摘要:

SummaryTraps placed within brassica crops to monitor changes in cabbage root fly activity could be made more selective by painting black the inner wall of the standard fluorescent yellow water‐traps. Traps could also be made more selective by covering them with cylinders of Netlon mesh, although this procedure reduces the numbers of cabbage root fly caught by about 70%. Of the single‐coloured traps tested, those painted “marigold” yellow were the most selective in capturing female cabbage root flies. Although white and certain blue traps were as effective as the best yellow traps at capturing cabbage root flies, such traps should be avoided, as they catch 4–5 times as many of the closely‐related bean seed fly. The presence of bean seed flies makes cabbage root fly identification more difficult and adds considerably to the time required to sort t

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1992.tb03397.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryThe botanical product RD‐Repelin® was highly repellent to pea aphids at concentrations of 1%, 4% or 10%. Repellency occurred prior to leaf contact by aphids at all three concentrations. RD‐Repelin® delayed symptom expression of zucchini yellow mosaic virus (ZYMV) in 81% of plants treated with 1% concentration, although virus transmission was not prevented. The effects of RD‐Repelin® on aphid settling behaviour, symptom expression and potential for pest management are d

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1992.tb03398.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryChlorpyrifos (Spannit 48% e.c.; PBI) was applied at the recommended rate of 0.72 kg a.i./ha to two pastures on which either Brent Geese (Branta bernicla) or Canada Geese (Branta canadensis) were grazing. Observations of the number of geese and their behaviour were made on two or three occasions before spraying and four or five occasions after. Observations enabled an activity index and a count of pecks/minute to be calculated. No changes in the numbers or behaviour of the geese that could be attributed to chlorpyrifos application were found. Thorough searches were made for cadavers of the experimental fields, their environs and the roosts the day after other observations were made. Only one cadaver was found which had died as a result of swallowing angling equipment. Samples for chlorpyrifos residue analysis in the herbage and goose faeces showed no chlorpyrifos to be present prior to spraying the fields and that the chemical was present after spraying in both the herbage and faeces but fell to negligible levels within a few days. At least in the short‐term, chlorpyrifos application to pasture appeared to have no perceptible or statistically significant effect on goose behaviour or well‐be

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1992.tb03399.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryField scale experiments carried out over three years showed that chlorpyrifos reduced the numbers of several carabid beetle species caught in pitfall traps. Fonofos seed treatment was also shown to affect selected species. Consideration of the biology of individuals of groups of species provided explanations of why some species such asNebria brevicollis, Notiophilusspp.,Bembidionspp., andTrechus quadristriatuswere severely affected by one or other of the chemicals, whereas other species (e.g.Amaraspp.,Harpalusspp.) were able to survive or recolonise pastures shortly after chemical application. Measurements of elytral and pronotal widths and counts of mature eggs inN. brevicollis, which was trapped in reduced numbers over a long period, were made and provided some information about the mode of action of these chemicals.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1992.tb03400.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryPowdery mildew infection of barley seedlings was significantly reduced using either pre‐inoculation or post‐inoculation sprays of the film‐forming polymers Nu‐Film P, Emerald or Vapor Gard. The greatest reduction in mildew infection was obtained with a pre‐inoculation spray of the polymer Vapor Gard. Although the addition of 1 mmα‐difluoromethylornithine (DFMO) to a 2% solution of Emerald or Vapor Gard resulted in better control of powdery mildew infection than that obtained using the polymer or DFMO alone, the reductions in infection were not significant. Reduction in mildew infection was greatest when the Vapor Gard + DFMO mixture was applied 1 day prior to inoculation with the fungus. Although substantial reduction in mildew infection was achieved using as little as 0.1 mmDFMO with 2% Vapor Gard, or reducing the polymer concentration to 1% in combination with 1 mmDFMO, best control was achieved using 2% Vapor Gard p

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1992.tb03401.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryTobacco plants expressing the coat protein of a lilac isolate of arabis mosaic virus (ArMV) poorly supported the replication of this virus and did not display any of the signs of systemic invasion produced in their untransformed counterparts or in transgenic plants expressing a different gene (β‐glucuronidase). These effects, were manifest whether the inoculum was virions or RNA. This is the first report of such coat protein protection with a nepovir

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1992.tb03402.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryPlants of two potato cultivars were transformed with disarmedAgrobacterium rumefaciens(LBA4404) containing a binary expression vector. The vector contained sequences that encode the coat protein of potato leafroll luteovirus (PLRV) under the control of the 35s promoter of cauliflower mosaic virus. RNA transcripts from the integrated viral gene were readily detected in the transgenic plants. PLRV coat protein was detected in only some of these plants when using sensitive immunoblotting techniques. Tubers were collected from transgenic plants that became infected following inoculation either by viruliferous aphids or by grafting with scions from infected plants. When these tubers were used to grow plants with secondary infection, less virus accumulated in each plant of some transgenic lines than in control plants. The PLRV concentration, estimated at different sampling times, in plants of cv. Désirée (transgenic line B1) and cv. Pentland Squire (transgenic line C4) was about 15% and 30% respectively of that in control plants. Among a number of conventionally‐bred clones of potato, some were resistant to virus multiplication and were found to accumulate little virus. The coat protein‐mediated resistance in transgenic potato plants is discussed in relation to the conventional gene‐mediated resistance found in some breeding

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1992.tb03403.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummarySoil compaction associated with frequent cultivation of potatoes was partly removed with a deep winged‐tine coulter. This increased the yield of tubers of cv. Cara in 1987 and 1988 and of cv. Désirée in 1987 in soil which was heavily infested with potato cyst‐nematode,Globodera rostochiensis(Woll.), and which was treated with oxamyl at 5.6 kg ha‐1. In 1988, in soil not treated with oxamyl, deep cultivation significantly decreased the yield of cv. Cara. In both years, oxamyl decreased numbers ofG. rostochiensiseggs in the soil following cv. Désirée potatoes but not following cv. Cara which were resistant to the

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1992.tb03404.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryThe putatively resistant lucerne cv. Euver was as susceptible to 11 English and 11 French populations of ‘lucerne race’ stem nematode,Ditylenchus dipsaci, as the susceptible cv. Europe. The ‘resistant’ cv. Vertus showed some resistance to five of the English and four of the French populations but was just as susceptible as Europe to three English and four French populations. Twelve annual species ofMedicagowere very resistant to a mixture of two English and two French populations of the nematode. None of 13 perennial spp. ofMedicagowas very resistant to the same mixture of nematodes but resistant plants were identified inM. borealis, M. dzhawakhetica, M. glutinosaandM. romanica. Twenty six spp. ofTrifoliumwere resistant to a mixture of two English and two French populations of ‘red clover race’ st

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1992.tb03405.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryThe effects of stem nematode (Ditylenchus dipsaci) infestation on the establishment of white clover sown in mixed swards with perennial ryegrass, were investigated in two field trials. Clover cultivars known to have different degrees of resistance were sown on land in which stem nematode was controlled either by aldicarb (Experiment 1) or crop rotation (Experiment 2). The establishment of white clover was greatly improved and subsequent clover yields were inversely related to stem nematode infestation. At the first harvest after sowing, clover yields were 3.6 and 3.3 times greater from aldicarb and rotation treatment plots than from check plots; over the first nine months, total clover yields were increased by 3.5 and 8.9 times by aldicarb and rotation treatments. In both trials, plots of resistant cultivars had less stem nematode infestation and yielded better than the very susceptible cultivar, S184. Stem nematode infestations eventually developed on all plots, after the establishment phase.This is the first report showing that resistant cultivars improve establishment of clover in mixed swards on stem nematode infested soils. In both experiments, plots became dominated by clover and even cv. S184 eventually produced good clover swards.Aldicarb and rotation treatments also controlled clover cyst and root lesion nematodes, and numbers of these were inversely related to first harvest yields. Other soil borne pests and diseases, although not prominent, have not been ruled out as possible confounding factors. There was no correlation between grass yield and aldicarb treatment.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1992.tb03406.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY