摘要:

AbstractSome 3′‐ or 4′‐alkylthio‐2‐iodobenzanilides and some 3′‐alkylthio‐2‐methylbenzanilides were testedin vitroandin vivoagainst fungal plant pathogens of different taxonomic classes and some showed activity, especiallyin vivo.Among all the tested compounds the 3′‐alkylthio‐2‐iodobenzanilides reve

ISSN:0031-613X    

DOI:10.1002/ps.2780280102

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractTwo insecticides, an insect repellent and an insecticide synergist have been complexed with β‐cyclodextrin yielding microcrystalline, wettable, non‐hygroscopic formulations. The insecticides fenitrothion and malathion, the repellent diethyltoluamide and the synergist MGR‐264 were found to form stable inclusion complexes with β‐cyclodextrin.The molecular encapsulation resulted in improved heat and chemical stability, storability, enhanced wettability and dissolution properties of these rather volatile, poorly water‐sol

ISSN:0031-613X    

DOI:10.1002/ps.2780280103

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThere was no difference in dose response to abamectin between a laboratory strain of Colorado potato beetle(Leptinotarsa decemlineata (Say))from North Carolina and a multiple resistant strain from Massachusetts(LD50= 1.95 and 1.98 ng larva−1, respectively). Two abamectin‐resistant strains were generated by separate means. The mutagen, ethyl methanesulfonate, was used to generate an abamectin‐resistant strain (LD50= 29.4 ng larva−1) from the susceptible laboratory strain. The other resistant strain(LD50= 45.3ng larva−1) was generated through an intense selection with abamectin of a field strain contained in cages set up in existing potato fields. Resistance ratios calculated fromLD50values for the two abamectin‐resistant strains were 15‐fold and 23‐fold, respectively. Resistance ratios calculated fromLD97values(21‐fold and 38‐fold, respectively) were higher than those calculated atLD50. Also, there were larvae in both resistant strains which were capable of surviving doses up to 100 ng larva−1, while the susceptible strain had no survivors at 10 ng larva−1. Although the logit mortality regression analysis produced statistically different lines for the two abamectin‐resistant strains, the slopes of each appear to be the same. Both resistance factors were determined to be autosomal and incompletely recessive (0.26 to 0.4, respectively) via reciprocal F1crosses to the susc

ISSN:0031-613X    

DOI:10.1002/ps.2780280104

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractNew routes to the title compounds, involving improved conditions for the cyclopropanation, and a new method of constructing the central three‐carbon unit (based on the coupling of a Grignard reagent with an allylic acetate) give access to products for which the previously reported route was not satisfactory. For the new route, a synthesis of 5‐bromo‐2‐fluoro‐diphenyl ether was developed. Previously deduced relationships between structure and insecticidal activity apply for the new compounds: alkenes are generally more active than corresponding alkanes; substitution at the 3‐ or 4‐position (but not the 2‐) of the 1‐aryl group can enhance activity. In addition, some fluorine‐containing substituents le

ISSN:0031-613X    

DOI:10.1002/ps.2780280105

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractFlusilazole is a potent inhibitor ofUstilago maydissporidial growth (I50= 20 μg liter−1). Incorporation of[14C]acetate into ergosterol of growing sporidia is inhibited 50% by 0.5 μg liter−1of the fungicide. Inhibition of ergosterol biosynthesis is concomitant with the accumulation of the precursors eburicol, obtusifoliol and 14α‐methylfecosterol. A novel cell‐free assay has been developed to measure the 14α‐demethylation of[3H]dihydrolanosterol. Flusilazole inhibits the cell‐free demethylation with an I50of 15 μg liter−1.These data provide strong evidence that the mode of action of flusilazole is by inhibiting ergosterol biosynthesis through direct inhibition of the 14α‐demethylation of

ISSN:0031-613X    

DOI:10.1002/ps.2780280106

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractResidues of tri‐allate in triticale (XTriticosecaleWittmack) were determined, after both preplant and pre‐emergence soil‐incorporated applications of tri‐allate at 1.4 kg ha−1, at the following crop stages: 2–3‐leaf, 5–6‐leaf, fully headed and mature (straw and grain). Tri‐allate residues were detected only in green tissue samples from the 2–3‐leaf stage of the crop. Recoveries of tri‐allate were in the order of 90 and 85%from the green tissue and grain at the 100 and 50 μg kg−1fortif

ISSN:0031-613X    

DOI:10.1002/ps.2780280107

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractDimethyl 2‐methyl‐5‐(chloropyridin‐2‐yl)pyrrole‐3,4‐dicarboxylates in which the chlorine atom is substituted at different positions of the pyridine ring have widely varying biological properties. The 3‐chloro analog (I) is a post‐emergence and pre‐emergence herbicide, the 4‐ and 5‐chloro analogs (II, III) are post‐emergence herbicides but not pre‐emergence, and the 6‐chloro analog (IV) is inactive. Computer graphic and molecular mechanics analyses of their molecular conformations showed that the 4‐ and 5‐chloro analogs adopt a coplanar, intramolecularly hydrogen bonded conformation whereas the 3‐chloro analog does not. High‐level quantum mechanical calculations of the conformational preferences of related model systems were in agreement with these results. Based on this, II and III were predicted to have higher octanol/water partition coefficients relative to I, leading to higher soil binding and weaker xylem transport, hence their observed weaker pre‐emergence activities. Experimental measurements of octanol/water partition coefficients, soil binding, and infrared hydrogen bonding studies verified these predictions. Molecular modeling techniques are usually used for designing compounds to fit enzyme active sites and designing putative receptor models. This study demonstrates the usefulness of these techniq

ISSN:0031-613X    

DOI:10.1002/ps.2780280108

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractPhotochemistry of the herbicide 3,5‐dibromo‐4‐hydroxybenzonitrile (bromoxynil) (I) was investigated by irradiating at approximately 313 nm. Aqueous phase photoreactions of 0.078–7.800 × 10−5m solutions of I were carried out at different pH values. Quantum yields for the loss of I in buffered solutions were 0.008 (±0.0004), 0.048 (±0.0024), and 0.044 (±0.0022) at pH 2.6, 7.0, and 11.0, respectively. In neutral and basic conditions, I absorbed more strongly at wavelengths>290 nm, an environmentally significant region. Phototransformation of I was monitored by HPLC and UV‐VIS spectrometry. All photoreactions of I gave rise to the generation of two products, 3‐bromo‐4‐hydroxybenzonitrile and 4‐hydroxybenzonitrile. The former photoproduct was tentatively identified from its mass spectral data. The photoproducts can be accounted for with a proposed mechanism

ISSN:0031-613X    

DOI:10.1002/ps.2780280109

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe effects of seven fungicides, seven herbicides and six insecticides on nitrogen fixation and nodulation by the dry bean(Phaseolus vulgarisL. cv “Bonus”) were investigated. All pesticides examined were found innocuous to nitrogen fixation (acetylene reduction) except bentazone, a post‐emergence herbicide. Bentazone at 3 × label rate (6.7 kg ha−1) consistently depressed nitrogen fixation rates within 48 h after application. However, rates recovered and were comparable to those of control plants after 6 days. No effects were observed on nodulation from any of the pesticides (3 × or label rate

ISSN:0031-613X    

DOI:10.1002/ps.2780280110

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe pond snailLymnaea stagnaliswas fed on maize pellets containing metaldehyde. With increasing concentration of metaldehyde there was a decrease in the meal length, number of bites per meal and amount of pellet eaten. The irregularity of biting and the amount of time spent pausing during the meal increased.Meals on maize pellets in the presence of acetaldehyde (one of the metabolites of metaldehyde) were shorter than control meals on maize pellets alone.The symptoms of poisoning after ingestion of metaldehyde or in the presence of acetaldehyde were similar. There was an increase in mucus secretion. Animals showed muscular spasms, undirected mouthing movements and uncoordinated locomotion. This was followed by a period of immobility.The isolated central nervous system ofL. stagnaliswas used to study the effects of metaldehyde and acetaldehyde on the neural activity underlying feeding. Application of metaldehyde or acetaldehyde led to an increase in firing activity and development of paroxysmal depolarising shifts in buccal motoneurons. It is argued that this type of activity could explain some of the symptoms of poisoning seen in the whole animal after ingestion of metaldehyde, and that acetaldehyde may be responsible for some of the toxic effects of metaldehyde.These results suggest that the CNS ofL. stagnalisprovides a useful model for screening molluscicides for their effects on a functional neuronal network.

ISSN:0031-613X    

DOI:10.1002/ps.2780280111

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY