Data publikacji: 28 May 2014 Zakres stron: 383 - 397
Abstrakt
Abstract
Chemical and analytical characteristics of dithiocarbamates are described in detail. Thorn and Ludwig (49) published an excellent book dealing in detail with a large number of problems discussed in this publication. Present pharmacological examinations give no indication as to the toxicological hazards of dithiocarbamates. With regard to the application of dithiocarbamates in general, food regulations (not referring to tobacco) issued by governmental authorities of the United States and New Zealand limit the maximal allowable concentrations of DTC-residues to 5 to 10 ppm. Measures against Peronospora tabacina Adam are controlled by governmental authorities or state monopolies. Successful preventive treatment of tobacco requires a dosage of approximately 1000 ppm. At the same time this quantity represents the tolerable limit up to which the tobacco taste is not detrimentally affected. Secondary impregnations with Zineb and Maneb above the 1000 ppm limit affected the taste somewhat. Dithiocarbamates as such do not pass into smoke
Data publikacji: 28 May 2014 Zakres stron: 398 - 410
Abstrakt
Abstract
In spite of the successful application of chemical compounds (Maneb, Zineb) the aim to control the disease is the breeding of resistant varieties. We propose to select (phenotypically) resistant isolated plants, a method which has proved to be rather successful in the breeding of tobacco resistant to Y-virus. Until now we have selected the air-curing types SC 13 and SC 14 and the flue-curing types SCV 23 and SCV 26 from spontaneous as well as X-ray mutations, and we tested them on a larger scale for their resistance to PTA. As far as material was available a survey is given of the resistant types and different grading schemes are described
Data publikacji: 28 May 2014 Zakres stron: 411 - 414
Abstrakt
Abstract
Investigations intended to establish the causes of the epidemical outbreak of Peronospora tabacina Adam in Northern Germany suggest the significance of particular climatic conditions, namely the so-called "critical weather'', which seems to be a predisposing factor for initiation and epidemical spread of the disease
Chemical and analytical characteristics of dithiocarbamates are described in detail. Thorn and Ludwig (49) published an excellent book dealing in detail with a large number of problems discussed in this publication. Present pharmacological examinations give no indication as to the toxicological hazards of dithiocarbamates. With regard to the application of dithiocarbamates in general, food regulations (not referring to tobacco) issued by governmental authorities of the United States and New Zealand limit the maximal allowable concentrations of DTC-residues to 5 to 10 ppm. Measures against Peronospora tabacina Adam are controlled by governmental authorities or state monopolies. Successful preventive treatment of tobacco requires a dosage of approximately 1000 ppm. At the same time this quantity represents the tolerable limit up to which the tobacco taste is not detrimentally affected. Secondary impregnations with Zineb and Maneb above the 1000 ppm limit affected the taste somewhat. Dithiocarbamates as such do not pass into smoke
In spite of the successful application of chemical compounds (Maneb, Zineb) the aim to control the disease is the breeding of resistant varieties. We propose to select (phenotypically) resistant isolated plants, a method which has proved to be rather successful in the breeding of tobacco resistant to Y-virus. Until now we have selected the air-curing types SC 13 and SC 14 and the flue-curing types SCV 23 and SCV 26 from spontaneous as well as X-ray mutations, and we tested them on a larger scale for their resistance to PTA. As far as material was available a survey is given of the resistant types and different grading schemes are described
Investigations intended to establish the causes of the epidemical outbreak of Peronospora tabacina Adam in Northern Germany suggest the significance of particular climatic conditions, namely the so-called "critical weather'', which seems to be a predisposing factor for initiation and epidemical spread of the disease