摘要:

AbstractA series of asymmetrical thio‐bis‐N‐methylcarbamate derivatives were synthesised by combining 3,4‐methylenedioxyphenyl N‐methylcarbamate with different N‐methylcarbamates. Some of these derivatives combined good insecticidal activity against the housefly with reduced acute oral toxicity to mice.The thio‐bis‐N‐methylcarbamates obtained exhibited a lower anti‐cholinesterase activity than the more toxic of the two carbamate moieties contained in each combination. The weak synergism of piperonyl butoxide on the insecticidal activity of the derivatives suggests the possibility of a self synergism phenomenon caused by the 3,4‐methy

ISSN:0031-613X    

DOI:10.1002/ps.2780260302

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractDiluted cypermethrin EC was sprayed on to radish plants in the laboratory and its toxicity to mustard beetle was assayed. Doses at or below an equivalent of 3g ha−1(LD6) were used to measure sublethal effects. A substantial reduction in egg laying occurred even at doses as low as 1 and 1.5 g ha−1. This was due to two factors, the toxicity factor and the antifeeding factor. Insects showing sublethal symptoms of poisoning laid fewer eggs, the reduction being proportional to the dose. On treated leaves, oviposition behaviour was abnormal, eggs being laid on the surface instead of in niches excavated by the female. Feeding was reduced on treated leaves and a positive correlation was demonstrated between the amount of feeding and the proportion of eggs laid in niches. A reduction in hatching occurred when eggs were not laid in niches.Doses of 3 g ha−1killed the first instar larvae even seven days after application. The effects on adult feeding and oviposition of a sublethal dose of 3 g ha−1persisted for a period up to 20 days post‐

ISSN:0031-613X    

DOI:10.1002/ps.2780260303

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe effectiveness of protectant and systemic seed‐treatment fungicides for control of common bunt caused by Tilletia caries(DC.) Tul. andT. foetida (Wallr.) Liro. in spring and winter wheats was evaluated at different locations from 1981 to 1987. The fungicides, tested at two rates (I and II), were of three types: (1) fungicides which were effective in all years and locations at levels approaching 100%; (2) fungicides which provided uniform bunt control in all years and locations at levels less than 100%, and (3) fungicides which were sensitive to environmental conditions within years and locations. Fungicides which were effective in all years and locations at levels approaching 100% were triadimenol II, myclobutanil I and II, diniconazole I and II, and flutriafol II, on spring wheat, and etaconazole and furmecyclox in the seed‐(SD), and seed‐ and soil‐ (SS) inoculation treatments, and triadimenol in the SD‐inoculation treatment on winter wheat. Fungicides which provided uniform bunt control in all years and locations at levels less than 100% included flutriafol I and triadimenol I in spring wheat, applied at rates below optimal, and carboxin dust and nuarimol on winter wheat, in SS‐ and SD‐inoculation treatments. Fungicides which were sensitive to environmental conditions within years and location included maneb, carboxin I and II on spring wheat, and carboxin solution and dust in the SD‐ and SS‐inoculation treatments on winter wheat. Comparisons of bunt levels in fungicide treatments with those in the infested controls revealed that some fungicides did not perform consistently across years and locations. Variation in efficacy of fungicides was classified into three types: (1) random environmental variation which occurred with all fungicide treatments tested; (2) non‐random environmental variation which occurred with maneb and carboxin fungicides, and (3) variation attributed to increasing bunt severity which occurred with the SS and SD carboxin fungicides used to control bunt in winter wheat. The implications of inadequate protection from currently registered seed‐treatment fungicides on wheat varieties that are highly susceptible

ISSN:0031-613X    

DOI:10.1002/ps.2780260304

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract2‐Nitro‐I‐phenylpropen‐3‐yl acetate (NPPA), the first metabolite of the fungicide fenitropan, reacted readily with glutathione in aqueous ethanol solutions at room temperature, producing at least two products. The first reaction step, which is believed to be a bimolecular nucleophilic (Michael) addition, had a strongly pH‐dependent reaction rate.Second‐order rate constants were calculated for the reactions of NPPA at pH 4 with glutathione and with some other low molecular weight thiols. Nucleophilic reactivity of the reacting thiolate anions is linearly related to the pKavalues of the thiols. However, as the concentration of thiolate anion is also determined by the thiol pKa,there is no simple relationship between second‐order rate constants and thiol pKa.Thus the blocking rate of the various essential sulphydryl groups in fungi by NPPA is determined by the sulphydryl pKavalues and the a

ISSN:0031-613X    

DOI:10.1002/ps.2780260305

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractSeveral species of rice plant‐ and leafhoppers cause serious yield loss by sucking the plant sap and/or by transmitting diseases. Rice plant‐ and leafhoppers show resistance to various organochlorine, organophosphorus, carbamate and pyrethroid insecticides and may also be resistant to compounds of two or more different chemical groups. Thus, it is important to monitor the levels of resistance in field populations, to control resistant populations and to retard the development of further resistance by appropriate tactics. The merits and shortcomings of the various tactical and monitoring techniques are discus

ISSN:0031-613X    

DOI:10.1002/ps.2780260306

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractStructural requirements for melanin biosynthesis inhibition were analysed by comparing known melanin biosynthesis inhibitors (MBIs) and an intermediate of melanin biosynthesis (1,3,8‐trihydroxynaphthalene (1,3,8‐THN)), on the assumption that the enzymatic inhibition by MBIs occurs competitively with the biosynthetic intermediate. On this basis, new chemicals in the form of phthalazine derivatives were designed.In biological tests, the synthesised phthalazine derivatives showed high activity against rice blast, caused by Pyricularia oryzae Cav. These compounds also inhibited the melanisation of this fungus at a low concentration, which suggested that they are similar to other MBIs in their mode of act

ISSN:0031-613X    

DOI:10.1002/ps.2780260307

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractTreatment of 4th and 5th instar larvae of Heliothis virescens with different amounts of fenoxycarb induced an increase in weight of the 5th larval instar, prolongation of the 5th larval instar period, or the formation of dauer larvae. No effects were observed during the 4th instar and the moult to the 5th larval instar. To check whether these effects were due to persistence of fenoxycarb in treated larvae, metabolism of this chemical was analysed. Larvae were fed with radio‐labelled fenoxycarb at the first day of the 4th or at the first day of the 5th larval instar. Behaviour of the radio‐labelled compounds was followed during each instar. At the time of gut purge, the whole of the radio‐labelled material was excreted. The effects observed during the 5th instar of 4th‐instar‐treated larvae do not appear to be due to the persistence of fenoxycarb.The main metabolites of fenoxycarb were identified using coupled gas chromatography and mass spe

ISSN:0031-613X    

DOI:10.1002/ps.2780260308

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractImmunochemical assays for small molecules such as pesticides are rapidly gaining acceptance among analytical chemists. These techniques are rapid, sensitive, cost effective and can easily cope with large sample loads. This review lists the advantages and disadvantages of the technique and describes the steps in assay development using examples from this laboratory, particularly the thiocarbamate herbicide molinate and the triazine herbicides. The focus is primarily on hapten synthesis strategies, assay format considerations, sample preparation and assay validation.

ISSN:0031-613X    

DOI:10.1002/ps.2780260309

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

ISSN:0031-613X    

DOI:10.1002/ps.2780260310

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

ISSN:0031-613X    

DOI:10.1002/ps.2780260311

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY