摘要:

AbstractUptake of various doses (0.27–4.06 g litre−1) of glyphosate acid formulated with various concentrations (0.27–5.42 g litre−1) of two polyethoxylated alcohol surfactants ‘Genapol’ T‐150, ‘Genapol’ T‐250) in wheat (Triticum aestivumL. cv. Ralle) 24 h after application was studied. Both surfactants greatly enhanced glyphosate uptake at concentrations up to 1.35 g litre−1. Uptake could be slightly further improved by ‘Genapol’ T‐150 up to 5.42 g litre−1while ‘Genapol’ T‐250 at this high concentration antagonized uptake a little. Uptake of glyphosate‐monoammonium formulated with a quaternary ammonium surfactant (‘Trimao’ (8PO)) in wheat and white mustard (Sinapis albaL. cv. Alba) was also studied. Uptake of glyphosate‐monoammonium in wheat was enhanced at surfactant concentrations up to 1.35 g litre−1. Beyond this concentration uptake continued to increase slightly but not significantly. Generally, glyphosatemonoammonium formulated with ‘Trimao’ (8PO) was not taken up as extensively by mustard as by wheat, and the optimum surfactant concentration is probably higher on mustard. The optimal combinations of surfactant concentration and glyphosate dose based on uptake 24 h after application were used in a time‐course study.Results from uptake studies were compared with the efficacy of similar formulations on wheat. The surfactant concentration range which gave the most pronounced effect on glyphosate uptake was found to be similar (0–1 g litre−1) in both studies. However, the surfactant concentration providing maximum herbicide uptake was found to be higher in the uptake study compared to the surfactant concentration providing optimal efficacy in the dose‐response experiments. A dose rate of 0.5 g litre−1of ‘Tween’ 20 (sorbitan monolaurate surfactant) improved efficacy of a formulation with an optimal mix of glyphosate‐monoammonium and ‘Trimao’ (8PO). Ammo

ISSN:0031-613X    

DOI:10.1002/ps.2780440202

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractFluchloralin [N‐(2‐chloroethyl)‐α,α,α,‐trifluoro‐2,6‐dinitro‐N‐propyl‐p‐toluidine] was transformed by two common soil fungi,Aspergillus flavus LinkandFusarium solani(Mart.) Sacc. in pure culture. The fungi were isolated from enrichment cultures of an analogous herbicidal compound, pendimethalin [N‐(1‐ethylpropyl)‐2,6‐dinitro‐3,4‐xylidine)]. Transformation of fluchloralin by these fungi resulted in the formation of several metabolites, 13 of which were identified. Besides the known mechanisms of microbial transformation of dinitroanilines, methylation of the anilino nitrogen and direct elimination of a nitro group at 2 position from the aromatic ring without any furth

ISSN:0031-613X    

DOI:10.1002/ps.2780440203

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe effect of a pyrethroid insecticide, deltamethrin, on water loss, metabolic rate and immobilisation was studied, using the epigeal spiderOedothorax apicatus(Blackwall) (Linyphiidae) as a test species. Water loss was measured gravimetrically at different temperatures, air humidities, and doses of deltamethrin. Metabolic rate and immobilisation were measured at different temperatures and doses. Immobilisation was measured at different relative humidities and temperatures. Water loss due to evaporation increased linearly with vapour pressure deficit. The slope of the latter relationship increased with temperature, indicating an increase in cuticle permeability with temperature. In addition to water loss by evaporation, deltamethrin treatment induced water excretion. This was positively related to dose and temperature, but independent of air humidity. Metabolic rate increased with temperature and dose. Immobilisation was highest at low temperatures in combination with low air humidity. The consequences of pesticide‐induced water excretion are discussed with respect to field‐ and laboratory‐based dose‐effect relationships for pyrethroids presented in the literature. The present results seem to offer an explanation for hitherto unexplained minima in temperature‐response curves in pyrethroid toxicity in some arthropod species. It is concluded that simultaneous measurements of metabolic rate, water‐loss rate and pesticide effects are a prerequisite for an understanding of the effects of pesticides on

ISSN:0031-613X    

DOI:10.1002/ps.2780440204

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe soil partition coefficients (Kdvalues) and ED50values of carbetamide, isoproturon, propyzamide, trifluralin and pendimethalin were determined on various soil types. Adsorption increased in the order carbetamide

ISSN:0031-613X    

DOI:10.1002/ps.2780440205

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThis paper reports the synthesis and the biological activity of substituted 6‐alkyl‐1,2,3,4‐tetrahydro‐1,1‐dimethylnaphthalenes in which the substituents at the 5‐ and/or 7‐position are varied with a multitide of functional groups. These compounds exhibited pre‐emergent herbicidal activity which was a function of the electron‐withdrawing ability and the size of the groups substituted at the 5‐ and/or 7‐position. Nitro and/or nitrile groups at these positions tended

ISSN:0031-613X    

DOI:10.1002/ps.2780440206

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractWith a combination of biological, analytical, electrophysiological, and video‐optical methods, it was possible to show that low concentrations of the new chloronicotinyl insecticide, imidacloprid, strongly affect the behaviour ofMyzus persicae(Sulz.), leading eventually to the death of the aphids. Tests to elucidate the biological properties were performed under laboratory conditions with cabbage leaf petioles placed in insecticidal solutions over different periods of time. LC15(24h)values were considered as low concentrations and calculated for imidacloprid and pirimicarb, respectively. Imidacloprid at low concentrations depressed the honeydew excretion of apterous adults ofM. persicaeby almost 95% within 24 h without affecting the vitality of the majority of aphids, whereas, at equitoxic concentrations, pirimicarb showed much weaker effects on honeydew excretion, which strongly coincided with mortality. In choice experiments with alate morphs ofM. persicaeover 48 h, their larvae almost always occurred on the untreated control leaf, and were not found on the leaf which was treated systemically with low concentrations of imidacloprid. Apterous aphids placed on cabbage leaves systemically treated with low concentrations of imidacloprid showed nearly the same decrease in weight as untreated starving aphids, suggesting that their death was caused by starvation. Aphids that were moved from imidacloprid‐treated to untreated leaves after 24 h began feeding on the latter and showed a steady increase in weight and honeydew production. This suggests that the behavioural response is reversible. Aphids on pirimicarb‐treated (equitoxic dose) leaves showed no decrease in weight. Electrical penetration graphs revealed thatM. persicaeon artificial membranes containing imidacloprid probed more often before feeding than aphids on control sachets. Time‐lapse videofilming of apterous adults placed on cabbage leaves revealed a migration from the leaf treated with low concentrations of imidacloprid to an untreated leaf. From the results of these experiments and the observed symptomatology it is possible to postulate two different and dose‐dependent modes of action of imidacloprid onM. persicae: (1) the well‐known mode of action with visually obvious irreversible symptoms (paralysis, tremor, uncoordinated leg‐movement) at field rates, and (2) the reversible starvation response as an antifeedant effect, which is not coupled with typical symptoms of neuronal disorder, at lower c

ISSN:0031-613X    

DOI:10.1002/ps.2780440207

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe potential of a new kind of light‐induced pesticide action was evaluated for a broad variety (32) of natural photosensitizers and their thione derivatives. The latter were synthesized to shift the absorption spectra towards the visible region and to increase the triplet and singlet oxygen quantum yields.Qualitative and quantitative evaluation of growth inhibition ofFusarium culmorum(F. G. Smith) Sacc. produced by these photosensitizers under UVA and visible light was performed on silica gel plates and in liquid medium. The results show that the phototoxicity per excited molecule of the thione derivatives using UVA light was similar to that of their parent natural compounds. On the other hand, only the thione derivatives were photoactive under visible light irradiation.These compounds show encouraging levels of phototoxicity againstF. culmorum, both in liquid culture and on silica plates, and may have potential for use as photoactive pesticide

ISSN:0031-613X    

DOI:10.1002/ps.2780440208

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractSimple, rapid and sensitive spectrophotometric methods have been developed for the microdetermination of fenvalerate, based on the formation of red‐purple compounds when one of the hydrolysed products of fenvalerate is condensed with 4‐nitrophenylhydrazine (4‐NPH) in the presence of methanolic potassium hydroxide. With this reagent the colour development was instantaneous and was stable for 52 hours. The method has been successfully adapted to the determination of fenvalerate in its formulation and residues on water and

ISSN:0031-613X    

DOI:10.1002/ps.2780440209

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe phenylpyrrole fungicide fenpiclonil inhibited the metabolism of glucose in mycelium ofFusarium sulphureumSchlecht at a concentration which only slightly inhibited mycelial growth (EC15). At the same concentration, fenpiclonil also inhibited accumulation and, to a greater extent, phosphorylation of 2‐deoxy[U‐14C]glucose in starved mycelium loaded with unlabelled 2‐deoxyglucose. Fenpiclonil did not affect cell‐free phosphorylation of 2‐deoxyglucose or the ATP content of mycelium. Therefore, the primary mode of action of the fungicide may be based on inhibition of transport‐associated phosphorylation of glucose. This may cause a cascade of metabolic events which eventually lead to fungal growth inhibition and death. One major event affected by inhibition of transport‐associated phosphorylation is the accumulation of polyols, such as glycerol and mannitol, in mycelium. This was not observed in an osmotically sensitive, fenpiclonil‐resistant laboratory isolat

ISSN:0031-613X    

DOI:10.1002/ps.2780440210

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractA total of 146 samples of different kinds of cheeses produced in Spain were analysed in order to ascertain the specific contamination pattern. The organochlorine compounds studied were those most commonly investigated in previous surveys: α‐HCH, β‐HCH, γ‐HCH (lindane), γ‐HCH, chlordane, aldrin, dieldrin, endrin, heptachlor, heptachlor epoxide, and the isomers and metabolites of DDT. α‐HCH, β‐HCH, γ‐HCH, chlordane,p,p′, DDT, andp,p′‐DDE were found in more than 76% of samples;p,p′‐DDE and γ‐HCH were the most frequently detected, with frequencies of 100 and 97.9% respectively. γ‐HCH, aldrin, dieldrin, heptachlor, heptachlor epoxide,o,p′‐DDT,p,p′‐DDD ando,p′‐DDD were observed at lower frequencies. No residues of endrin were detected in any sample. Insecticides exceeding the maximum residue limits (MRLs) were chlordane, β‐HCH, α‐HCH and γ‐HCH, with 42, 20, eight and six samples respectively. Mean residues of organochlorines found were as follows (μ kg−1butterfat): α‐HCH = 46.3; β‐HCH = 46.5; γ‐HCH = 54.2; δ‐HCH = 16.9; aldrin = 16.7; dieldrin = 9.7; heptachlor = 15.9; heptachlor epoxide = 14.8; chlordane = 50.2;o,p′‐DDT = 5.1;p,p′‐DDT = 12.4;o,p′‐DDT = 19.6;p,p′‐DDD = 46.7;o,p′‐DDE = 6.9;p,p′‐DDE = 40.7 (.DDT = 55.0).Estimated dietary intakes (EDIs) from cheese consumption were compared to acceptable daily intakes (ADIs) for the pesticides where residues exceeded the MRL. EDIs calculated were in all cases below ADIs, and, therefore, based on the ADIs, there is no h

ISSN:0031-613X    

DOI:10.1002/ps.2780440211

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY