bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activity of optical and geometrical isomers of the juvenile hormone analogue hydroprene on endogenous juvenile hormone levels in Larval Manduca sexta
Authors: Edwards J. P. 
Published: November 2006

AbstractThe geometrical and optical isomers of the insect juvenile hormone analogue hydroprene (ethyl (2E,4E)‐3,7,11‐trimethyldodeca‐2,4‐dienoate) were tested in vivo, both for ability to depress endogenous juvenile hormone titre and as juvenile hormone agents in larval Manduca sexta. The structure‐activity relationships of these isomers were found to be similar both for feedback inhibition of juvenile hormone levels, and for juvenile hormone activity as indicated by pigmentation changes in larval cuticle. In both cases, the (7S) (2E,4E) isomer was the most active of the materials tested.
Persistence and binding of DDT and gamma‐HCH in a sandy loam soil under field conditions in Delhi, India
Authors: Samuel Thomas , Agarwal Hari C. , Pillai Madathil K. K. 
Published: November 2006

AbstractPersistence and binding capacity of [14C]p, p′‐DDT and [14C]y‐HCH were studied for one year in a sandy loam soil of Delhi, India, after surface treatment during monsoon, winter and summer seasons under field conditions. Both DDT and HCH dissipated more rapidly under the Indian subtropical climate than reported for temperate regions. In all three seasons, both insecticides dissipated most rapidly during the initial 60 days. However, in the final six months there was very little change in the residue levels. After one year, the final soil burden of DDT varied from 33 to 36% and of HCH from 14 to 15% of the initial concentrations in the different experiments. HCH bound more with the soil as, out of the total residues present after one year, more than 75% of HCH was in bound form compared with only 24% of DDT. The observed time for 50% initial dissipation of DDT ranged from 60 to 120 days, while in the case of HCH it varied from 30 to 45 days. However, the rate of loss of residues which persisted for more than 6 months was equivalent to a half‐life of between 500 and 10000 days for DDT, and between 700 and 2000 days for HCH, thus illustrating the very long persistence of aged residues. Since degradation of both insecticides was apparently minimal, the data indicate that dissipation of DDT and HCH was largely due to volatilisation.
Enantioselective transformation of the herbicides diclofop‐methyl and fenoxaprop‐ethyl in soil
Authors: Wink Ottmar , Luley Ulrike 
Published: November 2006

AbstractThe separate enantiomers of diclofop‐methyl and fenoxaprop‐ethyl were incubated with two soils under aerobic conditions. Rapid hydrolysis to the corresponding acids diclofop and fenoxaprop was observed. At various time intervals after soil treatment the parent compound and its free acid were extracted and the extracts were investigated by high‐performance liquid chromatography. The determination of the K:S‐ratio using a chiral stationary phase revealed that no racemisation of the esters took place. However, inversion of the hydrolysis products was observed. In both soils the acids with the S‐configuration showed a significantly higher inversion tendency than the acids with the R‐configuration. In one soil the S‐acids of both herbicides were inverted (50% inversion in 4–7 days) to yield, ultimately, a residue containing 70% R‐ and 30% S‐enantiomer.
Uptake of triadimenol through wheat caryopsis after application by seed treatment
Authors: Thielert Wolfgang , Steffens W. , Führ F. , Kuck K. H. , Scheinpflug H. 
Published: November 2006

AbstractThe uptake of triadimenol was investigated by offering radio‐labelled chemical exclusively through the caryopsis in a special experimental design with single seed grains in plexiglass holders. In totally‐treated caryopses about 5% and, in partially‐treated caryopses (embryo untreated), 4.5% of the applied radioactivity reached the winter wheat shoots after 21 days up to the third leaf stage. Uptake of active ingredient through the pathway pericarp‐testa‐endosperm‐scutellum‐seedling up to the third leaf stage D(13) was therefore confirmed. Furthermore, [14C] triadimenol was also translocated through the caryopses into the roots and was released to the nutrient solution.
Factors influencing entry of pesticides into soil water
Authors: Nicholls Peter H. 
Published: November 2006

AbstractLeaching of pesticides and hence the risk of contamination of ground‐water depends on the physicochemical properties of the pesticide, the properties of the soil and the weather. Lipophilicity is the most important physicochemical property influencing the movement of un‐ionised pesticides through soil. Water solubility is usually only an important factor in leaching for a few moderately polar solids with high melting points. Organic matter content is the most important property of the soil for un‐ionised pesticides whilst the mobility of weak acids depends on soil pH. Permanent anions and weak acids can be very weakly adsorbed and hence might easily reach groundwater. Applications in autumn are more likely to reach groundwater than those in spring because soil temperatures are low and rainfall exceeds evaporation in winter, enabling mobile pesticides to penetrate to subsoils where degradation rates can be very slow. Concentrations of pesticide in water entering subsoils cannot be reliably simulated to an accuracy of better than an order of magnitude because the complex patterns of water flow and the slow diffusion processes of the pesticide are insufficiently understood. The consequences of applying a mobile pesticide to soil where drainage is impeded or where the water table is near the surface need to be anticipated before it is registered for treatment of the soil.
Uptake and utilisation of phosphonate ions by Phytophthora citrophthora and Nectria haematococca in relation to their selective toxicity
Authors: Barchietto Thierry , Saindrenan Patrick , Bompeix Gilbert 
Published: November 2006

AbstractPhosphonate ions, which are degradation products of aluminium tris‐O‐ethyl phosphonate (fosetyl‐aluminium) in plant tissues, had more effect in vitro against Phytophthora citrophthora than against Nectria haematococca.Both fungi were able to take up phosphonate ions. This uptake was realised against a concentration gradient and was affected by metabolic inhibitors. When examined over a 0.5 to 6.0 mm concentration range, phosphonate was carried by a single transport process obeying Michaelis‐Menten kinetics, with a low affinity (high K′m). Further analysis by means of Hofstee plots indicated a somewhat faster phosphonate uptake by N. haematococca than by P. citrophthora, so it appears clearly that uptake was not involved in the selective toxicity of this compound.The continuous uptake of phosphonate by N. haematococca is correlated with an important utilisation of this ion by the fungal cells. This fact could be explained by a detoxification process corresponding to the oxidation of phosphonate to phosphate which could account for the low sensitivity of this fungus.Phosphonate uptake by P. citrophthora reached a maximum level after 20 min and then decreased to a constant level over the following period. During the incubation period phosphonate was incorporated directly without oxidation into phosphate. This incorporation could lead to a disturbance of the cell metabolism.
Fungicide seed treatments to improve seedling emergence of perennial ryegrass Lolium perenne and the effect of different cultivars and soils
Authors: Lewis Graham C. 
Published: November 2006

AbstractSeeds of perennial ryegrass Lolium perenne treated with four fungicides, benomyl, captan, iprodione and metalaxyl, used singly and in all combinations were sown in soil in pots. The soil was maintained at a low moisture content to predispose the seedlings to pre‐emergence infection by soil‐borne fungi. Thirteen of the fifteen fungicide treatments significantly increased seedling emergence and all but one contained benomyl and/or captan. In another pot experiment, a combination of benomyl and captan was tested against four similar treatments, carbendazim+captan, thiabendazole+captan, thiabendazole+metalaxyl and thiabendazole+thiram and also drazoxolon. Only benomyl+captan and drazoxolon did not increase seedling emergence significantly. A natural infection of the seedlings by powdery mildew Erysiphe graminis was reduced significantly by all treatments except thiabendazole+thiram and drazoxolon. Only car‐bendazim+captan significantly increased the dry weight of seedlings per pot 98 days after sowing. Benomyl+captan seed treatment significantly increased seedling emergence in 9 of 16 soils collected from widespread sites. One perennial ryegrass cultivar, Parcour, was used in the above experiments and in a comparison with 12 other diploid cultivars its response to benomyl seed treatment was about mid‐range.
N‐benzoyl‐N′‐phenoxyphenyl‐ and N‐benzoyl‐N′‐carboxyphenyl ureas: A review of their chemical synthesis and biological profiles
Authors: Hofmeister P. , Künast C. , Lange A. 
Published: November 2006

AbstractSome highly active and broad‐spectrum representatives of the phenoxyphenyl‐ and carboxyphenyl urea groups of compounds are described. The products are relatively easily accessible, simple and economical to produce in high yield. Excellent biological activity has been detected using S. littoralis and a broad‐spectrum activity has been found on Lepidoptera, Diptera, Coleoptera and Hemiptera.Using two examples of phenoxyphenyl acylureas the high level of selectivity to certain larval stages has been shown in various noctuids. By altering the ester function to an ether group some indications of systemic activity could be achieved.Disturbances caused in cuticle formation have been investigated in ultrastructural studies of regenerating cockroach legs.
Iodometric calibration of organophosphorus insecticides and measurement of hydrolysis products
Authors: Desmarchelier James M. 
Published: November 2006

AbstractDialkylphosphoro‐thioic and ‐dithioic acids, hydrolysis products of most organophosphorus insecticides, react stoichiometrically with iodoacetic acid, under controlled conditions, to release iodide. At room temperature, dialkylphosphorodithioic acids react with iodoacetic acid at pH 7–9, and dialkylphosphoro‐thioic and ‐dithioic acids react with iodoacetic acid at pH 2 and below. This last reaction may be used for the determination of breakdown products in the presence of insecticides, such as fenitrothion, that are sufficiently stable to acid hydrolysis. The methods are suitable for measuring both active ingredients and hydrolysis products in formulations and in waterdiluted sprays.
Sterol metabolism in wheat treated by N‐substituted morpholines
Authors: Costet‐Corio Marie‐France , Benveniste Pierre 
Published: November 2006

AbstractWheat caryopses were treated with racemic fenpropimorph. As shown previously in other plant species, 9(β,19‐cyclopropyl sterols were found to accumulate markedly. A distinctive feature was a remarkable accumulation of 31 ‐norcyclobranol, a very rare sterol in nature. A8‐sterols were also identified. The ratio A8‐sterols: cyclopropyl sterols was shown to depend greatly on the configuration of the methyl substituent in position 2 of fenpropimorph. Whereas cyclopropyl sterols predominated in the case of seedlings treated with the (2S)‐2‐methyl enantiomer, A8‐sterols were shown to be very abundant in plants treated with the (2R)‐2‐methyl enantiomer. A8‐sterols were shown also to be more abundant in leaves than in roots. Experiments were conducted to find out whether the phytotoxic response of plants to fenpropimorph could be ascribed to its action on sterol biosynthesis. From the results obtained it appears that this is not the case and thus the phytotoxic effect is probably related to a cellular target other than sterol biosynthesis.
Partial purification and properties of an esterase from tomato cell suspension cultures hydrolysing the pyrethroid insecticide cyfluthrin
Authors: Preiss Ursula , Wallnöfer Peter R. , Engelhardt Gabriele 
Published: November 2006

AbstractAn esterase which hydrolyses the pyrethroid insecticide cyfluthrin, was isolated from tomato cell suspension cultures and purified 10‐fold. The apparent molecular weight of the enzyme was estimated to be 32 000 Dalton, the pH‐optimum 8‐0, and the temperature optimum 35°C. The esterase showed a low substrate specificity and hydrolysed certain esters, e. g. ethyl 4‐nitrobenzoate, p‐nitrophenyl acetate and dinoseb acetate, whereas ethyl butyrate and the organophosphates demeton‐S‐methyl sulfoxide and paraoxon could not be hydrolysed. Because of the additional strong inhibition of the enzyme by these organophosphates the cyfluthrin hydrolase is suggested to belong to the B‐esterase type. An apparent Km‐value of 6‐25 × 10−4 mol litre−1 was obtained for p‐nitrophenyl acetate as substrate.
Mechanism of cellular absorption of imidazolinones in soybean (Glycine max) leaf discs
Authors: van Ellis Mary Reider , Shaner Dale L. 
Published: November 2006

AbstractThe mechanism of uptake of imazapyr, imazethapyr, and imazaquin into soybean leaf discs was determined. Uptake into the leaf discs was linear with respect to external concentration from 10−8 to 10−3 M. Metabolic inhibitors and uncouplers (DNP, FCCP, CCCP, NaN3, NaCN, DCMU) decreased uptake 58 to 85 %. Uptake was also sensitive to temperature, with maximum uptake occurring at 23°C. The Q10 for uptake between 13 and 23°C was 1‐7. The uptake of all 3 imidazolinones was sensitive to the pH of the uptake solution. Maximum uptake occurred at pH 4. However, there were differences in the rate of uptake among the three herbicides. Imazaquin was absorbed the most rapidly followed by imazethapyr and then imazapyr. These differences in uptake reflected the differences in the lipophilicity of the chemicals at pH 4 and 7. The apparent Kow of imazaquin, imazethapyr and imazapyr at pH 4 was 7‐7, 1‐4, and 0‐1, respectively, and at pH 7 was 0‐04, 0‐02, and 0‐004, respectively. Based on these results the mechanism of uptake is probably best explained by ion trapping.
Methyl bromide residues in fresh cherries: Effects of parameters of fumigation
Authors: Sell Charles R. , Klag Narcy G. , Burditt Arthur K. 
Published: November 2006

AbstractDeterminations were made of the desorption rate of residual free methyl bromide from fresh sweet cherries during the aeration period that followed fumigation with methyl bromide. The results showed that the desorption followed approximately pseudo‐first‐order kinetics. Ventilation rates during aeration, which were greater than or equal to the rates used at commercial fumigation chambers, had no effect on desorption rate. The concentration and persistence of residue was dependent on two parameters of the fumigation: the load factor, which is the ratio of the volume of cherries to the volume of the fumigation chamber, and the pulp temperature of the cherries. The relationship between load factor, pulp temperature and desorption rate was used to derive a mathematical model of the desorption of methyl bromide from cherries. The model gave good estimates of residue concentrations over a wide range of load factors, pulp temperatures and aeration periods, and was used to predict the length of the aeration period required to reduce the residue to a proposed tolerance of 0‐1 mg kg−1.
The herbicidal activity of 3‐substituted 1‐phenylureas
Authors: Barnes Keith F. , Browning Ian R. , Clark Nigel G. , Clark Ronald J. 
Published: November 2006

AbstractA variety of 1‐phenylureas, substituted in the 3‐position with one acyl, alkoxycarbonyl or cyano group, and optionally with a lower alkyl group, have been synthesised and assessed for pre‐ and post‐emergence herbicidal activity against a range of monocotyledonous and dicotyledonous weed species. Generally, activity was associated only with compounds containing two small substituents in the 3‐position. Their possible metabolic fate is discussed in the light of comparisons with the activity of the commercial herbicides, fenuron, monuron and diuron, and their de‐methylated derivatives.
The herbicidal activity of 1‐substituted 1‐phenylureas
Authors: Barnes Keith F. , Browning Ian R. , Clark Nigel G. 
Published: November 2006

AbstractA selection of 1, 1‐dialkyl‐3‐phenylureas, additionally substituted in the 3‐position by methanesulphonyl, cyano, alkoxycarbonyl or methyl, have been synthesised and assessed for pre‐ and post‐emergence herbicidal activity against a variety of monocotyledonous and dicotyledonous weed species. The range of activities is compared with those of the structurally‐related commercial herbicides, fenuron, monuron and diuron, into which the novel compounds could be metabolised (‘lethal synthesis’).
Management of resistance in horticultural pests and beneficial species in New Zealand
Authors: Suckling David M. , Walker Jim T. S. , Shaw Peter W. , Markwick Ngaire P. , Wearing C. Howard 
Published: November 2006

AbstractTwo related insecticide resistance management programmes are under way in New Zealand horticulture. The first aims to limit the spread and impact of azinphos‐methyl resistant lightbrown apple moth (LBAM) in an applegrowing district. In the second, the introduction of pyrethroid (SP) resistance in organophosphate‐resistant (OP) Typhlodromus pyri makes it possible to undertake biological control of the European red mite that is compatible with SP and OP control of orchard pests.In the LBAM programme the resistant zone, which includes alternative host‐plant reservoirs, has been delineated by detailed resistance monitoring with topical application of males caught using female sex pheromone. In that zone, chlorpyrifos, to which the azinphos‐methyl resistant LBAM has low cross‐resistance, is used in the short term to control resistant moths, while alternative measures (e. g. other insecticides and mating disruption) are investigated. Recognition of the importance of immigration from alternative host plant reservoirs has led to specific tactics such as the application of pyrethroids to non‐crop areas. This resulted in a significant decrease of the resistant population. So far, however, SPs have not been registered in apple orchards because they kill OP‐resistant predatory mites which control the European red mite, and also because of the lack of residue tolerances for SPs in some overseas markets.Following the assessment of the potential value of pyrethroids in pipfruit, DSIR started field selection for pyrethroid resistance in predatory mites, which was later expanded to include laboratory selection. The successful development of pyrethroid‐resistant predators which retain organophosphate resistance is permitting the introduction of biological control of European red mite compatible with the use of these two classes of insecticides for control of other pests.In future, the lepidopterous pests on New Zealand apples may be controlled by pyrethroids, scales and other minor pests by organophosphates, and European red mite by multi‐resistant predatory mites.
Insecticide resistance in Heliothis armigera in Australia
Authors: Daly Joanne C. 
Published: November 2006

AbstractA voluntary insecticide resistance management strategy for the control of H. armigera was implemented in Australia in 1983 after an outbreak of resistance to synthetic pyrethroids. This strategy restricts the use of pyrethroids to three sprays within a 42‐day period in summer. The use of endosulfan is also restricted and rotation of other pesticides is encouraged. The effectiveness of the strategy is monitored by tests on larvae collected from two major cotton areas and from unsprayed crops in northern New South Wales. Research is under way to determine the genetic basis of two of the three mechanisms involved in resistance. One genetic component is associated with the mixed‐function oxidases. Selection in the field for this semi‐dominant gene (or genes) occurs in larvae 4 days or more old. It is not possible to evaluate directly the success of this strategy because there is no control area where it has not been implemented. While the long‐term outcome of the strategy is uncertain, it is likely that resistance will increase in frequency.
Problems of control of insecticide‐resistantPlutella xylostella
Authors: Cheng E. Y. 
Published: November 2006

AbstractIn the different regions of SE Asia, resistance problems in the diamondback moth (DBM), Plutella xylostella, are comparable, and depend on the type of insecticide used to control this pest. Resistance is especially high to insecticides metabolised by mfos (multifunctional oxidases), but since the detoxification of each such insecticide depends on different mfo(s), there is little cross‐resistance between insecticides. Thus, carbaryl, carbofuran and the synthetic pyrethroids, all detoxified by mfos, show little cross‐resistance. Resistance to cartap and some organophosphorus insecticides is much lower, and is often unstable. Those compounds are therefore essential in the rational control of DBM. The cross‐resistance relationships within the traditional insecticides have mostly been worked out. It is thus possible to use alternate spraying schedules with insecticides conferring minimum cross‐resistance potential. Alternating insecticides is better than using mixtures, because DBM can develop multiple resistance through treatment with mixtures.DBM has now developed resistance to the newly‐introduced IGRs and other experimental control agents. Possible resistance to these as well as to future DBM control agents has been examined, and their resistance‐inducing ability and cross‐resistance characteristics examined. Experience in monitoring the spectrum together with the strength of resistance of field populations of DBM suggest that control can only be achieved by wellplanned rational chemical control programs.
Present status and countermeasures of insecticide resistance in agricultural pests in China
Authors: Tang Z. H. , Gong K. Y. , You Z. P. 
Published: November 2006

AbstractOf the 23 species of agricultural pest known to resist insecticides in China, 4 are cotton pests, 4 rice pests and 5 are pests of brassicae. In the green rice leafhopper, malathion resistance is caused by increased carboxylesterase (CarE) activity, which plays a more important role in the resistance to dimethoate than the mixed‐function oxidases (mfos). The in‐vitro and in‐vivo results are in agreement with studies of synergism of malathion and dimethoate by TPP and EBP. These synergists delay the development of resistance, and EBP when added to malathion has limited the development of resistance to malathion in the green rice leafhopper. In the cotton aphid, resistance to organophosphates involves several factors: acetylcholinesterase (AChE) insensitivity, high CarE activity, slight (× 2) increase in glutathione S‐transferases (GSH‐ases), mfo activity as well as reduced penetration. In vitro, the I50 of the insensitive AChE is × 14 that of S aphids, and anaphthyl‐acetate CarE hydrolysing activity is 70 times greater in R than in S aphids. Insecticide mixtures, alternation or rotation can delay build‐up of resistance; resistance to malathion and trichlorfon was delayed in Culex pipiens pallens when the two insecticides were used together. Used singly each insecticide selected for high resistance within 25 generations. Mosaic rotation of dimethoate and fenvalerate delayed the onset of insecticide resistance in Lipaphis erysimi pseudobrassicae.