic streak virus in New Zealand has been found in Britain where it appears to be similar to, if not identical with, isolates of barley yellow dwarf virus transmitted specifically by Rhopalosiphum padi.
Evaluation of Potential Molluscicides for the Control of the Field Slug, Agriolimax reticulatus (Müll.)
Authors: SYMONDS B. V.
Published: April 2007

Nine candidate molluscicides were compared with methiocarb and metaldehyde in tests against the field slug, Agriolimax reticulatus (Müll.), in the laboratory and in small plot tests under glasshouse and field conditions. The candidate chemicals comprised two organo‐phosphates and seven carbamates. A mixture of one of the carbamates and metaldehyde was also tested. Formulations included pellets, granules and wettable powders. Only WL21959 (S‐2‐cyanoethyl N‐[(methyl carbamoyl) oxy] thioacetimidate) was more effective than proprietary pellets of metaldehyde or methiocarb. In field trials, pellets of WL 21959 at 5 kg/ha consistently caused the highest slug mortality; a wettable powder formulation was also effective under ideal conditions. In laboratory experiments, WL 21959 was active as a seed treatment for slug control in wheat. The effects of the chemicals on earthworms in field trials were also recorded. WL 21959, particularly the granular formulation, was the most toxic to earthworms.
The Effect on Verticillium Wilt of Strawberries of Plant Spacing, Fertilizer Application and Defoliation
Authors: WILLIAMS HEDLEY
Published: April 2007

The incidence of verticillium wilt in strawberries was markedly affected not only by cultivar, but by plant spacing, defoliation in the previous year, and fertilizer application. It is suggested that a closer study of these and other components of the environment might lead to a more satisfactory means of control than is at present available.
Strawberry Latent Ringspot Virus In Glasshouse Roses
Authors: SWEET J. B.
Published: April 2007

A study of 16 glasshouse rose crops in five Lee Valley nurseries revealed infections of strawberry latent ringspot virus (SLRV) in six crops and arabis mosaic virus (AMV) in one crop. Virutiferous Xiphinema spp. were detected in the soil of four of the 16 crops. Virus was not isolated from rose rootstock species and young nursery plants being propagated for rose crop production. It was concluded that Xiphinema was probably primarily responsible for the initial infection of subsequent rose crops with SLRV and the spread of the virus within a crop.
Systemic Nematicides for the Control of Tricbodorid Nematodes and of Potato Spraing Disease caused by Tobacco Rattle Virus
Authors: ALPHEY T. J. W. , COOPER J. I. , HARRISON B. D.
Published: April 2007

Field trials in Scotland in 1972 and 1973 tested the effects of three systemic nematicides (aldicarb, fenamiphos and oxamyl) and the fumigant dichloropropane‐dichloropropene mixture (D‐D) on the incidence of spraing in potato tubers (cv. Pentland Del) and on total numbers of trichodorid nematodes, the vectors of tobacco rattle virus. Spraing incidence was least in plots treated with, aldicarb or oxamyl. D‐D and fenamiphos were effective in decreasing spraing incidence in one year but not in the other. Whereas D‐D killed the trichodorid vectors, aldicarb and oxamyl did not kill them but apparently affected their behaviour. None of the chemicals was phytotoxic or decreased tuber yield.
Influence of Spray Timmg for the Control of Powdery Mildew on the Yield of Spring Barley
Authors: JENKINS J. E. E. , STOREY I. F.
Published: April 2007

The highest mean yield increase from a single spray of tridemorph applied for the control of powdery mildew was 540 kg/ha (12·1 per cent) more than the yield of unsprayed crops. Two or more sprays increased yields by 703 kg/ha (15·6 per cent). The more susceptible cultivars gave highest yield increases. Crops near winter barley gave higher yield increases than crops not near winter barley and responded best to early sprays whereas the other crops responded best to sprays applied later. Highest yield increases were obtained when sprays were applied as soon as 3–5 per cent of the leaf area of the oldest leaves was affected by mildew and this was the best criterion for timing sprays. Usually such sprays were applied during the growth stages 6–9 so that applying the fungicide with the herbicide up to growth stage 5 would not give the highest yield increase.

The best relationship between mildew and yield increase was obtained when a cumulative mildew index (per cent mildew x days) was used.
Comparative Effects of Septoria nodorum on Spring Wheat and Barley
Authors: JONES D. GARETH
Published: April 2007

Spore suspensions of Septoria nodorum isolated from wheat were used to initiate epidemics on the spring wheat cv. Cardinal and the spring barley cv. Proctor in a field trial. Inoculations were made at g.s.5, 9 and 10.5.4. as separate treatments in wheat and at g.s.5, 9 and 10.3 in barley. A multiple inoculation treatment consisting of all three inoculations was also included.

Disease symptoms were much more severe on wheat than on barley both on the leaves and the heads. The largest reductions in 1,000 grain weight were caused by the triple inoculations with decreases of 48 per cent in wheat and 31 per cent in barley. Inoculation at g.s.5 affected only the number of grains and the mean yield per ear and then only in wheat. Fertile tiller number was also reduced by this early inoculation but not significantly. The results are discussed both in relation to the differential reactions of the two hosts and in terms of the epidemiological implications of cross‐infection under field conditions.
Testing for Field Susceptibility of Potato Tubers to Blight (Phytophthora infestans)
Authors: HOWARD H. W. , LANGTON F. A. , JELLIS G. J.
Published: April 2007

A method using microplots is described for assessing the susceptibility of potato tubers to late blight. The relative amounts of tuber infection of five standard cultivars were consistent in tests carried out during five ‘non‐blight’ years except for Arran Banner in 1973. No results were obtained in a sixth year.
Yield‐loss Relationships in Cereals
Authors: RICHARDSON M. J. , WHITTLE A. M. , JACKS MARGARET
Published: April 2007

The results of six studies using precision methods to obtain quantitative yield‐loss relationships are reported. Losses ranged from 100 per cent for Pyrenophora graminea on barley, to 51 per cent in a simulated grazing trial on wheat, 20 and 8 per cent respectively for Fusarium nivale and Rhizoctonia solani causing culm lesions on wheat, and 12 per cent for yellow rust on barley. Evidence of interactions between seed treatment with mercury, F. nivale infection and mildew on barley is also presented, in which seed treatment was beneficial regardless of seed infection, and F. nivale intensified the loss due to mildew.
Evaluation of Benomyl Soil Drenches for the Control of Verticillium and Fusarium Wilt of Carnations
Authors: EVANS S. G,
Published: April 2007

Two benomyl soil drenches at 3–6 g a.i./ll i./m2 applied soon after wilt had appeared in the crop and again a fortnight later gave good control of Verticillium cinerescens in a commercial crop of carnations. Satisfactory control of wilt caused by Fusarium oxysporum f. dianthi was obtained in two commercial crops by drenches of benomyl at 3–6 g a.i./5.5 l./m2 when applied soon after planting and subsequently at three‐monthly intervals.
Hollow Heart of Field Bean (Vicia faba L.) Seeds
Authors: HARRISON J. G.
Published: April 2007

Hollow heart of field bean seeds Is described. It occurred in all cultivars and in all seed lots which were examined. Soaking seeds in water increased the incidence of the disorder.
Effects of Fungicide Spraying on Brown Rust and Yield in Spring Barley
Authors: MELVILLE S. C. , GRIFFIN G. W. , JEMMETT J. L.
Published: April 2007

In three field experiments in Cornwall in 1969–71, spraying 6–8 times with the fungicides zineb or oxycarboxin gave good control of severe attacks of brown rust (Puccinia hordei) in four cultivars of spring barley and increased the persistence of green leaf tissue. The disease developed late in the season, mainly after ear emergence, Other leaf diseases were slight, except for mildew (Erysiphe graminis) in 1971 in one cultivar. Spraying resulted in increases in grain yield ranging from 17 to 31 per cent and these were almost wholly due to increased grain weight (1000‐grain weight). One and two‐spray programmes of the fungicides gave only a partial control of brown rust and small yield increases. There was a statistically significant relationship between grain yield and brown rust recorded at growth stage 75 (11.1),* an increase of 10 per cent in brown rust on the second top leaf reducing yield by 7.7 per cent.
Effects of Chlorpropham and Storage Temperature on an Abnormal Form of Skin Spot on Potato Tubers
Authors: FRENCH W. M.
Published: April 2007

Samples of potato tubers, cv. Désirée showing abnormal skin spot lesions were subjected to different temperature and chlorpropham (CIPC) treatments. The depth of penetration, of lesions was greater at low temperature (5°C) and significantly greater in the presence of chlorpropharn at 5°C. At 10–15°C there was no further skin spot penetration in the presence or absence of chlorpropham.
The Timing of Hot‐water Treatment in Controlling Fusarium oxysporum Basal Rot of Narcissas
Authors: PRICE D. , BRIGGS J. B.
Published: April 2007

Narcissus bulbs were treated with various concentrations of formaldehyde in hot water at different times relative to lifting and planting. There was no improvement in control of Fusarium oxysporum basal rot by using formaldehyde concentrations greater than the usual 0.2 percent. The date of treatment was critical, and better control of the disease was obtained by treating in mid‐July than in mid‐August, although flower production in the following season was impaired.
Relationship between Day‐length, Root Growth and Infection of Chamaecyparis lawsoniana var. ellwoodii by Phytophthora cinnamomi Rands
Authors: FOSTER W. R. , SEABY D. A. , MALONE J. P.
Published: April 2007

Acute infection of Chamaecyparis lawsoniana var. ellwoodii by Phytophthora cinnamomi occurred when many zoospores were present and the roots were growing actively. Active root growth occurred during periods of long day‐length. It is suggested that chronic infection results when few zoospores are present or if infection takes, place when the majority of the root tips are dormant.
Biological Control of White Rot of Onion (Sclerotium cepivarum) by Coniothyrium minitans
Authors: AHMED A. H. M. , TRIBE H. T.
Published: April 2007

The fungus Coniothyrium minitans is pathogenic to Sclerotium cepivorum, the causal agent of white rot of onion. In a glasshouse experiment, pycnidial dust prepared from C. minitans was used in soil treatments and as a seed dressing to protect onion seeds sown in S. cepivorum infested soil. Comparison was made with seed dressed with calomel, the standard fungicide used for white rot control. Seed dressing with C. minitans or soil dusting with C. minitans protected the onion plants from white rot as well as did calomel dressing. The calomel‐treated plants showed markedly poorer development than those treated with pycnidial dust, presumably because of phytotoxicity. The pycnidial dust appears equally effective against white rot, is much safer than calomel and should be very much cheaper. It is recommended for development for practical control of white rot.
The Incidence of Aphis fabae Scop. on Spring‐sown Field Beans in South‐east England and the Efficiency of Control Measures
Authors: GOULD H. J. , GRAHAM C. W.
Published: April 2007

Surveys of crops of spring‐sown field beans from 1966 to 1974 in the counties of Hampshire, Berkshire, Buckinghamshire and Oxfordshire showed that the incidence of Aphis fabae Scop, infestation varied from season to season and often between counties in the same year. The heaviest infestations occurred in 1967, 1972 and 1973 and the lightest infestation was in 1968 vvhen few winged aphids colonized headland plants. Estimates for 1972 and 1973 showed that treatment was economically worth while on most fields in these years. Phorate was the most frequently used insecticide and gave good control, although it was less effective in years in which there was a dry spring. Disulfoton and sprays of demeton‐S‐methyl and menazon also gave good control, although menazon was less effective as an eradicant spray after colonies of aphids had become established.
Surveys of Foliar Diseases of Spring Barley in England and Wales, 1972–75
Authors: KING J. E.
Published: April 2007

Randomly selected crops of spring barley in England and Wales were sampled annually in July, when the grain was filling most rapidly, and the diseases affecting the flag and second leaves were assessed. Mildew was the most common disease in all years and was the most severe disease on both leaves, except in 1975 when it was slightly less severe on the flag leaf than yellow rust. Other frequently recorded diseases were brown rust, leaf blotch and, in 1972, 1973 and 1974, Septoria spp. Halo spot and net blotch were infrequent and generally not severe. Fungicides, applied as a seed treatment or foliar spray, were used on up to 47 per cent of the crops assessed and were associated with a decreased severity of mildew. It is estimated that in 1974 and 1975 at least 60 per cent of the crops which received no fungicide would have given an economic yield increase following treatment for mildew control. Annual estimates of national yield losses caused by mildew varied from 5·7 to 13·0 per cent: much greater than the 0·2 to 1·7 per cent estimated for brown rust or leaf blotch. Barley yellow dwarf virus was detected by transmission tests in the majority of the samples tested.
Phytophthora syringae Fruit Rot of Apples
Authors: UPSTONE M. E.
Published: April 2007

Apples affected by Phytophthora syringae (Kleb.) Kleb. fruit rot show a firm brown rot which spreads through the fruit and may later be masked by secondary rotting organisms. Occurrence of the disease in commercial apple crops in Kent and Sussex was extremely variable during the four fruit storage seasons 1973–77. Following initial infection in the orchard, the disease spread to adjacent healthy fruit during refrigerated storage. Post‐harvest treatment with benomyl in water had no consistent effect on the spread or development of the disease in fruit in the laboratory or in commercial crops. It is suggested that soil contamination of fruit and rain splash from soil are the means of infection in the orchard, and that the recent prevalence of the disease may be a result of the maintenance of bare soil in orchards and the increased use of dwarfing rootstocks and pruning systems so that fruit are grown nearer to the ground.
Large‐scale Rearing of Wheat Bulb Fly (Delia coarctata (Fall.))
Authors: JONES MARGARET G. , MOORE R.
Published: April 2007

summary

Methods for large‐scale collection and rearing of wheat bulb flies are described. About 80 000 eggs were obtained from about 4000 flies collected from infested fields in eastern England. When larvae fed on wheat plants, 55–70 per cent of those that hatched from the eggs became flies. At 15°C the time taken from hatching of the larvae until the emergence of flies was about seven weeks. Thirty‐eight artificial media were tried for rearing larvae, but none was successful.
The Period of Susceptibility of Red Beet to Streptomyces Scab
Authors: ADAMS M. J. , LAPWOOD D. H.
Published: April 2007

Red beet growing in pots, either out‐of‐doors in Hertforoshire or in the glasshouse, was inoculated with a pathogenic Streptomyces isolate. The Plants which become susecptible at decortication (about five weeks after sowing), became resistant after about a further two weeks. This allows a relatively short period during which a potential control measure would need to be effective.
Treatment of Chrysanthemum Stools against White Rust (Puccinia horiana P. Henn.)
Authors: DICKENS J. S. W.
Published: April 2007

Chrysanthemum stools (cvs Yellow American Beauty and Purple Favourite) were treated against Puccinia horiana P. Henn. by immersion for 5 min in water at 46·1°C, by dipping in suspensions containing benodanil or zineb, by spraying them with a suspension containing dmoseb in oil or by removal of all visible green parts. Only the hot‐water treatment prevented the rust from surviving on the stools.
Internal Browning of Hyacinth caused by Erwinia rhapontici
Authors: SELLWOOD JENNIFER E. , LELLIOTT R. A.
Published: April 2007

A yellow‐brown necrosis of the innermost scale leaves of hyacinth bulbs was shown to be caused by Erwinia rhapontici (Millard) Burk‐holder. This finding extends the known host range of this pathogen, which now includes wheat, hyacinth and possibly clover as well as rhubarb. Its existence on apple and pear was established, thus supporting speculation that it is a widespread and an opportunist pathogen. An amended description of E. rhapontici is given.
Effect of Inoculating Soils with Phialophora radicicola var. graminicola on Take‐all Disease of Wheat
Authors: Gutteridge R. J. , Slope D. B.
Published: April 2007

In a glasshouse pot experiment two successive wheat crops were grown to near maturity in soils naturally infested by the take‐all fungus, Gaeumannomyces graminis var. tritici, with or without inoculum of Phialophora radicicola var. graminicola (PRG) added before the first crop was sown. PRG decreased take‐all in both crops. More PRG infections were recorded on plants in soil taken from continuous wheat than in soil from a second wheat crop or beans. Field plants were also more infected by PRG in continuous wheat than in first, second or fourth wheat crops after beans, but fewer root pieces were infected than on plants from pots. Evidence to suggest that PRG may contribute to the decline of take‐all in continuous wheat was inconclusive. No PRG was recorded on Alopecurus myosuroides.
Crown Gall of Blackberry: Field Spread and Susceptibility to Disease
Authors: GARRETT CONSTANCE M. E.
Published: April 2007

In two commercial blackberry plantations almost all the bushes became infected with crown gall (Agrobacterium tumefaciens (Smith & Townsend) Conn) within five years of establishment from nursery stock in which there was some infection. Inoculations to determine the relationship between time of pruning and crown gall susceptibility showed that there was no safe time for cutting out old canes, their cut surfaces remaining susceptible for several days at least, Leaf scars and lateral cuts were susceptible throughout the year but were most readily infected during the growing season.
Effect of post‐harvest fungicide drenches on stored winter white cabbage
Authors: GEESON J. D. , BROWNE K. M.
Published: April 2007

In five commercial‐scale storage trials of winter white cabbage during 1974–78, post‐harvest drenches of benomyl, thiabendazole or iprodione gave good control of rotting by Botrytis cinerea Pers. ex Pers., which was the main cause of spoilage in untreated cabbage stored at 0–1°C and about 95 per cent relative humidity. All three fungicides controlled rots caused by Mycosphaerella brassicicola (Duby) Lindau and iprodione also controlled Alternaria spp. Some drench treatments resulted in more bacterial rots due to Pseudomonas marginalia (Brown) Stevens, and the early development of ‘pepper‐spot’ (a non‐microbial leaf necrosis disorder) was accelerated by drenching. However, the recovery after 30 or 36 weeks’ storage of trimmed cabbage suitable for coleslaw manufacture was increased by up to 11 per cent by the fungicide treatments, which could also extend the storage season and reduce trimming costs.
Records of crop damage by some species of cyst nematodes in eastern England, 1967–77
Authors: SAVAGE M. J.
Published: April 2007

Records of crop damage in eastern England from 1967 to 1977 inclusive are tabulated and mapped for the cereal cyst nematode (Heterodera avenae Woll.), carrot cyst nematode (Heterodera carotae Jones), brassica cyst nematode (Heterodera cruciferae Franklin) and pea cyst nematode (Heterodera goettingiana Liebscher). Although distributions of crop damage by these cyst nematodes have not altered significantly from previous reports, the frequencies show distinct fluctuations from year to year.
Effect of aldicarb on ectoparasitic and migratory endoparasitic nematodes and on the yields of spring barley
Authors: SAYNOR M.
Published: April 2007

In six trials in 1971 on two different soils in eastern England, aldicarb at 4.4 kg active ingredient per ha reduced the numbers of Pratylenchus in the roots of spring barley during the season and also the numbers of Pratylenchus and ectoparasitic nematodes in the soil after harvest. Yields of barley were increased in only two of the five trials harvested. P. neglectus (Rensch) Chitwood & Oteifa was the commonest species of Pratylenchus at all six sites, but small numbers of P. penetrans (Cobb) Chitwood & Oteifa were found at three sites and at two of these aldicarb increased yields slightly.
Survey of diseases of glasshouse tomato crops in England and Wales in 1976
Authors: FLETCHER J. T. , HARRIS PATRICIA A.
Published: April 2007

One hundred and forty‐six tomato crops throughout England and Wales were assessed for diseases. The commonest fungus pathogen was Botrytis cinerea Pers. ex Fr. which caused stem lesions in 64 per cent of the crops, leaf lesions in 38 per cent and fruit ghost spot in 46 per cent. Benomyl tolerance was widespread in isolates of this pathogen and was detected in 50 of the 68 crops examined. Seventy‐seven per cent of isolates from crops sprayed with a methyl benzimidazole carbamate (MBC) fungicide were tolerant compared with 34 per cent from crops where these fungicides had not been used. Fulvia fulva (Cooke) Ciferri was found in 28 per cent of the crops but was severe in only three per cent. Didymella lycopersici Kleb. occurred in seven per cent of the crops. Tomato mosaic (TMV) symptoms were seen in 34 per cent of the crops, although 47 per cent of those surveyed were of resistant cultivars in which no virus symptoms were seen. The Dutch avirulent TMV strain MII‐16 was used for crop protection on 27 per cent of the nurseries. TMV strains collected from crops with symptoms were predominantly strain 1 (85 per cent) and 96 per cent of isolates from crops inoculated with MII‐16 were of this strain. No new strains or tobacco forms of TMV were found.

Root rots were extremely common at the end of the crops, varying in intensity according to the pre‐planting soil treatment. Steam treatment was most effective (28 per cent root rot) with methyl bromide the next best (30 per cent), followed by dazomet (42 per cent). Methyl bromide was used by 45 per cent of growers, whereas 17 per cent used steam and 11 per cent dazomet. Peat‐bag culture was used on five per cent of the nurseries. In peat‐bag culture there was little root rot (11 per cent). Verticillium spp. were isolated from 25 per cent of crops in the survey and Fusarium oxysporum Schl. from eight per cent. Chimeras were found in 34 per cent of the crops, but only in 1.1 per cent of the affected plants was the chimera affecting the growing point and likely to affect yield. There was a tendency for early‐planted crops to have a greater incidence of chimera. Generally the cultural factors recorded did not appear to be connected with disease incidence, but there was a significant increase in the amount of Botrytis in the stopped plants. Benomyl, either as a spray or a drench, was the most commonly used fungicide, but more than a third of the crops did not receive any fungicidal treatments.
Tolerance of Botrytis cinerea to iprodione and vinclozolin
Authors: DENNIS C. , DAVIS R. P.
Published: April 2007

Isolates of Botrytis cinerea Pers. ex Pers. from slow‐developing lesions on strawberries from plants treated with iprodione or vinclozolin fungicides were found to grow on potato dextrose agar (PDA) containing 10 000 p.p.m. iprodione or 1000 p.p.m. vinclozolin. At smaller concentrations, the presence of these fungicides sometimes stimulated growth of these tolerant isolates. When isolates of B. cinerea sensitive to iprodione and vinclozolin were placed on PDA containing between 1 and 5 p.p.m. of one of these fungicides, a few of the cultures showed mycelial growth after extended incubation for seven days. These cultures were also able to grow when subcultured on fresh PDA containing 5 p.p.m. of iprodione or vinclozolin.
The presence of pathotype Pa2 of Globodera pallida in the United Kingdom
Authors: STONE A. R. , FULLER J. M. , HOWARD H. W.
Published: April 2007

Globodera pallida (Stone) Behrens pathotype Pa2 is reported from the United Kingdom for the first time. This pathotype, rather than Pa3, may be the most common among populations designated E in the former UK pathotyping scheme.
The Effects of Pesticides on a Perennial Ryegrass Sward
Authors: PLUMB R. T. , JENKYN J. F. , BROOM E. W.
Published: April 2007

Dazomet, applied to the soil in September 1972, increased the dry matter yield in 1973 of perennial ryegrass (Lolium perenne L.) cv. Gremie sown that spring in Hertfordshire. The greatest increase (60 per cent) was where least nitrogen had been applied and was not apparently the result of differences in pathogen or pest incidence. Sprays of the fungicides benodanil and benomyl, and drenches of captafol, did not affect yield in 1973 or 1974, although benodanil controlled crown rust (Puccinia coronata Corda) in August and September 1973.

Sprays of the acaricide cndosulfan and the aphicide menazon had no detectable effects in 1973. In 1974, endosulfan sprays, either alone or with menazon, controlled Abacarus hystrix (Nal.), the mite vector of ryegrass mosaic virus (RMV), decreased RMV incidence from 54 to 26 per cent and increased dry matter yield by six per cent.

Mildew (Erysiphe graminis DC.) was observed in 1973 and leaf spot (Drechslera spp.) was common in 1973 and 1974, but infection by both diseases was only slight. The incidence of barley yellow dwarf virus was slight and not apparently affected by the treatments. Root discoloration was common but not affected by dazomet or captafol. Fusarium culmorum (W. G. Smith) Sacc. was commonly isolated from very discoloured roots and one isolate, which was weakly pathogenic to ryegrass, killed wheat seedlings. After cutting, patches of grass in plots given 150 kg nitrogen/ha/cut showed poor regrowth, but this could not be associated with pathogens. Mildew and RMV were most common on plots given most nitrogen (150 kg N/ha/cut). RMV and its vectors were apparently more detrimental during the experiment than were other pathogens.
Observations on the epidemiology of Leptosphaeria macutans stem canker in winter oilseed rape
Authors: GLADDERS P. , MUSA T. M.
Published: April 2007

The main source of Leptosphaeria maculans (Desm.) Ces. & de Not. infection on winter oilseed rape in Cambridgeshire was stubble debris from the previous season. Heavy leaf spot infection of seedlings near unploughed oilseed rape stubble resulted in complete crop loss. The fungus actively colonised stubble debris after harvest and perithecia were formed predominantly on tissues colonised during this period. Ascospores were detected throughout the year, mainly from October to April. The degree of leaf spot infection in the autumn was correlated with stem canker infection at the end of flowering and with severe stem lesions at harvest. The incidence of leaf spot infection was greater in the spring than in the autumn, particularly during the period of extension growth and early flowering. Stem canker infections were first seen in March and continued to develop up to and after harvest.
Observations on the natural mortality of the overwintering pupa of the cabbage root fly, Delia brassicae (Wiedemann), in Ireland
Authors: RYAN J. , RYAN M. F.
Published: April 2007

The mean winter loss of pupae in four cabbage root fly populations in two peatland sites in Ireland in 1971/72, 1974/75 and 1975/76 was 58 · 4 per cent. Predation by carabids may have been involved as pupal loss was associated, in three winters, with the abundance of either Nebria brevicollis (F.) adults or carabid larvae. The parasites Trybliographa rapae (Westw.) (Hymenoptera: Cynipidae) and Aleochara bilineata Gyll. (Coleoptera: Staphylinidae) were recorded at average rates of 10·4 and 3·9 per cent respectively.
Colorado beetles reported in England, Wales and Scotland, 1979
Authors: BARTLETT P. W.
Published: April 2007

In 1979, 29 adults and one larva of the Colorado beetle, Leptinotarsa decemlineata (Say), were found associated with imports in England; 19 of these specimens were alive. This is the lowest annual total for seven years. Details of these finds are presented. None was found in Wales. One dead beetle was found in Scotland. No breeding colony of Colorado beetle was found. Live female beetles kept in the laboratory after capture laid an average of 524 eggs each (range 0–644) and the average percentage hatch was 24 (range 0–42).
Control of lettuce big‐vein disease by soil sterilisation
Authors: WHITE J. G.
Published: April 2007

Lettuce plants grown in the glasshouse in big‐vein‐contaminated soil previously treated with methyl bromide at 125–2000 kg/ha (x 0.125– 2.0 the dose used in the field) did not develop big‐vein symptoms, although at dosages up to 500 kg/ha their roots were infected by Olpidium brassicae(Wor.) Dang., the vector of the disease. Soil treatment with dazomet, chloropicrin, 1, 3‐dichloropropene or metham sodium gave symptom‐free plants at doses corresponding to those normally applied in the field. When applied to contaminated field plots, methyl bromide at 750 or 1000 kg/ha controlled the disease, but 10 per cent of plants showed big‐vein symptoms in plots treated at 500 kg/ha. All methyl bromide treatments significantly increased lettuce head weight compared with the untreated controls, and resulted in bromide residues in the plants of 2300–5300 ng/g of dry tissue compared with 30 μg/g in plants from untreated plots. Plants were harvested 12 weeks after completion of methyl bromide application, by which time there was evidence of leaching of bromide from the upper 10 cm of soil.
Observations on the termination of diapause in eggs of the wheat bnlb fly (Delia coarctata (Fall.)) and soil temperature
Authors: McKINLAY R. G.
Published: April 2007

The temperature of the soil 15 cm deep was recorded before, during and after hatching of wheat bulb fly eggs at several sites in eastern Scotland during 1976 and 1978–80 inclusive. Eggs were extracted from soil cores and examined microscopically to monitor the progress of hatching. In 1976, 1978 and 1979, the difference between the minimum and maximum soil temperatures was small just before the start of hatching and large at or immediately afterwards. The termination of diapause and initiation of hatching of wheat bulb fly eggs in Scotland appeared to be associated with diurnal fluctuations of more than 5°C between the minimum and maximum soil temperatures.
The spread of arabis mosaic virus through non‐cultivated vegetation
Authors: McNAMARA D. G.
Published: April 2007

Soil sampling for Xiphinema diversicaudatum (Micol.) Thorne over several years suggested that arabis mosaic virus was spreading through an elm woodland into an adjoining pasture. The rate of spread was estimated to be 11 m/year. Nematode movement was not believed to be entirely responsible for such a relatively high rate; other contributory factors were thought to be systemic movement of virus within root systems and the dissemination of virus‐infected seed.
The toxicity of diflubenzuron to honey bee (Apis mellifera L.) colonies in apple orchards
Authors: EMMETT B. J. , ARCHER B. M.
Published: April 2007

The effect of diflubenzuron on honey bees in apple orchards in southeastern England was studied in 1976. In two experiments apple trees cv. Cox's Orange Pippin, in full flower and with honey bees foraging on the blossom, were sprayed with diflubenzuron at 0.11, 0.20 or 0.40 kg a.i.†/ha, HCH at 0.25 kg a.i./ha or malathion at 2.52 kg a.i./ha. Diflubenzuron did not reduce the numbers of adult or larval bees, whereas HCH or malathion killed many adult bees. In a third experiment in 1978 in eastern England diflubenzuron at 0.22 kg a.i./ha was sprayed on to bees returning to their hive. Neither adult nor larval bees were killed by this treatment. Small quantities (0.11 and 0.30 μg/g) of diflubenzuron were found in samples of honey from hives sited in plots treated with this insecticide.
Colorado beetles reported in England, Wales and Scotland, 1980
Authors: BARTLETT P. W.
Published: April 2007

In 1980, 110 adults of the Colorado beetle, Leptinotarsa decemlineata (Say), were found associated with imports in England and Wales; 89 of these specimens were alive. This is the highest annual total for three years and the highest annual total of live beetles for 28 years. Details of these finds are presented. The outstanding features were the large numbers associated with imports of Italian spinach (55) and Portuguese timber (25). Fourteen beetles were found in Scotland of which one was alive and 13 were dead preserved specimens reported as a hoax. No breeding colony of Colorado, beetle was found. Live female beetles kept in the laboratory after capture laid an average of 871 eggs each (range 165–2462) and the average percentage hatch was 46 (range 0–73). Observations on egg laying by beetles found during the past six years showed that 34 per cent of females were capable of laying fertile eggs when they arrived in the United Kingdom.
Interaction between barley yellow dwarf virus and powdery mildew in four barley genotypes
Authors: POTTER L. R. , JONES I. T.
Published: April 2007

The effect of infection by barley yellow dwarf virus (BYDV) on host reaction to powdery mildew (Erysiphe graminis DC. f. sp. hordei Marchal) in four barley genotypes with different types of resistance to barley mildew isolate AB3, was studied in pot‐grown plants at 7,12 and 26 days after mildew inoculation. Cv. Engledow India (hypersensitive resistance) showed necrotic spotting only at the third scoring date, but the area showing symptoms was significantly less in BYDV‐infected than in control plants. On Vada (intermediately resistant), the reaction type value (a measure of host/pathogen compatibility), the percentage leaf area covered with mildew and the coefficient of infection (C.I., a mathematical combination of the other two characters mentioned) were initially less and subsequently greater on BYDV‐infected than on virus‐free plants. However, the initial trend was significant only for reaction type and C. I., and the subsequent trend only for percentage mildew cover and C.I. Reaction type values, percentage mildew cover and C.l. on cv. Emir (susceptible with some degree of adult plant resistance) and cv. Golden Promise (very susceptible) were also initially significantly less on BYDV‐infected plants, but subsequently all three characters increased to amounts not significantly different from those on virus‐free plants.
Some hosts of a Meloidogyne ardenensis population found in Scotland
Authors: THOMAS P. R. , BROWN D. J. F.
Published: April 2007

Forty‐one candidate host plant species were grown in pots of soil infested with Meloidogyne ardenensis Santos. Females and eggs were found on 11 of them: Cucumis sativus L., Daucus carota L., Fragaria x ananassa Duchesne, Fraxinus excelsior L., Hordeum vulgare L., Lolium multiflorum Lam., Lycopersicon esculentum Mill., Pinnus spinosa L., Rosa canina L., Sambucus nigra L. and Triticum aestivum L. Saccate larvae only were found on seven plant species, namely Allium cepa L., Anemone coronaria. L., Beta vulgaris L., Chenopodium album L., Poa annua L., Rubus idaeus L. and Stellaria media (L.) Vili., while females only were found on Acer pseudoplatanus L., Avena sativa L. and Chenopodium quinoa Willd. No stage of Meloidogyne ardenensis was found on any of the remaining 20 plant species. A morphometric study of specimens from this population confirmed the identify of the nema‐ tode.
Field tests with acaricides for the control of Tetranychus urticae Koch on strawherries
Authors: GOULD H. J. , JESSOP N.
Published: April 2007

Twenty‐three pesticides were evaluated in 18 trials in 1974–79 for the control of red spider mite (Tetranychus urticae) on strawberries in areas in England where strains of mites resistant to the organophosphorus pesticides and dicofol were known to occur.

The organophosphorus pesticides chlorpyrifos and triazophos continued to give good control at most of the sites. Demeton‐S‐methyl, dioxathion and omethoate used at only two of the sites significantly reduced the number of mites. Pirimiphos‐methyl, dimethoate and quinalphos used at only a few sites did not give a significant control. The carbamates aldicarb, thiofanox, formetanate and methiocarb usually gave significant control.

Of all the pesticides tested, cyhexatin consistently gave the best control The specific acaricides amitraz, dienochlor, dinobuton, fenbu‐ tatin oxide, propargite and quinomethionate were usually effective. Dicofol gave much more variable results than in earlier trials, probably because of resistance.
Characterization of isolates derived from single resting spores of Plasmodiophora brassicae and studies of their interaction
Authors: JONES D. R. , INGRAM D. S. , DIXON G. R.
Published: April 2007

A technique for inoculation of Brassica seedlings with single resting spores of Plasmodiophora brassicae is described. Three isolates derived from single spores were produced from one population of P. brassicae. They gave different reactions with the European Clubroot Differential (ECD) series, and two gave different reactions from those of the spore suspensions from which they were derived. When two isolates were mixed together, spores of one isolate restricted infection by spores of the other isolate.
The persistence of Botrytis allii in field soil
Authors: MAUDE R. B. , BAMBRIDGE JUDITH M. , PRESLY A. H.
Published: April 2007

Neck rot (Botrytis allii) affected bulbs of onions for 2 successive years when these were grown either in the field in soil from which an infected crop had been cleared 6 months previously or when infected debris was incorporated into field soil 6 months before the first crop was sown. These sources did not continue to cause infection of onion crops grown on the contaminated areas in the four succeeding years.

The white storage tissue of onion bulbs (healthy or infected) persisted for less than 6 months in unsterile field soil contained in pots while sclerotia present in similar soil varied in their rate of decay but lost their capacity to produce conidiophores of B. allii after 6 months. In one sample, sclerotia were not recovered after 5 months; Gliocladium roseum, a mycoparasite, was present in this sample and may have affected survival.
Field assessment of resistance to powdery mildew in mature wheat plants
Authors: BENNETT FIONA G. A. , WESTCOTT B.
Published: April 2007

Rankit transformation of mildew scores was used in regression analyses to compare the times and methods of scoring resistance. This showed that time and method of assessment significantly altered the relative rank positions of different cultivars. Examination of 10 cultivars in detail showed that changes in rank were associated with differences in organ resistance.

Whole plot assessments based on a 0–9 scale provided a rapid and reliable means of ranking cultivars. Where possible, and particularly for breeders, at least two assessments are recommended, the first at or soon after flowering to estimate foliar infection, and the second 2 or 3 weeks later to estimate ear infection. For general comparisons of cultivars, sufficient information may be acquired from a single assessment when all plant organs are present and when the disease has had time to become well established.
Translocation of 14C‐labelled photoassimilates to roots in barley: effects of mildew on partitioning in roots and the mitotic index
Authors: WALTERS D. R. , AYRES P. G.
Published: April 2007

First leaves of barley seedlings grown in solution culture were inoculated with powdery mildew when the second leaf was fully emerged. 14C‐labelled carbon dioxide was fed to either first or second leaves of infected and non‐infected plants. Translocation of labelled photoassimilates into roots, and partitioning into soluble, storage and structural fractions were studied in tip, mid and basal regions of primary roots 24 h after feeding. Mildew reduced the total activity in the plant, but had little effect on assimilate distribution since the percentage activity translocated to roots was only transiently reduced, approximately 7 days after infection. Reduced import led to a reduction in the specific activity of different fractions within roots, reductions being greatest in root tips. These changes were similar whichever leaf was fed. Changes in specific activity became progressively more pronounced in the 10 days following infection, and were paralleled by a reduction in the mitotic index of root tips. It is concluded that meristematic activity, and thus the growth, of primary roots of barley is particularly sensitive to reductions in photoassimilation caused by powdery mildew infection.
Interactions between Cercospora arachidicola and Phoma arachidicola, and their effects on defoliation and kernel yield of groundnut
Authors: COLE DESIRÉE L.
Published: April 2007

Cercospora arachidicola and Phoma arachidicola spread independently on groundnuts when leaf area was not limiting, but where C. arachidicola colonized leaves early, it usually spread at the expense of P. arachidicola. Juice extracted from leaflets infected with C. arachidicola and separated by thin‐layer chromatography contained unidentified compounds which were not present in juice from uninfected leaflets, and prevented the growth of P. arachidicola. Cercospora leaf spot reduced photosynthesis and was the major contributor to premature leaf drop, which had an adverse effect on yield. Well blotch (P. arachidicola) only caused defoliation and depressed yield where there was very little Cercospora leaf spot present.
A rapid method of counting spores of fungal pathogens by infra‐red reflectance analysis
Authors: ASHER M. J. C. , COWE I. A. , THOMAS C. E. , CUTHBERTSON D. C.
Published: April 2007

A method of counting freshly harvested spores of powdery mildew (Erysiphe graminis f.sp. hordei), yellow rust (Puccinia striiformis) and brown rust (P. hordei) of barley as well as brown rust (P. recondita) of wheat, using infra‐red reflectance spectrophotometry was investigated. A Neotec 6350 Research Composition Analyser was used to scan spore samples on glass‐fibre filter disks in the near infra‐red region of the spectrum (1100–2500 nm) and the amount of energy reflected at 1400 different wavelengths recorded. Three wavelengths (1900, 2252 and 2308 nm) that together gave the best multiple correlation with spore populations counted on a haemocytometer slide were selected. Partial regression coefficients for each fungal species were derived by relating reflectance energy values to direct spore counts. Utilizing these and the energy reflected at the three selected wavelengths, it was possible to count spore samples with high precision. Correlations >0.9 between numbers estimated by the instrument and those obtained using a haemocytometer slide (within the range 0–30000 spores) were achieved with all the fungi examined. Application of the technique to smaller, fixed‐filter instruments as a routine method of counting spores is discussed.
Effects of nitrogen and potassium fertilizer application on Drechslera spp. and Puccinia coronata on perennial ryegrass (Lolium perenne) foliage
Authors: LAM A. , LEWIS G. C.
Published: April 2007

In a field experiment nitrogen (N) fertilizer was applied to small plots of perennial ryegrass (Lolium perenne) at rates equivalent to 0, 200, 400 and 600 kg N/ha/yr at each of two levels of potassium (K) 0 and 200 kg K/ha/yr. Plots were cut at 6‐week intervals during 1977–79 and dry matter yield was determined. Water‐soluble carbohydrate and N content of the foliage were measured at three harvests in 1977. The incidence and severity of Drechslera spp. were assessed at and between harvests; attack by Puccinia coronata was assessed each autumn. Most foliar damage was caused by Drechslera spp. This was increased by N application which also altered the relative proportions of the Drechslera spp. present. K application had no apparent effect on disease incidence. Puccinia coronata was more prevalent on older leaves and on one occasion its incidence was increased by N application.