摘要:

SUMMARYStamen blight, caused byHapalosphaeria deformansSyd., is a disease of a number ofRubusspecies. It is widespread on commercial raspberries in Angus and east Perthshire. Evidence indicates that spread is from diseased flowers to the axillary buds of young canes during the summer and entry into these buds is complete by autumn, after which it is unlikely that the pathogen can be reached even by an eradicant fungicide. Attempts to infect young canes artificially, however, have failed. Rain splash appears to be of considerable importance in dispersal, but some spread by wind and pollinating insects could occur. Possible control measures are discussed and the importance of planting canes from spawn beds, where no flowering canes are kept, is emphasized.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1967.tb04486.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYThe emergence of a new stable strain ofClaviceps purpureais described. The strain formed the sphacelial stage very weakly on rye, and was unlikely therefore to be able to initiate an epidemic under field conditions, but the sclerotia contained chanoclavine as the major alkaloid in contrast to the ergotamine component of the parent strain. Isolates ofC. purpureaderived from ryegrass ergots were also shown to parasitize rye.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1967.tb04487.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYThe frequency with which intact leaves and epidermal leaf strips of wheat seedlings were penetrated byPuccinia graminis tritici, strain 21 Anz 2, was observed following exposure of inoculated material to various regimes of illumination/darkness and temperature.Epidermal strips, at 24°C, were penetrated most frequently when continuous light (540 ft‐c) was commenced at either 4 or 8,20 or 24, or 36 or 40 h after inoculation or when a 4 h period of light was applied at these times. With both treatments, the curve obtained when the length of the dark period preceding illumination was plotted against the frequency of penetration showed a series of alternate peaks and troughs and the periodicity of the curves was significant at the 1 % probability level. In the former curve the best form of regression was linear modified by a cosine function, while in the latter the linear term proved to be non‐significant. When dark periods of different lengths were applied, penetration was more variable on intact leaves than on epidermal strips. Penetration of intact leaves was influenced by the light intensity to which the seedlings were exposed after the dark treatment.The time of day when intact leaves were inoculated influenced penetration when they were grown under controlled conditions. Greatest penetration of the variety Little Club occurred when leaves were inoculated at 1.30 a.m. The time of day when epidermal strips were inoculated did not influence penetration.The inhibitory effect of continuous light on penetration of epidermal strips was overcome by changing the temperature from 18·5 to 24°C. Greatest penetration was obtained when the change was made 24 or 28 h after inocu

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1967.tb04488.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYEnclosing carnation blooms in polythene increased rotting associated with naturally occurringBotrytisinfections and accelerated the rate of conidia development when flowers were artificially inoculated before being stored at 1·7 °C. Petal infections were observed 16 and 48 h after inoculation and incubation at 18·3 and 1·7 °C respectively. The products of exosmosis from petals kept at 18·3 °C for 7 days stimulated germination ofB. cinereaconidia. Slight pectic enzyme activity was detected in a liquid medium, derived from carnation petals, after incubatingB. cinereacultures at 18·3 °C for 6 days. Although cultures ofBotrytisevolved virtually no ethylene, the surge of ethylene produced by uncontaminated ageing flowers occurred sooner after inoculation. A spray containing 1·2% a.i. of 2‐aminobutane controlled rotting but dama

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1967.tb04489.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYInocula of spores ofPenicillium digitatumin water applied to apparently uninjured skin of oranges do not cause lesions to develop. Addition of citric acid, orange juice, or various extracts of rind had little effect on susceptibility to infection.When spores in water are applied to wounds madebetweenoil vesicles, lesions develop only from wounds that penetrate deeply into the albedo. The flavedo of most oranges seems to be resistant to infection even when damaged, but in a few consignments it showed much less resistance. Increasing the number of conidia in the inoculum caused more lesions to develop but some fruits developed lesions from inocula containing very few spores. The method and timing of spore application to wounds had a considerable effect on the incidence of lesions; emanations from infected fruit had no effect.Lesions developed more rapidly and readily when suspensions of spores in water were applied to wounds in the skin that damaged oil vesicles; wounds as shallow as 0–25 mm allowed lesions to develo

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1967.tb04490.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYA soil‐borne inoculum ofMycosphaerella ligulicolawas found to be mildly pathogenic to leaves or stems of globe artichoke, rudbeckia, zinnia, sunflower and dahlia, but severely pathogenic to lettuce. This is the first report of an infection by this fungus of plants other than chrysanthemum or pyrethrum. It was found that, with successive passages of the fungus through lettuce and chrysanthemum respectively, an increase in virulence to these hosts occurred. After a single passage through lettuce a reduction in virulence to chrysanthemum resulted, but with further passages through lettuce there was no further reduction in virulence to chrysanthemu

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1967.tb04491.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYChloropicrin, dazomet, formaldehyde, and D‐D soil treatments all decreased the incidence ofFusariumwilt in a wilt‐susceptible variety of pea grown in wilt‐infested soil, but only chloropicrin and dazomet gave satisfactory control of the disease. All four fumigants decreased root nodulation, but no adverse effects on plant growth were detected. With dazomet, formaldehyde, and D‐D, decreased nodulation is largely attributed to the extra soil nitrogen mineralized, whereas with chloropicrin the almost complete suppression of nodulation probably reflects the lethal effect of this material on theRhizobiumb

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1967.tb04492.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYSeventeen species in the Tiliaceae, Sterculiaceae and Bombacaceae were tested for susceptibility to three virus isolates from naturally infectedCola chlamydanthatrees and three fromAdansonia digitatatrees in Ghana. Seven species of Pseudococcidae were tested as vectors of the six isolates. These studies indicate that theColaisolates should be classified with cocoa swollen shoot virus and those fromAdansoniawith cocoa mottle leaf virus.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1967.tb04493.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYStrawberry latent ringspot virus (SLRV) was found in diseased rose bushes growing in a glasshouse where the soil containedXiphinema diversicaudatum(Micol). Adult female, adult male and juvenileX. diversicaudatumall transmitted the virus to cucumber seedlings, and nematodes kept without plants for 32 days after acquiring SLRV later transmitted it. When transferred to fresh plants every 2–4 days for 3 weeks, single nematodes transmitted up to three times; one nematode did not transmit until 19 days after the transfers began. One adultX. diversicaudatum, out of 141 tested, transmitted both SLRV and arabis mosaic virus. In all respectsX. diversicaudatumbehaved as a vector of SLRV as it does as a vector of arabis mosaic viru

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1967.tb04494.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYPot tests and field trials in 1966 confirmed earlier observations that pathotype A potato cyst‐eelworm(Heterodera rostochiensisWoll.) showed marked colour differences from pathotypes B and C during development on the roots of susceptible potatoes. In hatching tests started in July, newly formed brown cysts of pathotype A released four times as many larvae as those of pathotypes B and C, without entering an immediate diapause; the latter produced larvae after a rest period of 18–21 days. Subsequent second‐generation cyst production in glass‐tube culture was greater from pathotype A. Field observations suggested that all pathotypes mature at about the same time and give rise to only one flush of cysts on both early and maincrop potatoes in the growing season.Cyst colour surveys in commercial crops, and pot and field trials using resistant potato selections, confirmed that pathotypes B and C are both dominant and widespread in the East M

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1967.tb04495.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY