ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1965.tb07949.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SUMMARYThe preparation of new esters ofo‐coumaric and cinnamic acids is described. Spray applications ofo‐coumaric acid were inactivein vivoagainstVenturia inaequalison immature leaves but alkyl esters of the acid penetrated intact leaves more readily and reduced the incidence of disease. Isobutylo‐coumarate was the most active compound. In contrast too‐coumaric acid, cinnamic acid gave some measure of control but esters of this acid were not consistently better. The most satisfactory formulation mixture for these materials contained acetone, Tween 80 and Triton X‐100, giving a fine crystalline suspension.Systemic action of isobutylo‐coumarate in shoots of the apple variety Cox's Orange Pippin was demonstrated, and its presence in the upper epidermis of the first five leaves above those to which it had been applied was shown by thin‐layer chromatography of extra

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1965.tb07950.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SUMMARYThe methods needed to decrease losses from potato blight in the variety Majestic are different from those required for King Edward. Few Majestic tubers become infected and control depends chiefly on prolonging the life of the haulm to ensure the maximum yield of tubers. With King Edward, infected tubers often cause more loss than premature defoliation. Tuber infection often occurs very early in the attacks, when profuse sporulation coincides with sufficient rain to penetrate through soil to the tubers.Spraying with fungicide delayed initial tuber infection of King Edward but did not necessarily decrease the proportion of tubers infected at harvest. The largest yield of sound tubers from fungicide‐sprayed plots in the 1960 epidemic was obtained after killing the haulm when only 5% had been destroyed by blight. Allowing the foliage to survive later than this stage did not increase the yield of sound tubers even in years when blight attacks were late and slow. Protection with fungicide and haulm destruction are complementary treatments, both of which require careful timing to obtain the best result with tuber‐susceptible variet

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1965.tb07951.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SUMMARYThree laboratory methods are described for comparing formulations of potato blight fungicides; all use the upper surfaces of leaflets detached from glasshouse‐grown King Edward plants, and artificial rain in some form.Rain‐fastness (tenacity) was quickly estimated by measuring advancing acutecontact anglesof distilled water (representing rain) on dry spray deposits.Tenacityitself was measured by 'rain‐washing' deposits with 0·65 in. of tap water in 30 min. (light 'rain') or up to 2·5 in. in 40 mm. (heavy 'rain'). Contact angles and tenacities of copper oxychloride deposits were usually positively correlated. Inbioassaytests, deposits were washed with 2·5 in. of heavy 'rain', inoculated with sporangia ofPhytophthora infestans(Mont.) de Bary, and later classed as infected or not infected; results were analysed by the probit method. With copper oxychloride and triphenyl tin (fentin) acetate, differences in effectiveness of 2·5 times or more were usually significant when fifty to sixty leaflets were used per fo

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1965.tb07952.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SUMMARYIn spore trapping studies in 1963 and 1963, apple mildew (Podosphaera leucotricha(Ell. and Ev.) Salm.) conidia were not detected in the atmosphere until just before the pink bud stage. Spore concentrations reached a maximum in June, thereafter a series of minor peaks occurred until the end of September in 1962 and the end of August in 1963.The June peak of spore release was followed approximately 2 weeks later by a rise in the incidence of new leaf infections.The importance to the perennation of the disease of these high spore concentrations and possible methods of restricting their increase are discussed.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1965.tb07953.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SUMMARYResults of surveys on oil‐palm estates in Malaya have shown that the incidence ofGanodermainfection of oil palms is greatest: (1) on old trees over 25 years of age, and (2) on younger plantings on sites which had previously borne coconut palms. The incidence of disease in stands either newly cleared from jungle or formerly planted with rubber was not serious.On former coconut sites disease levels were variable and probably due to a soil factor. On these sites infection appeared typically at about the fifth or sixth year after planting, and in some instances disease levels approaching 50% were reached by the fifteenth year. Coconut tissues colonized byGanodermaare considered to become infection foci for disease spread, principally by root contact with stumps left in the ground. From limited information, disease hazard also appears serious in replanting oil palms on old oil‐palm stands. The survey results are discussed in relation to potential losses and disease control. Complete removal and destruction of all coconut‐palm and oil‐palm tissues is suggested as the only method of disease control available at

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1965.tb07954.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SUMMARYSuccessive developmental stages ofSalmo gairdneriishowed marked differences in their resistance to the action of the non‐ionic surfactant, nonyl phenol ethoxylate. The alevins, immediately after hatching, were highly resistant and survived concentrations of up to 42 p.p.m. for 6 hr. This resistance gradually decreased with the absorption of the yolk sac: when the yolk had been completely absorbed and before the fry had fed the lethal concentration was 2·5 p.p.m.After several days of feeding, resistance slightly increased but showed no further rise after 15 days. A concentration of 5·2 p.p.m. of nonyl phenol ethoxylate for 6 hr. was toxic both to 40‐ and to 210‐day‐old fish.It is considered that these changes in resistance are not correlated with changes in respiratory activity of the fish but with their water m

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1965.tb07955.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SUMMARYThe distribution of carbaryl resulting from helicopter and ground spray applications on Rhodesian‐grown cotton plants at different stages of growth has been measured. Results for dosage distributions on leaves indicate that at all stages of growth the deposit after helicopter spraying was greatest on the top part of the plant, particularly on the upper surface of the leaves. In general considerably more even cover, though again with higher relative deposit on the upper leaf surface, was recorded after the ground spray treatment

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1965.tb07956.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SUMMARYUsing the indicator variety, Lord Lambourne, apple chat‐fruit virus was detected in some plants of the apple rootstock clones M. IV and M. VII but not in clones M. I, M. II, M. III, M. IX, M. XII, M. XVI and Crab C. The virus occurred in three nurserymen's Lord Lambourne scion material but not in that of a fourth.Fruit weights were more reliable than visual observations for diagnosis of chat‐fruit disease, especially in young trees. Natural spread of the disease in these field trials was very slow and insufficient to interfere with interpretation of results.Infection was not fully systemic in apple trees, so that both healthy and infected trees were propagated from affected trees, some buds from which, when used as graft‐inoculum, transmitted the virus to test trees while others did not.Two previously unrecorded effects of chat‐fruit disease were observed: circular spots on the fruit and delayed fru

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1965.tb07957.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SUMMARYA strain of tobacco ringspot virus (TRSV) was isolated from severely necroticAnemone coronariaplants in Somerset in 1957, and was named anemone necrosis virus (ANV). ANV infected, by sap‐rubbing inoculation, fifty‐eight of 103 plant species tested, in twenty‐one out of thirty‐two families. Experimental infection of anemone plants induced symptoms of necrosis and die‐back, but less virulent than those seen in the field. The virus was cultured and assayed inNicotiana clevelandiiorN. tabacum.Thein vitroproperties in crude sap were: maximum infective dilution 1/125 to 1/10,000 according to the source plant; thermal inactivation point (10 min.) 70°C.; survivalin vitro21 but not 28 days at 18°C., and at least 12 weeks at 0°C. Preparations preserved by vacuum sublimation (freeze‐drying) were still infective after 5 years. SomeN. tabacumplants could be freed from ANV by growing at 37°C. for 4–6 weeks.Although less easily than TRSV, ANV was purified by extraction ofN. clevelandiileaves macerated for 1–5 days at 0°C. in butanol + phosphate buffer, followed by differential centrifugation. Purified preparations were highly infective, serologically active, gave specific light‐scattering zones in density‐gradient centrifugation, and contained numerous angular particles (c.29 mμ diam.) in electron micrographs. Antisera to ANV and to TRSV had specific titres up to 1/16,384. The two viruses were serologically closely related, very similar in host range and symptoms,in vitroproperties, density‐gradient zones and particle form; they differed principally in the ways in which they could be purified.Anemone necrosis disease is apparently localized in Brit

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1965.tb07958.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY