摘要:

SUMMARYPrevious work showed that the leaf‐area index (L) of kale crops in their later stages of growth can be much above the optimum for dry‐matter production, which was between 3 and 3.5. WhenLwas held close to 3.5 during July‐September 1955, by repeated thinning of plants, the total yield of dry matter including thinnings was increased by about 6%. When thinning was more severe yield was not increased. In a similar period in 1956, thinning that heldLbetween 3.5 and 4 or between 3 and 3.5 did not increase total yield of dry matter, because in this year optimalLwas much higher than before. The explanation of the seasonal variation in optimalLis not

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1962.tb05981.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYMembers of the homologous series (CH3)2NC(S)S(CH2)nCO2Hn= 1–6, were prepared and their plant growth‐regulating activities were examined in three different tests. Derivatives of some of these acids with methyl groups in the fatty acid chain were also studied. The metabolism in wheat and broad‐bean plant tissues of two of the homologues were investigated, the products of metabolism being identified by chromatography. All results are shown to be consistent with the theory that the fatty acid chain in this series of compounds becomes degraded in the plant by β‐o

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1962.tb05982.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYThein vitrofungicidal activity of 2‐methyl‐4,6‐dinitrophenol (DNC) and fifteen of its esters was determined in mycelial growth tests. The aliphatic esters possessed similar activity to that of DNC and the aromatic esters were much less fungitoxic. The benzoic ester was only weakly active against mycelial growth and in preventing spore germination but as a protectant fungicidein vivoit was very effective. It was established that DNC‐benzoate is stable in light, under conditions of high humidity and in the presence of fungal spores, but it was shown that some degree of hydrolysis occurs on the leaves of broad bean to yield the parent cresol. This hydrolysis does not lead to phytotoxicity but the small quantities of DNC produced could account for the protectant fungicidal activity of this c

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1962.tb05983.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYThe solubility, olelyl alcohol‐water partition coefficient, fungistatic activity toAlternaria tenuisandNeurospora crassa, and spore uptake byN. crassaof captan and six analogues have been determined. The analogues were structurally similar, possessing a phthalimide moiety and ‐NSCCl3group, but differed in their lipid solubility. This variation in lipid solubility was not reflected in either fungitoxicity or spore uptake except for the two compounds with the lowest partition coefficients,N‐(trichloromethylthio)‐3,6‐endoxohexahydrophthalimide andN‐(trichloromethylthio)‐4,5‐epoxyhexahydrophthalimide. The high levels of uptake of the compounds required to inhibit spore germination and the high values of their estimated thermodynamic activities suggest unspecific mechanisms of toxicity and possible detoxication of the fungicides before they reach vital

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1962.tb05984.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYA study has been made of the factors controlling the uptake of captan from aqueous solution by conidia ofNeurospora crassa.The uptake process has been found to deviate from normal diffusion in the effects of captan concentration, temperature, salts, oxygen supply, and metabolic poisons. It is suggested that the captan absorbed by the spores is decomposed on or within the cell protoplast by a process requiring cell metabolic energy. Pre‐treatment of the spores with thiol reagents such as iodoacetic acid andp‐chloromercuribenzoate markedly decreased the uptake of captan without affecting spore viability or captan toxicity. This suggests that much of the high level of captan uptake required to inhibit spore germination is in fact being decomposed by cell thiols before reaching its site of toxic act

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1962.tb05985.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYA technique is described whereby detached cocoa pods can be inoculated with zoospores ofPhytophthora palmivorato produce multiple lesions. The number of lesions developing can be correlated with the concentration and efficiency of protectant fungicides applied to the pod before inoculation. A number of fungicides have been tested by this method and the results are in general agreement with those obtained from field trials.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1962.tb05986.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYThe tenacity of a number of fungicide formulations when sprayed on to cocoa pods has been tested by applying artificial rain produced in an experimental rain tower. A general relationship between leaching of deposits and rainfall has been obtained. The effect of incomplete drying on the tenacity has been correlated with observations in the field. The effect of pod growth on the attenuation of fungicide deposits was demonstrated and possible improvements to formulations and spraying techniques are discussed.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1962.tb05987.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYTwo field trials of fungicides for the control ofPhytophthora palmivoraon cocoa in Nigeria are described. The results obtained during two harvest periods have been subjected to two methods of analysis and are compared and discussed. The field results have been correlated with the results of laboratory bio‐assays and a close agreement is demonstrated. Possible reasons for the poor control ofP. palmivorain the field trials are considered in the light of results obtained from laboratory tests of fungicides (Hislop&Park, 1962a, b

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1962.tb05988.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYThe effect of diphenyl on potato dry‐rot infection was investigated in laboratory tests and field trials. Diphenyl reduced infection in the laboratory but failed to give consistent control in the field, where such treatments as were effective also proved phytotoxic. Treated tubers were also tainte

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1962.tb05989.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

SUMMARYPathogenicity tests with forty‐nine isolates ofPhytophthora fragariae, cause of red core disease of strawberry, using the strawberry varieties Huxley, Perle de Prague, Climax, Talisman, Aberdeen and Cambridge Vigour, revealed the existence of twelve physiological races of the fungus on the basis of a pathogenic or non‐pathogenic reaction. Further differentiation, on the basis of degree of pathogenicity to Perle de Prague and to Climax, allowed the recognition of nineteen races.Varying the concentration of zoospores used as inoculum, and the length of inoculation period, which did not affect the relative pathogenicities of two isolates tested, had greater effects on the level of invasion with a highly pathogenic isolate than with a slightly pathogenic one.Amongst the isolates differences uncorrelated with other characters such as pathogenicity were demonstrated in growth characters in agar culture and in abundance of zoospore product

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1962.tb05990.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY