摘要:

AbstractThe pre‐emergent herbicidal activities of various 2,2‐dialkyl‐2‐cyanoacetanilides and their derivatives are reported, and the relationships between their structure and activities on a range of plant species are examined. Their selectivity behaviour is compared with that of a 2‐alkyl‐2‐cyanoacetanilide and a 2‐chloroacetanilide herbi

ISSN:0031-613X    

DOI:10.1002/ps.2780130112

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThe kinetics of the hydrolysis reactions of chlorpyrifos‐methyl and chlorpyrifos, in the presence of copper(II), have been measured in buffered aqueous solutions. For each reaction, a rate law of the type ‐d[pesticides]/dt=k2[pesticides][Cu2+] was observed. As the concentration of copper(II) increased, a corresponding increase in the rate of hydrolysis was observed until the concentration of copper(II) reached about 1.0 × 10−2M. At this point, the rate of hydrolysis became independent of the concentration of copper(II) in both reactions. Using the experimental data, a mechanism for each reaction is proposed, in which the copper(II) ion forms a six‐membered ring complex with the nitrogen in the ring structure and the sulphur of the phosphorothioate moiety. The rate of hydrolysis increased with increasing pH. At higher pH values, precipitation of Cu2+was observed and general base‐hydrolysis reactions became more and more important. The differences in the rate constant observed is explained using the inductive effect theory of the a

ISSN:0031-613X    

DOI:10.1002/ps.2780130113

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractLarvae and adults of three strains of the yellow fever mosquitoAedes aegyptiL. were tested to determine the presence or absence of a diurnal rhythm of susceptibility to the organochlorine insecticides dieldrin and DDT. Each strain showed different patterns of larval susceptibility to the toxicants. Larvae and adults of the same strains produced opposite time‐dependent responses to treatment. The significance of daily patterns of changing susceptibility in toxicological studies is discusse

ISSN:0031-613X    

DOI:10.1002/ps.2780130114

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThe development of resistance to pesticides in populations of organisms as diverse as those of bacteria, insects and mammals, provides outstanding examples of adaptation by natural selection. The integration of Mendelian genetics and the Darwinian hypothesis, known as the neo‐Darwinian theory of evolution, can account for such genetic responses to changes in environment. There is one problem: that of its weak falsifiability. Selected subsets of theory can explain almost anything. An attempt is made to identify phenomena that are involved in adaptive responses of higher organisms to changes in environment. These are discussed with particular reference to the development of resistance in mammalian populations. Recent developments in genetics pertinent to this problem are outline

ISSN:0031-613X    

DOI:10.1002/ps.2780130115

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractA strain (BKPM) ofAedes aegyptifrom Bangkok, after some mass selection with permethrin, showed an initial resistance level to permethrin of about 20‐fold compared with a standard susceptible strain. The strain was subjected to a programme of single‐family sib selection, concurrently with further mass selection. The F1and F2results of single‐family sib selection established thatBKPMwas heterogeneous for resistance to permethrin. The most resistant family in the F1and F2was inbred to an F3. The results indicated that this family was homogeneous. A strainBKPM3 was established from this family and found to have a resistance level of about 30‐fold. Despite the heterogeneity ofBKPM, five generations of mass selection failed to raise the resistance level to permethrin. The selection procedure was then changed, in as much that the insects were sorted at the end of the 60‐min exposure instead of after the 24‐h holding period, and concentrations were chosen to give a higher selective effect. This resulted in an almost immediate rise in resistance to a level similar to that ofBKPM3, and subsequent mass selection failed to raise this further. The possible effects of the changes in selection procedure ar

ISSN:0031-613X    

DOI:10.1002/ps.2780130116

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

ISSN:0031-613X    

DOI:10.1002/ps.2780130101

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY