bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water‐borne spore dispersal in coffee berry disease and its relation to control*
Authors: WALLER J.M. 
Published: February 2008

SUMMARYDevices are described which were used to catch rain‐dispersed Colletotrichum conidia within and between coffee trees infected with coffee berry disease (CBD). The amount of CBD inoculum dispersed was related to the number of diseased and sporulating berries but not to the sporulating capacity of the fungus in maturing bark. Wet conditions encouraged spore production and dispersal, and spraying with fungicides prolonged sporulation of diseased berries.The amount of pathogenic inoculum, subsequent disease development and crop losses were greatly increased by the presence of only a few diseased berries during growth of the young crop. Spore concentrations were greatest close to diseased berries, but most spores within trees were dispersed downwards through the canopy. Some spores were dispersed between trees by wind‐driven rain‐splash and vectors such as pickers.Inoculum sources in tree tops are most important during CBD epidemics and disease can be restricted by removing or spraying the tops of multiple‐stem trees. Fungicide applied to tree tops effectively controls CBD, because spores dispersed during rain are accompanied by redistributed fungicide
Ecological studies on potato mop‐top virus in Scotland
Authors: Jones R. A. C. , HARRISON B. D. 
Published: February 2008

SUMMARYPlants with symptoms of potato mop‐top virus (PMTV) occurred in many commercial seed stocks of Arran Pilot and Red Craig's Royal potato in Scotland, but their incidence rarely exceeded 5%. In nuclear stocks of seed potatoes, most varieties examined in 1967 and 1968 were infected at one or more locality, but infected plants did not occur in all clones or at all stages of propagation of any one variety. infection of nuclear stocks resulted both from propagation on virus‐infested land and from unwitting selection of infected plants to start new clones. PMTV was detected in farm soils ranging from light sands to heavy loams, in five Scottish counties. Soil was infested throughout the ploughed layer but the severity of infestation varied greatly within any one field; some sites of former potato clamps were heavily infested. PMTV was detected in field soil 12 years after potatoes were grown.In glasshouse tests many British crop and wild plants were colonized by Spongospora subterranea. Within some families all species tested were moderate to good hosts. (Solanaceae, Chenopodiaceae and Cruciferae), in others, species differed greatly in susceptibility (Compositae and Umbelliferae), and in a few, species were poor hosts or were not infected (Caryophyllaceae and Gramineae). Of the British crop and weed species that were moderate to good zoosporangial hosts of S. subterranea, only Solanum nigrum, potato, spinach and sugar beet were hosts of vector‐borne PMTV. Potato probably survives between potato crops mainly in the resting spores of S. subterranea. PMTV was probably first brought to Europe with potatoes from South or Central America.
The pathogenicity and increase of Heterodera rostochiensis on tomato cultivars, self‐rooted or grafted on to rootstocks.
Authors: HESLING J. J. , ELLIS P. R. 
Published: February 2008

SUMMARYSelf‐rooted tomatoes ‘Ailsa Craig’ and ‘Kingley Cross’, and scions of ‘Ailsa Craig’ grafted on to different rootstocks, were grown in soil infested with different numbers of Heterodera rostochiensis (Mainly pathotype A). Three rootstocks (RS4, RSKN, ISKVF) tolerated damage from nematode populations of up to 125 eggs/g soil, but nematodes increased up to x45 on them. Two nematode‐resistant F1 hybrid rootstocks, B6633 (ex Lycopersicon pimpinellifolium B6173) and B6015 (ex L. hirsutum var. glabratum B6013), tolerated up to 125 eggs/g soil; nematode populations declined as much as 80% under B6633, and increased little under B6015. On the self‐rooted ‘Ailsa Craig’ and ‘Kingley Cross' the numbers of nematodes increased markedly (maximum increase x40), and greatly affected growth and yield so that initial populations greater than 62 eggs/g soil caused crop failure.
Chemosterilization of the cabbage root fly under field conditions
Authors: FINCH S. , SKINNER G. 
Published: February 2008

SUMMARYRemoving hedgerow feeding sites from within 40, 80 or 160 m of cauliflower plots, failed to reduce populations of the cabbage root fly (Erioischia brassicae (Bouché)). Oviposition on the plots was unchanged but the efficiency of yellow water‐traps was improved. Traps along‐side cleared hedgerows caught more gravid than non‐gravid females. In cages, 94% of the eggs laid were sterile when both sterilant baits containing tepa [tris‐(i‐aziridinyl) phosphine oxide] and hedgerow flowers were present.In the field, maximum egg‐sterility rarely exceeded 30% when sterilant was present when natural sterility averaged 8%. Chemosterilization was an inadequate control since sufficient eggs and larvae survived to produce root‐damage indices of 49 % in contrast to 2 % on insecticide‐treated plants.Most eggs were sterile when chemosterilant baits were placed 0.75 m apart and bait was most effective when placed around the crop during the pre‐oviposition period and through the crop at the time of maximum oviposition. Increasing the concentration of tepa failed to increase the effectiveness of the bait but a higher proportion of the eggs laid were sterile on large than on small plots. When chemosterilant treatments were stopped, egg‐fertility gradually reverted to the natural level.Protracted immigration, an innate tendency for females to disperse, reductions in the competitiveness of sterile males, and the failure of males to re‐disperse once sterilized, appeared to be the main factors limiting the levels of sterility in root‐fly populations exposed to tepa‐baited lures in the field.
Further studies on seed transmission in the ecology of some aphid‐transmitted viruses
Authors: TOMLINSON J. A. , WALKER VALERIE M. 
Published: February 2008

SUMMARYA small proportion (1–4%) of the seeds of Stellaria media extracted from fallow soil from three widely separated areas contained cucumber mosaic virus (CMV). S. media seeds buried for 21 months produced 5 % infected seedlings. S. media plants from Britain, N. America and Australia were least severely affected by the CMV strain obtained from their country of origin and showed more severe reactions when infected with two alien strains.Several weed species were experimentally infected with lettuce mosaic, turnip mosaic and cauliflower mosaic viruses but, although virus was detected in the seeds of some species, it was not transmitted to any of their seedlings.
Studies in vitro and in vivo with powdery mildew fungicides
Authors: CLIFFORD D. R. , HISLOP E. C. 
Published: February 2008

SUMMARYDroplets of 4‐(i‐cycloalkylalkyl)‐2,6‐dinitrophenols often protect areas of leaf very much greater than that of the initial deposit against powdery mildew. For a given alkyldinitrophenol, this type of protection is greater on apple than on marrow leaves. This zonal protection is not correlated with vapour activity in vitro or in vivo, or with inhibition of conidial germination in vitro, but is correlated with the degree of protection obtained when leaves are sprayed to give good cover. By contrast, crotonic esters of these alkyl‐dinitrophenols do not show zonal activity, but nevertheless often exhibit protectant activity comparable with that of the parent phenols. These results suggest that exploitation of favourable hydrogen bonding characteristics in the fungicide molecule may lead to better control of fungal diseases in the field as a result of enhanced movement of fungicide in or on the leaf cuticle (zonal movement) or easier penetration of the fungal conidium.
An apparatus for the isolated propagation of foliar pathogens and their hosts
Authors: JENKYN J. F. , HIRST J. M. , KING G. 
Published: February 2008

SUMMARYEpidemiological studies, especially of obligate pathogens, often require healthy test plants and the incubation of infections in isolation. Ventilation of glasshouses with spore‐free air is helpful but costly, and provides only a few discrete environments. The apparatus described is cheap and simple and enables many separate covered plant pots to be supplied with filtered air. It was designed to help measure the incubation time and frequency of viable conidia ofErysiphe graminis, but may also be useful for studying other pathogens and, with some modification, for plant breeding or quarantine.
Chemical investigations on resistance to coffee berry disease in Coffea arabica. An antifungal compound in coffee cuticular wax
Authors: LAMPARD J. F. , CARTER G. A. 
Published: February 2008

SUMMARYInvestigations have been made into the possibility of a chemical basis for resistance to coffee berry disease in certain Coffea arabica varieties. Chloroform extracts of the cuticular wax of berries, purified by fractionation and chromatography, proved toxic to a range of fungi including Colletotrichum coffeanum, the causal organism of coffee berry disease. Leaf cuticular wax also contained this fungitoxic principle, though at a lower level. The possible importance of this antifungal material in determining resistance to coffee berry disease is discussed.
The production of pure stocks of self‐pollinating cereal varieties
Authors: HANSON PETER 
Published: February 2008

SUMMARYThe method of cereal pure stock production used at the Plant Breeding Institute is described. Multiplication from fifty plants to commercial seed stocks takes 5 years; individual ears are inspected each year and an ear‐row/ear‐row progeny system is used. An accelerated system reducing the period of multiplication to 4 years is also described. The advantages and disadvantages of other multiplication methods are discussed.
Laboratory rearing, biology and chemical control of the mushroom sciarid Lycoriella auripila (Diptera: Lycoriidae)
Authors: BINNS E. S. 
Published: February 2008

SUMMARYThe mushroom sciarid was found to develop on a plant‐derived diet of oat or soya meal. Details of simple rearing techniques and insecticidal assays of treated casing are given. In laboratory tests using ten chemicals, chlorfenvinphos and pirimiphosethyl showed persistent activity against larvae when used at 15 ppm and are suggested as suitable for incorporation in peat‐chalk casing mixtures to give protection throughout cropping. The low figures obtained for phytotoxicity and residues in the crop suggest this technique would be acceptable in commerce. Diazinon remained active in casing for only a short time.
Bionomics of aphids reared on cereals and some Gramineae
Authors: DEAN G. J. W. 
Published: February 2008

SUMMARYIn controlled temperature, light and relative humidity, Metopolophium dirhodum and Sitobion avenae multiplied more on young Proctor barley than on Blenda oats, and less on Cappelle wheat. Rhopalosiphum padi increased in number fastest on barley and slowest on oats. More survived, and generation lengths seemed shorter, on barley for M. dirhodum and S. avenae and on wheat for R. padi.Tests with young cereals outdoors generally agreed with those in controlled conditions. On mature plants, there were more M. dirhodum on barley, more R. padi on wheat and more S. avenae on oats than on the other cereals.Given a free choice in large cages outdoors, most aphids were found on barley. When allowed to choose between grasses, more M. dirhodum were on Dactylis glomerata, Poa pratensis and Festuca pratensis, more R. padi on Lolium perenne and F. pratensis, and more S. avenae on D. glomerata and L. perenne. Most aphids of all species combined were on F. pratensis, Lolium and Phleum, and fewest on Festuca rubra and Holcus mollis.
The effect of benomyl on the infection of tomatoes by Fusarium oxysporum f.sp. lycopersici and Botrytis cinerea
Authors: CHANNON By A. G. , THOMSON MOIRA C. 
Published: February 2008

SUMMARYIn glasshouse experiments at Auchincruive, drench applications of benomyl (100 or 142 mg per plant) to the soil surface around the stem bases of pot‐grown tomato plants before inoculation with Fusarium oxysporum f.sp. lycopersici reduced the penetration of the fungus up the stems and/or decreased the development of vascular discoloration and associated severity of wilting. Similar drenches applied after establishment of the fungus in the stems either halted or considerably retarded the growth of the pathogen up the vessels. This again was reflected in reduced vascular discoloration and wilt symptoms.In experiments with benomyl over 2 years at a commercial holding in Argyll, the application of soil drenches (at the rates above) shortly after planting out and again 5 weeks later, coupled with a programme of stem and foliar sprays (at 0–05 % a.i.) during the summer, reduced the development of stem lesions caused chiefly by Botrytis cinerea and increased the general survival of plants more than did drench or spray treatments alone. There were indications that ‘ghost spotting’ of the fruit, particularly where spray applications were made, was also slightly reduced, but the magnitude of the effect was not consistent.
Studies on plant growth‐regulating substances: XXXV. Ethylene production by coleoptiles treated with auxin‐type chemicals
Authors: GOLDWIN G. K. , WAIN R. L. 
Published: February 2008

SUMMARYWheat coleoptile sections were treated with a range of auxins and with compounds of related chemical structure which do not exhibit auxin properties. Methods used for measuring the rates of elongation and ethylene evolution of these sections are described.Ethylene was evolved some time after elongation in all cases and increased ethylene production occurred only with compounds showing auxin activity. The results indicate that ethylene evolution was related exponentially to growth.Simultaneous applications of mannitol and 2, 4‐dichloro‐phenoxyacetic acid (2, 4‐D) to wheat sections markedly reduced ethylene evolution compared with the 2, 4‐D controls, even though the level of 2, 4‐D in the tissue apparently remained unchanged.Ethylene significantly inhibited the elongation of wheat coleoptile sections, and it is suggested that ethylene is a natural plant growth inhibitor which becomes mobilised to limit excessive growth.
Aphid colonization of spring cereals
Authors: DEAN BY G. J. 
Published: February 2008

SUMMARYIn 1970‐1, Metopolophium dirhodum, Rhopalosiphum padi and Sitobion avenae were the commonest alatae trapped from April/May to August, with most in July and early August. The first alatae appeared in the Rothamsted survey suction trap 0–34 days before aphids were found on the cereals, but during May and June no relationship was found between the numbers trapped and the number on the crop. Most species occurred first near the sheltered edge of the crop, but M. dirhodum was widespread over the field. Most infestations were quickly dispersed by the movements of older morphs; adults only stayed in one place for about 2 days. Alate M. dirhodum moved more often than apterae, but both morphs of S. avenae moved equally often and more frequently between larvipositions than did those of M. dirhodum. Apterae deposited more nymphs in a ‘group’ than alatae, and M. dirhodum deposited more than S. avenae. Few ‘groups’ persisted for more than a week. Although M. dirhodum occupied the crop area faster than S. avenae, all 0–3 m lengths of row sampled being infested within 2–5 wk of their first appearance, most or all of the tillers were colonized only in late July 1970.
The survival of Mycosphaerella pinodes on pea haulm buried in soil
Authors: SHERIDAN J. J. 
Published: February 2008

SUMMARYWhere haulm was left on the soil surface the mycelium of Mycosphaerella pinodes went through cycles of active saprophytic growth, followed by inactive phases during the earlier parts of the year. Burial at either 15 or 25 cm brought about a decrease in survival with time. The majority of the mycelium was on the outer portions of the stem pieces, with only a small amount of penetration into the plant remains. Experiments on root surface colonization showed that mycelium of M. pinodes was capable of growing saprophytically on the host roots in competition with the normal soil microflora.
Fungitoxic and phytotoxic effects of fungicides controlling powdery mildew on apple
Authors: BUTT D. J. , KIRBY A. H. M. , WILLIAMSON CYNTHIA J. 
Published: February 2008

SUMMARYBenomyl, pyrazophos (HOE 2873), triarimol, triforine and the non‐systemic fungicide diethyl phthalimidophosphonothionate (Dowco 199) were sprayed at c. 200 gal/acre (2250 1/ha) at 14‐day intervals from pink bud (late April/early May) on seven apple cultivars including Cox's Orange Pippin, Golden Delicious and Jonathan. Compared with binapacryl or dino‐cap (and with elemental sulphur on the sulphur‐tolerant cv. Golden Delicious), these compounds were more phytotoxic without substantially or consistently improving the control of Podosphaera leucotricha; fruit russet was increased and the crop and fruit size of some cultivars were reduced in some trials. In 1969 the inclusion of bis(dimethylthiocarbamoylthio)‐methylarsine (44 ppm) as Urbacid(R) in the sprays reduced russeting by benomyl and Dowco 199 so that these fungicides became as safe as captan on several cultivars; Dowco 199 was also safened by captan (500 ppm). Urbacid(R) (88 ppm a.i.) safened benomyl and triarimol on fewer cultivars in 1970 when russet was less severe. The addition of Urbacid(R) did not prevent yield losses caused by sprays in either year.The crop is most sensitive to spray damage from pink bud until late June. This is a crucial period for the control of mildew, and unless new fungicides are less phytotoxic, palliatives may become necessary adjuvants.
A self‐powered portable insect suction sampler and its use to assess the effects of azinphos methyl and endosulfan on blossom beetle populations on oil seed rape
Authors: ARNOLD A. J. , NEEDHAM P. H. , STEVENSON J. H. 
Published: February 2008

SUMMARYA new portable insect suction sampler, powered by a small petrol engine, is described. It has been in use for three seasons, and examples given of samples taken from oil‐seed rape demonstrate that the suction method is more informative than visual counts or sweep‐net sampling for assessing blossom beetle populations.
Activity of six fungicides against cereal foliage and root diseases
Authors: JENKYN J. F. , PREW R. D. 
Published: February 2008

SUMMARYDuring 1970 and 1971 six systemic fungicides were compared as seed dressings and sprays against foliage and root diseases of cereals. The fungicides differed greatly in effectiveness against mildew, loose smut, rusts and eyespot but none controlled take‐all. Effects were also noted on germination, seedling growth and leaf‐surface microflora.
Stomatal control of gas exchange in barley awns
Authors: BISCOE P. V. , LITTLETON E. J. , SCOTT R. K. 
Published: February 2008

SUMMARYThe gas exchange of barley ears and awns was measured in the field using a gas analysis system and a diffusion porometer. Awn stomatal resistance decreased with increasing irradiance but to a smaller extent than leaf stomatal resistance. Measurements on ears immediately before and after successively removing awns showed that awn transpiration and photosynthesis were proportional to awn area and that awns accounted for 73% of transpiration by the ear. Although the maximum rates of photosynthesis of which awns were capable declined with age, awns accounted for 80–115% of the net CO2 uptake of complete ears because the ears‐less‐awns could respire more CO2 than they absorbed. Ear photosynthesis accounted for 52% of the weekly increment in ear dry weight after ear emergence, but 5 weeks later photosynthesis by the ear balanced respiration. Overall photosynthesis by the ear accounted for 35 % of its final weight. Differences in the light response curves of leaves and ears can be fully accounted for by the different relationships between stomatal resistance and irradiance of the two organs.
Effects of population density on alienicolae of Aphis fabae Scop.: The expression of migratory urge among alatae in the field
Authors: SHAW M. J. P. 
Published: February 2008

SUMMARYAlate Aphis fabae from field infestations on beans and sugar beet were tested for flight before parturition and divided into migrants, flyers and non‐flyers. More alatae were produced, fewer nymphs were deposited before flight and the proportions of migrants among alatae increased with population density on each of the three crops. After the population peak, proportions of migrants decreased, more interforms were produced and more nymphs were deposited before flight.
Effects of population density on alienicolae of Aphis fabae Scop.: V. Variations in size, relative wing length and numbers of antennal sensorla of field alatae
Authors: SHAW M. J. P. 
Published: February 2008

SUMMARYSize, relative wing length and numbers of antennal sensoria of alate Aphis fabae caught in a suction trap 12.2 m above ground and of migrants, flyers and non‐flyers among alate A. fabae from field infestations on beans and beet are compared. The size of aphids in successive samples decreased throughout the period of colonization but, on average, beet aphids were bigger and broad bean aphids were smaller than field bean aphids. There were very few migrant alatae among the very large or the very small aphids from any of the crops, neither were aphids of these extreme sizes caught in the suction trap. Non‐flyers and beet aphids generally had relatively shorter wings than migrants and bean aphids respectively. The numbers of antennal sensoria differed more between aphids from the three crops than between classes of alatae from the same crop, although trap aphids, presumed to be migrating from field beans had more sensoria than alatae taken from that crop. The mean dry mass of flyers was usually less than that of migrants of a similar size, although if the mass of nymphs deposited before flight is added, it is apparent that a flyer would be heavier than a migrant of the same size at maturity. This additional mass is thought to be due to increased development of the embryos in the ovarioles of flyers at this time and indicative of their greater adaptation for reproduction.
Fluctuations in populations of wheat bulb fly (Leptohylemyia coarctata) at Rothamsted
Authors: BARDNER R. , FLETCHER K. E. , JONES MARGARET G. , LOFTY J. R. 
Published: February 2008

SUMMARYSeveral field experiments at Rothamsted have rotations including plots fallowed before sowing to winter wheat each year, which provide ideal conditions for maintaining infestations of wheat bulb fly (Leptohylemyia coarctata). In eight consecutive years of one experiment, a mean of 13% of the eggs laid on fallows in these rotations eventually survived to become adults. There was a considerable variation between years, ranging from a maximum survival of 28 % to a minimum of 7%. Most deaths occur in the larval stage, and although previous work showed that survival of the larvae increases with the number of shoots available for infestation, much of the variability in survival rates between seasons was apparently caused by other factors, possibly climatic.Eggs laid in fallows were sampled in most years from 1953 to 1972. They varied from 3.57 to 0.02 million/acre (8.81–0.05 million/ha), depending on the season and site; the mean was 1.08 million/acre (2.67 million/ha). Egg populations varied in synchrony at all the three sites studied; there were cycles lasting several years between peaks of abundance or scarcity but there was no consistent tendency for populations to increase or decrease. Fewest eggs were laid when the weather was cold and wet during July and August, i.e. when adults are active. Weather was more closely correlated with the number of eggs laid expressed as a fraction of those laid in the previous year (net reproductive rate) than with the number of eggs laid/acre.