摘要:

SUMMARYA laboratory method for testing cruciferous plants for their non‐preference resistance to cabbage root fly is described. Test plants were fully randomized on a turntable inside a large chamber containing cabbage root flies. The apparatus was housed in a controlled environment room. The root‐fly eggs, laid in the sand surrounding test plants, were extracted using a flask flotation method which was quicker and more efficient than the stirring technique which it superseded. Two batches of plants were tested alternately, one being exposed to the flies, while the other was sampled for eggs. Each batch of test plants received three 1‐day exposures to egg‐laying, their positions within the test chamber being changed for each exposure to ensure complete randomization.This test method gave highly consistent results and indicated that there were differences in the flies' preference both between cultivars of radish and cauliflower and for individual plants within cultivars. Plants representing the extremes of preferences discovered in the two crops were saved for further study.It was not possible to correlate seed weight, time of seedling emergence, foliage surface area, or hypocotyl attitude in relation to soil level, with the egg‐laying preference of the cabbage r

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01581.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYStomata on growing potato tubers are changed to lenticels by about the third internode from the apical bud (A‐3). In wet soil lenticels proliferate, while in dry soil the filling cells become suberized by about the fifth internode (A‐5).Lenticels did not proliferate in the field after mid‐August, and laboratory experiments on freshly harvested and stored tubers showed that lenticels proliferated less readily as tubers aged. Proliferation occurred more readily on stored tubers induced to sprout than on tubers from which the eyes had been removed, but nevertheless proliferation is unlikely during winter st

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01582.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYIn laboratory tests, proliferation increased the susceptibility of lenticels on mature tubers to infection byErwinia carotovoravar.atroseptica.No differences in susceptibility toE. c. atrosepticaandPhytophthora infestanswere detected on tubers lifted at different stages of growth from soil kept wet or dry for 3 wk prior to each sampling. As tubers aged, fewer lenticels became infected by either pathogen or were penetrated by fluorescein dye, presumably because cells had been suberized and cork barriers formed.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01583.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYA virus causing maize wallaby ear disease was transmitted experimentally byCicadulina bimaculatato fourteen species of monocotyledonous plants. It was also transmitted byNesoclutha pallida, and by grafting. The symptoms obtained resemble closely those reported for maize leaf gall disease in the Philippines and maize rough dwarf virus in Italy and Israel.About 85% ofC. bimaculatacaught in the field carried maize wallaby ear virus (MWEV), and many of their progeny were viruliferous even when not allowed access to infected plants. The proportion of infective individuals in clones bred for nine generations from selected non‐transmitting adults decreased from 85% in the first nymphs to less than 1%; such individuals were difficult to rear, as their fecundity and longevity decreased greatly.N. pallidatransmitted MWEV after injection with partially purified extracts of infected plants.Spherical particlesc.85 nm in diameter were found in the salivary glands of viruliferousC. bimaculata, but not in those of non‐transmitting individuals. The particles occurred in tubules in the cytoplasm and each had a densely stained corec.50 nm in diameter. Particles similar in size to the core were found in extracts of infected but not uninfected maize, and in extracts of viruliferous but not in non‐viruliferousC. bimaculataandN. pa

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01584.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYPurified preparations of an isolate of black raspberry latent virus (BRLV) contained quasispherical particles with a mean diameter of 28·5 nm; these particles were resolved into three sedimenting components (s20, w= 82S, 95Sand 104S), but when centrifuged to equilibrium in caesium chloride solution they formed a single infective band (σ= 1·35 g/cm3). During electrophoresis in polyacrylamide gels, virus particles separated into three classes, and virus RNA was resolved into three major (mol. wt 1·35, 1·10 and 0·85 × 106) and one minor (mol. wt 0·4 × 106) component. The protein from virus particles had an estimated mol. wt of 28000. Isolates of BRLV were found to be serologically related but not identical to some strains of tobacco streak virus.No symptoms developed in black raspberry seedlings infected with BRLV by mechanical inoculation, nor in eight red raspberry cultivars infected by graft inoculation. However, graft inoculation of BRLV toRubus henryi, R. phoenicolasiusand Himalaya blackberry induced symptoms typical of necrotic shock

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01585.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYThe influence of various factors on the performance of organomercury seed treatments in controlling seed‐borneSeptoria nodorumwas studied in laboratory experiments. Control was least effective on the most heavily infected seed samples. On heavily infected seed ethyl mercuric chloride was more effective than phenyl mercuric acetate, although 5 wk storage of the treated seed before sowing increased the effectiveness of the latter compound. Effectiveness was not generally influenced by differences in soil moisture. Seedling vigour was significantly improved by levels of mercury below those applied commercially. The significance of seed treatment in the epidemiology ofSeptoriadisease is discusse

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01586.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYThe systemic anti‐mildew activity shown by homologous series of alkoxy‐, alkylamino‐ and alkylthio‐trichloroethyl formamides when applied to the roots of wheat or cucumber seedlings has been measured. In general the thio compounds were much less active than their oxy and amino analogues. The alkyl grouping giving most activity varied from one series to another and with test method. In cucumber plants the most prolonged protection against mildew was given by thesec‐butoxy andsec‐butylamino compounds. When inoculated disks of cucumber leaf tissue were floated upon solutions of the compounds, smaller differences in anti‐mildew activity were found than when application was made thro

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01587.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYFive fungicides and two fumigants were tested in five trials against the club root disease of cabbage. Methyl bromide provided the best control of the disease. Quintozene also gave satisfactory results, and its phytotoxic effects could be avoided or minimized by applying it at least 5–6 wk before seeding or transplanting.The use of hydrated lime gave relatively poor control of club root, but, either alone or in combination with fungicides, it improved the growth and establishment of seedlings and transplants. It was concluded that quintozene used in combination with hydrated lime provided an effective and practical means of controlling the diseas

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01588.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYA study was made of the effects of concentrations of 2 to 32 ppm of oximecarbamate, organophosphate and benzimidazole nematicides on the hatch, larval viability and migration ofMeloidogyne javanica, M. incognitaandM. haplaand on development ofM. javanicain roots. Aldicarb at less than 8 ppm had little effect on hatch and methomyl markedly affected only the hatch ofM. hapla.As little as 2 ppm of fenamiphos or thionazin markedly reduced hatch of all three species but less than 8 ppm ethoprophos significantly reduced only the hatch ofM. incognitaand phorate had little effect on hatch. Benomyl and thiabendazole had no significant effects on hatch. When egg masses ofM. incognitawere transferred from nematicides which suppressed hatch to water, hatching occurred, but aldicarb, fenamiphos, ethoprophos and thionazin significantly reduced total hatch.None of the nematicides killed larvae of the three species immersed in 16 and 32 ppm solutions of them for 3 days. Aldicarb at 2 ppm reduced migrations of all three species; the effects of methomyl, fenamiphos or thionazin on migration varied according to species, while phorate, ethoprophos, benomyl or thiabendazole had little or no effect on migration. Aldicarb or thionazin at 2 ppm stopped development ofM. javanicain roots of tomato seedlings while methomyl, ethoprophos or fenamiphos at 4 ppm reduced development by 60% and at 8 ppm of ethoprophos or fenamiphos or 16 ppm of methomyl, development was stopped. Phorate had little effect on development and benomyl or thiabendazole had no effect. Nematicide concentrations which reduced development prevented the normal orientation of larvae in the roots and reduced or prevented giant cell formation.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01589.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYFour experiments tested a range of doses of the growth‐retardant glyphosine on sugar‐beet crops between 1970 and 1972. The period of time between application and harvest was varied. One experiment (1972) in nutrient mist culture examined its effect on seedling root development.The growth‐retardant decreased root, sugar and top yield of sugar beet at all doses in excess of 0·56 kg a.i. ha‐1at all treatment times. It increased the α‐amino nitrogen content of beet roots significantly (P<0·05) with doses in excess of 1·12 kg a.i. ha‐1. When applied to the leaves of seedlings with their roots in nutrient mist culture, glyphosine at 500 ppm and 2000 ppm of a.i. in aqueous solution slowed or stopped

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1975.tb01590.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY