bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced biodegradation of γ‐hexachlorocyclohexane (γ‐HCH) in HCH (commercial) acclimatized flooded soil: Factors affecting its development and persistence
Authors: Bhuyan Sasmita , Sreedharan Bindu , Adhya Tapan Kumar , Sethunathan Nambrattil 
Published: November 2006

AbstractMoist surface soil samples from a flooded soil, pretreated twice with a commercial formulation of an isomeric mixture of hexachlorocyclohexane (commercial HCH) to induce accelerated aerobic biodegradation of γ‐HCH, were incubated at 20, 25 and 35°C with and without replenishment of water lost by evaporation. Soil samples, kept continuously moist, retained the capacity for accelerated aerobic biodegradation of added γ‐HCH even after 40 days incubation at all three temperatures, but the enhancement factor (causing accelerated degradation of γ‐HCH) was inactivated at 25 and 35°C, and not at 20°C, within 20 days when commercial HCH‐acclimatized soil samples were subjected to moisture stress. Evidence suggested that temperature‐induced moisture stress caused the inactivation of the enhancement factor, especially at 35°C. The enhancement factor developed almost with equal ease in both rice‐straw‐amended and unamended soil irrespective of water regime (flooded or non‐flooded) after multiple applications of a commercial formulation of HCH. The population of γ‐HCH‐degrading aerobic, but not anaerobic, micro‐organisms increased distinctly after each successive application of commercial HCH, interestingly at identical rates in both flooded and non‐flooded soils.Sphingomonas paucimobilis isolatedfrom flooded soil degraded α‐,β‐,δ‐ and γ‐isomers of HCH under aerobic conditions.
Progress and developments in adjuvant use since 1989 in the usa
Authors: Foy Chester L. 
Published: November 2006

AbstractOver 50 articles on adjuvants have been published in Weed Science and Weed Technology, journals of the Weed Science Society of America (WSSA), from July 1989 through September 1992. More than 30 presentations on adjuvants were made at the 1990, '91 and '92 Annual Meetings of WSSA. Research involved c. 45 herbicides, 31 weed species, 19 crops, and numerous adjuvants. Results obtained indicated that the adjuvants tested either enhanced or had no effect on herbicide efficacy. Efficacy was enhanced in the majority of the studies. Some herbicides at lower rates plus adjuvants provided weed control equal to that achieved with higher rates of the same herbicides. Absorption, penetration, and translocation of several herbicides were enhanced with adjuvants. Some adjuvants also enhanced rates of herbicide photolysis, decreased antagonism, prevented herbicide injury to crops, altered the pH of spray solutions, increased deposition and enhanced retention of herbicides, increased rainfastness, promoted better germination of mycoherbicide spores, and were effective formulating agents. Adjuvants appeared to have no effect on herbicides in soil. Product labels of 19 agrochemical companies, involving c. 485 formulations of crop protection chemicals for use in 1992, recommend use of adjuvants with 49% of such formulations; 5% specify that no additional adjuvants are recommended, while the remaining 46% (including granular formulations) do not mention adjuvant use. Adjuvants are recommended with 71% (and not recommended with only 3%) of herbicide (including defoliant) formulations, and recommended with c. 30% and not recommended with c. 14% of the other classes of crop protection chemicals including plant growth regulators, insecticides, miticides, nematicides, fungicides, larvacides, seed treatments, soil fumigants, and repellents. More than 30 types of adjuvant are mentioned on product labels. Several new adjuvants for use with agrochemicals were marketed during 1990–92.
Adjuvants for use with foliar fungicides
Authors: Steurbaut Walter 
Published: November 2006

AbstractAdjuvants for use with fungicides have been known since the first studies on formulation efficiency and it is now well known that the activity of systemic fungicides can be improved by a proper choice of additives and/or adjuvants. Several studies have clearly demonstrated that these improvements result from changes in such factors as droplet formation, surface contact and behaviour of the deposit, penetration into the leaf (transcuticular or stomatal) and transport within the plant, as well as interactions within the fungal cell.The transfer of these results from laboratory studies to field trials often yields inconsistent results and simulation models often fail to predict the behaviour of adjuvants under field conditions. This is probably because many factors are involved which cannot be controlled in the field. For example, droplet formation can be very different, leaf structure and canopy formation can interfere, and results for one particular fungicide/crop/fungus/adjuvant combination cannot be translated to another situation. This multiplicity of very complex interactions is probably the main reason why there has been no general breakthrough in practical adjuvant use with fungicides. More applied research is needed to optimise the specific application conditions for each crop/fungicide/fungus combination.There are still some unresolved problems associated with the use of adjuvants such as loss of selectivity and the occurrence of phytotoxic side‐effects. Also some unexpected specific interactions between adjuvants and formulation constituents can influence the activity which necessitate more fundamental studies on the biochemical and physicochemical background of their mode of action.
Pesticide application as affected by spray modifiers
Authors: Hall Franklin R. , Chapple Andrew C. , Downer Roger A. , Kirchner Loren M. , Thacker J. Richard M. 
Published: November 2006

AbstractSpray modifiers are materials which affect the physicochemical characteristics of pesticides and hence can enhance or detract from the eventual biological effect. The purpose of this paper is to discuss the effect that spray modifiers (especially adjuvants) have on the interactions and complexities of the pesticide application process.Foliar application of Crop Protection Agents (CPAs) includes a complex of inter‐linked events: atomization, transport, impaction, retention, deposit formation, movement on or in the plant, and the final biological result. New regulatory constraints question the benefits of many adjuvants and thus use of spray modifiers will be brought to increasingly higher research interest.At the Laboratory for Pest Control Application Technology (LPCAT), studies on spray modifiers have addressed the problem of identifying (and understanding) these interactions, many of which can be mathematically modelled. The overall aim of the research discussed is to identify the benefits and costs of using spray modifiers and to better understand the role that they may have in the pest control process.
Possible mechanisms for surfactant‐induced foliar uptake of agrochemicals
Authors: Stock David , Holloway Peter J. 
Published: November 2006

AbstractIn the past many mechanisms of action have been proposed to explain the surfactant‐induced uptake of agrochemicals applied to foliage. These are reviewed briefly and discussed in relation to potential sites of uptake activation, particularly in the light of recent radiochemical work on the foliar uptake behaviour of surfactants on intact plants in the presence or absence of model penetrants and pesticides. The body of evidence available is examined in relation to the many outstanding problems that still exist in understanding the role and use of surfactants as uptake activators in agrochemical formulations.
Antagonism of the foliar uptake of glyphosate into grasses by organosilicone surfactants. Part 2: Effects of surfactant structure and glycerol addition
Authors: Gaskin Robyn E. , Stevens Peter J. G. 
Published: November 2006

AbstractA systematic investigation into the effects of a range of organosilicone surfactants on the foliar uptake of radiolabelled glyphosate into wheat revealed significant antagonism associated with the chemical structure of these adjuvants. Rates of herbicide uptake were influenced by the ratio of the ethylene oxide (EO) hydrophile to siloxane hydrophobe, the mean EO chain length of the surfactant and the chemical nature of the terminal group on the EO chain. In general, antagonism was reduced, or even eliminated, by increasing the polarity of the organosilicone surfactant molecule. Typically, these surfactants markedly enhanced the initial rate of glyphosate uptake, which then slowed abruptly to reach a maximum within 4 h, in contrast to the approximately linear uptake response of the herbicide alone over 24 h following foliar application. The addition of glycerol further increased the initial rapid rate of glyphosate uptake in the presence of an organosilicone, but had no effect on the subsequent slowing down of foliar uptake. These findings are discussed in relation to the possible mechanisms by which these surfactants affect the cuticular penetration of glyphosate.
Adhesion of spray droplets to foliage: The role of dynamic surface tension and advantages of organosilicone surfactants
Authors: Stevens Peter J. G. , Kimberley Mark O. , Murphy Dennis S. , Policello George A. 
Published: November 2006

AbstractMeasurements of the dynamic surface tension of seven surfactants (four organosilicones, two ‚conventional’︁ hydrocarbon‐based surfactants and an organosilicone + hydrocarbon‐based blend; 0.5 to 5.0 g litre−1) have been combined with data on the adhesion of their spray droplets to pea leaf. The latter were determined by a method enabling the surface age, and thus surface tension of the droplets at impact, to be calculated. Adhesion was directly related to the dynamic reduction in surface tension (2 to 50 mN m−1) prior to impact. The organosilicone surfactants and the blend reduced surface tension more rapidly and to lower values than did the organic surfactants. Adhesion was also inversely related to droplet size (110 to 880 μm diameter), droplet velocity (0.3 to 2.8 m s−1) and angle of incidence on the leaf (0 to 67.5 degrees). These physical factors were of less importance than surface tension in controlling adhesion. Relative adhesion varied among the surfactants both with their concentration and with surface tension. These findings are discussed with respect to their implications for the possible involvement of surface viscosity in the spray impaction process.
Pyrethroid residues in sediment and water samples from mesocosm and farm pond studies of simulated accidental aquatic exposure
Authors: Hadfield Stephen T. , Sadler Jill K. , Bolygo Elek , Hill Sarah , Hill Ian R. 
Published: November 2006

AbstractThis paper describes the residue analysis of water and hydrosoil samples taken from two separate large‐scale aquatic ecotoxicology trials designed to assess the environmental fate and effects of the pyrethroids lambda‐cyhalothrin and cypermethrin. Comparison of the results demonstrates the high degree of reproducibility of the chemical residue found the day after treatment using experimental mesocosms (lambda‐cyhalothrin) as opposed to an in‐use farm pond (cypermethrin). Both studies showed that pyrethroid residues were rapidly lost from the water column: residues of lambda‐cyhalothrin were less than 2 ng litre−1 following the final application of a cumulative seasonal exposure equivalent to twelve ‚drift’︁ and six ‚run‐off’︁ events, each delivering a dose equivalent to that expected from a typical event under field conditions. Hydrosoil appeared to act as a sink for pyrethroid residues and, under the stringent test conditions of the mesocosm study, lambda‐cyhalothrin residues reached 3.2 μg kg−1 following the seasonal exposure described above. The cypermethrin farm‐pond study illustrated the localised pattern of exposure expected under natural field conditions, with site topography and cultivation practices which represent an average ‚worst case’︁. Residues in hydrosoil reached a maximum level of approximately 25 μg kg−1 in one sampling zone at one interval, and thereafter declined to a level of < 9 μg kg−1 within four months.
The influence of variable precipitation patterns on simulations of pesticide mobility
Authors: Roth Georg , Stahl Georg , Iwan Jörg 
Published: November 2006

AbstractThe behaviour of pesticides in the soil is governed by a variety of complex processes including the climatic conditions. To investigate the influence of these specific factors, a Monte‐Carlo Method was used to generate sequences of daily precipitation and temperature data representing natural weather behaviour. Simulations of the leaching process were performed for different compounds with these sequences while all other environmental parameters were held constant. The results indicated that the use of stochastic variables yields new insight into the leaching process. It is shown that the naturally occurring variability of the weather pattern has a crucial influence on the leaching of pesticides.
Antifungal activity of flavonoids and their mixtures against different fungi occurring on grain
Authors: Örner Martin Weidenb , Jha Hem Chandra 
Published: November 2006

AbstractThe antifungal activity of three flavones and one flavanone and of different mixtures of these flavonoids was investigated on malt extract agar against four fungi usually occurring on grain. As pure substances the unsubstituted flavone and flavanone showed higher activity than the hydroxylated flavones. Mixtures containing flavone and 7‐hydroxyflavon or flavone, flavanone and flavonol caused higher inhibition of fungal growth than the remaining ones.
The biochemical mode of action of some newer azole fungicides
Authors: Kwok Iris M.‐Y. , Loeffler R. Thomas 
Published: November 2006

AbstractThe effects of the newer azole fungicides BAS 480F, flusilazole, and tebuconazole on growth and sterol composition of the plant pathogenic fungi Botrytis cinerea, Pyrenophora teres, Pyricularia oryzae, Rhynchosporium secalis, Ustilago maydis and Erysiphe graminis f.sp. hordei were compared with those of flutriafol and propiconazole. The results indicate that all the compounds are inhibitors of sterol 14α‐demethylase, and rule out any additional modes of action on sterol biosynthesis.
The microimmersion bioassay: A novel method for the topical application of pesticides to spider mites
Authors: Dennehy Timothy J. , Farnham Andrew W. , Denholm Ian 
Published: November 2006

AbstractA novel and versatile method is described for measuring the contact activity of acaricides against spider mites. The microimmersion (MI) bioassay involves drawing batches of 25 mites into small pipette tips under vacuum, immersing them for 30 s in 35 μ1 of a test solution, and then confining the treated subjects on clean foliage in holding cells. Evaluations of amitraz, bifenthrin, chlorpyrifos and dicofol against susceptible strains of Tetranychus urticae Koch showed the MI bioassay to be equally applicable to formulated and technical acaricides (the latter dissolved in acetone + distilled water; 20 + 80 by volume), and to give LC50 values that corresponded well with those from a conventional residual bioassay. The most important difference between bioassay methods was the consistently greater slope of probit lines from MI tests. Results were not highly sensitive to varying the immersion period between 15 and 60 s, and low control mortality was observed with ethanol or acetone concentrations of up to 500 ml litre−1, and surfactant concentrations of up to 10 g litre−1. The potential of this method for assessing the relative toxicity of both fast‐ and slow‐acting acaricides, screening small quantities of experimental compounds for acaricidal activity, and improving the laboratory procedure for selection and characterization of acaricide resistance is discussed.
Potential of biopesticides in agriculture
Authors: Rodgers Paul B. 
Published: November 2006

AbstractAll living organisms are subject to predation, parasitism or competition from other organisms. The study of these interactions has led to the identification of many potential opportunities for the use of living organisms as biopesticides to protect agricultural crops against insect pests, fungal, bacterial and viral diseases, weeds, nematodes and mollusc pests. A range of biopesticide products (including as active agents bacteria, fungi, nematodes, protozoa, viruses and beneficial insects) are now available commercially for control of insect pests, fungal and bacterial diseases and weeds. However, world biopesticide sales in 1990 were estimated to be $120 million, representing less than 0–5% of the world agrochemical market. Over 90% of biopesticide sales are represented by a single product type, containing Bacillus thuringiensis Berl., for control of insect pests. Nevertheless, biopesticide sales are estimated to be increasing at 10–25% per annum whilst the world agrochemical market is static or even shrinking. There has been a significant renewal of commercial interest in biopesticides as evidenced by the substantial number of alliances forged between major agrochemical companies and biotechnology companies which allow these major companies access to marketing rights to novel biopesticides.This paper reviews the current commercial status of biopesticides and discusses the technical and commercial constraints which have impeded development of biopesticides in the past. Novel developments in R&D, which may enable some of these constraints to be overcome, are examined by reference to a number of specific examples (some of which arise from the author's own experience in a biotechnology company). The future prospects for biopesticides are discussed in the light of technical advances and commercial and regulatory requirements.
Mutual antagonism between sterol demethylation inhibitors and phosphorothiolate fungicides on Pyricularia oryzae and the implications for their mode of action
Authors: Sugiura Hisao , Hayashi Keisuke , Tanaka Toshinobu , Takenaka Mitsuaki , Uesugi Yasuhiko 
Published: November 2006

AbstractJoint action between a phosphorothiolate (PTL) fungicide, iprobenfos, and a sterol demethylation inhibitor (DMI), pefurazoate, was tested by crossed paper technique on three types of field isolates of Pyricularia oryzae Cavara that differed in PTL sensitivity and metabolism. Mutual antagonism in anti‐fungal action between iprobenfos and pefurazoate was observed in a wild‐type field isolate of the fungus sensitive to PTL and in an isolate moderately resistant to PTL, but not in a PTL‐resistant isolate lacking the ability to metabolize PTL. Antagonism of the antifungal action of iprobenfos by pefurazoate seemed to be a result of inhibition of activation by cleavage of the P‐S bond of iprobenfos mediated by mixed‐function oxygenase (mfo) activity, while antagonism of the anti‐fungal action of pefurazoate by iprobenfos may be caused by the binding of pefurazoate by large amounts of an iprobenfos‐induced mfo which results in reduced inhibition of ergosterol biosynthesis. In the PTL‐resistant isolate, the mutually antagonistic action was not observed, presumably because the induction of the mfo‐metabolizing iprobenfos was lacking. Similar antagonism was also observed when another PTL, edifenphos, was used instead of iprobenfos, and when other DMIs, propiconazole, prochloraz and hexaconazole were used instead of pefurazoate. The results of the present experiment indicate that DMIs may also bind to and inhibit an inducible type of fungal mfo which metabolizes xenobiotics, and that PTLs may be activated by an mfo prior to their anti‐fungal action.
Cross‐resistance relationships between benzimidazole fungicides and diethofencarb in Botrytis cinerea and their genetical basis in Ustilago maydis
Authors: Ziogas Basil N. , Girgis Sobhy M. 
Published: November 2006

AbstractAfter nitrosoguanidine‐ or UV‐mutagenesis, three different benzimidazole‐resistant phenotypes were isolated on media containing benomyl or a mixture of carbendazim and diethofencarb from wild‐type strains of Botrytis cinerea Pers. ex Fr. and Ustilago maydis (D.C.) Corda. Mutants of B. cinerea with moderate (MBr) or low (LBr) resistance to benzimidazoles and high resistance to diethofencarb (Dr) were isolated from the fungicide‐mixture‐containing medium in low frequency (7–1 × 10−8). Only benzimidazole‐resistant strains highly sensitive to diethofencarb (HBrDs) were identified on benomyl‐containing medium at a frequency of 6.6 × 10−6. Fitness‐determining characteristics such as sporulation, germination and germ‐tube elongation, were found to be reduced significantly in the mutants of B. cinerea that were resistant to both benzimidazoles and diethofencarb. However, pathogenicity of a MBrDr mutant strain on cucumber seedlings was equal to that of the wild type and a carbendazim + diethofencarb mixture was found to control grey mould caused by the wild type, but was not effective when the plant cotyledons were infected by the mutant strain.Three benzimidazole‐resistant phenotypes (HBrDs, HBrDr, MBrDr) were isolated easily in U. maydis from a benomyl‐containing medium. In contrast with B. cinerea, only one‐tenth of the benzimidazole‐resistant strains were sensitive to diethofencarb. Genetic analysis of benzimidazole resistance in U. maydis showed that the three benzimidazole‐resistant phenotypes were due to three allelic mutations in a single gene and one of them was responsible for the negative cross‐resistance between benzimidazoles and diethofencarb.
Chloroaniline peroxidation by soybean peroxidases
Authors: Laurent François M. G. 
Published: November 2006

Abstract4‐chloroaniline was oxidized by soya cell‐wall peroxidases in the presence of hydrogen peroxide. The main product, an orange compound with a maximal absorbance at 455 nm, was probably 4, 4′‐dichloroazobenzene. The optimum pH of the reaction was 4. Michaelis constants, determined as described by Dalziel, were 21 mM for 4‐chloroaniline and 94 μM for hydrogen peroxide. Syringaldazine was an uncompetitive inhibitor of 4‐chloroaniline peroxidation (Ki =46 μM) and modified the progress of the reaction with the appearance of a lag period. By contrast, 4‐chloroaniline was a non‐competitive inhibitor of syringaldazine peroxidation with a Ki value of 21 mMx at pH 7.5. Therefore, these two inhibiting effects were compatible with the presence of two binding sites for two different hydrogen donors. Both sites were linked by allosteric interactions. The inferences on chloroaniline binding are discussed.
Inhibition of chitinolytic enzymes from Streptomyces griseus (bacteria), Artemia salina (crustacea), and a cell line from Chironomus tentans (insecta) by allosamidin and isoallosamidin
Authors: Spindler Klaus‐Dieter , Spindler‐Barth Margarethe 
Published: November 2006

AbstractThe influence of allosamidin and its diastereoisomer isoallosamidin on chitinase activity from an insect cell line of Chironomus tentans, the crustacean Artemia salina and the bacterium Streptomyces griseus was studied. The rank order of susceptibility of chitinase activity to both inhibitors was found to be: insects »crustaceans« fungi, although isoallosamidin is about 600‐fold (insect) or 400‐fold (crustacea) less active than allosamidin and does not inhibit chitinase from Streptomyces at all. The complete and exclusive inhibition of N‐acetyl‐β‐D‐glucosaminidase by an acetylgluconolactone‐derivative and chitinase activity by allosamidin indicates that both enzymes can be determined separately in crude extracts, (containing both enzymes), with the substrates 4‐methylumbelliferyl‐N‐acetylglucosaminide or 4‐methylumbelliferyl‐chitoriose, respectively.