摘要:

AbstractThe potential insecticidal activity ofSpilanthes acmellaMurr. (Compositae) extracts was assessed in this study. The extracts were shown to be toxic against adults of American cockroach,Periplaneta americanaL. The active component inS. acmellaextract was isolated and identified as N‐isobutyl‐2,6,8‐decatrienamide (spilanthol). The results from topical application of spilanthol show that it has a high acute toxicity and spilanthol was the most potent compound when compared to three conventional insecticides. The potency was found to be 1.3, 2.6 and 3.8 times more toxic than carbaryl, bioresmethrin and lindane, respectively. Electrophysiological studies indicated immediate hyperexcitation followed by complete inhibition of the cockroach cercal nerve act

ISSN:0031-613X    

DOI:10.1002/ps.2780250402

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractOf the numerous fractions obtained from the crude plant extracts ofChenopodium ambrosioides, Conyza dioscordisisandConvolvulus arvensis, 11 were found to be active against stored grain pests. The chemical structures of compounds present in the 11 fractions were found by gas chromatography/mass spectrometry to include predominantly long‐chain fatty acid esters of hexadecanoic, arachidonic, and octadecanoic acid

ISSN:0031-613X    

DOI:10.1002/ps.2780250403

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractAccelerated degradation of vernolate, EPTC and butylate but not of cycloate was detected in soils from three locations in Israel which were treated annually with vernolate. Repeated application of EPTC to soils with and without a history of vernolate application, under laboratory conditions, resulted in a progressive increase in its rate of dissipation with each application. Accelerated degradation of EPTC was also rapidly induced by mixing small amounts (5%) of soil with a history of vernolate treatment with soil that had never received vernolate. Liberation of14CO2from [14C]EPTC was more rapid in vernolate‐treated soils than in untreated soils, indicating a development of microbial populations in soil capable of rapidly degrading the EPTC. Degradation of [14C]EPTC was faster in soil previously cropped with maize than in non‐cropped soil, but slower in soils cropped with cotton or pean

ISSN:0031-613X    

DOI:10.1002/ps.2780250404

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe simultaneous HPLC determination of carbendazim, thiabendazole and thiophanate‐methyl in apples, pears and their pulps is described. The method is based on a clean‐up procedure carried out on an Extrelut 20 cartridge followed by HPLC analysis on a Diol column using hexune+isopropanol as mobile phase. Average recoveries of 83.8% for carbendazim, 82.9% for thiabendazole and 68.8% for thiophanate‐methyl on apple matrix were obtained; recoveries on pear matrix were in the same range. Detection limits with UV detection at 285 nm of 100 ng ml−1for carbendazim, 140 ng ml−1for thiabendazole and 500 ng ml−1for thiophanate‐methyl

ISSN:0031-613X    

DOI:10.1002/ps.2780250405

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractSecondary compounds serve both endogenous and exogenous functions in higher plants because they are involved in plant growth and development as well as intraspecies and interspecies interactions. Documentation of the effects of pesticides on secondary compound biosynthesis in higher plants is increasing. While several herbicides have been reported to reduce levels of secondary compounds by non‐specific mechanisms, a few herbicides, such as alachlor and glyphosate, directly affect specific biosynthetic steps. Alachlor reduces flavonoid synthesis at a step late in the biosynthetic pathway, and glyphosate blocks synthesis of all cinnamate derivatives by inhibiting 5‐enolpyruvyl shikimate‐3‐phosphate (EPSP) synthase. Inhibition of EPSP synthase also leads to the accumulation of high levels of shikimate, benzoic acids and benzoic acid derivatives. The sulfonylureas and p‐nitro‐substituted diphenylether (DPE) herbicides can cause increases in the level of cinnamatederived phenolic compounds and the DPEs can cause dramatic increases in terpenoid stress metabolites. Certain fungicides are thought to act through enhancing the capacity of plants to produce phytoalexins. These and other data suggest that sublethal effects of pesticides on target and non‐target plants can significantly affect agricultural ecosystems by altering the synthesis of compounds important in inter‐ and intraspeci

ISSN:0031-613X    

DOI:10.1002/ps.2780250406

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractA goat was dosed orally with [14C]tefluthrin, twice daily for 4 days, at a rate equivalent to 10.9 mg kg−1in its diet. Within 16 h of the final dose, 70.1% of the dose had been excreted (urine 41.4%, faeces 28.7%). Extensive metabolism occurred in the goat by ester cleavage and oxidation at a variety of positions on the molecule. Low radioactive residues were detected in the milk (0.076 mg kg−1), fat (0.076 mg kg−1) and muscle (0.016 mg kg−1), with tefluthrin as the largest individual component of the residue (milk 66.5%, fat 76.7%, muscle 34.2%). Higher residues were present in the kidney (0.3 mg kg−1) and liver (1.0 mg kg−1) and only a small percentage of this residue was due to tefluthrin (kidney 3.4%, liver 6.1%). The remainder of the residue in the kidney and liver was a complex mixture of metabolites. Most of the kidney metabolites were identified, but a high proportion of the liver residue was due to six unidentified pola

ISSN:0031-613X    

DOI:10.1002/ps.2780250407

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractNo registered fungicide controls Mucor piriformis, a cause of severe postharvest storage rot in pears, but the experimental fungicide RH 886 (active ingredients: 77% 5‐chloro‐2‐methylisothiazol‐3‐(2H)‐one and 23% 2‐methylisothiazol‐3‐(2H)‐one) has an ED50of 23.1 μg ml−1in 5 min exposure for germination of sporangiospores of M. piriformis and an ED50of 9.9 μg ml−1for mycelial growth. Mixing RH 886 into infested, amended soil at 8 mg g−1soil or mixing copper sulfate into soil at 1 mg g−1soil prevented sporulation of M. piriformis. Application of RH 886 to pear fruits prior to inoculation, or immersion of fruits in solutions of RH 886 containing sporangiospores of M. piriformis signific

ISSN:0031-613X    

DOI:10.1002/ps.2780250408

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract‘Suspoemulsions’ (SE) is the term used to describe combined formulations of solid and liquid active ingredients as dispersed systems. The parameters influencing an SE were investigated with reference to four examples (one solid and three liquid products) in various mixing ratios. Apart from the type and amount of the partners and the energy dissipation density used, the recipe and viscosity particularly had effects on the formation and properties of an SE. The solid particles in the suspension promoted the comminution of the liquid phase. However, they had practically no influence on the flow behaviour in the three degrees of comminution fineness investigated. The causes of the phenomena discovered are discussed. The storage stability of the SE was equal to that of suspension concentrate (SC) formulations. The advantageous effect of the addition of a thickener on storage stability was similar to that in the case of an

ISSN:0031-613X    

DOI:10.1002/ps.2780250409

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe characterisation of emulsions at dilution rates greater than 1:20, currently used in most international specifications for agrochemical emulsifiable concentrate (EC) formulations, is becoming increasingly important. CIPAC MT36.2 is the internationally‐accepted test method for determining the bulk stability of emulsions containing 10 ml litre−1or less of added EC. A new nephelometric version of this test method has been examined which, although not as accurate as the official method, gives more rapid results. An assessment of the new method against the official method at a working concentration of 5 ml litre−1is reported. Agreement is good, despite the semi‐empirical nature of the new method, but only if emulsions are re‐emulsifiable at the end of the standing period. The scope of the method is discussed and areas of application

ISSN:0031-613X    

DOI:10.1002/ps.2780250410

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe characterisation of emulsions at dilution rates greater than the 1:20 used in most international specifications for agrochemical formulations is becoming increasingly important. The internationally‐agreed CIPAC MT 36.2 test depends upon the determination of the shift in bulk concentration between the upper and lower halves of an emulsion after a period of standing. An analytical method specific to the active ingredient is stipulated. This paper reports an investigation of the use of CIPAC MT 36.2 with an emulsifiable concentrate (EC)‐soluble dye which allows a colorimetric finish. This new method should be applicable to almost all ECs, and uses less costly instrumentation than the standard method. It could therefore allow more convenient use of CIPAC MT 36.2 for formulation development purposes. The limitations and range of applicability of the new method are discussed. For ECs of poor spontaneity it is shown that emulsion stability is strongly influenced by the emulsification technique used. Techniques within the frame of CIPAC MT 36.2 have been discovered which give repeatable results for such

ISSN:0031-613X    

DOI:10.1002/ps.2780250411

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY