bluuebunny/crossref_metadata_2025 huggingface dataset:
The Egg‐shell of the Cabhage Root Fly, Erioischia brassicae (Bouché)
Authors: Jones Margaret G.
Published: April 2007

The electroscan microscope was used to show details of the external structure of the egg of cabbage root fly. The median area between the hatching lines differs from the more solid structure of the longitudinal ridges on the rest of the surface. On the pointed posterior end are small holes in the outer layer, but in contrast to wheat bulb fly, Leptohylemyia coarctata (Fall.), there are no distinct plastron areas around the micropyle at the blunt anterior end. The egg of cabbage root fly also lacks small plastron areas among the longitudinal ridges.
The Resistance of Hybrids of Solanum tuberosum ssp. andigena and S. multidissectum to Heterodera rostochiensis Pathotype E
Authors: Parrott D. M. , Trudgill D. L.
Published: April 2007

Some Fl progeny of crosses between resistant and susceptible cultivars of potato contain resistance to Heterodera rostochiensis pathotype E (British notation) supplementary to that conferred by genes H1 and H2. This resistance in hybrid K2/6 was equal to that of its parent D40 and could be incorporated in a useful resistant cultivar.
The Relative Importance of Weather, Soil‐ and Seed‐borne Inoculum in determining the Incidence of Common Scab (Streptomyces scabies) in Potato Crops
Authors: Lapwood D. H.
Published: April 2007

Potato seed tubers, cv. Majestic, without or variously affected by common scab, were planted between 1964 and 1967, in two fields at Rothamsted, one known to produce only slightly scabbed and the other severely scabbed potato crops.

The amount of scab at lifting depended most on whether June or early July was wet or dry. If wet, there was little infection on progeny tubers irrespective of the amount of inoculum in soil or on seed tubers. When dry weather allowed infection, inoculum in soil had more effect than that on seed.
A Micro‐container Technique for Studying Virus Transmission by Nematodes*
Authors: VALDEz R. B.
Published: April 2007

Previous methods for studying virus transmission by nematodes were improved to achieve up to 100 per cent infection when using single specimens of Xiphinema diversicaudatum(Micol.) and small petunia test plants grown in micro‐containers kept inside moist chambers. Four ml of steamed soil/sand (2:1) mixture were used during test feeding, and more was added as the plants grew. The roots were tested for infection by inoculating appropriate indicator plants and the virus was identified serologically.
Lolium Mottle Virus
Authors: Brook John A.
Published: April 2007

A previously unrecorded virus with isometric particles 27 nm diameter, has been isolated from Lolium perenne L. and Cynosurus cristatus L. from Eire and from C. cristatus from Yorkshire, and named lolium mottle virus (LMV). The virus could be inoculated into cultivars of wheat, oats, barley and rye, and Lagurus ovatus L. It is symptomless in Lolium multifloriim Lam. and Phleumpratense L. Some properties of LMV are reported. The virus, though readily sap transmissible, was not transmitted by two Oulema species (Coleoptera) or by three species of aphids (Hemiptera).
Fireblight: Occurrence of Bacterial Strands on Various Hosts under Glasshouse Conditions
Authors: Eden‐green S. J. , Billing Eve
Published: April 2007

Exudate extruded in the form of aerial strands or threads has been observed on shoots and leaves of apple, pear, hawthorn and quince infected with fijreblight under glasshouse conditions. Strands were up to 100 mm long, with diameters 6–300 μm; colourless, amber or brick red; unstable at high humidities and instantly soluble in water. Aqueous solutions gave viable bacterial counts equivalent to 107— 108cells/mm3 dry strand.

The possible significance of these findings in disease epidemiology is discussed.
Continuous Breeding of Wheat Bulb Fly, Leptohylemyia coarctata(Fall.)
Authors: Jones Margaret G.
Published: April 2007

Wheat bulb flies were bred successfully at all times of the year. Larvae were obtained out of season by delaying hatching; the emerging larvae successfully infested wheat seedlings kept at 15°C or below. When larval development was complete, infested plants were moved to cages in a glasshouse for pupation and adult emergence. After emergence and during the pre‐oviposition period (one month) the flies were provided with a diet of aphid honeydew, honey solution, dried milk and yeast mixture, and mammalian blood. After mating, the females were moved to lantern‐glass breeding chambers kept at about 20°C, where they laid eggs. The eggs were stored for 8 wk at 20°C followed by at least 14–16 wk at 0°C before being used to infest winter wheat seedlings. More flies were produced when plants were kept at temperatures fluctuating between 5 and 15°C than at constant temperatures of 10 and 15°C.
Effects of Thiahendazole on Verticillium Wilt of Lucerne
Authors: Dixon G. R.
Published: April 2007

Experiments using thiabendazole (2‐(4‐thiazolyl) benzimidazole) for thé control of Verticillium albo‐atrum in lucerne are described. In in vitro tests thiabendazole completely inhibited fungal growth. In the glasshouse, spray treatments were ineffective but a soil drench treatment using 50 p.p.m. of active ingredient proved the most effective. In some other treatments phytotoxicity was observed. In most cultivars in a field trial there appeared to be a cumulative reduction in wilt development with further applications of fungicide: in cvs. Du Puits, Europe, Flamande and Provence the reduction occurred more quickly than in Cardinal, Emeraude, Eynsford and FD100.
The Effect of Systemic Fungicides on the Aphid Pathogen, Cephalosporium aphidicola
Authors: Wilding Neil
Published: April 2007

Development of Cephalosporium aphidicola was inhibited in vitro by the fungicides benomyl and triarimol but not by dimethirimol. However, neither triarimol nor dimethirimol inhibited the fungus in individuals of the aphid. Aphis gossypii, that fed on cucumber plants treated with the fungicides. Plants treated with benomyl were aphicidal.
Studies on the Host Range and Properties of Cocksfoot Mottle and Phleum Mottle Viruses
Authors: Benigno D. A. , A'Brook John
Published: April 2007

Further studies on cocksfoot mottle and phleum mottle viruses have extended their known host ranges amongst the Gramineae, and examination of their physical properties confirms the suggestion by Walters (1969) that these viruses belong in the southern bean mosaic group of beetle‐transmitted plant viruses.
Influence of Stubble Treatment and Autumn Application of Nitrogen to Stubbles on the subsequent Incidence of Take‐all and Eyespot
Authors: Shipton P. J.
Published: April 2007

Commercial‐scale field trials on farms in North Hampshire over four seasons (1963 to 1968) showed that nitrogen applied to wheat or barley stubble after harvest in the autumn failed to reduce the incidence of take‐all and eyespot in the succeeding wheat or barley crop, or produced only minor reductions in the spring which were not maintained up to the stage of crop maturity. There were no consistent significant differences in levels of disease between rate or form of nitrogen applied as urea/ammonium nitrate spray at 0, 12, 24 or 48 units/acre (1 unit/ac × 1·25 kg/ha), ammoniacal gas liquor spray at 48 units/acre and anhydrous ammonia injected at 40 units/acre. Burning‐off stubbles with high‐output flame cultivators did not significantly reduce the incidence of either disease.
Effect of ‘Dowco 275’, a New Organophosphorus Nematicide, on Potato Cyst Nematode
Authors: Whitehead A. G. , Ahmed S. N.
Published: April 2007

‘Dowco 275’ (0,0‐diethyl 0‐(6‐fluoro‐2 pyridyl) phosphorothioate) at 2·5, 5 and 10 p.p.m. in pots of sandy loam controlled potato cyst nematode (Heterodera rostochiensis Woll.). At 5 p.p.m. the control was as effective as with aldicarb.
The Effects of Fruit Tree Red Spider Mite (Panonychus ulmi) on Yield of Apple Trees in Kent
Authors: Light W. I. St. G. , Ludlam F. A. B.
Published: April 2007

Yields of apple fruits over 55 mm or 2 1/4 in. in diameter of CV. Cox's Orange Pippin in orchards studied in Kent were significantly decreased in only two out of five years between 1965 and 1971 by infestations of fruit tree red spider mite. In both these years, early peak populations of the mite occurred before mid‐July.
Spread and Control of Fusarium Wilt of Carnations
Authors: Fletcher J. T. , Martin J. A.
Published: April 2007

Symptom production was recorded during a 31 month period in a commercial crop of carnations infected by Fusarium oxysporum f. dianthi. In the first year spread was slow but increased to approximately 12 in. (0·305 m) of bed length per month by the end of the crop.

The degree of infection and colonization of the plants did not differ greatly at 18–20°C or 23–25°C, although symptoms appeared more rapidly at the higher temperature.

Benomyl, applied as a drench to each plant at the rate of 1·5 g and 3·0 g/4·5 l./200 ml. suppressed symptom expression and was not markedly phytotoxic. Best results were obtained when the fungicide was applied within a week of planting into infested soil. Bioassay results of treated plants indicated a maximum level of activity within the plant 10–14 days after application.
Effects of Three Soil Fumigants on Carabidae
Authors: Critchley B. R.
Published: April 2007

The effects on Carabidae of using ethylene dibromide, chloropicrin or dazomet to control Heterodera rostochiensis Wollenweber in a sandy loam soil in field plots near Ascot, Berkshire, were assessed after treatments in 1965 and 1966. Immediate and longer term effects of the soil fumigants were estimated by pitfall trapping beetles that were active on the surface of the plots. All the compounds tested were initially toxic or repellent, as indicated by a fall in numbers trapped, with dazomet appearing to have the greatest effect soon after application. When assessed 6–8 months after treatment, ethylene dibromide appeared to have the greatest effect; this difference with time could be attributed to the larger molecular weight of ethylene dibromide allowing it to persist longer.
A Preliminary Proposal for the Detection of Barley Mildew Infection Periods
Authors: Polley R. W. , King J. E.
Published: April 2007

The development of powdery mildew of barley was studied during May and June in 1971 and 1972. Spore trapping data, and experiments involving the exposure of mildew‐free plants in a barley crop, established that periods when there was a high incidence of infection, with subsequent disease development, generally coincided with days on which large numbers of Erysiphe conidia were trapped above the crop. Meteorological criteria are described which have detected high risk infection periods for the two years under consideration.
Observations on Winter Survival and Diapausing Behaviour of Red Spider Mite (Tetranychus urticae) on Glasshouse Roses
Authors: French N. , Ludlam F. A. B.
Published: April 2007

Observations on the diapausing behaviour of red spider mite (Tetranychus urticae (Koch)) on glasshouse roses were made during the winters of 1969–70, 1970–71 and 1971–72 in a total of 11 glasshouses on six nurseries in Kent and Sussex. In one glasshouse no diapausing forms occurred but in another nearly all mites went into diapause. In the other glasshouses different proportions of diapausing and non‐diapausing forms occurred. On the three nurseries where tests were made diapausing mites were resistant to demeton‐S‐methyl. Diapausing behaviour was not apparently affected by different methods of growing roses.
The Early Prediction of Slug Damage to Potatoes
Authors: Symonds B. V.
Published: April 2007

Between 1968 and 1970 potato tubers were used to measure slug activity before planting potato crops in fields in central and southern England. Some evidence was obtained to indicate a relationship between this activity and subsequent slug damage to the ware crop.
Beet Mosaic ‐ a Declining Disease in England
Authors: Heathcote G. D.
Published: April 2007

Surveys made by fieldmen of the British Sugar Corporation since 1946 showed that beet mosaic virus has declined in importance. Root crops in the Felsted and Spalding beet‐sugar factory districts have been most affected by the virus. Disease control in beet‐seed crops, well‐timed treatment of sugar‐beet root crops with systemic insecticides, and a decrease in the mangold crop acreage have contributed to its decline. However, common weeds, especially wild beet are persistent hosts for the virus.
Laboratory and Field Tests of Insecticides against Douglas Fir Seed Wasp (Megastigmus spermotrophus Wachtl)
Authors: Stoakley J. T.
Published: April 2007

Tests were made to select insecticides which would kill adult seed wasps in crowns of cone‐bearing Douglas ftr trees. In the laboratory, gamma BHC, malathion and diazinon were found to be active against females. In further tests, on males and females, gamma BHC and malathion were active when the insects were allowed contact with treated surfaces; fenitrothion was less active. The effectiveness of gamma BHC was partly due to fumigant action whereas malathion and fenitrothion had no fumigant effect. In separate field experiments between 1962 and 1966 in Kent and Herefordshire, gamma BHC and fenitrothion gave no control but malathion gave good control. In 1968, trees in Kent to which malathion was apphed three times at 10‐day intervals during June had about 13 per cent infestation of potentially sound seed, when assessed in September, compared with about 45 per cent infestation on unsprayed trees. Malathion plus gamma BHC did not further reduce infestation.
Control of the Take‐all Fungus by Grass Leys in Intensive Cereal Cropping
Authors: Deacon J. W.
Published: April 2007

Colonization of wheat roots by Gaeumannomyces graminis (syn. Ophiobolus graminis), the take‐all fungus, was slower in inverted grass turves or soils from beneath grass crops than in fallow soil. Control of the growth of G. graminis in turves was completely lost when they were sterilized and recolonized by micro‐organisms from fallow soil, and was therefore due to micro‐organisms present on the grass roots. Most, if not all, of this control is ascribed to Phialophora radi‐cicola, because the effectiveness of different turves was directly proportional to their populations of P. radicicola; fallow soil inoculated with a natural population‐level of this fungus restricted colonization of wheat roots by G. graminis.

The high populations of P. radicicola in all English grasslands examined, its rapid build‐up to these levels and the considerable carry‐over on successive wheat crops after grass (Deacon, 1972) suggests a role for short‐term grass leys in the control of take‐all in intensive cereal rotations. But, grasses can partially maintain the population of G. graminis between cereal crops, and so they should not be sown immediately after a heavily‐infected crop.
Infection of Cricket Bat Willow (Salix alba var. caerulea) Sm. by Erwinia salicis (Day) Chester detected in the Field by the Use of a Specific Antiserum
Authors: Wong W. C. , Preece T. F.
Published: April 2007

The use of a slide agglutination test on squeezed‐out sap of cultivated cricket bat willow trees allowed rapid diagnosis of infection by Erwinia salicis in the field. By this means, infection of “classically” diseased willow trees with both red leaf and wood staining was confirmed. Trees with either red leaf or wood stain, but not both symptoms, were also shown to be infected. Symptomless infection of cricket bat willow trees was detected. E. salicis was viable in the stumps of trees felled five years previously. Some of these stumps were in an advanced state of decay and some were producing symptomless leafy shoots. Trees dying with severe die‐back symptoms and infected with Armil‐ laria mellea, were shown to be infected with E. salicis. Salix caprea and S. vitellina, two wild species of willow, were also shown to be infected.
Chemical Control of Wheat Bulb Fly in the East Midlands, 1968–70
Authors: Mathias P. L. , Roberts P. F.
Published: April 2007

Under severe infestation pressure and delayed emergence following mid‐October drilling, only dieldrin seed dressing gave an acceptable control of wheat bulb fly, Leptohylemyia coarctata (Fall.). The control afforded by commercial seed dressings of BHC, carbopheno‐thion, chlorfenvinphos, ethion and the experimental compounds GS 13006 and pirimiphos‐ethyl, and by chlorfenvinphos granules was markedly inferior to that obtained with dieldrin seed dressing.

In short‐row screening trials, bendiocarb, C 10015, C 18244, carbo‐furan, dialifor, ethoprop, iodofenphos, methiocarb, ‘Phosvel’, PPC‐3, propoxur and RD 21192 showed little promise. Phoxim and pirimiphos‐ethyl showed some promise but were not sufficiently active to warrant further study. Special seed dressing formulations of ‘Dursban’ did not overcome the inherent phytotoxicity of the compound to germinating wheat seed.
Chemical Control of Carrot Fly (Psila rosae (F.)) on Parsnip
Authors: Hill D. S.
Published: April 2007

During the past few years the recommended treatment for the control of carrot fly larvae on parsnip roots has been phorate granules applied ‘bow‐wave’ at drilling at 31b active ingredient/acre (3·36 kg/ha), followed by two foliar sprays of chlorfenvinphos each at 2 lb a.i./acre (2·24 kg/ha). This has been the standard recommendation for the control of carrot fly on carrots grown on peat soils. In a trial in 1972 this treatment gave useful control of a heavy carrot fly infestation on parsnips on a peat soil in eastern England. Protection lasted for approximately 30 weeks, after which the amount of damage increased sharply. Of the granular insecticides tested in the same trial as alternatives to phorate at drillng, chlorfenvinphos was reasonably eifective, but neither disulfoton nor diazinon gave adequate control.

Two sprays of chlorfenvinphos applied later in the season to previously untreated parsnips were ineffective.

Parsnips in untreated plots were heavily attacked by both first and second generation larvae; 37–40 per cent of the untreated plants were actually killed by the first generation larvae.
A Survey in England and Wales for Ring Rot of Potatoes caused by Corynebacterium sepedonicum
Authors: Lelliott R. A.
Published: April 2007

Ring rot is not known to occur in Gt. Britain but was intercepted at Enghsh ports in 19 consignments of ware potatoes from Europe during the period 1958–67. No ring rot was detected in a survey of 4,417 stored potato crops on farms in England and Wales made in the winters of 1967–68 and 1968–69, indicating that if the disease had been present for more than a few years prior to the survey it is most unlikely that it would have escaped detection.
Side‐Effects of Downy Mildew Fungicides on the Incidence of Hop Powdery Mildew (Sphaerotheca humuli)
Authors: RMoyle D. J. , Griffin M. J.
Published: April 2007

In a trial on 10 acres (4 ha) of hops in 1972, three downy mildew fungicides were superimposed on to a routine dinocap schedule and compared for their effects on powdery mildew control. Both mildew diseases built up to fairly high levels between the last spray applications and harvest. Copper oxychloride was significantly superior to zineb in restricting development of powdery mildew in hop cones while propineb appeared to be only slightly inferior to copper. There were no differences between fungicides for control of downy mildew.

Cone yield was significantly correlated with the amount of downy mildew, but not of powdery mildew, at harvest.
Tolerance to Benomyl in Botrytis cinerea and Penicillium corymbiferum
Authors: Jarvis W. R. , Hargreaves A. J.
Published: April 2007

Isolates of Botrytis cinerea which grew rapidly and sporulated on media containing 1,000 p.p.m. benomyl were obtained from mummified fruits of (a) strawberry plants treated one year previously with a Benlate drench to control Verticillium dahliae, and (b) raspberry plants variously sprayed with Benlate to control B. cinerea. Isolates of Penicillium corymbiferum with the same level of benomyl tolerance were obtained from Benlate‐treated tulip bulbs. Isolates of V. dahliae were also obtained from the strawberry plants treated one year previously with Benlate drench, but they were intolerant of benomyl.
Damage to Glasshouse Lettuce by Pratylenchus penetrans (Cobb, 1917) Chitwood and Oteifa, 1952
Authors: Winfield A.L. , Kingham H. G. , Young C. J.
Published: April 2007

The lesion nematode Pratylenchus penetrans was associated with stunting and reduced production of glasshouse lettuce crops on several smallholdings in Cambridgeshire in 1972. Short‐duration pot experiments in which oxamyl* was used to control the nematodes showed that damage in untreated soil began soon after lettuces were transplanted. P. penetrans was probably the cause of the poor growth both in untreated soil in pots and in the commercial crops.
Factors affecting Occurrence of the Ophiobolus Patch Disease of Turf and its Control by Phialophora radicicola
Authors: Deacon J. W.
Published: April 2007

Phialophora radicicola is present in large amounts in most grasslands in Britain and probably restricts the occurrence of Gaeumannomyces graminis var. avenae, the cause of ophiobolus patch disease. Its absence from turf of low pH (< c. 4‐5) could explain why such turf often develops the disease after liming. High water content of turf is also associated with the disease, but does not seem to affect P. radicicola; therefore, it possibly prevents grassses from forming new roots to replace diseased ones. Grasses show a wide range of tissue resistance to G. graminis var. avenae, which explains their reaction in the field: all species tested were apparently more resistant than wheat and oats, so this resistance might contribute to the success of P. radicicola in controlling the take‐all fungus on grasses.

By implicating P. radicicola in its control, many aspects of the disease are explained, for example, its geographical distribution in Britain and development in relation to turf management.

Provisional recommendations for avoiding and controlling the disease are made. These include manipulation of turf pH, inoculation with P. radicicola and more restricted use of broad‐spectrum fungicides and soil fumigants so as not to destroy the resident population of P. radicicola.
Nematode‐transmitted Viruses of Sugar Beet in England, 1965–1972
Authors: Heathcote G. D.
Published: April 2007

Tobacco rattle virus occurs in about 10 per cent, and tomato blackring virus in about 5 per cent, of fields in England affected with Docking disorder. Leaf symptoms caused by TRV, TBRV or by both viruses together may be indistinguishable in sugar beet. Sugar‐beet plants showing TRV in June were symptomless in October and were then only half the weight of symptomless neighbouring plants. Sugar beet infected through the seed with TBRV were symptomless and not stunted under glasshouse conditions. Treatment with either ‘D‐D’ soil fumigant or the systemic nematicide methomyl decreased the proportion of plants showing TRV in the field. Although widely distributed in England, neither TRV nor TBRV seems likely to cause a serious disease of sugar‐beet crops.
The Effect of Yellow Rust and its Control on the Yield of Joss Cambier Winter Wheat
Authors: Mundy E. J.
Published: April 2007

Foliar sprays of fungicides were evaluated in a field where winter wheat cv. Joss Cambier was subject to a severe natural infection of yellow rust (Puccinia striiformis Westend.). Almost complete freedom from the disease was achieved on the leaves from repeated applications of BAS 3170F. This material prevented the development of appreciable disease for up to four weeks after spraying. Other chemicals gave varying degrees of protection but most lacked persistence. Control of ear infection was less satisfactory. The untreated crop, which was heavily attacked by yellow rust, showed a yield reduction of 34 per cent compared with the crop receiving greatest protection. The relationship between yield and yellow rust at growth stage 11.1 was statistically significant; the loss of yield recorded was 0‐022 t/ha for each one per cent increase in the level of yellow rust on the flag leaf.
Verticillium Wilt Disease of Strawberry: Cultivar Reaction and Effect on Runner Health and Production
Authors: Jordan V. W. L.
Published: April 2007

Runner production from strawberry plants was markedly affected by severity of verticillium wilt. Runners from 10 cultivars examined became infected by transmission of the pathogen through the stolon as well as from the soil. The ready isolation of the pathogen from symptomless parent plants and runners indicates one method by which this disease is spread to new plantations.
A Method of Turf Sampling and Extraction of Leatherjackets
Authors: Blasdale P.
Published: April 2007

An apparatus for the extraction of leatherjackets (larvae of Tipula paludosa Meig.) from turf samples is described. Cores are retained in metal cutting cylinders and are stood turf surface downwards in dishes of cold water while heat is applied to the other end. The temperature gradient drives the leatherjackets down into the water. The system is very convenient to operate and is of acceptable efficiency.
Mediyl Bromide for Control of Bulb Scale Mite, Steneotarsonemus Jaticeps (Halb.)
Authors: Gurney Barbara , Gandy Doreen G.
Published: April 2007

In small‐scale trials narcissus bulbs, cultivar Standard Value, heavily infested with bulb scale mite (Steneotarsonemus laticeps (Halb.) were treated with methyl bromide over a range of concentration x time products from 102 to 251 mg.hr/1. at temperatures between 19 and 24°C. All treatments killed both the mites and their eggs without damaging the bulbs. Fumigated bulbs flowered normally without stunting or distortion.
Celery Mosaic Virus in England
Authors: Pemberton A. W. , Frost R. R.
Published: April 2007

A virus has been isolated from celery crops in Lincolnshire, Cambridgeshire, and Norfolk, from eight different cultivars on 15 of 18 farms sampled, but has not been found in any cultivars on 10 farms in Lancashire. It has also been isolated from hemlock on three farms in Cambridgeshire. The incidence of infection has varied considerably with an average level of about 15 per cent but 90 per cent crop infections have been observed.

The virus causes most prominent symptoms in cvs. Lathom Blanching and Fenlander, causing a slight stunting of the former and a more serious reduction in growth of the latter. It is aphid‐transmitted in a non‐persistent manner. The virus has flexuous rod‐shaped particles approximately 780 nm in length, and is apparently restricted in its host range to the Umbelliferae. Its relationship to Western celery mosaic virus */*: */*: E/E: S/Ap is discussed.
A Field Survey of Watermark Disease of Cricket Bat Willow in Essex and Observations on Some of the Probable Sources of the Disease
Authors: Wong W. C. , Nash T. H. , Preece T. F.
Published: April 2007

The geographical distribution of trees of cricket bat willow (Salix alba var. caerulea) showing watermark symptoms of infection by Erwinia salicis (Day) Chester during 1955 to 1972 is recorded. In an attempt to control the disease by eradication, 23,172 trees were destroyed in this 18‐year period, as were 911 mother trees (stools) producing propagating material. During an intensive survey in 1972, 301 trees and seven stools were found to be infected out of an estimated total crop of 400,000 trees. In that year, agglutination tests and culturing sap were used in addition to the examination of trees with symptoms other than watermarking in the wood. The field observations, together with some experimental inoculations, indicate that the main sources of the disease in the field each year probably are (1), the nearby stumps of felled diseased trees and (2) infected propagating material.
Sources of Potato Blight (Phytophthora infestans) in the East of Scotland
Authors: Boyd A. E. W.
Published: April 2007

Since 1965, 146 early occurrences of blight on field crops were recorded in the East of Scotland before the end of July. Of these, 119 were investigated to determine the source of infection, and 78 were found to be associated with heaps of discarded potatoes on which Phytophthora infestans was actively sporulating.

From samples of bright‐affected foliage taken from such dumps a wide range of races was detected.

In 1971 and 1972, attempts were made to control growth on discard heaps throughout East Lothian, a county in South‐east Scotland relatively isolated with regard to spread of blight, to determine whether this would delay the onset of blight in this area. In 1971, blight was recorded first on 17 August whereas further north in the counties of Perth, Angus and Fife it was noted on 5 July. The same pattern obtained in the latter counties in 1972 but no field cases of blight were recorded in East Lothian during the whole season. However, neither season was a ‘blight year’.

The lack of sources on potato dumps may have contributed to this delay, or even absence, of blight but other factors may well have had more influence. In the counties where blight occurred early i.e., in July, there was a highly significantly greater total acreage of potatoes, and also the proportion of this acreage devoted to the tuber‐susceptible cultivar King Edward was very highly correlated with the incidence of early reports. The influence of such a cultivar was illustrated by the fact that 45 per cent of the outbreaks of blight recorded up to the end of July related to King Edward.
Susceptibilities of Carrot Cultivars to Carrot Fly (Psila rosae (F.)
Authors: Hill D. S.
Published: April 2007

In 1972 a trial on susceptibility to carrot fly infestation was conducted on peat soil in East Anglia using 17 carrot cultivars sown on two dates one month apart. The only insecticide applied to the carrots was an aphicidal spray. The early‐sown carrots were damaged by the first generation of larvae, but, by the second sampling date in October, there were no infestation differences between the two sowings. At harvest in December, significant differences in infestation levels occurred; these ranged from 82 per cent damaged roots for Amster‐dammer Bak, 87 and 88 for two stocks of Royal Chantenay, to 97 per cent for Danvers 126. It is not yet clear whether the differences can be profitably exploited as an adjunct to other methods for controlling this pest.
Preliminary Evaluation of Fungicides to Control Red Core of Strawberry
Authors: Montgomerie Isabel G. , Kennedy D. M.
Published: April 2007

In pot experiments, the fungicides captafol, chloraniformethan, dimethirimol, dinocap, dithianon, drazoxolon, folpet, miancozeb, mancozeb and zineb, terrazole, FUN 52.133, R 22395 and R 45173 decreased the per cent by number of strawberry roots infected by zoospores of Phytophthora fragariae. Only terrazole and R 22395 were more effective than Bayer 22555 which was used as a standard.
The Perennation and Control of Pear Scab (Venturia pirina Aderb.)
Authors: WILLIAMSON CYNTHIA J. , BURCHILL R. T.
Published: April 2007

The production of ascospores of Venturia pirina from overwintered infected leaves, and of conidia from stem lesions was assessed in 1969 and 1970. Autumn post‐harvest dips of infected leaves in phenylmercuiic chloride (0·01 per cent), benomyl (0·0125 per cent a.i.), thiabendazole (0·0125 per cent a.i.) and urea (5–3 per cent) prevented ascospore formation in the following spring. Spring pre‐bud‐burrst dips in these chemicals partially suppressed ascospore production., but conidia production from stem lesions in spring was stimulated by autumn, followed by pre‐bud‐burst, sprays of benomyl, urea and PMC.
Lettace Root Aphid Control by Means of Plant Resistance
Authors: DUNN J. A. , KEMPTON D. P. H.
Published: April 2007

At Wellesbourne, Warwick, in 1968, not all plants of the lettuce cv. Webb's Wonderful protected against lettuce root aphid. Pemphigus bursarius (L.), by diazinon pre‐sowing treatments remained uncolonized throughout a relatively light aphid attack but no colonization of unprotected plants of cv. Avoncrisp occurred. In a second experiment in 1972, in which plants were untreated and exposed to an intense aphid attack, the lettuce cvs. Mildura, Borough Wonder, Webb's Wonderful, Avoncrisp and Avondefiance all attracted similar large numbers of winged root aphid rnigrants. No root colonies formed on the resistant CVS. Avoncrisp and Avondefiance. All plants of the other cultivars became severely damaged and most were killed.
The Effects of Benomyl on Sensitive and Tolerant Isolate of Botrytis cinerea infecting Strawberries
Authors: JORDAN V.W.L. , RICHMOND D. V.
Published: April 2007

Strawberry plants cv. Cambridge Vigour growing in a walk‐through polyethylene tunnel were experimentally inoculated with one benomyl‐sensitive and two benomyl‐tolerant isolates of Botrytis cinerea alone and in combination.

Three applications of benpmyl significantly increased the number of infected fruits in four out of the six treatments. There was no significant increase in infection on plants inoculated only with the benomyl‐sensitive isolate. Plants inoculated only with a slow growing, benomyl‐tolerant isolate showed an increase in infection which was not quite enough to be significant at the 5 per cent level.

The fast growing benomyl‐tolerant isolate spread more rapidly from plot to plot than the slow growing isolate.
The Incidence of Ryegrass Mosaic Virus in Crops of Ryegrass grown for Seed in some Southern Counties of England
Authors: HEARD A. J. , BROOK B. A. , ROBERTS E. T. , COOK R. J.
Published: April 2007

Italian ryegrass, cultivars Aberystwyth S22 and perennial ryegrass, CV.S321, grown for the production of seed in the A.D.A.S. S.E. Region and Wiltshire were surveyed for ryegrass mosaic virus (RMV). Visual leaf symptoms were used to assess infection; the diagnosis was checked using the electron microscope.

RMV infection was widespread in both grasses and about 30 per cent of the fields carried an infection level greater than 10 per cent (based on number of plants infected/examined). Higher levels of infection were encountered in crops of Italian ryegrass than in perennial ryegrass. Out of 69 fields of Italian ryegrass, only 12 showed no infection whilst nine fields showed a level of infection greater than 30 per cent. Twenty‐eight of the 61 fields of perennial ryegrass showed no infection and the highest level of infection found was 26 per cent.

All of the Italian and most of the perennial ryegrass crops were in their first harvest year. Since Italian ryegrass crops were occasionally encountered with more than 70 per cent of the plants infected, it is obvious that RMV can spread very quickly.

In perennial ryegrass fields an increase in the amount of N fertilizer applied in the spring led to an increase in RMV; an increase from 100 to 200 kg N/ha led to an increase in the level of RMV from 9 to 37 per cent.

By the first harvest year, fields sown in the spring of the previous year (usually under a cereal crop) were generally much more heavily infected than those sown in the autumn of the same year.
The Distribntion and Abondance ot Parasitaphelenchus oldkami, a Nematode Parasite of Scolytus scolytus and S. multistriatus, the Bark Beetle Vectors of Dutch Elm Disease
Authors: HUNT D. J. , HAGUE N. G. M.
Published: April 2007

In 1971 and 1972 populations of Scolytus scolytus (F.) in several counties in England were heavily parasitized by Parasitaphelenchus oldhami Rühm, but in S. multistriatus (Marsh.) P. oldhami was markedly less abundant. Infestation of S. scolytus was 54 per cent in 1971 and 61 per cent in 1972, while the mean number of parasites per infested beetle was 32 and 41 respectively. For S. multistriatus the comparable figures were 55 per cent in 1971 and 44 per cent in 1972 with means of 12 and 10 parasites per beetle. Despite the high levels of parasitism, no pathological effects on the beetles were observed.
Effects of Metopolophium dirhodum on Spring Wheat in the Glasshouse
Authors: LOWE H. J. B.
Published: April 2007

Pot‐grown plants of spring wheat, cultivar Maris Dove, Were subjected, commencing at ear emergence, to different, constant levelsof infestation hy Metopolophium dirhodum (Wlk.) in a glasshouse. Infestation with six aphids per stem over 11 days had no significant effect on yield. Infestations with either six or 50 adult aphids or their equivalents, when maintained until ripening, resulted in lower yields of both grain and straw dry matter. Loss of grain was due to reduction in both 1,000 grain weight and the average number of grains per fiertile spikelet. Harvested dry matter content of leaf blades was unaffected by infestation, but the dry matter, content of stems was reduced in infested plants. In breeding aphid‐resistant cereals for Britain, resistance characters restricting aphid multiplication are most likely to reduce yield losses due to aphid attack.
Fireblight in Hawthorn in England and Denmark
Authors: BILLING EVE , BECH‐ANDERSEN J. , LELLIOTT R. A.
Published: April 2007

Hawthorn is a common reservoir of the fireblight pathogen in England and Denmark. As in other hosts, the pathogen may overwinter in infected shoots, twigs and branches. Symptoms of canker, shoot and blossom infections are similar to those described for pear and apple. Eradication of fireblight in hawthorn is not a practical possibility in either country and alternative means for containing the disease are discussed.
Interactions between Varieties of Gaeumannomyces graminis and Phialophora radicicola on Roots, Stem Bases and Rhizomes of tbe Gramineae
Authors: DEACON W.
Published: April 2007

Interactions between varieties of the take‐all fungus, Gaeumannomyces graminis (syn. Ophiobolus graminis) and of Phialophora radicicola on living hosts are considered. This follows the earlier recognition of both morphologically and ecologically different varieties of these fungi. Interactions occur between all combinations of these fungi tested, so the fungus common in British grasslands, P. radicicola var. graminicola, is not peculiar in being able to restrict colonization of roots by the take‐all fungus in unsterile soil. However, the outcome of these interactions (that is, both the direction in which and the intensity with which they occur) depends on (1) the relative inoculum levels of the fungi; (2) the host species or organ; it also depends on the relative inoculum potentials of the fungi. Thus, under suitable conditions the weakly and non‐pathogenic ones compete successfully with the pathogen, G. graminis var. tritici (wheat take‐all fungus) and so reduce disease levels. But this fungus, itself, can restrict growth of its potential competitors, which may explain why grass leys often carry‐over take‐all between cereal crops, because despite the known ability of P. radicicola var. graminicola on grass roots to compete with the pathogen, the pathogen population is at first much higher than that of P. radicicola var. graminicola.

Possible explanations are offered as to why rhizomatous grasses commonly harbour the take‐all fungus in old pastures.

Results of this and of previous work are discussed in relation to prospects for biological control of turf and cereal diseases caused by varieties of G. graminis and similar fungi, like Leptoshaeria narmari and L. korrae.
Notes on the Biology of Carrot Fly in Eastern England
Authors: COPPOCK L. J.
Published: April 2007

Observations on the biology of carrot fly (Psila rosae (F.)) were made in the important carrot‐growing areas of eastern England in the period 1948–72.

Adults of the spring generation usually emerged in May and peak numbers were usually swept during the third and fourth weeks of May. Eggs were found from the end of May and larval damage was evident from late June. Calculations of accumulated day‐degrees of air temperature above 42°F (5.6°C) showed that peak emergence could generally be associated with a total of 422 day‐degrees commencing on 1 April. Both separate and combined totals of accumulated day‐degrees for February and March were markedly different in years of early and late fly emergence. Adults of the second generation appeared from late July onwards and oviposition occurred mainly during August and September, although in some years eggs were found much later. Resulting larval damage was present by October and increased in severity until the crop was harvested.
Aspects of Damage by Strawberry Ground Beetle (Pterostichus madidus (F.))
Authors: LUFF M. L.
Published: April 2007

Damage to strawberries by strawberry ground beetle (Pterostichus madidus (F.)) was studied by laboratory experiments and observations in a walled garden in south Northumberland during 1969 and 1970. Beetles preferred ripe to unripe fruit, eating holes mainly at the widrat part of the fruit. A beetle density of 4.2 per m‐ thrioughout the fruiting season resulted in a peak of 13 per cent of the fruit being damaged, with up to four holes per fruit. Both starvation and desiccation increased the beetles capacity for strawberry feeding, although hunger had more effect than thirst.
Laboratory Observations on tbe Effect of Soil Compaction on Slug Damage to Winter Wheat
Authors: STEPHENSON J. W.
Published: April 2007

When the aggregates of fairly dry, medium‐coarse soil were broken down and firmed over the seed by moderate or heavy pressure, slug damage was reduced. Coarse soil aggregates did not break down so well, particularly under heavy pressure; many seeds remained exposed and were damaged. The seed was also protected by deep planting, with the penalty of late emergence of the seedlings.
Assessment of Loss caused by Barley Mildew using Single Tillers
Authors: RICHARDSON M. J. , JACKS MARGARET , SMITH SUSAN
Published: April 2007

A method for estimating losses due to foliar diseases with more precision, using little space and time and without the need for artificially producing different levels of disease, is described. Randomly selected tillers were labelled with their mildew level on leaf 2 at growth stage 10.5 and the ripe ears harvested to obtain values for seed number, seed weight and yield for each ear. Regressions of all three parameters on mildew level were negative and highly significant. Converted to per cent loss equations the mean regression coefficients for cvs. Ymer and Golden Promise were:—seed weight on mildew, 0·257; seed number on mildew, 0·291; and yield/ear on mildew, 0·498. There was no evidence of non‐linearity in the response of yield loss to mildew.
Resistance to Binapacryl in Field Populations of Fruit Tree Red Spider Mite, Panonychus ulmi (Koch)
Authors: CRANHAM J.E.
Published: April 2007

Assays in 1969 on larvae of Panonychus ulmi from English apple, orchards showed an average 4x resistance to binapacryl after three to five years' use and, except for one population, a low degree of cross‐ resistance to dinocap. In contrast, there was no resistance to dinocap after four to ten years' use of this material. A resistant strain, after prolonged selection with binapacryl in the laboratory, showed 16x resistance to binapacryl and 2x cross‐resistance to dinocap in assays on adult female mites.
Specific Feeding Preferences of Tortricid Larvae on Flowering Strawberry Plants
Authors: ALFORD D. V.
Published: April 2007

Examination of the feeding preferences of tortricid larvae attacking strawberry plants in eastern England during the main pre‐harvest blossom periods of 1972 and 1973 indicated that most larvae (85–6 per cent) of Acleris comariana (Lienig & Zell.) fed on foliage rather than on flowers or developing jfruitlets. However, this was not true for Clepsis spectrana (Treits.) (87–7 per cent on flowers), Olethreutes lacunana (Denis & Schiif.) (77–6 per cent on flowers) and Cnephasia interjectana (Haw.) (98–5 per cent on flowers). At densities of up to 12–5/m2, larvae of A. comariana had no observable effect on strawberry yields. Neither fruit quality nor quantity was correlated with pest (larval) numbers. The possible economic importance of A. comariana is considered in the light of these results and in comparison with published data for more directly damaging tortrix species. The role of the parasite Litomastix aretas (Wlk.) in controlling A. comariarm populations in East Anglia is also discussed.
The Effect of Phorate, a Wide‐spectrum Pesticide, on the Occurrence of Spraing in Twelve Cultivars of Potato
Authors: SYKES G. B.
Published: April 2007

During 1973 the susceptibility to spraing of 12 commercial potato cultivars was tested on land in North. Worcestershire infested with viruliferous Trichadorus nematodes.

The wide‐spectrum pesticide phorate reduced spraing in the harvested crop by over 60 per cent compared with untreated plots, bat the order of symptom expression was similar in both treated and untreated plots.
The Effect of Heat on the Hatch of Potato Cyst Eelworms
Authors: STONE L. E. W. , WESLEY D. P.
Published: April 2007

The effect of heat on potato cyst eelworm cysts, Heterodera pallida Stone (British pathotype E) and H. rostochiensis Woll. (British pathotype A) was investigated in the laboratory in 1967–69.

Hatching from wet cysts of H. pallida was completely inhibited after 4 minutes’ exposure to 50°C and above. Air‐dry cysts were more resistant to heat; hatching was only prevented at 90°C.

Results indicate that H. pallida is more susceptible to heat than H. rostochiensis.
Soil Placement of Insecticide Granules for the Control of Cabbage Root Fly on Transplanted Canliflowers
Authors: BEVAN W. J. , KELLY I. R.
Published: April 2007

Seven organophosphorus insecticides were evaluated as granular formulations for the control of cabbage root fly, Erioischia brassicae (Bouche), in west Yorkshire, on transplanted cauliflowers from 1966 to 1970 inclusive. The insecticides were chlorfenvinphos, diazinon, dimethoate, fonofos, mecarbam, pirimiphos‐ethyl and thionazin. Various methods of application were compared and the work evolved into a comparison of the effectiveness of continuous bands of granules applied below the surface immediately before plant insertion with that of surface bands applied immediately after plant insertion. The methods employed and the equipment involved are described.

Chlorfenvinphos was the most effective chemical for protecting the roots from cabbage root fly attack. Diazinon, dimethoate, fonofos, mecarbam and thionazin all reduced damage in the early part of the season (except when applied by the bow‐wave method). The subsurface method of placement of all these chemicals except dimethoate was consistently more effective in reducing root damage and promoting higher yields than surface placement. Pirimiphos‐ethyl was not effective in protecting the roots by either method.
Attempts at Cultural Control of Carrot Fly Damage to Carrots in East Anglia
Authors: COPPOCK L. J. , MASKELL F. E. , GAIR R.
Published: April 2007

At sites in Norfolk in 1970, 1971 and 1972, growing carrots were covered in situ with soil or straw for varying periods in attempts to prevent egg laying and subsequent late‐season damage by larvae of the carrot fly (Psila rosae) (F.))‐ Neither soil nor straw was sufficiently effective in this respect. Carrots chemically defoliated and/or covered during the main egg‐laying period in August and September were adversely affected in size and quality.
The Role of Mites in the Transmission of Smoulder in Narcissus
Authors: GRAY E. G. , SHAW M. W. , SHIEL R. S.
Published: April 2007

Infection by Sclerotinia narcissicola Greg, was observed in narcissus bulbs during autumn, in leaf initials colonized by bulb scale mites (Steneotarsonemus laticeps (Halb.)), and on lesions of varying extent on the corresponding tissue after emergence.

Presence or absence of smoulder sclerotia on outer scales of bulbs was not related to the incidence of infection of shoots.

There was no evidence that smoulder was reduced by treatment for control of bulb mites (Rhizoglyphus echinopus (Fum. & Rob.)).