bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modelling the microbial breakdown of pesticides in soil using a parameter estimation technique
Authors: Vink Jos P. M. , Nörtersheuser Peter , Richter Otto , Diekkrüger Bernd , Groen Klaas P. 
Published: November 2006

AbstractResults of field measurements and laboratory experiments were used to simulate the behaviour of 1,3‐dichloropropene (1,3‐D) in a loamy sand soil. Microbial activity was described using pre‐set conditions to compute transformation rates as dependent on compound concentrations and temperature. These kinetics could only be analysed using non‐linear transformation rates. To link the development of microbial populations and the consumption of the compound over time, an iterative technique was used to estimate the necessary parameters.
The induction and characterisation of isolates of Pseudocercosporella herpotrichoides with altered sensitivity to the fungicide prochloraz
Authors: Julian Angela M. , Hardy Josephine E. , Lucas John A. 
Published: November 2006

AbstractIsolates of Pseudocercosporella herpotrichoides (Fron.) Deighton, causal agent of eyespot disease of cereals, with reduced sensitivity to the imidazole fungicide prochloraz were produced by spontaneous selection on fungicide‐amended media or by successive rounds of ultra‐violet (U V) irradiation of conidia. Resistance frequencies were similar to those obtained for other sterol‐biosynthesis‐inhibiting (SBI) compounds. Stability testing indicated that a large proportion of the UV‐induced mutants reverted rapidly to wild‐type sensitivity levels. However, the spontaneously selected strains, and strains produced after the third round of mutation proved more stable. Strains produced by spontaneous selection and from a single round of UV irradiation showed relatively low levels of resistance, in most cases within the range shown by the European field population. Subsequent rounds of UV irradiation raised resistance levels by factors of between 5 and 16 times. Growth rate in culture and sporulation ability were impaired in some, but not all. strains. Spontaneous mutants showed no decrease in pathogenicity to cereal hosts while UV‐induced strains were more variable, with some giving significantly reduced infection scores. The spontaneous mutants, and some of the UV‐induced strains, gave higher infection scores on plants treated with prochloraz than on untreated plants. This may have been due to changes in the stem base microflora resulting in reduced competition. The findings from this study suggest a multi‐factorial basis for resistance, resulting in directional rather than disruptive selection for field resistance.
Insecticidal properties of monoterpenoid derivatives to the house fly (diptera: Muscidae) and red flour beetle (coleoptera: Tenebrionidae)
Authors: Rice Pamela J. , Coats Joel R. 
Published: November 2006

AbstractMonoterpenoid derivatives were synthesized and their insecticidal activities were evaluated against red flour beetles, Tribolium castaneum (Herbst), in fumigant bioassays and against house flies Musca domestica (L.) in topical, fumigant, and ovicidal bioassays. Acetate derivatives and haloacetate derivatives were compared with each other, and with the parent monoterpenoid to determine structure‐activity relationships. Acetate derivatives were more active than the propionate derivatives of cyclic monoterpenoids in the topical, fumigant, and ovicidal bioassays. Pivalates were topically more insecticidal than acetates to adult house flies, while the acetates had the greater ovicidal activity. Acetates and pivalates were more effective than haloacetates in the topical, red flour beetle fumigation and ovicidal bioassays. Fluoroacetates of cyclic monoterpenoids were the most effective house fly fumigants, followed by acetates, and trichloroacetates. Several derivatives were produced that displayed enhanced activity relative to the parent alcohols or phenols.
The transmission of geminiviruses by Bemisia tabaci
Authors: Markham Peter G. , Bedford Ian D. , Liu Sijun , Pinner Marion S. 
Published: November 2006

AbstractThe cosmopolitan whitefly species, Bemisia tabaci (Gennadius) and Trialeurodes taporariorum (Westwood) have always been regarded as pests to a large range of worldwide crops. Both species are capable of transmitting plant viruses, with T. vaporariorum being the vector of only a few ‘clostero’‐like viruses and B. tabaci the vector of viruses in several groups. The largest group of viruses transmitted by B. tabaci are the geminiviruses and B. tabaci is known to transmit around 60 members.Until recently, B. tabaci had been associated with only a limited range of host plants within any one region, although its total potential host range was large. Virus transmission was confined within the plant host range of each regional population of B. tabaci. The emergence of the polyphagous ‘B’ biotype of B. tabaci with its increased host range of more than 600 plant species, has resulted in geminiviruses infecting previously unaffected crops. As the ‘B’ biotype spreads further into Europe, European field and glasshouse crops have been shown to be susceptible to whitefly‐transmitted viruses already endemic to other parts of the world.More than 20 colonies of B. tabaci, including both ‘B’ and non‐‘B’ biotypes from disparate global locations have been compared for their ability to transmit more than 20 geminiviruses. All but two highly host‐specific colonies were capable of transmitting most geminiviruses tested. However, some viruses were transmitted more efficiently than others. The virus coat protein or capsid is essential for vector recognition and transmission. By comparing transmissible viruses at the molecular level to viruses that are no longer whitefly‐transmissible, the active epitope on the virus coat protein could be identified for designing future virus control strategies.
Studies on the effect of different cyclohexane‐1,3‐diones on de‐novo fatty acid biosynthesis in poaceae
Authors: Maier Anja , Golz Andrea , Lichtenthaler Hartmut K. , Meyer Norbert , Retzlaff Günter 
Published: November 2006

AbstractCyclohexane‐1,3‐diones such as the herbicides cycloxydim, sethoxydim, alloxydim and clethodim are known to be specific inhibitors of the plastid‐located acetyl‐CoA carboxylase (ACCase) in Poaceae, a key enzyme of de‐novo fatty acid biosynthesis in higher plants. Using several new cyclohexane‐1,3‐dione derivatives and known herbicides, the relationships between chemical structure and enzyme inhibition have been studied. The basic cyclohexane‐1,3‐dione structure was modified at three different positions. These compounds were tested for inhibition of the de novo fatty‐acid biosynthesis in test systems of etioplasts isolated from Avena sativa L. and Hordeum vulgare L. seedlings and also for inhibition of the isolated barley ACCase. The I50 values of these cyclohexane‐1,3‐diones were determined. The influence of the modification of alkyl chains (length and type of substituent) on the degree of ACCase‐inhibition is discussed. Several new compounds were found that were about two orders more active than the known herbicides cycloxydim or sethoxydim in the etioplast and ACCase test systems but not necessarily on the level of whole plants.
The impact of resistance on the use of second‐generation anticoagulants against rats on farms in Southern England
Authors: Cowan David , Dunsford Gary , Gill Erica , Jones Ainsley , Kerins Gerard , Macnicoll Alan , Quy Roger 
Published: November 2006

AbstractResistance amongst rats to second‐generation anticoagulants, notably difenacoum, has been recognised since the 1970s. Although initially considered to be of practical significance, doubts were subsequently expressed that the degree of resistance was sufficient to explain ineffective rodenticide treatments. Research published elsewhere demonstrated the overriding importance of poor poisoned bait consumption, caused by the influence of certain ecological factors on rat behaviour, in reducing the effectiveness of second‐generation anticoagulant treatments on farms in southern England. In this paper we consider, however, the subtle effects of resistance to anticoagulants on treatment outcome. The prevalence of resistance was increased amongst survivors of treatments and bait consumption by resistant survivors was higher than amongst susceptible survivors. The overall prevalence and degree of resistance to second‐generation anticoagulants does not, however, currently represent a practical problem. Nevertheless, selection favouring increased resistance remains a long‐term threat to the effectiveness of both difenacoum and bromadiolone.
Inheritance of resistance to a Bacillus thuringiensis toxin in a field population of diamondback moth (Plutella xylostella)
Authors: Martínez‐Ramírez Amparo C. , Escriche Baltasar , Real M. Dolores , Silva Francisco J. , Ferré Juan 
Published: November 2006

AbstractInheritance of resistance to the Bacillus thuringiensis Berl. CryIA(b) crystal protein was studied in Plutella xylostella L. (diamondback moth). A field population 50‐fold more resistant to CryIA(b) than a control susceptible strain was used. Dose‐mortality curves of the resistant population, the susceptible strain and the F1 from the two reciprocal crosses were compared. Resistance transmission to the F1 was dependent on the sex of the resistant progenitor. Sex ratio of the survivors to high doses of CryIA(b) in the F1 of the two reciprocal crosses did not corroborate the preliminary hypothesis of resistance being due to a recessive sex‐linked allele. Since, in a previous work, the loss of CryIA(b) binding capacity of resistant insects had been demonstrated, binding to midgut tissue sections from F1 individuals was also analysed. The presence of binding in all of the F1 preparations showed that, at least, a recessive autosomal allele was responsible for the loss of binding capacity in the resistant population.
Characterization of new photosynthesis‐inhibiting imidazolidine derivatives. 1. Interpretation of post‐emergence herbicidal performance from photosynthesis‐inhibiting activity and systemicity
Authors: Yanase Daisuke , Chiba Misako , Andoh Akihide , Gotoh Takeshi 
Published: November 2006

AbstractAn attempt was made to account for quantitatively measured herbicidal performance of foliage‐applied 5‐hydroxy‐3‐methyl‐2–oxo‐imidazolidine‐1‐carboxamide derivatives by their photosynthesis‐inhibiting activity and systemicity. Photosynthesis‐inhibiting activity was estimated from the increase of chlorophyll fluorescence intensity in Chlorella vulgaris Beijer cells measured by a microplate scanner, and systemicity was also evaluated by computer‐aided chlorophyll fluorescence imaging. The highest herbicidal performance was recorded for N‐cyclohexyl‐5‐hydroxy‐3‐methyl‐2‐oxo‐imidazo∼idine‐l‐carboxamide, a compound with the second strongest photosynthesis‐inhibiting activity and intermediate systemicity. Though neither photosynthesis‐inhibiting activity nor systemicity showed significant correlation with the actual herbicidal performance in simple regression analyses, a high predictability was found for a multiple regression on both parameters as two independent variables, suggesting that these two factors work cooperatively in the field performance.
Age‐related mechanisms of propanil tolerance in Jungle‐rice, Echinochloa colona
Authors: Leah Jon M. , Caseley John C. , Riches Charles R. , Valverde Bernal 
Published: November 2006

AbstractUptake and metabolism of propanil were measured in both susceptible (S) and resistant (R) biotypes of Jungle‐rice, Echinochloa colona (L.) link at different growth stages. Results showed that there was no significant difference in uptake between S and R biotypes of E. colona at any given growth stage, but that uptake was significantly reduced at older plant growth stages in all biotypes studied. Metabolism of propanil was more rapid in R biotypes than in S biotypes at all growth stages studied. Specific and total aryl acylamidase activity, responsible for the first stage of propanil metabolism, was higher in R biotypes than in S at all growth stages, but declined to about 50% of the maximum at older growth stages, confirming the importance of this enzyme in conferring resistance to this herbicide. The area of necrosis that developed around a single drop of propanil deposited on the adaxial leaf surface was used to assess the degree of propanil resistance; it was found that resistance increased at older E. colona growth stages in contrast to the rate of propanil metabolism and amidase activity. Treatment of leaves with the amidase inhibitors, carbaryl or piperophos, simultaneously with propanil, caused a decrease in resistance at growth stages where amidase activity was greatest. This treatment was less effective at older growth stages. These results show that, in E. colona, propanil metabolism is important for conferring resistance in younger plants (four‐six‐leaf stage). It is suggested that restricted uptake confers resistance in older plants.
Synthesis and herbicidal activity of isoxazoledicarboxylic acid derivatives
Authors: Münster Peter , Freund Wolfgang , Maywald Volker , Kükenhöhner Thomas , Gerber Matthias , Grossmann Klaus , Walter Helmut 
Published: November 2006

AbstractStarting from bulk chemicals, novel isoxazoledicarboxylic acid esters were prepared and converted to the corresponding dicarboxylic acid mono‐amides in a few reaction steps and in high overall yields. Key intermediates for the cycloaddition step were chlorooximinoacetates or amides as nitrile oxide equivalents, prepared in one‐pot reactions from diketene or acetoacetic acid esters. Isoxazoledicarboxylic acid monoamides combined good herbicidal activity with chemical flexibility. They were characterized as inhibitors of photosynthesis. Particularly, they affected the photosynthetic electron transport in photosystem II and the rate of carbon dioxide assimilation. Applied post‐emergence, the new compounds were found to control a broad spectrum of key weeds in corn. Excellent activity was found on Abutilon theophrasti (L.) Medik., Amaranthus retroflexus L., Chenopodium album L., Ipomoea spp., Polygonum persicaria L., Solanum nigrum L. and Xanthium strumarium L. with rates between 0.2 and 0.5 kg ha−1. As a side‐effect, the compounds also showed activity against grass weeds. The compounds are excellent tank‐mix partners, e.g. for sulfonyl‐ureas, to complete the weed spectrum (Chenopodium album L., Solanum nigrum L.) and/or to reduce the risk of developing herbicide‐resistant weeds.
Behaviour modifying effects of low systemic concentrations of imidacloprid on Myzus persicae with special reference to an antifeeding response
Authors: Nauen Ralf 
Published: November 2006

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 of Myzus 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 of M. persicae by 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 of M. persicae over 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 that M. persicae on 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 on M. 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 concentrations.
Analysis, sorption and residues of a homologous series of isothiocyanates on wheat
Authors: Shaaya Eli , Desmarchelier James M. 
Published: November 2006

AbstractA series of isothiocyanates (R‐NCS, R, 1–6 carbon atoms) was applied in the vapour phase to wheat in sealed containers. The speed of sorption, as measured by the rate of loss from the intergranular air space, was inversely proportional to molecular weight; e.g. the time for 50% sorption of hexyl isothiocyanate was over 100 times longer than for the methyl analogue. Despite extensive sorption, most of the applied chemicals was recovered from the fumigated wheat seven days after dosing, indicating that sorption did not lead to extensive degradation. Purge and trap techniques proved suitable for recovery of low‐boiling, but not high‐boiling chemicals.
The pyrethrins and related compounds part XL— structure‐activity relationships of pyrethroidal esters with acyclic side chains in the alcohol component against resistant strains of housefly (Musca domestica)
Authors: Farnham Andrew W. , Khambay Bhupinder P. S. 
Published: November 2006

AbstractActivities of a range of pyrethroidal esters, incorporating structural variations in all regions of the acid and alcohol components, have been measured against two fully characterised and homozygous resistant strains of Musca domestica (kdr and super‐kdr). The results, limited in this paper to esters of alcohols with acyclic side chains, show the same level of uniform resistance as the kdr strain observed previously, across a range of acid and alcohol variations. Against the super‐kdr strain, in contrast to the cyclic side chain set, resistance factors are barely higher than for the kdr strain. Against super‐kdr flies, some dependence of resistance factor on the position of the side chain substituent was detected. Polyfluorobenzyl esters confer particularly low resistance factors.
Guanidinium and amidinium fungicides: A new class of carbocation mimetic ergosterol biosynthesis inhibitors
Authors: Arnold Mary L. , Duriatti Albert D. , Jung Michel , Katz Ruth B. , Liebeschuetz John W. 
Published: November 2006

AbstractA novel class of chemical has been designed with the aim of inhibiting the Δ14‐reductase and Δ8‐Δ7‐isomerase enzymes in the ergosterol biosynthesis pathway in fungi. Use was made of knowledge about the mechanisms of both enzymes and the mode of action of known, fungicidal inhibitors of these enzymes. Pioneer examples have been synthesised and have been demonstrated to be potent inhibitors of ergosterol biosynthesis in Ustilago maydis (DC) Corda, acting in the same manner as the commercial fungicide fenpropimorph. They also showed excellent fungicidal activity against Erysiphe graminis DC f. sp. hordei Marchal (powdery mildew of barley) and Puccinia recondita Rob. ex Desm. (wheat leaf rust) in in‐vivo glasshouse tests. Using these compounds as a starting point, systematic structural variation has been carried out. Testing of a wide range of analogues at high volume confirms the potential of this class of compound to control mildew and rust pathogens at levels comparable to those of the standards. Correlation of in‐vivo and enzymatic data is good and the structure‐activity relationship developed for this series of compounds closely parallels that found for the morpholine/piperidine class of fungicides, suggesting a common mode of action.
Metabolites of some biological control agents
Authors: Dickinson Julia M. , Hanson James R. , Truneh Almaz 
Published: November 2006

AbstractThe evidence is reviewed for the structure and biosynthesis of some metabolites of Trichoderma and Gliocladium species that are being considered as fungal biological control agents. The diverse biosynthetic capability of these organisms is proposed as a criterion for their potential application as bio‐control agents.
Mode of action of the anilino‐pyrimidine fungicide pyrimethanil. 1. In‐vivo activity against Botrytis fabae on broad bean (Vicia faba) leaves
Authors: Daniels Alison , Lucas John A. 
Published: November 2006

AbstractThe effect of timed protectant applications of pyrimethanil on the natural infection process of isolates of Botrytis fabae Sardina on broad bean leaves was investigated using a range of light and electron microscopic techniques. At 400 mg litre−1, there was some inhibition of spore germination, and a significant reduction in germ tube extension. These responses were variable between isolates, treatment times and dose rates. Appressorium formation and function (i.e. penetration of the host epidermis) were not affected. However, there was a significant reduction in the numbers of host cells killed at each penetration site, resulting in retarded, or, with some isolates, arrested lesion development. This response was similar for all isolates tested. The likely mode of action of pyrimethanil as a pathogenesis inhibitor is discussed.
How can a statistician improve your interpretation?
Authors: Fenlon J. S. 
Published: November 2006

AbstractFour examples are given of how discussion between scientist and statistician enhanced both the analysis and interpretation of experimental data. They cover both the design and analysis of field experiments, and some of the problems associated with interpreting data from dose‐response assays. There is little doubt that the statistician, with his array of analytical and diagnostic tools, can often improve a scientist's interpretation of experimental data, although a statistician cannot compensate for a poorly designed or inadequately replicated experiment.
Photolysis of bromoxynil (3,5‐dibromo‐4‐hydroxybenzonitrile) in aqueous solution
Authors: Machado F. , Collin L. , Boule P. 
Published: November 2006

AbstractThe formation of 3‐bromo‐4,5‐dihydroxybenzonitrile accounts for about 65% of the photochemical conversion of the title product in aqueous solution, in contrast to 3‐bromo‐4‐hydroxybenzonitrile and 4‐hydroxybenzonitrile previously reported.