bluuebunny/crossref_metadata_2025_split huggingface dataset:
Absorption, translocation, and metabolism of ethalfluralin and trifluralin in Solanum spp
Authors: Vandeventer John W. , Meggitt William F. , Penner Donald 
Published: November 2006

AbstractSeedlings of Solanum scabrum Mill. and Solanum ptycanthum Dun. were treated with [14C]ethalfluralin (N‐ethyl‐α,α,α‐trifluoro‐N‐(methylallyl)‐2,6‐dinitro‐p‐toluidine) and [14C]trifluralin (α,α,α‐trifluoro‐2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine) supplied in nutrient solution to determine the basis for differences in response by these two species to these two herbicides. Plants of S. scabrum absorbed more [14C]ethalfluralin and [14C]trifluralin than plants of S. ptycanthum. During the first 24 h, S. scabrum seedlings, but not S. ptycanthum seedlings absorbed more [14C]ethalfluralin than did plants treated with [14C]trifluralin. More [14C]ethalfluralin than [14C]trifluralin was found in the shoots of plants of both species. Seventy‐two hours after treatment with [14C]herbicides, the conversion to water‐soluble metabolites was greater for [14C]ethalfluralin than for [14C]trifluralin. In the shoots of plants from both species an average of nearly 55% of the 14C recovered was found in the water‐soluble fraction following [14C]ethalfluralin treatment whereas an average of only 40% was found in the water‐soluble fraction following [14C]trifluralin treatment.
Control of Solenopsis invicta with delayed‐action fluorinated toxicants
Authors: Meer Robert K. Vander , Lofgren Clifford S. , Williams David F. 
Published: November 2006

AbstractThe fire ant, Solenopsis invicta Buren, was accidentally imported into the southern United States and has become a serious medical and agricultural pest of nine southeastern states and Puerto Rico. For a bait toxicant to be effective in fire ant control it must have delayed activity over a wide range of concentrations. Less than 1% of the 7500 compounds screened since 1958 has had delayed action. This paper describes several classes of fluorinated compounds that exhibit delayed activity. These compounds are used to illustrate the following three approaches to the discovery of delayed‐action toxicants: (a) random screening of compounds for delayed action; (b) design of delayed activity through the synthesis of pro‐insecticides; and (c) serendipity. As a result of these investigations two new classes of insecticides were discovered. A compound from one of these classes (tetrahydro‐5,5‐dimethyl‐2(1H)‐pyrimidinone (3‐(4‐(trifluoromethyl)phenyl)‐1‐(2‐(4‐(trifluoromethyl)phenyl)‐ethynyl)‐2‐propenyl‐idene) hydrazone, has been commercialised, while one or more compounds from the second new chemical class (fluorinated sulphonamides) are under development. Fluorinated delayed‐action insecticides have made significant contributions to current fire ant control and will no doubt play a role in the future.
Mechanism of gamma‐HCH resistance in a strain of granary weevil (Sitophilus granarius L.)
Authors: Le Patourel Geoffrey N. J. , Salama Mohamed A. 
Published: November 2006

AbstractThe uptake, accumulation, metabolism and excretion of gamma‐HCH (the gamma isomer of 1,2,3,4,5,6‐hexachlorocyclohexane) by a highly gamma‐HCH‐resistant strain of Sitophilus granarius was studied. It was found that the resistant strain was able to excrete a large proportion of a topically‐applied dose of gamma‐HCH in its frass pellets; under comparable conditions a susceptible strain accumulated a high body load of gamma‐HCH. Neither strain metabolised gamma‐HCH to any significant extent over a 48‐h period after dosing.
Activity of 2‐(1‐alkenyl)‐3‐hydroxy‐1,4‐naphthoquinones and related compounds against Musca domestica
Authors: Jacobsen Niels , Pedersen Lars‐Erik K. 
Published: November 2006

AbstractA series of 2‐(1‐alkenyl)‐3‐hydroxy‐1,4‐naphthoquinones has been prepared and their toxicities assessed against Musca domestica. By comparison with analogous compounds having saturated 2‐alkyl substituents, or unsaturated substituents with an unconjugated double bond (e.g. lapachol), it was demonstrated that the α‐unsaturation of the substituent is responsible for a significant increase in the toxicity. The effect of the compounds against several other insect species and Tetranychus urticae follows completely different patterns.
Cytological and physiological studies of the effects of IBP on Pyricularia oryzae (II): Effects on apical cells of single hyphae
Authors: Ishizaki Hiroshi , Kobayashi Issei , Kunoh Hitoshi 
Published: November 2006

AbstractThe effects of IBP (S‐benzyl O,O‐diisopropyl phosphorothioate) on tips of single hyphae of Pyricularia oryzae were investigated by interference contrast microscopy. Labelling hyphae with calcofluor white followed by IBP treatment revealed that elongation of apices of almost all hyphae at the colony margin was inhibited after treatment for 4 h. Successive observations on single hyphae of an IBP‐sensitive isolate indicated that apical cells stopped elongating approximately 10 min after the onset of treatment with 2 μg IBP ml−l. Small vacuoles appeared after 50 min; later they increased in number and size, and coalesced, finally producing a chain‐like arrangement of vacuoles in the cytoplasm. When hyphae were treated with 10 μg IBP ml−1, cessation of elongation and vacuolation occurred earlier than when treated with 2 μg ml−1. Apical cells of hyphae of an IBP‐tolerant isolate appeared unaltered even when treated with 10 μg ml−1. These results indicate that a major effect of IBP is to inhibit specifically the growth of apical cells of the IBP‐sensitive isolate.
Biologically active substances from higher plants: Status and future potential
Authors: McLaren James S. 
Published: November 2006

AbstractPlant breeding and selection, husbandry techniques and crop protection technology, including agrochemicals, have all made substantial contributions to the present‐day level of crop productivity. However, yield losses due to disease, pests and weeds must continue to be minimized in order to meet the food supply demands from an ever growing population. Appropriate synthetic chemicals are becoming increasingly difficult to discover and develop due to stricter requirements on efficacy, selectivity, toxicology and general environmental impact. Consequently, there is a growing interest in understanding and utilising natural mechanisms as the basis for crop protection products. Plants themselves are a rich source of biologically active substances which could potentially be harnessed to modify crop growth or to protect crops against disease and pests. This review describes briefly the current status of understanding relative to plant–plant (herbicide and plant growth substances), plant–fungal (fungicide) and plant–insect (insecticide) interactions. Future prospects are considered in relation to directed synthesis, cell culture, microbial pesticides and plant genetic engineering. The opinion expressed is optimistic and suggests that science today can be utilised to secure the food supply of tomorrow. However, utilising either natural products or molecular biology may require an improved understanding of crop physiology and new developments in agronomy. Therefore, the time‐frame for major impact of the ‘new’ technologies on crop productivity may be longer than is commonly predicted.
Photosensitisers from plants
Authors: Dodge Alan D. , Knox J. Paul 
Published: November 2006

AbstractThe absorption of solar radiation by certain phytochemicals leads to excitation to the singlet state. If unquenched, intersystem crossing occurs, and a longer‐lived triplet state arises. Triplet states may directly induce damage to biological molecules by type I reactions, or by interaction with triplet or ground state oxygen (3O2) generate singlet oxygen (1O2) in a type II reaction.1O2reacts with lipids, proteins and nucleic acids, and thus induces considerable cellular damage if unquenched. Chlorophyll is the most widespread plant photosensitiser, and damage to chloroplasts and plant cells will occur if, for example, photosynthesis is inhibited and excited chlorophyll unquenched. The endogenous formation of chlorophyll precursors from δ‐aminolaevulinic acid fed to darkened leaves has been shown to have a phytotoxic effect in subsequently illuminated plants. In animals a number of breakdown products of chlorophyll, such as phylloerythrin, promote secondary sensitisation, and a condition in sheep known as geeldikkop is induced if these compounds are not metabolised further in the liver. Hypericism is a well‐known case of primary photosensitisation in which the ingested molecule acts as the photosensitiser. The active compound hypericin is produced in the glands of variousHypericumspecies and is offensive to grazing animals and insect predators. Damage is promoted by the photosensitised generation of1O2. A related compound, fagopyrin from buckwheat, is similarly toxic, as also are a number of fungal quinones such as cercosporin. This compound is produced byCercosporaspecies and promotes a leaf‐spot disease in certain crop plants. A large number of furanocoumarins such as psoralen and xanthotoxin are particularly offensive to phytophagous insects. Phototoxicity may involve ultraviolet sensitised binding to DNA as well as type II reactions. Numerous other polyacetylenes and thiophenes are also activated by ultraviolet radiation, and have a role as plant protectants.
The pyrethrins and related compounds. Part XXVIII: Alkenyl‐ and alkynyl‐substituted benzyl esters
Authors: Elliott Michael , Elliott Richard L. , Janes Norman F. , Khambay Bhupinder P. S. , Pulman David A. 
Published: November 2006

AbstractOver 100 benzyl esters of pyrethroidal acids were synthesised and tested for insecticidal activity to establish detailed structure–activity relationships in compounds with side‐chains similar to those in the natural pyrethrins. Alkenyl, and corresponding alkynyl, side‐chains were effective, both at the 3‐ and 4‐positions, as were side‐chains with extended substitution in either E or Z forms. A cyano group at the α‐position increases activity if the side‐chain is at C‐3, but lowers it drastically if the substituent is at C‐4. Similarly, methyl groups at C‐2 and/or C‐6 may increase activity whether the unsaturated side‐chain is at C‐3 or C‐4, but only in the absence of an α‐cyano group.
The pyrethrins and related compounds. Part XXIX: Haloallylbenzyl esters
Authors: Elliott Michael , Elliott Richard L. , Janes Norman F. , Khambay Bhupinder P. S. 
Published: November 2006

AbstractSynthesis and bioassay of a series of esters based on pyrethroidal acids established that the activity of halosubstituted allylbenzyl esters depends on the position and stereochemistry of substitution in the allyl side‐chain, on the substitution pattern on benzyl, on the esterifying acid, and, to a lesser extent, on the nature of the halogen substituent itself. The most powerful combination of the first four parameters for activity against houseflies is in (Z)‐3‐haloallylbenzyl esters of the (1R)‐cis 3‐(2,2‐dibromovinyl) acid. Other combinations have moderate to low activity. Some aspects of the variation conform to previously recognised patterns, others define more precisely the requirements for the side‐chain to confer activity. The pattern of response of activity to cyano‐substitution at the α‐position, noted earlier, persists in the current compounds, and is here analysed quantitatively.
The pyrethrins and related compounds. Part XXX: Esters from acids with mono‐halovinyl side chains
Authors: Elliott Michael , Janes Norman F. , Khambay Bhupinder P. S. 
Published: November 2006

AbstractEsters of 3‐phenoxybenzyl alcohol and its α‐cyano derivative with 2,2‐dimethylcyclopropanecarboxylic acids bearing (E)‐ or (Z)‐3‐monohalovinyl side chains (haloiodo, bromo, chloro or fluoro) were synthesised and had moderate to high insecticidal activities, but these were generally lower than those of established pyrethroids with the corresponding 3‐(dihalovinyl) side chains. Compounds with 3‐(2‐chloroprop‐1‐enyl) side chains were intermediate in potency between the related chrysanthemates and 3‐(dichlorovinyl) esters.
Studies on the mode of action of asulam, aminotriazole and glyphosate in Equisetum arvense L. (field horsetail). I: The uptake and translocation of [14c]asulam, [14C]aminotriazole and [14C]glyphosate
Authors: Marshall George , Kirkwood Ralph C. , Martin David J. 
Published: November 2006

AbstractThe uptake and translocation of [14C]asulam (methyl 4‐aminophenyl‐sulphonylcarbamate), [14C]aminotriazole (1‐H‐1,2,4‐triazol‐3‐ylamine) and [14C]glyphosate (N‐(phosphonomethyl)glycine) were assessed in Equisetum arvense L. (field horsetail), a weed of mainly horticultural situations. Under controlled‐environment conditions, 21°C day/18°C night and 70% r. h., the test herbicides were applied to 2‐month‐old and 2‐year‐old plants. Seven days following the application of 0.07‐0.09 °Ci (1.14mg) of the test herbicides to young E. arvense, the accumulation of 14C‐label (as percentage of applied radioactivity) in the treated shoots, untreated apical and basal shoots was as follows: [14C]asulam, 13.2, 0.18 and 1.02%; [14C] aminotriazole, 67.2, 3.65 and 1‐91%; [14C]glyphosate, 35.9, 0.06 and 0.11%. The equivalent mean values for the accumulation of 14C‐label in 2‐year‐old E. arvense were [14C]asulam, 12.0, 1‐15 and 1.74%; [14C]aminotriazole, 58.6, 9.44 and 4.12%; [14C]glyphosate, 33.1, 0.79 and 2.32%. In the latter experiment, test plants received 0.25‐0.30 °Ci (4mg) of herbicide, they were assessed after a 14‐day period and the experiment was carried out at 3‐week intervals between 2 June and 25 August on outdoor‐grown plants. Irrespective of test herbicide or time of application, very low levels of 14C‐label accumulated in the rhizome system. Only 0.2% of the applied radioactivity was recovered in 2‐year‐old plants and 0.4% in 2‐month‐old plants. In the young plants [14C]asulam accumulated greater amounts and concentrations of 14C‐label in the rhizome apices and nodes than [14C]aminotriazole or [14C]glyphosate treatments. Inadequate control of E. arvense under field conditions may be due to limited basipetal translocation and accumulation of the test herbicides in the rhizome apices and nodes.
Acaricidal 1,2,4,5‐tetrazines
Authors: Brooker Peter J. , Parsons John H. , Reid Jim , West Peter J. 
Published: November 2006

AbstractA series of 1,2,4,5‐tetrazines has been synthesised and screened for acaricidal activity. Laboratory tests have shown several of the compounds to be highly active mite ovicides. Further examination in the field has identified a highly active compound, which gives prolonged control of mites on top fruit. The selected compound (clofentezine) is shown to be safe to mite predators and beneficial species and has been developed commercially for use on top fruit. (Clofentezine is the B.S.I. approved common name of 3,6‐bis‐(2‐chlorophenyl)‐1,2,4,5‐tetrazine).
Synthesis and insecticidal activity of lipophilic amides. Part 2: Effect of heteroatom replacements and of introducing methyl groups in the pentadiene system
Authors: Elliott Michael , Farnham Andrew W. , Janes Norman F. , Johnson Diana M. , Pulman David A. 
Published: November 2006

AbstractFollowing the discovery of insecticidal activity in (2E,4E)‐N‐(2‐methylpropyl)‐6‐phenylhexa‐2,4‐dienamide, structural analogues containing variations of the central pentadiene system have been examined. They include the five compounds with extra methyl groups on each of the five carbons in turn, and compounds in which heteroatoms have been introduced instead of, or additional to, the original CH or CH2 groups. All were insecticidally inactive, indicating for the first time the severe limitations on this group if activity is to be retained.
Synthesis and insecticidal activity of lipophilic amides. Part 5: Influence on activity of varying the substituent on nitrogen
Authors: Elliott Michael , Farnham Andrew W. , Janes Norman F. , Johnson Diana M. , Pulman David A. 
Published: November 2006

AbstractIsomerisation or shortening of the 2‐methylpropyl group in (2‐methylpropyl)‐6‐phenylhexa‐2, 4‐dienamide lowers insecticidal activity, as does methylation at nitrogen. Methylation at each carbon atom in turn, and, within limits, in combination, gives compounds with substantial, sometimes increased, activity. Cyclic and olefinic equivalents of the effective alkyl substituents are mostly less active.
Gas‐liquid chromatographic determination of NDMA in dimethylamine and in laboratory prepared herbicidal dimethylamine formulations
Authors: Wigfield Yuk Y. , McLenaghan Charles C. 
Published: November 2006

AbstractA method is described for the analysis of trace levels of N‐nitroso‐dimethylamine (NDMA) in anhydrous and in 60% (w/w) aqueous dimethylamine (DMA). Anhydrous DMA was converted to 60% (w/w) aqueous DMA, which was diluted with absolute ethanol and analyzed by a gas‐liquid chromatograph coupled to a thermal energy analyzer (g.l.c./t.e.a.) for the presence of NDMA. Experiments showed that NDMA was not generated in the g.l.c. injection port during analysis. The NDMA contents in seven samples of aqueous DMA and four samples of anhydrous DMA ranged from 55.0 μg −1 of 60% (wlw) aqueous sample to non‐detectable levels. The minimum detectable amount was 40 pg, which corresponds to 0.1 μg g−1. Anhydrous DMA was found to contain the lowest level of NDMA. 2, 4‐Dichlorophenoxyacetic acid (2, 4‐D), 4‐chloro‐2‐methylphenoxyacetic acid (MPCA) and 3, 6‐dichloro‐ 2‐methoxybenzoic acid (dicamba) were formulated with 60% (w/w) aqueous DMA into the corresponding DMA salts. The resulting herbicides were analyzed for NDMA, the levels of which were compared with the initial levels present in the 60% (w/w) aqueous DMA. Heating and stirring during formulation were found to be the main factors causing increased levels of NDMA.
N‐Nitrosodimethylamine content of aqueous dimet hylamine and phenoxy herbicide/dimethylamine formulations during storage
Authors: Wigfield Yuk Y. , McLenaghan Charles C. 
Published: November 2006

AbstractN‐Nitrosodimethylamine (NDMA) levels in samples of 600 g litre−1 aqueous dimethylamine (DMA) solution stored at 4, 25 and 40°C, in formulations of the DMA salt of 2, 4‐dichlorophenoxyacetic acid (2, 4‐D) and of the DMA salt of 4‐chloro‐2‐methylphenoxyacetic acid (MCPA) at 40°C were monitored using a gas‐liquid chromatograph coupled with a thermal energy analyser (g.l.c./t.e.a.). The NDMA content of aqueous DMA at 4°C increased from 0.32μgg−1 to 8.6μgg−1 in 156 days. At 25°C it increased from 0.20μgg−1 to 10.5 μgg−1 in 156 days and at 40°C from 0.76μgg−1 to 7.12μgg−1 in 54 h. At 40°C, the NDMA in the 2, 4‐D/DMAsalt increased from 0–53μgg−1 to 2.79μgg−1 in 96 days and in the MCPA/DMA salt from 0.48μgg−1 to 5.51 μgg−1 in 21 days.
Permethrin treatments in canadian forests. Part 2: Impact on stream invertebrates
Authors: Kreutzweiser David P. , Kingsbury Peter D. 
Published: November 2006

AbstractA series of experiments was conducted between 1977 and 1981 to evaluate the effects of aerially applied permethrin on forest stream invertebrates. All permethrin applications to forest streams resulted in large drift increases, and most produced measurable reductions in benthos density. Recovery of benthic fauna following the various permethrin applications was apparent from 1 to 18 months post‐spray. In double‐application experiments, the second treatments reduced benthos density to a point at which recovery of numbers was slower than after the impact resulting from a single application of the same dosage.
Phloem translocation of weak acids in ricinus communis
Authors: Rigitano Renê L. O. , Bromilow Richard H. , Briggs Geoffrey G. , Chamberlain Keith 
Published: November 2006

AbstractUptake of weak acids by roots of Ricinus communis and their translocation to shoots increased as the pH of the nutrient solution decreased, the behaviour being closely similar to that observed for the same compounds in barley. Phenoxyacetic acids (p Ka ˜3) with log Kow, for the undissociated acid of between 1 and 3 were readily taken up and translocated in phloem to the apical leaf and the upper stem of R. communis following injection into the petioles of mature leaves; strong retention of these chemicals in the stem rapidly depleted their concentration in phloem down the stem so that very little was found in roots. A more polar and a more lipophilic phenoxyacetic acid were poorly translocated from the petioles, and flamprop (pKa 3.7, log Kow, 2.9) was predominantly xylem‐mobile. Maleic hydrazide (pKa 5.65, log Kow, −0.6) was taken up from the petioles rather slowly but was readily phloem‐translocated from the mature leaves, and little was retained by the stem, permitting appreciable amounts to reach the roots and nutrient solution. Concentrations of these weak acids in leaf phloem were up to ten times higher than in the adjacent leaf cells, and could be predicted reasonably well assuming that accumulation in phloem was purely a physico‐chemical process occurring due to the ion‐trap effect, taking values obtained from barley roots for the ratio of the permeabilities of membranes to the undissociated and dissociated forms of the acids.
Triapenthenol—a new plant growth regulator
Authors: Lürssen Klaus , Reiser Wolf 
Published: November 2006

AbstractTriapenthenol is the proposed common name for a new plant growth regulator (E)‐l‐cyclohexyl‐4, 4‐dimethyl‐2‐(1, 2, 4‐triazol‐l‐yl)‐l‐penten‐3‐01. Its main influence upon plants is an inhibition of shoot growth. Root growth is not inhibited at normal dosages. Growth inhibition in dicotyledons is achieved by either foliar or root uptake, while in monocotyledons, root uptake is necessary and foliar treatment fails to produce growth inhibition. Mainly acropetal transport of the compound is assumed to be responsible for this behaviour. Apart from growth inhibition, a marked influence upon water relations in plants was observed. In barley, water consumption was reduced for whole plants. Calculations also revealed a reduction of transpiration per unit leaf area. In rape only an initial reduction of water consumption was observed. The fresh weight/dry weight ratio of plants was increased by the compound. The total nitrogen content per plant was unchanged but increased when calculated on a dry weight basis. The compound exerted retardant effects by interfering with gibberellin biosynthesis, but the shape of the dose‐response curves with increasing gibberellin concentrations in the presence and in the absence of triapenthenol suggests that this may not be the only effect of the compound on the plant metabolism.
Persistence of carbendazim in field‐grown soybeans following application of thiophanate‐methyl fungicide
Authors: Lyons Philip C. , Lyda Stuart D. 
Published: November 2006

AbstractCarbendazim was quantified spectrophotometrically in leaves, petioles, stems and pods from upper and lower halves of entire soybean plants following one or two foliar applications of thiophanate‐methyl fungicide (1.1 kg ha−1 a.i.). Following the first application, the highest carbendazim concentrations occurred 1‐4 days post‐application and declined thereafter to undetectable (⩽0.12 mg kg−1) or barely detectable levels by day 26. The highest concentrations were in the leaves where carbendazim levels exceeded 3.5 mg kg−1 on day 4 and remained above 1.0 mg kg−1 until day 19. Concentrations in petioles and upper pods were initially in excess of 1.0 mg kg−1 and remained above 0.5 mg kg−1 for 12 days. In lower pods and in stems, concentrations were very low and often not detectable. Typically, concentrations were higher in samples from the upper half of the plant than in those from the lower half. A second application on day 18 resulted in carbendazim concentrations similar to those immediately after the first application; however, concentrations declined rapidly coincidentally with a period of rain. This decline may have been facilitated by poor fungicide uptake due to senescence of the plants.