bluuebunny/crossref_metadata_2025 huggingface dataset:
Coccinellid Beetles on Sugar Beet in Eastern England, 1961–75
Authors: HEATHCOTE G. D.
Published: April 2007

The times of flight and the annual fluctuations in the numbers of coccinellid beetles on sugar beet crops in eastern England from 1961 to 1975 were determined using yellow, cylindrical sticky traps and by examining plants in plots which had not been treated with insecticide. Adalia bipunctata (L.) was the coccinellid most often trapped and it formed 33 per cent of the total catch. Propylea 14‐punctata (L.) formed 25 per cent of the total catch. Coccinella septempunctata L. was less often caught, forming only nine per cent of the total catch on traps, and it was uncommon on sugar beet except when the plants were heavily infested with Aphis fabae Scop, in August. The ‘plagues’ of C. septempunctata occasionally recorded on the East Anglian coast occurred only in years when aphids had been common on cereal crops.

Although coccinellids are one of the causes of the rapid decline of aphid populations on sugar beet in August, no evidence was found that they play an important part in controlling the spread of yellowing viruses. However, they may prevent a crop from becoming heavily infested with aphids which are potential vectors in the spring and they may destroy aphids overwintering on virus‐infected weeds and other sources of infection.
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 endosulfan 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 d0iseases 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.
Chemical Control of Leatherjackets (Diptera: Tipulidae) in Grassland
Authors: RAYNER J. M.
Published: April 2007

The control of leatherjackets in grassland by insecticides which were potential alternatives to DDT was tested in four series of field trials between 1968/69 and 1975/76 at sites throughout England and Wales. Satisfactory control was obtained with sprays of chlorpyrifos or triazophos, both of which gave results similar to spraying with DDT. Fenitrothion sprays gave good control at sites in high rainfall areas. Gamma‐HCH as a spray was effective only at a high rate of application; in bran bait or bait pellets it did not give consistently good results. Parathion granules or methiocarb spray also failed to give good control.
Reactions of some Cultivars of Lucerne to various Isolates of Verticillium albo‐atrum
Authors: FLOOD JULIE , ISAAC I. , MILTON J. M.
Published: April 2007

Medicago sativa L. cvs. Dupuits, Maris Phoenix, Maris Kabul and Sabilt were used to compare the pathogenicity of two isolates of Verticillium albo‐atrum Reinke & Berth. from the USA with two of European origin. The American isolates were much more virulent than those from Europe, causing disease in cvs. Maris Kabul and Sabilt which were previously regarded as resistant to V. albo‐atrum.
Light‐trap Catches of Fruit Tortricid Moths in Kent, 1964–74, and Associated Temperature Sums
Authors: LOW L. R. WARD , BAKER C. R. B. , LUDLAM F. A. B.
Published: April 2007

Light‐trap catches of five tortricid species were recorded at orchard sites in Kent over an 11‐year period. The dates on which moths of Hedya nubiferana (Haw.), Cydia pomonella (L.) and Archips podana (Scop.) were caught in light traps were strongly correlated with accumulated temperatures in day‐degrees above a base of 8°C. The correlation was less good for catches of Pandemis heparana (Denis & Schiff.) and it was slightly better for those of Cydia pomonella above 10°C than above 8°C. The data were insufficient to calculate temperature sums for catches of Adoxophyes orana (Fisch. v. Rösl.). Moth catches of all five species showed differences between years in the timing of first and second generations. The dates of first catches are compared with dates estimated from the following temperature sums: for H. nubiferana 226 day‐degrees above 8°C, for C. pomonella 268 day‐degrees above 8°C and 149 day‐degrees above 10°C, for Archips podana 326 day‐degrees above 8°C and for P. heparana 386 day‐degrees above 8°C. In the 11‐year period, estimated dates of first catch were within ± 5 days of first actual catch of moths in light traps in nine years for C. pomonella, eight years for H. nubiferana and A. podana, but only five years for P. heparana.
Further Experiments on the Control of Slugs in Potatoes by means of Molluscicidal Baits
Authors: RAYNER J. M. , BROCK ADELINE M. , FRENCH N. , GOULD H. J. , LEWIS SERFIAH
Published: April 2007

This further series of field trials in 1972–75 at sites in England and Wales confirmed that a useful, but not wholly adequate, degree of control of slugs in maincrop potatoes could be achieved with one application to the growing crop of 5–6 kg/ha of methiocarb pellets from mid‐July. Increasing the rate of application to 11–2 kg/ha improved control marginally, as did the addition of a second application of 5–6 kg/ha later in the season.

Measurement of rainfall and slug activity did not provide a basis for improving control by more appropriate timing of applications, although bait‐trapping slugs gave some indication of the level of crop damage to be expected.
A Rapid Method of Extracting Sap from Grass Blades or other Fibrous Material
Authors: SEABY D. A. , SURGEONER R.
Published: April 2007

Large yields of sap (40 per cent of fresh weight) were extracted from fibrous leaves, such as grass blades or conifer needles, using a modified pestle and mortar made from a short piece of polythene tubing, a nylon stopper and a modified stainless steel spatula.
A study of common crop pests in allotment gardens around Leeds
Authors: ATKINSON H. J. , GIBSON N. H. E. , EVANS H.
Published: April 2007

Questionnaires completed by 140 growers from 12 allotment sites around Leeds, West Yorkshire, listed a wide range of crop pests. Of the seven crops grown by over 50 per cent of the growers, brassicas, potatoes and carrots were damaged more frequently than expected from the average frequency for all 20 crops, peas and celery less often, and beans and onions at about the expected frequency. The main pests reported for brassicas and potatoes were slugs, and the most common pest of carrots was carrot fly. Further examination of 92 plots revealed a large number of pests; slugs, carrot fly (Psila rosae (F.)), aphids and cabbage root fly (Delia brassicae (Wiedemann)) were the most common. Results for soil samples showed pale potato cyst nematode (Globodera pallida (Stone) Behrens) to be at potentially damaging population levels in 21 out of 33 plots sampled at 10 allotment sites established for more than five years and in one of six plots sampled at two newly formed allotment sites. Soil sampling for carrot fly at eight allotment sites revealed widespread overwintering populations of about 1·5 larvae and pupae/100 ml of soil. Baiting for slugs on one plot indicated that a large population of these animals was present.

Pesticides were not used by 22 of the 140 growers in the survey. The most widely favoured chemicals with at least 20 users each were a disinfectant, slug pellets, organophosphates and calomel.
Combining methyl bromide fumigation with cold storage to eradicate Spodoptem littoralis on chrysanthemum cuttings
Authors: POWELL D. F.
Published: April 2007

Eggs of Spodoptem littoralis (Boisd.) in commercial boxes of chrysanthemum cuttings were treated with combinations of cold storage at 0–2°C for one, two or four days and fumigation using four dosages of methyl bromide each at a different temperature. After laboratory tests at Harpenden and commercial trials in the Canary Islands and the United Kingdom, cold storage at 0–2°C for four days followed by fumigation at 15°C with methyl bromide at a dosage (CTP) of 54 mg. h/1. for a period of four hours was employed as a routine measure to prevent the entry of S. littoralis and other cutworms into the United Kingdom.
Possibilities of forecasting potato storage diseases from tests on seed tuber and crop samples
Authors: LAPWOOD D. H. , BELL F. , HARRIS R. I. , HIDE G. A. , ADAMS M. J.
Published: April 2007

In 1975 and 1976 commercial potato crops, mainly cv. King Edward, grown on farms in Bedfordshire, Cambridgeshire and Hertfordshire were sampled to investigate the possibilities of forecasting storage disease from assessment of actual disease or latent infection, both on the seed tubers used and on the growing crop. Crops were stored in various conditions on the farms where they were grown or in a common store at the Potato Marketing Board Experimental Station at Sutton Bridge, Lincolnshire, at 3°C in 1975 or at Rothamsted in 1976.

Skin spot, silver scurf and black scurf showed the greatest range of disease incidence between crops and skin spot the closest relationship between latent infection in growth and disease in store. In general the closer to harvest that tests were done, the closer the relationship to subsequent disease in store.

In each year potatoes from only one farm had much gangrene and this was related to the incidence on the seed used and to the large amount of damage done to these tubers at harvest. There was little bacterial soft rot in either year. The assessments of disease and inoculum potential did not produce results sufficiently closely related to the amount of subsequent storage rot or disease to be helpful in making decisions on storage strategy, although the potential benefits from accurate forecasting would be great.
Colorado beetles reported in England, Wales and Scotland, 1978
Authors: BARTLETT P. W.
Published: April 2007

In 1978, 37 adults of the Colorado beetle, Leptlnotarsa decemlineata (Say), were found in England and Wales, of which 13 were alive. This is the lowest annual total for six years. Details of these finds are presented. No beetles were found in Scotland. Live female beetles kept in the laboratory after capture laid an average of 717 eggs each (range 101–1738) and the average percentage hatch was 16 (range 0–35).
The value of soil sterilants for the control of clubroot on a field scale
Authors: BUCZACKI S. T. , WHITE J. G.
Published: April 2007

In field experiments in Kent and Warwickshire a 98 per cent dazomet prill applied at 200 or 400 kg/ha or Telone II (mainly 1, 3‐dichloropropene) applied at 450 or 900 l./ha reduced significantly the percentage of plants infected with clubroot and increased the mean head weight of cabbage. Dazomet prill at 400 kg/ha, incorporated to 24 cm depth, combined the best disease control (a reduction from 47 to 6 per cent plants affected) with substantial yield increase (from 781 to 949 g mean head weight).
Interpreting results from co‐operative trials of insecticide treatments against cabbage root fly on summer cauliflowers
Authors: GRAHAM C. W. , WHEATLEY G. A.
Published: April 2007

The parameters used to assess the performances of soil surface and sub‐surface bands of chlorfenvinphos, chlormephos, diazinon, and fonofos granules against the cabbage root fly (Delia brassicae (Wiedemann)) in field trials at five sites in different parts of England in 1971 were: the root damage indices (RDIs) 4–5 weeks after transplanting and at harvest, the numbers of eggs, larvae and pupae per plant, the marketable yield and the percentage of plants with marketable curds. When the treatments were ranked for each parameter, the numbers of eggs or of larvae and pupae were no more informative than the RDIs 4–5 weeks after treatment or at harvest. Ranking also indicated that the percentages of plants yielding marketable curds, which could be determined without harvesting, revealed the relative effects of the treatments on yield as satisfactorily as the weights of the curds or the calculated numbers of crates per hectare.

When the data for all parameters were summarised by ranking, the sub‐surface applications of chlormephos, chlorfenvinphos and fonofos were consistently the most effective treatments. Surface bands of chlormephos or diazinon granules were ineffective or, at some sites, enhanced root damage.
The persistence of benomyl tolerance in Botrytis cinerea in glasshouse tomato crops
Authors: MILLER M. W. , JEVES T. M.
Published: April 2007

Benomyl‐tolerant strains of Botrytis cinerea Pers. ex Pers. were obtained from all of the 17 commercial glasshouse tomato crops sampled in Lancashire in 1977, although benzimidazole fungicides had not been used on some nurseries for up to three years. Tolerant strains were found in 64.3 per cent of lesions sampled, although in some lesions sensitive strains were also present. In a detailed study of crops growing in the same glasshouses at two sites in 1976, 1977 and 1978, there was only a small change in the number of tolerant isolates collected, although benzimidazole fungicides had not been applied since 1974.
Effect of the cereal cyst nematode, Heterodera avenae, on the early growth of oats, wheat and barley
Authors: SPAULL ALISON M.
Published: April 2007

The effect of Heterodera avenae Woll. upon the early growth of cultivars of oats, wheat and barley was measured. During the first two weeks the rate of root growth was retarded in some barley cultivars although shoot growth was stimulated in all the oats and in two cultivars each of barley and wheat. Later, infestation slowed growth of all the cultivars grown, except Drost barley. When uninfested, some cultivars resistant to H. avenae grew more slowly than did susceptible ones.
Crop loss assessment on winter wheat attacked by the grain aphid, Sitobion avenae (F.), 1974–77
Authors: GEORGE K. S. , GAIR R.
Published: April 2007

Forty‐nine experiments were done during 1974–77 on commercially grown winter wheat crops in England and Wales to investigate the effects on grain yield of feeding on the ear by the grain aphid, Sitobion avenae. The results show that one spray of pirimicarb applied at the beginning of flowering when there were five or more aphids per ear and the number was rising gave an increase in grain yield of approximately 12.5 per cent. Much lower increases were recorded when sprays were applied later than this growth stage or when the number of aphids did not reach the specified level.
Meteorological aspects of the numbers and distribution of the rose‐grain aphid, Metopolophium dirhodum (Wlk.), over south‐east England in July 1979
Authors: COCHRANE J.
Published: April 2007

Exceptionally large numbers (Metopolophium dirhodum were observed i n the air over south‐east England, and caught in suction traps, during July 1979. Meteorological data show that these aphids were probably derived from a native population, increasing exponentially at a time when weather, predators and disease did not impose any significant limitation on the rate of increase, and that few, if any, of these aphids were of continental origin.
Forecasting Septoria nodorum on winter wheat in England and Wales
Authors: TYLDESLEY J. B. , THOMPSON N.
Published: April 2007

The regional incidence of septoria (Septoria nodorum Berk), on winter wheat, as found in the National Winter Wheat Leaf Disease Survey for 1970–75, was related to weather variables and amounts of inoculum. The relation between disease shortly before harvest and days with rain through the growing season was explored by a correlation method and it was found that the closest association was with days with 1 mm or more of rain (wet days) in the period mid‐May to mid‐June, When explored in detail, the relation between infection and wet days showed both non‐linearity and asymmetrical scatter, A graphical technique was therefore used to develop simple forecast rules. These performed well when tested against data for 1976–78, although these years did not include a septoria epidemic.

In addition to wet days, the influence of other weather variables was investigated by a multiple regression technique. Sunshine in May and June and temperatures in July were found to have a slight effect on septoria incidence, as did the previous year's infection (taken as a measure of inoculum) but the overall reduction of variance was slight. It is suggested that these additional variables, together with others not treatecl quantitatively, may best be used to decide the regional forecast in marginal cases, and to make it applicable to individual crops.

Attempts to relate septoria at individual sites in northern England to wet days at nearby rainfall stations were not successful; nor did rainfall data from all these stations contribute to a better regional forecast of septoria than did a few stations chosen at random.
Effects of late‐season fungicide sprays on yield of winter wheat
Authors: COOK R. J.
Published: April 2007

Sprays of broad spectrum fungicides were applied to winter wheat between the start of flag leaf emergence and the milky ripe stage of grain development in 118 experiments between 1970 and 1978. Although diseases were generally sHght, an average yield response of 0·185 t/ha (3·31 per cent) was recorded. Sprays apphed before the start of flowering gave the largest responses of up to 0·218 t/ha. Only those sprays applied between flag leaf emergence and the in‐boot stage showed evidence of an increasing yield response as the yield of untreated plots increased. The 1000‐grain weight of treated plots showed an increase of 1·9 per cent over untreated plots.
Ascochyta fabae on winter beans (Vicia faba): pathogen spread and variation in host resistance
Authors: BOND D. A. , POPE M.
Published: April 2007

In two crops of winter beans (Vicia faba L.) grown in Cambridgeshire, one in 1975 and the other in 1976, a decreasing frequency of Ascochyta‐infected winter bean plants from the border to the centre suggested that spread from volunteer plants in adjacent fields was a much more important source of infection than infected seed. From February to May in both years the disease spread into the field for a distance of at least 120 m.

Within a trial situated in a heavily infected area in 1975, differences in degrees of infection between genotypes were recorded. On 21 May 1975 the trial entries IB19, Bulldog, Banner, Buccaneer, IB7CS, IB18 and Maris Beagle had significantly fewer lesions than Throws MS, HYBSYN, WHT, IB15, IB17 or IB14.
Ohservations on the incidence of Botrytis pod rot on Vicia faba
Authors: JELLIS G. J. , BOND D. A.
Published: April 2007

Pod rotting caused by Botrytis cinerea Pers. ex Pers. occurred in breeding material of spring‐sown field beans (Vicia faba L.) at Cambridge in July and August 1979. Tick beans (V. faba var. minor) were less susceptible to infection than types with longer, ffeshier pods. The incidence of aggressive lesions was less under irrigated than un‐irrigated conditions. Most lesions originated at the end of the pod distal to the stem, possibly as a result of earlier infection of fioral parts.
Factors influencing the development of potato pink rot (Phytophthora erythroseptica)
Authors: LENNARD J. H.
Published: April 2007

In affected crops sampled in the Lothian Region of Scotland during 1973–74, the incidence of pink rot (Phytophthora erythroseptica Pethybr.) increased during the latter part of the growing season. The number of plants with tuber symptoms increased but the number of rotted tubers per plant usually remained small. Earlier lifting usually resulted in the development of more pink rot in storage because tubers carrying inoculum or latent infection could not be detected or discarded. Application of fertiliser to the drill tended to give slightly more pink rot than broadcast application, perhaps because chemical damage to roots and stolons facilitated entry of the pathogen. Dry seasons may aggravate this effect. Disinfection of seed tubers, or selection of seed from healthy plants instead of from plants showing diseased tubers, did not significantly influence infection in the subsequent crop. Tests on varietal susceptibility showed differences, some inconsistent, among cultivars, but all those investigated were susceptible to infection by P. erythroseptica. Arran Pilot and Home Guard seemed the most susceptible; Record and Stormont Enterprise the least susceptible.
Aerial migrations of the rose‐grain aphid, Metopolophium dirhodum(Wlk.), over Europe in 1979
Authors: DEWAR A. M. , WOIWOD I. , DE JANVRY E. CHOPPIN
Published: April 2007

Aerial migrations of Metopolophium dirhodum over Europe in 1979 measured by suction traps at a height of 12.2 m indicated that alates flew first in the south of France where the warm climate probably encouraged early population increase. Subsequent spread across Europe was gradual and northerly, with the largest populations occurring in East Anglia in late July. The date of the population peak at each site was correlated with latitude, being later at northerly sites, and probably also with crop development.
Take‐all severity and yield in winter wheat: relationship established using a single plant assessment method
Authors: POLLEY R. W. , CLARKSON J. D. S.
Published: April 2007

Random samples of 500–600 single plants were taken from four winter wheat crops in eastern England during 1977–79 to establish the relationship between grain yield and severity of take‐all (Gaeuman‐ nomyces graminis(Sacc.) Arx & Olivier var. tritici J. Walker) on the roots at harvest. In each crop separate samples were taken from areas of stunted plants with much take‐all infection and from areas with apparently normal growth.

The root system of each plant was assessed for take‐all severity using four infection categories: healthy, slight (less than 25 per cent of the root system infected), moderate (25–75 per cent) and severe (more than 75 per cent). The assessment figures were compared with ear number, grain number and grain dry weight, which were also recorded for each plant individually.

Shght take‐all had no effect on yield. Moderate take‐all had no effect on the number of ears per plant but significantly reduced grain number per plant, 1000‐grain weight and grain dry weight per plant by 6–9, 10–6 and 15–6 per cent respectively. The reduction in grain dry weight per plant associated with severe take‐all was between 53.1 and 61.6 per cent.

Estimates of minimum national loss caused by take‐all in winter wheat in the years 1977–79 were 0‐9, 2–6 and 2–8 per cent respectively.
Bacterial disease of coriander
Authors: Taylor J. D. , Dudley C. L.
Published: April 2007

A Pseudomonas sp., which on serological and biochemical characters falls in Pseudomonas Group IA (similar to P. syringae van Hall), infected the inflorescences and caused seed decay of coriander in Britain. The pathogen was seed transmitted. Seed infection was reduced by slurry treatments with the antibiotics streptomycin at 2–5 g/kg seed or kasugamycin at 0–25 g/kg seed.
Key for the identification of lepidopterous larvae infesting brassica crops
Authors: EMMETT B. J.
Published: April 2007

A key is given for the identification of the larvae of nine species of Lepidoptera attacking the aerial parts of brassica crops.
The efficacy of fumigation of nematode‐infested soil following different methods of soil sealing
Authors: ALPHEY T. J. W.
Published: April 2007

In a pot experiment and field tests in eastern Scotland during 1978, soils infested with Pratylenchus spp., Rotylenchus robustus(de Man) Filipjev, Trichodorus primitivus(de Man) Micoletzky, T. velatus Hooper and Paratrichodorus pachydermus(Seinhorst) Siddiqi were treated with a liquid fumigant, either 1, 3 dichloropropene or metham sodium. A resin spray, Concure or Vinamul, was then used to seal the surface of the treated soil or granules of the sterilant dazomet were incorporated in the soil. The addition of resin sprays failed to improve nematode mortahty in the pot test but enhanced control in several field tests. Addition of dazomet, even at a low rate, increased nematode mortality when incorporated in the soil efliciently.
Surveys of apple‐grass aphid on apple in southern England, 1965–76
Authors: LIGHT W. I. ST. G.
Published: April 2007

Surveys of oviparae of the apple‐grass aphid, Rhopalosiphum insertum(Wlk.), were made in southern England in each autumn from 1965 to 1976 inclusive. Resuhs varied considerably between years; greatest numbers were recorded in 1966 and 1969 and smallest numbers in 1972. The numbers of oviparae were compared with the numbers of gynoparae caught from mid‐September to the end of October in the traps operated by the Rothamsted Insect Survey. The correlation was sufficiently good for the latter to be used to forecast the hkely abundance of these aphids on fruit trusses in the following spring. The autumn surveys of oviparae were, therefore, discontinued. In Kent the numbers of oviparae were positively correlated with rainfall in the previous July and August.
The effect of iprodione in granule or combined granule and stem‐base applications on white rot disease (Sclerotium cepivorum) of spring‐sown salad onions
Authors: ENTWISTLE A. R. , MUNASINGHE H. L.
Published: April 2007

Iprodione, formulated as granules and placed in the seed furrow, was tested in field plots in Warwickshire for control of white rot (Sclerotium cepivorum Berk.) of spring‐sown salad onions. At 0.25 g iprodione/m row the granules were nearly as effective as seed treatment at 125 g iprodione/kg seed, which reduced infection in 1978 from 88 per cent plants infected to 13 per cent. At 0.063 or 0.125 g iprodione/m row, granules were less effective but gave control similar to that with calomel seed treatment at 500 g/kg, which reduced infection to 46 per cent.

In 1979, excellent control was achieved by combining the pre‐planting granule treatment with a later application of iprodione to stem bases. Granules applied at 0.063 g iprodione/m row combined with a single post‐emergence stem‐base application of iprodione at 0.031 g/m row (equivalent to a total rate of 2.8 kg iprodione/ha) gave complete control of the disease.
The effect of aldicarb on the control of red spider mite, Tetranychus urticae (Koch), by the predator Phytoseiulus persimilis Athias‐Henriot on year‐round chrysanthemums
Authors: CROSS J. V.
Published: April 2007

In the summer of 1979 a study was made of the effect of aldicarb application to glasshouse chrysanthetnums on the interaction between Phytoseiulus persimilis and aldicarb‐resistant Tetranychus urticae. Different rates of aldicarb were applied to chrysanthemums three weeks after planting and predators were introduced three weeks later. Whilst exceptionally large numbers of red spider mite were controlled in a mean of 25 days on untreated beds, control took 42 days where aldicarb had been applied at the rate of 11 kg active ingredient per hectare. The delay in control when intermediate rates of aldicarb were used was roughly proportional to the dose of aldicarb.
Pirimicarb resistance in the melon and cotton aphid, Aphis gossypii Glover
Authors: FURK C. , POWELL D. F. , HEYD S.
Published: April 2007

The resistance to pirimicarb of populations of Aphis gossypii Glover from several glasshouses in England was studied in the laboratory by topical applications of insecticide and by electrophoresis and isoelectric focusing of aphid esterases. When compared with a known susceptible population, the aphids were found to be resistant to pirimicarb. Esterase patterns produced from resistant populations by poly‐acrylamide gel and starch gel electrophoresis and by isoelectric focusing consistently differed in both numbers of bands and migration rates from the susceptible type. Resistant A. gossypii were found infesting only chrysanthemums and would not transfer to cucumber, the host of the susceptible population.
Forecasting egg populations of wheat bulb fly, Delia coarctata (Fall.), from catches of adult females in water‐traps
Authors: COOPER D. A.
Published: April 2007

Between mid‐July and the end of August in 1977 and 1978, wheat bulb flies were caught in white water‐traps at 16 oviposition sites in eastern Scotland. The numbers of females caught per site and the subsequent egg populations, estimated from soil‐cores from each site, were linearly related. Water‐trapping may therefore provide a reliable and early forecast of egg numbers, independent of soil‐sampling, and so enable seed treatment to be limited to years when the risk of damage is great.
An analysis of the variability in yield of pea crops attacked by Heterodem goettingiana, Helicotylenchus vulgaris and Pratylenchm thomei
Authors: GREEN C. D. , DENNIS E.B.
Published: April 2007

In 1977 and 1978 the effect of nematodes and oxamyl treatment on the growth of a pea crop was examined at a site known to be ‘pea sick’ in an area of heavy clay loam soil in Worcestershire, In 1977, Heterodera goettingiana lieb., Helicotylenchus vulgaris Yuen and Pratylenchus thornei Sher & Allen were associated with decreased pea plant growth. The losses caused by each were additive but complicated by an inverse relationship between numbers of Het. goettingiana and Hel. vulgaris. Crop losses and the benefits of nematicide application could be predicted by using multiple regiession coefficients to account for the effects of all species. In 1978, when numbers of Het. goettingiana were great, crop loss in nematicide‐treated plots was correlated with numbers of the nematode.
Biological control by predatory mites (Phytoseiulus persimilis Athias‐Henriot) of red spider mite (Tetranychus urticae Koch) infesting strawberries grown in walk‐in' plastic tunnels
Authors: PORT C.M. , SCOPES N.E.A.
Published: April 2007

During 1 978 and 1979, the control of red spider mite on strawberries by the predacious mite Phytoseiulus persimilis was studied at two sites in Hampshire where crops were grown in ‘walk‐in’ plastic tunnels.

An introduction of at least two predators per plant in March was required to control red spider mite in one experiment. In the second experiment, introductions of small numbers of predators (fewer than two per plant) in August controlled mites on newly planted runners before diapause. Similar numbers of predators introduced in the following March, 10 days after red spider mite eggs were seen, controlled mite infestations throughout the growing season. Controlling mites in the autumn before diapause was considered important.
The influence of soil pH on the severity of swede powdery mildew infection
Authors: BRAIN P. J. , WHITTINGTON W. J.
Published: April 2007

Field and pot experiments at Nottingham during 1976–78 confirmed previous evidence that swede powdery mildew infection was greater on plants grown in soils of high rather than low pH. This effect appears to be related to the manganese content of the leaves because there was more manganese in leaves grown at low pH and progressively less mildew infection on plants supplied with increasing quantities of manganese.
Chocolate spot of field beaes in Scotland
Authors: HARRISON J. G.
Published: April 2007

Although Botrytis fabae Sard, was frequently isolated from spring‐sown Scottish field bean crops in 1976–80, chocolate spot is not regarded as such a serious problem in Scotland as it is in England and Wales, where a large proportion of the crop is autumn‐sown. Pieces of leaf (with lesions) from bean crops grown on two farms at different sites in Scotland were plated on agar during the five seasons 1976–80. The calculated date on which B. fabae was recovered from 50 per cent of the pieces each year was consistently earher on one farm than on the other, despite apparently similar climates. There was a highly significant correlation (coefficient of 0.90) between the severity of chocolate spot disease in different regions of England and Wales and temperatures during May. This, however, may merely reflect regional differences in the proportions of autumn‐ and spring‐sown crops.
The distribution and importance of cabbage stem flea beetle (Psylliodes chrysocephala (L.)) on winter oilseed rape in England
Authors: GRAHAM C. W. , ALFORD D. V.
Published: April 2007

Following several cases of serious damage to winter oilseed rape by cabbage stem flea beetle in eastern and south‐eastern England, surveys and obsei‐vations throughout England from 1974 to 1979 showed that infestations occurred mainly in Buckinghamshire, Cambridgeshire, Huntingdonshire and Northamptonshire; the heaviesl attacks also occurred in these areas. Minor infestations were recorded locally in 13 other counties. No attacks occurred elsewhere in England.
Post‐harvest tuber indexing in the seed potato certification schemes of England and Wales, 1978
Authors: WOOSTER P.
Published: April 2007

In a voluntary scheme in autumn 1978, 100‐tuber samples of certified and basic category seed potatoes were tested for infection with severe viruses (potato virus Y and potato leafroll virus). One sprouted eye was removed from each tuber and grown on in the glasshouse for visual assessment of symptoms. Breaking dormancy of the samples was difficult, possibly because of the young physiological age of the mother crops and the interval between haulm destruction and treatment to break dormancy. Correlation between results from the glasshouse tests and assessments on plants grown from the same tubers in the field at Cambridge the following season was within three per cent for the majority of samples. Some results were less accurate owing to difficulties with certain cultivars under glasshouse conditions. Statistically, the sampling method was unsuitable for detecting small amounts of virus infection in seed stocks. Also, the results were obtained too late to influence seed tuber sales from the crops tested.
Introduction of American serpentine leaf miner, Liriomyza trifolii, into England and Wales and its eradication from commercial nurseries, 1977–81
Authors: BARTLETT P. W. , POWELL D. F.
Published: April 2007

The American serpentine leaf miner, Liriomyza trifolii (Burgess), was first seen in England in 1977, at a nursery where chrysanthemums were being grown from cuttings imported from Kenya and Malta. Eradicatory action was taken at this and 14 other nurseries where infestations were found during that year. In 1978, 12 infestations were found, originating on chrysanthemum cuttings from Kenya and the Canary Islands and on Gerbera from the Netherlands. In 1979, 132 infestations were found; by then the sources also included Denmark and the USA. Following the withdrawal of the licence permitting imports of chrysanthemum cuttings from Kenya, 63 infestations were found in 1980 and 48 in 1981.

Eradication measures rarely required the destruction of infested crops hut frequently required the selective destruction of infested imported plants, together with the application of various insecticidal treatments. To kill adults, fogs and smokes were used; to kill larvae, foliar sprays were applied and persistent systemic insecticides were incorporated in the planting beds; to kill pupae, soil drenches and sterilants were necessary.

By the adoption of this control programme and the vigilance of the plant health authorities, eradication of L. trifolii has been, achieved wherever it has been found in England and Wales.
The eradication campaign against American serpentine leaf miner, Liriomyza trifolii, at Efford Experimental Horticulture Station
Authors: POWELL D. F.
Published: April 2007

In May 1979 an outbreak of Liriomyza trifolii (Burgess) was detected on glasshouse chrysanthemums, at Efford Experimental Horticulture Station in Hampshire, England. The pest spread to glasshouse tomatoes and then to cultivated and wild hosts outside. An intensive eradication campaign included pest and weed control, monitoring adults with yellow sticky traps, and extensive surveys of potential host plants to determine the spread of the pest. Eleven new hosts of the pest were recorded. In November 1980, following a series of surveys, the pest was deemed not to have survived in the area.
Crown rot (Phytophthora cactorum) in glasshouse‐grown strawberries at East Mailing Research Station
Authors: HARRIS D. C. , STICKELS J. E.
Published: April 2007

From 1973 to 1977 the spread of crown rot (Phytophthora cactorum(Leb. & Cohn) Schroet.) in glasshouse‐grown strawberries at East Malling Research Station (EMRS) threatened to disrupt the production of virus‐tested stocks. An eradication programme involving trickle irrigation of plants, rooting ranners above the level of mother plants, regular inspection for disease and routine tests for latent infection, special precautions at repotting and annual renewal of mother plants eliminated the disease in two years, except in a quarantine house containing new importations.

Isolates of P. cactorum from strawberry plants and apple trees were moderately or highly virulent to their original hosts but caused only latent infection or limited necrosis in reciprocal inoculations. This supports the separation of the strains commonly attacking these hosts as distinct pathotypes. The evidence suggests that crown rot entered the strawberry stocks at EMRS with infected introduced plants and not from local field sources.
Use of forced buds to extend the period of serological testing in surveys for fruit tree viruses
Authors: TORRANCE L.
Published: April 2007

Forced buds were investigated as, a source of test material to determine whether they could be used to extend the period of reliable serological testing in routine surveys for some fruit‐tree viruses. Dormant bud‐sticks of cherry, plum and apple were cut in midwinter and either stored at 4°C or used immediately. Buds were forced in one to three weeks by keeping the budsticks at about 18°C. The emergent flower and leaf tissues were tested by enzyme‐linked immunosorbent assay for the presence of cherry leaf roll (CLRV), prune dwarf (PDV), strains of prunus necrotic ringspot (NRSV) and plum pox (PPV) viruses. PDV and the cherry serotype of NRSV (NRSV‐C) were detected in cherry and plum, CLRV in cherry, PPV in plum and the apple serotype of NRSV in plum and apple. Virus detection was not affected when cherry and plum budsticks were stored for 10 weeks at 4°C before testing. PDV, NRSV‐C and CLRV were still detected in cherry leaf and flower tissue wliich was forced and then stored at either 4 or ‐ 18°C for one to two months.
Observations on Globodera pallida and G. rostochiensis on early potatoes
Authors: WEBLEY D. P. , JONES F. G. W.
Published: April 2007

Observations in south Wales during 1971–78 on population changes in the cyst nematodes G. pallida (Stone)‐Behrens Pal and G. rostochiensis(Woil.) Behrens Rol on early potatoes grown in concrete‐bounded microplots confirmed that populations can be controlled by early harvesting. When potatoes were planted on 11 Match, harvesting 83 days later led to a decline in the population density of G. pallida in every year except 1976, which was exceptionally warm. The best estimate of the rate of decline was 55 per cent per annum. Harvesting after 91 days resulted in population densities otily slightly less than harvesting after 103 or 120 days, when population densities fluctuated around an equilibrium of 120 eggs/g soil. Sitnilarly, when plots infested with G. rostochiensis were harvested after 83 days, population densities declined. Harvesting after 91 days resulted in fluctuations about an equilibrium of 7 eggs/g soil and after 103 and 120 days around an equilibrium of 120 eggs/g.

Females of G. pallida developed faster and produced eggs sooner than those of G. rostochiensis over the spring temperature range. Therefore, early harvesting would favour G. pallida and, if done routinely, would lead to the selection of this species and the replacetnent of G. rostochiensis. Harvesting a fixed number of days after planting would probably give satisfactory population control in most years, but harvesting on the basis of accumulated temperature above a known basal development temperature would probably be better, especially in years in which, the temperature departs appreciably from the average.
Use of continuous light to improve diagnosis of potato leaf roll virus in tuber indexing tests
Authors: JONES R. A. C.
Published: April 2007

Controlled environment cabinets were used to determine light.and temperature conditions needed for full expression of potato leaf roll virus (PERV) symptoms in potato plants grown from eyeplugs taken from tubers of cv. Désirée. PLRV symptom development was poor under conditions in which growth was etiolated. In general, typical rolling of lower leaves developed faster and was more distinct at 18 than at 22°C, and when light intensity was increased, but the two continuous light regimes used gave better results than any of those involving 10‐or 18‐h photoperiods. At 18°C, distinct symptoms suitable for scoring during tuber indexing developed in all infected plants after four to five weeks or five to six weeks with continuous light at 7000 or 4000 lux respectively, but only after six to eight weeks with 18 h/day at 7000 lux, which was the best of the 10‐ and 18‐h regimes. Yellowing and shedding of lower leaves developed faster in healthy plants kept under either of the continuous light regimes than in healthy plants kept for 18 h/day at 7000 lux or in infected plants kept in any of these three regimes, and was very obvious after only six weeks. In terms of symptom appearance in infected plants and defoliation m. healthy ones, a regime of 23 h/day at 7000 lux gave similar results to those obtained with continuous light at 7000 lux. In trials done in winter in a heated glasshouse illuminatcd by mercury vapour lights, continuous illumination had the same effects: distinct PLRV symptoms and obvious loss of lower leaves devefoped after only five weeks in all the infected and healthy plants respectively.
Effects of covering potato crops with clear polyethylene film on spread of potato virus Y
Authors: GIBSON R. W. , GUNENC YILDIZ
Published: April 2007

Plots of potatoes in eastern England were covered at planting with finely slit, clear polyethylene film which remained over the foliage until harvest. Spread of potato virus Y and the numbers of aphids on the leaves in these plots were compared with those in uncovered plots. In two years fewer tubers of covered plants were infected with potato virus Y and in the first year the covered plants had fewer Myzus persicae(Sulz.) and Macrosiphum euphorbiae (Thos.).
Procedures for the generation of formaldehyde vapour to fumigate structures
Authors: CONNOLLY G. P. , FLETCHER J. T.
Published: April 2007

Formaldehyde gas concentrations were measured following the mixing of potassium permanganate and formalin within a 1 ‐m3 chamber. Similar concentrations of gas were measured irrespective of the order of mixing of the reactants at the lower ratios used (1 KMnO4:4–8 formalin), but at the higher ratio (1:2–4) more gas was produced when the KMnO4was added to the formalin than when the reverse sequence was followed. Spores of Botrytis cinerea were all killed at the dosages tested (0.18–0.30 mg formaldehyde per litre).
Degradation of maackiain by a cell‐free extract from Sclerotinia trifoliorum
Authors: MACFOY C. A. , SMITH I. M.
Published: April 2007

Preliminary results are presented on a cell‐free system extracted from mycelium of Sclerotinia trifoliorum, which caused the disappearance of maackiain from solution. Activity depended on prior exposure of the mycelium to maackiain and on the inclusion of a protease inhibitor in the extraction buffer. No activity was found in culture filtrates.
Factors affecting tests for differential pathogenicity in populations of Plasmodiophora brassicae
Authors: JONES D. R. , INGRAM D. S. , DIXON G. R.
Published: April 2007

Factors affecting the use of the European Clubroot Differential (ECD) series for determining the differential pathogenicity of Plasmodiophora brassicae were studied. Replicate tests made with one collection of P. brassicae did not give consistent results. Collections were shown to be heterogeneous for differential pathogenicity. Selection of components of a collection occurred during passage through a range of differential host cultivars. ECD host 06 was shown not to be uniform. There was a linear relationship between the logarithm of spore concentration in the inoculum used in tests and the incidence of disease, and some ECD hosts required a higher concentration of spores than others to give the same incidence of disease. The implications of these findings for the future use of the ECD series are discussed.
Studies on the reinfection and yield of virus‐tested and commercial stocks of rhubarb cv. Timperley Early
Authors: WALKEY D. G. A. , CREED C. , DELANEY H. , WHITWELL J. D.
Published: April 2007

Ten commercial stocks of rhubarb cv. Timperley Early were found to be infected with turnip mosaic, arabis mosaic and to a lesser extent cherry leaf roll, strawberry latent ringspot and cucumber mosaic viruses. Significant yield differences were recorded between the stocks in forcing experiments, but these were not related to virus incidence. The performance of a mixture of these infected commercial stocks was compared with that of virus‐tested stocks in canning, early green‐pulled, and forcing experiments. A significant yield advantage was recorded in the first 2 years from the virus‐tested stock harvested for canning, but not in the other two experiments. Of the five viruses isolated, turnip mosaic most frequently reinfected virus‐tested stocks and there appeared to be a connection between reinfection of the healthy plants and subsequent reduction in their yield.
Detection of Spiroplasma citri in plants and insect hosts by ELISA
Authors: ARCHER D. B. , TOWNSEND R. , MARKHAM P. G.
Published: April 2007

Enzyme‐linked immunosorbent assay (ELISA) was shown to be a sensitive method for the detection of Spiroplasma citri in plants and insect hosts. S. citri was detected in Vinca rosea less than 1 week after infection by grafting, and reached a peak litre of up to 109 spiroplasmas per gram of tissue in infected shoots and root tips. Multiplication of S. citri in the leafhopper Euscelidius variegatus was also monitored by ELISA. S. citri could be detected in a single insect, showing that this technique is suitable for screening insect populations in the field for potential vectors of Spiroplasma diseases. A method is described for raising a pathogen‐specific antiserum from V. rosea infected with S. citri which reacted with cultured S. citri and also with S. citri in plant tissue.