bluuebunny/crossref_metadata_2025_split huggingface dataset:
Validation of the AGDISP Aerial Spray Deposition Prediction Model
Authors: Duan Baozhong , Yendol William G. , Mierzejewski Karl , Reardon Richard 
Published: November 2006

AbstractExperimental evaluation of the computerized aerial spray prediction program (AGDISP) was conducted. Spray was applied over a flat site with a fixed‐wing aircraft. Spray droplets were collected on flat cards 15 cm above the ground. Aircraft parameters were recorded during the trials. Deposits were analyzed with image analysis equipment to establish droplet‐size spectra. A set of statistical parameters was applied to the measured and model‐predicted droplet deposition. The results indicate that the model can predict the average droplet density and volume deposition over seven spray runs within a factor of two of actual measurements.
Role of Cytochrome P450 in Tulip Bulb Probed by Substrate‐Binding Studies
Authors: Kelly Steven L. , Topal Aysegul , Barnett Ian , Kelly Diane E. , Hendry George A. F. 
Published: November 2006

AbstractMicrosomal fractions from dormant and wounded (sliced, aged) tulip bulbs showed a Soret peak at 448 nm in the carbon monoxide difference spectrum of dithionite‐treated membranes characteristic of cytochrome P450. Wounding and ageing induced a seven‐fold increase in P450 content. The enzyme‐substrate binding spectra and substrate affinity constants found under different conditions implied different forms of cytochrome P450. Of the several xenobiotics examined, two of them, benzo[a]pyrene and the herbicide 2,4‐dichlorophenoxyacetic acid, were inferred to be substrates from the production of P450 substrate‐binding spectra and varied substrate affinity constants were observed using the different microsomal preparations. In the wounded tissue, geraniol binding was also observed, which may reflect the endogenous function of the P450, possibly as part of a defence mechanism.
Spider webs are efficient collectors of agrochemical spray
Authors: Samu Ferenc , Matthews Graham A. , Lake Debra , Vollrath Fritz 
Published: November 2006

AbstractSpiders are important arthropod predators in natural and agricultural environments. This laboratory study aims to determine the uptake of agrochemical spray by orb webs. Orbs of Araneus diadematus were exposed under controlled conditions to sprays of variable pressure, volume, forward speed and droplet size. Using a tracer dye we determined, by photospectrometry, the amount of spray collected under different conditions which enabled us to calculate the exact volume collected by webs. The spraying treatment simulated four different field practices as well as drift to the field edge. In all cases webs were excellent collectors of spray. Regarding the pure area of the threads, they collected one order of magnitude more of the spray than paper strips did. Moreover, webs were especially efficient in collecting small droplets. We conclude that orb webs (and the spiders who ingest them) are severely exposed to agricultural sprays. Furthermore, due to the uptake of drift, even webs in hedgerows and at field margins may receive high levels of pesticides. The risk of exposing these beneficial arthropods to spray might be reduced by better control of droplet size.
The Affinity Purification of Serum Carboxylesterase from Pigeons Columba livia
Authors: Jackson John B. , Thompson Helen M. , Walker Colin H. 
Published: November 2006

AbstractPreliminary studies indicate that 3‐butylthio‐1,1,1‐trifluoropropan‐2‐one (BTFP) is a potent, competitive inhibitor of pigeon serum α‐naphthyl acetate esterase (α‐NAE); I50, 9·5 nM.The synthesis of an affinity resin with 3‐(4‐mercaptobutylthio)‐1,1,1‐trifluoropropan‐2‐one (MBTFP) as the ligand is reported; α‐NAE from serum bound strongly to this. To remove protein from the resin, washing with 3‐octylthio‐1,1,1‐trifluoropropan‐2‐one (OTFP) and subsequent boiling in aqueous sodium dodecylsulfate (SDS) were employed. Recovered protein run on SDS‐PAGE showed a single major protein band at 58–60 kDa which agrees well with previous determinations of the molecular weights of carboxylesterases.
Fate of [14C]Mancozeb in Egg Plants (Solanum melongena L.) during Summer under Sub‐tropical Conditions
Authors: Kumar Uday , Agarwal Hari C. 
Published: November 2006

AbstractThe fungicide mancozeb belongs to ethylenebis(dithiocarbamate) group of fungicides which is used to control brown and black rust, leaf spot, leaf blight, downy mildew etc. on a variety of plants including egg plants, tomato, potato and others. [14C]mancozeb, when applied to the foliage of egg plants (Solanum melongena L.) during summer months, dissipated very rapidly with a half‐life of only 10·6 days. Ethylenethiourea (ETU), ethyleneurea (EU), ethylenethiuram disulfide (ETD), ethylenethiuram monosulfide (ETM) were the metabolites of [14C]mancozeb detected in all the plant parts at different times after the treatment. The amount of ETU in fruits after fourteen days of treatment was only 206 μg kg−1 which is below the maximum permissible level and ultimately came down to 4·6 μg kg−1 after 42 days. EU was found to be the predominant metabolite, suggesting the breakdown of unstable ETU to relatively stable EU under subtropical conditions.
Mobility and persistence of isazofos in granular and microencapsulated formulations in two soils, using field lysimeters
Authors: Bowman Bruce T. 
Published: November 2006

AbstractField lysimeters were used to assess the mobility and persistence of microencapsulated and granular formulations of the soil insecticide, isazofos, in Plainfield sand, and the microencapsulated formulation in Vittoria loam soil, using two moisture regimes, rainfall and supplementary watering. Mobility and persistence comparisons were made with an earlier lysimeter study which used emulsifiable concentrate (EC) and granular formulations of isazofos in Plainfield sand. Isazofos mobility in Plainfield sand increased in the following order for the tested formulations: microencapsulated < granular ≦ EC. Atrazine, which was applied as a suspension concentrate to all lysimeters as an internal reference, appeared to exhibit retarded disappearance rates during initial stages of the study when in the presence of granular isazofos in the rainfall treatment. The degradation of isazofos was faster in Vittoria loam than in Plainfield sand for the microencapsulated formulation in the field lysimeters (only formulation tested), and for all three formulations in a laboratory study.
Measured and computed concentrations of 1,3‐dichloropropene in the air around fumigated fields
Authors: Berg Frederik Van Den 
Published: November 2006

AbstractConcentration patterns of both isomers of 1,3‐dichloropropene in air around two fields were computed with a gaussian plume model for six time intervals after injection of the fumigant into the soil and compared with concentrations measured in the air. During the first three days after the injection of 1,3‐dichloropropene into the soil of one field, the downwind concentrations of 1,3‐dichloropropene in air computed for a height of 1.5 m above the ground ranged up to 19 μg m−3, whereas the downwind concentrations measured ranged up to 29 μg m−3. For the period from five to ten days after injection, the concentrations computed and those measured ranged up to 36 μg m−3 and 16 μg m−3, respectively. For the other field, the computed downwind concentrations in air ranged up to 0.6 μg m−3 during the first three days after injection, whereas those measured ranged up to 23 μg m−3. For the period from four to nine days after injection, the concentrations computed and those measured ranged up to 2.3 and 1.3 μg m−3, respectively. The computations under‐estimated the concentrations in air during the first three days following application, but on later days the computed and measured concentrations were mostly at the same level.
Synthesis and fungicidal activities of CGA 80000 (α‐[N‐(3‐chloro‐2,6‐xylyl)‐2‐methoxyacetamido]‐ν‐butyrolactone) and of its four isomers
Authors: Eckhardt Wolfgang , Francotte Eric , Herzog Jürg , Margot Paul , Rihs Grety , Kunz Walter 
Published: November 2006

AbstractThe preparation of CGA 80000 (α‐[N‐(3‐chloro‐2,6‐xylyl)‐2‐methoxy‐acetamido]‐ν‐butyrolactone) and the separation of the four optical isomers and the diastereomeric pairs of enantiomers are described. The relationships between their absolute configurations and fungicidal activities have been examined. Biological tests have proved that one of the four isomers, with the absolute configuration (aS, 3R) is mainly responsible for the fungicidal activity of CGA 80000.
Conformational analysis of the fungicide fenpropimorph by molecular mechanics calculations and NMR spectroscopy
Authors: Jensen Jette Sandholm , Jørgensen Flemming S. , Klemmensen Per D. , Hacksel Uli , Pettersson Ingrid 
Published: November 2006

AbstractFenpropimorph is an inhibitor of Δ8→Δ7‐isomerase and Δ14‐reductase in fungi and cycloeucalenol‐obtusifoliol‐isomerase and Δ8→Δ7‐isomerase in higher plants. A detailed conformational analysis of the most potent enantiomer (S)‐fenpropimorph is described. The conformational analysis is based on three different methods: molecular mechanics calculations. NMR spectroscopy and X‐ray crystallography.In solution several conformations coexist. The molecular mechanics calculations using MM2(85) show a folded conformation of the unprotonated form of fenpropimorph to be stabilized by at least 3 kcal mol−1 relative to the next lowest energy conformer, suggesting only one conformation of fenpropimorph to be present. A corresponding stabilization of the protonated form (5.4 kcal mol−1) is obtained. However, this stabilization is found partly to be due to attractive steric interactions and may be a phenomenon occurring only in vacuum. In the solid state, fenpropimorph exists in an L‐shaped conformation resembling one of the low‐energy conformers obtained with MM2(85).Based on comparison with the natural substrate, a totally extended conformation of fenpropimorph is suggested to be the biologically active conformation for interaction with the Δ8 → Δ7‐isomerase in fungi.
Targets for pathology research in protected crops
Authors: Rattink Henk 
Published: November 2006

AbstractDue to the need to diminish the amount of pesticides used, alternative ways of controlling fungal diseases have to be developed. Foliar diseases have been managed mainly by chemicals, but research has been started to develop integrated control programmes. Data from studies on epidemiology, in combination with nutritional and climatic management and use of partial resistant cultivars will lead to a reduced use of chemicals. Models used are: Botrytis cinerea in gerbera and roses, and powdery mildew in roses and cucumbers. Research has been intensified on biological control of these pathogens. In closed systems, with recirculation of the nutrient solution, soil‐borne fungi can cause serious problems. Not only do diseases known from traditional cultural systems, like fusarium wilt of carnation, fusarium crown and root rot of tomato and Phytophthora and Pythium spp. in several crops occur, but also new problems like a new Phytophthora sp. and Gnomonia sp. in roses and a Cylindrocladium sp. in Spathiphyllum spp. To prevent introduction of pathogens in recirculation systems, emphasis is put on developing an integrated disease management programme by using disease‐free planting material, disease‐free irrigation water, strict hygienic measures, resistant cultivars, methods of disinfecting the nutrient solution and biological control. Research over the last 5–6 years has revealed good prospects for biological control, especially in closed systems with a limited amount of substrate. Wilt in carnation, caused by Fusarium oxysporum f.sp. dianthi can be prevented effectively by adding a non‐pathogenic isolate of F. oxysporum and/or Pseudomonas spp. There are indications that non‐pathogenic isolates of F. oxysporum are also effective against wilt disease in other crops. An isolate of Trichoderma harzianum appears to be very effective against fusarium crown and root rot of tomato. More applications of this, and other, biocontrol agents seem possible. However, translation of the results of research to practical application and registration is still very difficult.
Metabolism of amitrole in apple: II. Bound residues from mature fruits
Authors: Schneider Bernd , Stock Manfred , Schütte Horst R. , Schreiber Klaus , Köster Johannes , Kaußmann Ernst U. 
Published: November 2006

AbstractSignificant radioactivity detected in mature fruits, harvested from apple trees (Malus domestica Borkh., cv. ‘Golden Delicious’ and ‘Gloster’) that were soiltreated with [3,5‐14C]amitrole, remained in the insoluble plant material after exhaustive extraction. These bound residues were solubilized with a mixture of pectinases and cellulases. Thus, separation and characterization of carbohydrates and xenobiotic moieties released during this procedure became possible. A part of the radiolabel was incorporated into natural products, indicating degradation of the applied amitrole and reassimilation of [14C] carbon dioxide.
Biological activity of neem seed kernel extracts and synthetic azadirachtin against larvae of Plutella xylostella L
Authors: Verkerk Robert H. J. , Wright Denis J. 
Published: November 2006

AbstractThe activity of two neem extracts, AZT and NEEM‐AZAL (containing 30 and 3 mg azadirachtin ml−1 respectively) and synthetic azadirachtin (AZ) against second‐instar larvae (L2) of Plutella xylostella L. was examined using leafdip bioassays. On Chinese cabbage, AZ was significantly (P <0.05) less toxic (3 to 4‐fold; LC50 0.54 μg AZ ml−1) than either neem extract against a laboratory strain of P. xylostella (FS). The LC50 values for AZT against the FS and another laboratory strain (Wellcome) were not significantly different on Chinese cabbage. The activity of AZT against the FS and Wellcome strains was similar on Chinese cabbage and Brussels sprout. AZT was significantly less toxic (3‐fold) on Brussels sprout against an acylurea‐resistant field strain (Sawi) when compared with the FS strain on Chinese cabbage. Larval mortality (at day 13) was found to increase with increasing exposure time of P. xylostella (FS) larvae to AZT‐treated Chinese cabbage, although there was little difference in mortality between 48 and 120 h exposure. When AZT, NEEM‐AZAL and AZ were applied at a dose (1 μg AZ ml−1) which gave end‐point mortalities between 50 and 90% (at day 13), all treatments delayed the development of a proportion of surviving larvae but no morphogenetic abnormalities were observed in larvae which reached pupation. Evidence for antifeedant (reduced weight gain) and repellant effects (choicechamber) for AZT were observed with L2 P. xylostella (Wellcome) on Chinese cabbage. AZT was also shown to have ovicidal activity against P. xylostella (Wellcome) at relatively high dose ranges (10‐1000 μg AZ ml−1) as well as some contact activity (FS strain) in topical bioassays. In residual bioassays on glass with adults of the hymenopteran endo‐larval parasitoid of P. xylostella, Diadegma semiclausum (Ichneumonidae), AZT showed little or no activity at rates up to 1000 μg AZ ml−1. In medium‐volume (MV, 200 litre ha−1) and ultra‐low‐volume (c. 1 litre ha−1) spray bioassays on Brussels sprout, AZT gave 16‐92% and 88‐100% mortality respectively (Wellcome strain) at rates approximating to 1‐20 g AZ ha−1. The residual activity of AZT and NEEM‐AZAL against P. xylostella (FS) on Brussels sprout (MV spray) was observed to decrease appreciably after three days, the decline in activity being particularly marked for NEEM‐AZAL.
Bacterial biodegradation of ethoxylated surfactants
Authors: White Graham F. 
Published: November 2006

AbstractAgricultural, industrial and domestic use of surfactants leads to the entry of these compounds into terrestrial and aquatic ecosystems. Synthetic surfactants vary significantly in structure, but most consist of alkyl or alkylphenol groups attached to nonionic or anionic hydrophilic moieties. Continued use of these compounds is usually justified on the basis that they do not cause pollution problems because they undergo biodegradation by micro‐organisms present in soils and surface waters. In accomplishing biodegradation, micro‐organisms, predominantly bacteria, are exploiting these potentially useful resources of reduced carbon to derive energy and support growth in situations which are otherwise frequently oligotrophic. This paper reviews aspects of surfactant biodegradation, especially in relation to alcohol and alkylphenol ethoxylates used extensively as adjuvants for agrochemicals. In principle, bacteria can employ two strategies to gain access to the aliphatic chains in alcohol ethoxylate surfactants: separation of the hydrophobic chain from the hydrophile (central fission), or direct attack on the ‐terminal of the alkyl chain of the intact surfactant. Direct exo‐cleavage of ethylene glycol units from the polyethylene glycol (PEG) chain also provides a third route to assimilable carbon. In pure cultures of known degraders or in mined environmental samples, all three strategies are exploited, some even within the same organism. Central fission occurs predominantly at the alkyl‐ether bond, but may also occur within the PEG chain itself, thus producing various glycol intermediates which accumulate in pure cultures but appear only transiently in mixed environmental samples. Against this background, the relative resistance of some alkylphenol ethoxylates to biodegradation can be assessed in mechanistic terms. The steric bulk of the aryl nucleus effectively eliminates the central fission pathway. Moreover, some alkyl phenol ethoxylates contain branched alkyl chains which restrict ω‐β‐oxidation. As a result, ethoxylate shortening appears to be the major course of biodegradation observed so far. Not surprisingly, these surfactants are observed to undergo extensive primary biodegradation (removal of surfactant properties) but relatively restricted ultimate degradation to carbon dioxide and normal cell components.
Determination of imidazolidine‐2‐thione (ethylenethiourea) in ethylenebisdithiocarbamate formulations
Authors: Lo Chi‐Chu , Ho Ming‐Hsun 
Published: November 2006

AbstractZineb was most seriously contaminated with imidazolidine‐2‐thione (ethylenethiourea; ETU), followed by mancozeb, and maneb. The type of formulation also affects ETU generation and a wettable powder produced ETU more easily than a flowable formulation. The ETU contents of the ethylene‐bisdithiocarbamate (EBDC) mixed fungicides formulations were erratic. Low ETU contents were found in EBDC mixed fungicides, even though some samples had been stored in the laboratory for five years. The cupric ion and the N, O‐containing group of other fungicides might have a stabilizing effect on the degradation of EBDC to ETU. The survey indicated that EBDC mixed formulations could be a useful means of suppressing ETU generation in commercial products.
Comparative excretion of DDT analogues into milk of indian buffalo, Bubalus bubalis L. following oral administration
Authors: Kapoor Sudesh K. , Kalra Rajinder L. 
Published: November 2006

AbstractFour groups of Indian buffaloes were fed daily with 25 mg of p,p′‐DDT p,p′‐TDE p,p′‐DDE or o,p′‐DDT for 100 days. Milk was analysed for organochlorine residues during this period and also for 100 days after pesticide administration had been discontinued. For the period showing ‘plateau level’ residues, 17.2% of p,p′‐DDE, 17% of p,p′‐TDE, 14% of p,p′‐DDT as p,p′‐DDT (3.5%); p,p′‐TDE (10.5%); 3.2% of p,p′‐DDT as o,p′‐DDT (1.3%) and o,p'‐TDE (1.9%) of their administered amounts were excreted in the milk. Since these compounds were excreted at different rates, the residue levels in the milk expected from a given feed would depend on their concentration and proportional distribution in the feed. The maximum tolerable content of DDT analogues in feed was derived to be 0.1 mg kg−1 (dry weight basis) by using the maximum accumulation coefficient and incorporation of the necessary safety margin. It is concluded that Indian buffaloes fed with rations contaminated with a total of DDT analogues below this limit will yield milk of acceptable quality. Following the termination of feeding with contaminated rations, the elimination of p,p′‐DDE in the milk took the longest time and that of o,p′‐DDT the shortest. These results suggest that the time required for the initial high residue concentration to decline to less than the legal limit would be determined by the relative amounts of DDE, TDE and DDT in the milk, after elimination of the potent source of contamination.
Effect of insecticide—synergist combinations on the survival of Spodoptera exigua
Authors: Van Laecke Kristiaan , Degheele Danny 
Published: November 2006

AbstractThe chitin synthesis inhibitors diflubenzuron and teflubenzuron have recently become ineffective for the control of Spodoptera exigua in floricultural crops. An extended laboratory test with second‐instar larvae of S. exigua on Vicia faba plants was carried out to determine the influence of synergists on the biological activity of three benzoylphenyl ureas (BPUs). The co‐application of piperonyl butoxide, an oxidase inhibitor, did not increase the activity of diflubenzuron, teflubenzuron or hexaflumuron. The best results were obtained with diethyl maleate, for suppressing glutathione S‐transferase activity, and with dimethoate, as a hydrolase inhibitor. A joint application of diflubenzuron (at a concentration which resulted in 43% survival) with diethyl maleate or dimethoate gave only 6.2 and 8.9% surviving larvae, respectively. In addition, development to fourth‐instar larvae was inhibited. The more stable teflubenzuron was synergized by both compounds to a much lesser extent than diflubenzuron. None of the synergists had a significant effect on the activity of hexaflumuron, which was the most potent insecticide of the three BPUs tested against S. exigua.
Simulation of atrazine persistence in Spanish soils
Authors: Obrador Ana , Lechón Yolanda , Tadeo JoséL. 
Published: November 2006

AbstractThe persistence of atrazine was monitored in three fields at different sites in Spain during two consecutive years (1990 and 1991). Laboratory assays for determining the influence of temperature and soil moisture content on the rate of herbicide degradation were carried out on soil samples from the same fields. The degradation constants derived from these assays, together with weather records for the period of the field experiments, were used in a computer program which simulated herbicide persistence in the field. Some adjustments were made to adapt the model to Spanish conditions. The model predicted with reasonable accuracy the persistence of the herbicide in two soils, although there was a tendency to overestimate the residues at early dates. Discrepancies between predicted and measured residues were greater in the third soil, due to rapid initial losses that were not predicted by the program. In this case, the agreement was improved if the program was run taking time zero to be one month after herbicide application. Possible reasons for these discrepancies are discussed.
Purification and herbicide metabolism studies on tulip (Tulipa gesneriana) cytochrome P450
Authors: Topal Ayşegül , Adams Nancy , Dauterman Walter C. , Hodgson Ernest , Kelly Steven L. 
Published: November 2006

AbstractMicrosomal cytochrome P450 from tulip bulbs was solubilized and purified to a specific content of 12.66 nmol mg protein−1. The cytochrome P450 was present as a mixture of two cytochrome P450 polypeptides in approximately equal proportions. Their molecular masses were 52.5 kD and 54.5 kD. Similarities between these proteins included cross‐reactivity with the same antibody. Activity of the purified sample was investigated in a reconstituted enzyme system using the herbicide 2,4‐D (2,4‐dichlorophenoxyacetic acid) as a substrate. A polar product of 2,4‐D was produced which co‐migrated on several chromatography systems with 2,4‐dichlorophenol.