bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Globodera rostochiensis on the growth of reciprocal grafts between two potato cultivars of different tolerance in a field trial
Authors: TRUDGILL D. L. 
Published: February 2008

SUMMARYThe tolerance of plants produced from reciprocal grafts between cv. Cara and cv. Pentland Dell were compared in field plots containing different initial population densities of Globodera rostochiensis. Both stock and scion contributed to the greater tolerance of cv. Cara as compared with cv. Pentland Dell. Ground cover measurements, made by a novel photographic method, showed that a heavy infestation of G. rostochiensis decreased the top growth of all plants: more for those with scions of Pentland Dell than those with scions of Cara. The stock did not initially affect the extent to which top growth was reduced in the heavily infested plots but later measurements showed a progressively increased effect on top growth for plants with stocks of Pentland Dell and a decreased effect for those with Cara. In a destructive harvest 13 wk after planting the relatively small effect of G. rostochiensis on the top growth of plants with Cara scions was not reflected in the tuber yields which were markedly decreased. However, plants with Cara stocks were considerably more tolerant (i.e. tuber yields were affected less) than those with stocks of Pentland Dell. Overall, plants of Pentland Dell scions on Cara root stocks were most tolerant at this stage. Between 13 and 16 wk, when a second destructive harvest was made, plants with Pentland Dell scions were senescent and their yield increased little. In contrast, plants with Cara scions were still growing and their yield increased markedly so that by 16 wk the most tolerant combination was Cara on Cara.
Changes in the second stage juveniles of Globodeva rostochiensis prior to hatching in response to potato root diffusate
Authors: ATKINSON H. J. , TAYLOR JILL D. , FOWLER M. 
Published: February 2008

SUMMARYcAMP levels in eggs of G. rostochiensis and the diameter of the nucleolus of the nucleus within the dorsal pharyngeal gland cell of the second stage juvenile have been measured as indicators of the response of the nematode to the hatching stimulus in potato root diffusate. The nucleolus increased from 2.72 ± 0.103 μm for unhatched individuals to 3.28 ± 0.14 μm and 3.88 ± 0.15 μm after soaking eggs in potato root diffusate for 3 and 4 days respectively. Juveniles expressed from unstimulated eggs in water to potato root diffusate for 4–5 days showed a similar increase in size of the nucleolus to 3.94 ±0.15 μm but those released into water for this time had smaller nucleoli of 3.20 ± 0.98 μm. The change in diameter of the nucleolus is probably related to the accumulation of secretions in this gland cell before hatching.Preliminary results with dibutyryl analogues of CAMP and cGMP showed some inhibition of hatch in 10% potato root diffusate. Theophylline had a similar effect but NaF was dissimilar in that the effect of this inhibitor was not reversible. A standard radioimmunoassay showed that significant changes in cAMP levels occurred in the unhatched juveniles within cysts after treatment with potato root diffusate for 2.5 or 8 h compared with values for cysts kept in water. This change occurs before other known responses of the juveniles to potato root diffusate and it defines the period of interest for future work on the initial action of hatching factor.
Control of beet cyst‐nematode, Heterodera schachtii, by aldicarb applied to the soil by a vertical band‐reciprocating harrow technique or by rotary cultivation
Authors: WHITEHEAD A. G. , TITE D. J. , FRASER JANET E. , NICHOLS A. J. F. 
Published: February 2008

SUMMARYAs little as 0.8 kg aldicarb ha‐1 applied to bands of soil 15 cm wide × 15 cm deep, in which sugar beet seeds were sown, increased beet yields as much as did 2.6 or 5.0 kg ha‐1 rotary cultivated into the top 15 cm of soil lightly or moderately infested with beet cyst‐nematode, Heterodera schachtii. In a very heavily infested soil, 1.7 kg ha‐1 applied to the bands of soil increased beet yields as much as 2.6 kg ha‐1 rotavated into the top 15 cm of the soil; yields were further increased by 5.0 and 9.9 kg ha‐1 rotavated in but not by 3.5 kg ha‐1 in the bands of soil. Soil populations of the nematode increased little or not at all whether the soil was treated with aldicarb or not. The band treatment was achieved by a vertical band‐ reciprocating harrow technique, which is described. The advantages of this new technique for the control of beet cyst‐nematode and other soil pests of widely spaced row crops are safer application of less pesticide, thereby minimising cost of treatment and any risk to the environment, faster seedbed preparation and adequate control of pest population increase on the susceptible crop, especially if coupled with biological control.
Post‐harvest age‐induced seed dormancy ofAcer ginnalaand its alleviation by growth regulator and low temperature treatments
Authors: NORTON COLIN R. 
Published: February 2008

SUMMARYOne‐month‐old fruits ofAcer ginnalawith winged pericarp attached gave 44% germination and this was not increased by cold treatment at 4°C for 0, 10, 20, or 30 days, gibberellic acid treatment at 0, 1, 10, 100 or 1000 mg litre‐1, or ethephon treatment at 0, 2, 20, 200 or 2000 mg litre‐1.After 6 months of storage at 20–25 °C, germination of untreated fruits fell to 5% but could be restored to that of 1‐month‐old fruits by incubation at 4 °C for 30 days.After 9 months storage, no germination occurred in untreated fruits. Cold treatment (30 days at 4 °C partially restored germination (26%). Treatment with either gibberellic acid (1000 mg litre‐1) and 30 days at 4 °C (40%) or ethephon (100 mg litre‐]and 30 days at 4 °C improved germination (69%). The combination of all three treatments, i.e. 100 mg litre‐1gibberellic acid, 100 mg litre‐1ethephon and 30 days at 4 °C, optimised germination (86%).Thus, dormancy ofA. ginnaladeveloped during storage but could be reversed by a combination of treatment with low temperature and growth regulators. The highest germination (86%) was achieved after low temperature and growth regulator treatment of stored fruit.
Effects of growth retardants on bulbil production by Narcissus twin‐scales
Authors: HANKS GORDON R. 
Published: February 2008

SUMMARY Narcissus twin‐scale propagules, cut from various positions in the parent bulb, were incubated with gibberellic acid (GA3) or growth retardants. Bulbil production was inhibited in all cases by GA3 at 10–100 mg/litre. Chlormequat chloride, chlorphonium chloride and paclobutrazol also inhibited bulbil production; in the case of paclobutrazol, outer twin‐scales were more sensitive to lower concentrations of the retardant than inner ones. Ancymidol enhanced bulbil production (in numbers by up to 15%) in the outermost twin‐scales, and had no stimulatory effect on the inner twin‐scales. Treatments affected bulbil numbers and bulbil lengths about equally.
The effect of cane management techniques on raspberry yellow rust (Phragmidium rubi‐idaei)
Authors: ANTHONY VIVIENNE M. , WILLIAMSON B. , SHATTOCK R. C. 
Published: February 2008

SUMMARYThe effects of various cane removal treatments on the epidemiology of Phragmidium rubi‐idaei were studied in four experiments in infected raspberry plantations in Wales and Scotland. In 1981, removal of 15 cm high young canes either by cutting or by spraying dinoseb‐in‐oil reduced infection of a second flush of canes (replacement canes) compared to that of the first flush of canes on untreated plots of cv. Mailing Delight in Wales and of cv. Glen Clova in Scotland. In 1982, removal of 20 cm high young canes reduced infection of cv. Mailing Delight in Wales but in Scotland only removal of 60 cm high canes by cutting reduced infection of replacement canes. Removal of all fruiting canes and old cane stubs reduced rust infection of young canes, but removal of successive flushes of replacement canes did not reduce infection of lateral shoots on the fruiting canes.Dinoseb‐in‐oil applied to the bases of fruiting canes before emergence of young canes had no effect on infection of young canes in Wales or Scotland. The production of basidiospores was inhibited in vitro by dinoseb‐in‐oil at concentrations over 1.0 μg a.i./ml.
The effect of irrigation on powdery scab and other tuber diseases of potatoes
Authors: ADAMS M. J. , READ P. J. , LAPWOOD D. H. , CAYLEY G. R. , HIDE G. A. 
Published: February 2008

SUMMARYIn field experiments seed tubers affected with powdery scab cankers were planted and the effect on disease incidence of timing of irrigation and some seed‐tuber fungicides was investigated over 3 yr. For 2 yr, irrigation to maintain soil wetter than—20 centibars (—20 kPa) during the first half of the growing season increased disease compared to unirrigated plots. Disease incidence was not affected by irrigation at 2 wk intervals or when applied during the second half of the season. Little disease developed in 1983 even in irrigated plots, probably because of high soil temperatures. None of the fungicides tested gave consistent disease control.Common scab and silver scurf were both decreased by irrigation but in two years, black dot was increased. The relative importance of black dot could increase in irrigated crops where fungicides are used to control silver scurf.
Possible explanations of synergism in fungicide mixtures against Phytophthom infestans
Authors: SAMOUCHA Y. , GISI U. 
Published: February 2008

SUMMARYSingle foliar sprays of oxadixyl, mancozeb or cymoxanil alone or the mixtures oxadixyl/mancozeb and oxadixyl/cymoxanil were applied to tomato plants (cv. Baby) one day before inoculating with a sensitive or a phenylamide‐resistant strain of Phytophthora infestans. Fungicide mixtures were far more effective in controlling both sensitive and resistant strains compared to the individual components alone, representing significant levels of synergistic interactions. When analysed by the Abbott method, synergy ratios continuously decreased with increasing amounts of fungicides in the mixture. All fungicide mixtures showed higher synergy ratios against resistant strains when using the Abbott method, whereas only mixtures containing cymoxanil showed this phenomenon when using the Wadley method for interpretation of interactions. Synergism significantly decreased when the components were used as foliar split applications with intervals of 48 and 72 h. A combination of a drench application of oxadixyl and a single spray application of mancozeb or cymoxanil resulted in a high level of synergism. The explanation of synergism may be that the exposure of sporangia to sublethal concentrations of one fungicide affects them to an extent that sublethal doses of the other fungicide becomes detrimental.
Chemical control of stem nematode, Ditylenchus dipsaci, in field beans (Vicia faba)
Authors: WHITEHEAD A. G. , TITE D. J. 
Published: February 2008

SUMMARY‘Giant race’ stem nematode (Ditylenchus dipsaci) was well controlled in spring beans (Vicia faba) by up to 5 kg aldicarb or carbofuran ha‐1 applied to the seed furrows at sowing. Carbofuran was rather more effective in the clay loam soil used than was aldicarb. The best treatments almost eliminated injury to the stems and nematode infestation in the harvested seed. Similarly applied, oxamyl and fenamiphos were less effective and phorate, dimethoate and disulfoton were ineffective. Applying part of the dosage of an effective nematicide to the seed furrows and part along the plant rows mid‐season was no more effective and was sometimes less effective than applying the whole dose to the seed furrows. Treating the plant rows mid‐season with aldicarb or phoxim sometimes enhanced control but thiabendazole applied thus did not. Seed furrow applications of aldicarb or carbofuran were much less effective in controlling the nematodes in winter beans and seed dressings were less effective than seed furrow treatments. In one experiment, in plots in which aldicarb or oxamyl had been applied to the seed furrows, phoxim or thiabendazole applied over the rows of plants, enhanced nematode control. In two other experiments, thiabendazole was ineffective when applied in this way or when applied as a combined soil and plant treatment.
Effects of host stage on the development of the facultative autoparasitoid Encarsia tricolor (Hymenoptera: Aphelinidae)
Authors: AVILLA J. , COPLAND M. J. W. 
Published: February 2008

SUMMARY Encarsia tricolor is a facultative autoparasitoid of the glasshouse whitefly, Trialeurodes vaporariorum, with a potential in biological control. The rate of development, number of mature oocytes at emergence, number of ovarioles and size of the emerged adults were studied. Five nymphal instars (N1, N2, N3, N4, and pharate adult) of T. vaporariorum were used as hosts for the females. Female larvae and pupae of E. tricolor and Encarsia formosa were used as hosts for the males. Females developed faster when the egg was laid on N3 (18.0 days from egg to adult) and slower on N1 (22.3 days). Females were bigger when developing from N1 and N3 than from N4 and pharate adult. On emergence the mean number of mature oocytes was always small (0.8–2.6). Males developed faster and were smaller than females, and developed faster and were larger on larvae of E. formosa.
Effect of waterlogging yam vines on vegetative growth and tuber yield
Authors: IGWILO NDUBISI , UDEH ARTHUR C. D. 
Published: February 2008

SUMMARYThe effect of waterlogging the vines of two yam varieties for 24, 48 and 72 hours at two stages of growth, with or without fertiliser application, was studied in the field.Waterlogging caused a progressive degeneration of the leaf starting with the development of fresh lesions on the lower leaf surface, through necrotic spots or portions, to complete leaf necrosis. The degree of leaf damage was greater with Um 680 (Dioscorea alata) than with Obiaoturugo (D. rotundata). Waterlogging also caused the breakdown of the apical buds of the vines. The degree of damage increased with the duration of waterlogging. Younger plants suffered more damage than older plants, and plants treated with fertiliser suffered more than plants without fertiliser. Waterlogging ultimately hastened the final senescence of the yam vine.Waterlogging vines for 24 h had no effect on tuber yield, while waterlogging for 48 and 72 h reduced tuber yield by 32.4% and 43.2% respectively (P< 0.01). Waterlogging vines at the early growth stage produced 47.6% (P <0.01) less yield than waterlogging at a later stage.It is suggested that short‐term or long‐term waterlogging of the yam vine, or parts thereof, is the main cause of reduced leaf area and low yield in unstaked compared with staked yarn crops. Waterlogging may also be a predisposing factor to disease infection of yam vines by soil‐borne micro‐organisms.
The inhibition of potato sprout growth by light.
Authors: McGEE E. , BOOTH R. H. , JARVIS M. C. , DUNCAN H. J. 
Published: February 2008

SUMMARYWhen potato seed tubers (Solanum tuberosum cv. Pentland Javelin) were stored in darkness or diffuse daylight at 9°C and transferred at intervals to conditions suitable for sprouting, their capacity for sprout growth was unaffected by the presence or absence of light during previous storage. When similar tubers were stored at 10°C, 18°C or 25°C, sprout growth commenced earliest at 25°C, but the date was unaffected by fluorescent light. It was concluded that light did not affect the length of the dormant period, but only the rate of sprout elongation after that period had ceased.When tubers with growing sprouts at 10°C or 18°C were transferred from darkness into fluorescent light, sprout growth virtually ceased. Transfer from light into darkness resulted in immediate sprout growth, at a rate comparable with tubers stored continuously in the dark.Tubers of three Peruvian cultivars, stored in farm‐scale diffuse‐daylight stores, grew progressively shorter sprouts with increasing daily exposure to light from 30 min to 12 h. Storage of cv. Wilja under 21 Wm‐2 (total) of white fluorescent light for 10 h per day maintained the sprouts at the same length as ten times this light intensity for 1 h per day. In a subsequent experiment with cv. Bintje the 10 h, low‐intensity light regime gave slightly shorter sprouts. It appeared that the total light energy falling on the tubers was the dominant factor controlling sprout growth.
Seasonal radiation interception, dry matter production and yield determination for a semi‐leafless pea (Pisum sativum) breeding selection under contrasting field conditions
Authors: HEATH M. C. , HEBBLETHWAITE P. D. 
Published: February 2008

SUMMARYRadiation interception, dry matter accumulation, flower and pod production and yield were measured for a semi‐leafless pea (Pisum sativum) breeding selection (BS3) on three contrasting sites. Differences in soil moisture availability were largely responsible for a three‐fold difference in yield between sites.Radiation interception was related to dry matter production by calculating photosynthetic efficiencies. In the absence of lodging, crop canopies converted intercepted radiation into dry matter with constant efficiency (ɛ) throughout the season; under conditions of moisture stress ɛ was reduced. Serious lodging during the post‐flowering period on one site resulted in a mean seasonal photosynthetic efficiency (ɛ) 17% lower than ɛ.The ability of the pea crop canopy to intercept radiation was related also to yield components.
Effects of cypermethrin and deltamethrin on the feeding behaviour of Aphis craccivora and transmission of cowpea aphid‐borne mosaic virus
Authors: ATIRI G. I. , THOTTAPPILLY G. , LIGAN D. 
Published: February 2008

SUMMARYThe effects of two synthetic pyrethroids, cypermethrin and deltamethrin, on the feeding behaviour of Aphis craccivora and its transmission of the nonpersistent cowpea aphid‐borne mosaic virus (CAMV) were compared to those of an organophosphate (dimethoate) and carbamate (pirimicarb) in greenhouse and laboratory tests. Cypermethrin at 100, 150 and 200 mg a.i. litre‐1 and deltamethrin at 75, 100 and 150 mg a.i. litre‐1 restricted the acquisition and inoculation of CAMV, whereas dimethoate and pirimicarb had no significant effect. Cypermethrin protected against transmission of CAMV longer after application than deltamethrin and there was a strong interaction betweenThe duration of the first probe was shorter on pyrethroid‐treated plants than on dimethoate‐or pirimicarb‐treated plants, and on pyrethroid‐treated plants aphids probably did not probe long enough to acquire or inoculate CAMV.It is concluded that the use of synthetic pyrethroids is potentially valuable in controlling CAMV in the field until resistance against the virus has been bred into cultivars.
Thickening and browning of cortical cell walls in seminal roots of wheat seedlings infected with Gaeumannomyces graminis var. tritici
Authors: PENROSE L. 
Published: February 2008

SUMMARYThis paper examines a little studied reaction of wheat roots to invasion by Gaeumannomyces graminis var. tritici, namely the thickening and browning of cortical cell walls. Examination was confined to distal segments of young seminal roots grown in sand. Browning and thickening of walls of cells were associated with the lignification of tissue and appeared to be a response of living or recently live cells to invasion by weakly virulent isolates. Wheat genotypes differed in their ability to thicken and lignify cell walls, and the difference between two wheat cultivars appeared to be under simple genetic control. There was some evidence that cortical browning temporarily retarded radial invasion by hyphae of G. graminis into young seminal roots of wheats.
Comparison of paint and gel formulations for the treatment of Nectria cankers on apple trees
Authors: CLIFFORD D. R. , GENDLE P. , HOLGATE M. E. , HUNTER T. 
Published: February 2008

SUMMARYA gel formulation containing carbendazim and triadimefon completely eradicated infection from scraped or unscraped cankers and none became re‐infected. Paint formulations containing mercuric oxide or octhilinone completely eradicated infection from scraped cankers but 30–50% of unscraped cankers receiving these treatments became re‐infected. Scraping alone encouraged callus tissue formation but did not greatly reduce infection.Fungicide moved from gels into the wood beneath cankers and persisted there for up to 6 months; movement of fungicide from mercuric oxide or octhilinone paints was minimal.Carbendazim was more effective than thiophanate‐methyl and xanthan gum than sodium alginate or alginate ester as fungicide and gel component respectively. Rainfall shortly after treatment probably aided movement of fungicide from gels into the wood but salt formation, by incorporation of acid, did little to improve fungicide performance.Unequivocal assessment of efficacy of canker treatment requires data on canker area changes, movement and persistence of active ingredient in the wood and extent of re‐infection after 12 months.
Effects of fungicide spray regimes on incidence of dicarboximide resistance in grey mould (Botrytis cinerea) on strawberry plants
Authors: HUNTER T. , BRENT K. J. , CARTER G. A. , HUTCHEON J. A. 
Published: February 2008

SUMMARYIn tunnel experiments, the efficacy of dicarboximide sprays in controlling grey mould of strawberries was greatly decreased by the presence of dicarboximide‐resistant forms of Botrytis cinerea. The use of dichlofluanid, as a tank‐mix or in an alternating programme, with a dicarboximide fungicide, procymidone, helped to maintain the efficacy of disease control but failed to prevent an increase in the proportion of dicarboximide‐resistant forms of the pathogen.Alternative ‘partner’ fungicides (thiram, chlorothalonil) delayed build‐up of resistance to dicarboximides. Build‐up of resistance was absent or relatively small in unsprayed plots. Application of dichlofluanid alone was always associated with a substantial increase in dicarboximide resistance, although less than in procymidone‐treated plots. Monitoring dicarboximide resistance in the tunnels during the winter, when no further sprays were applied, revealed a gradual decline in the proportion of dicarboximide‐resistant forms in all previously treated plots.In laboratory studies on inoculated leaf debris, dichlofluanid treatment induced the build‐up of dicarboximide‐resistant forms of B. cinerea. Leaf‐disc tests revealed cross‐resistance of dicarboximide‐resistant isolates towards dichlofluanid but not towards thiram or chlorothalonil. Dichlofluanid is widely used for control of B. cinerea and the implications of these results for the practical management of dicarboximide resistance in this pathogen are discussed.