bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on pesticides based on coumarin. II. Synthesis and antifungal activity of ten 2‐alkyl‐7, 8‐dihydro‐3‐hydroxynaphtho[1,2‐c]chromen‐6‐ones
Authors: Gupta Bharat B. , Singh Raj V. , Malik Om P. , Kataria Hans R.
Published: November 2006

A series of 2‐alkyl‐7, 8‐dihydro‐3‐hydroxynaphtho[1,2‐c]chromen‐6‐ones was synthesised by the condensation of ethyl 3, 4‐dihydro‐1‐oxonaphthalene‐2‐carboxylate with substituted phenols in the presence of POCl3. The compounds were characterised and tested for their toxicity towards the mycelial growth of seven phytopathogenic fungi in culture. Drechslera oryzae, Rhizoctonia solani and Colletotrichum falcatum exhibited maximum sensitivity to these compounds whereas Macro‐phomina phaseolina, Fusarium solani, Alternaria alternata and Pythium aphanidermatum were less sensitive. 2‐Ethyl‐7, 8‐dihydro‐3‐hydroxy‐naphtho[1,2‐c]chromen‐6‐ones possessed greatest toxicity with EC50 values ranging from 0.2 to 2.5 μg ml−1 against all fungi except A. alternata and P. aphanidermatum.
Photochemical isomerization of fluazifop‐butyl
Authors: Frigerio Alberto , Pusino Alba , Gessa Carlo
Published: November 2006

Fluazifop‐butyl, butyl (RS)‐2‐[4‐(5‐trifluoromethyl‐2‐pyridyloxy)‐phenoxy]propionate, as a thin film on glass, was photo‐rearranged by ultraviolet irradiation at 254 nm to the isomer, butyl (RS)‐2‐[4‐hydroxy‐3‐(5‐trifluoromethyl‐2‐pyridyl)phenoxy]propionate. The reaction followed first‐order kinetics. A mechanism that accounts for the formation of this product is proposed.
Mechanism of inhibition of sterol biosynthesis enzymes by N‐substituted morpholines
Authors: Taton Maryse , Benveniste Pierre , Rahier Alain
Published: November 2006

Tridemorph, fenpropimorph and derivatives have been tested in vitro on Δ8→Δ7‐sterol isomerase (SI) from maize seedlings. The results show that these N‐substituted morpholines strongly inhibit this enzyme (I50: 0.4 μM for fenpropimorph, 0.6 μM for tridemorph). In fenpropimorph, where a chiral centre is present at C‐2 of the alkyl chain, good enantioselectivity was observed for enzyme inhibition. Inhibition of SI and of the cycloeucalenol‐obtusifoliol isomerase (COI), another enzyme of plant sterol biosynthesis, is probably due to protonation of the N‐substituted morpholines, giving a positively charged nitrogen atom, at the pH (7.4) of the enzyme assays. In order to test this hypothesis, the pH dependence of the inhibition constants has been measured. Fenpropimorph, (pKa 7.5) which can be protonated to give a morpholinium cation and N‐methylfenpropimorph, the corresponding quaternary ammonium derivative, have been tested as inhibitors in a pH range from 6 to 8.5. The I50 value of fenpropimorph toward the SI increased 20 times as the pH increased from 6 to 8.5. In contrast the I50 value of fenpropimorph for COI did not change significantly in this pH range. While the I50 value of N‐methyl fenpropimorph towards COI decreased more than 50 times as the pH increased from 6 to 8.5, its I50 value for SI only varied slightly in this pH range. Taken together, these results suggest the existence of an interaction of the morpholinium cations with one or several enzyme amino acid residues of a much higher pKa in the case of COI than SI. Moreover for maize COI, the pKa of the amino acid residue(s) interacting with these morpholines derivatives is probably close to that of these molecules.
Interaction of azole derivatives with cytochrome P‐450 isozymes in yeast, fungi, plants and mammalian cells
Authors: Vanden Bossche Hugo , Marichal Patrick , Gorrens Jos , Bellens Danny , Verhoeven Hugo , Coene Marie‐Claire , Lauwers William , Janssen Paul A. J.
Published: November 2006

Yeast and plant membranes contain rather small amounts of cytochrome P–450 as compared with membrane fractions prepared from bovine adrenal cortex, piglet testis and rabbit liver.

The agricultural fungicides azaconazole, penconazole, propiconazole and imazalil showed a much greater affinity for microsomal cytochrome P–450 isozymes of Saccharomyces cerevisiae and Candida albicans (ATCC 28516) than for cytochrome P–450 in microsomal fractions prepared from Jerusalem artichoke tubers, maize shoots, pea seedlings or tulip bulbs and for cytochrome P–450 isozymes in mitochondrial or microsomal fractions from rabbit liver, piglet testis and bovine adrenals. The medicinal azole antifungals miconazole, clotrimazole, ketoconazole, fluconazole and itraconazole also interacted at much lower concentrations with the microsomal cytochrome P–450 isozymes from S. cerevisiae and C. albicans (ATCC‐28516, ATCC 44859, B 34226/1) than with those in mammalian membranes. Itraconazole showed the highest selectivity; bifonazole was much less selective.

The microsomal fraction prepared from C. albicans (isolate B 41628) contained cytochrome P–450 isozymes with a lower affinity than the microsomal fractions from other isolates for miconazole, ketoconazole, fluconazole and itraconazole. However, itraconazole showed still high affinity for these cytochrome P–450 isozymes. In animal models this C. albicans isolate was less pathogenic and was shown to be less sensitive to azole antifungals both in vitro and in vivo.

Azole antifungals inhibited ergosterol synthesis at nanomolar concentrations whereas almost micromolor concentrations were needed to obtain a similar inhibition of cholesterol or phytosterol synthesis. This inhibition coincided with the accumulation of 14α‐methylsterols such as 14‐methyl‐fecosterol, 14‐methyl‐24‐methylene‐ergosterol, 14‐methyl‐ergosta‐8, 24 (28)‐dien‐3β, 6α‐diol, obtusifoliol, lanosterol and 24‐methylenedihydro‐lanosterol. In 24‐h‐old cultures of C. albicans the 3β, 6α‐diol was the major sterol. It is speculated that by making the 14α‐methylsterols less lipophilic the cells are trying to eliminate these membrane‐disturbing compounds. This suggests that the azole‐induced ergosterol depletion might represent a greater contribution to their fungicidal activity than the accumulation of 14α‐methylsterols.
Inactivation of fenitrothion on stored maize at different moisture contents
Authors: Samson Peter R. , Parker Russell J. , Keating Julie A.
Published: November 2006

Biological activity of fenitrothion on stored maize at various moisture contents and at different times after application was measured by biological assay using adults of Tribolium castaneum (Herbst). Inactivation of actual residues over time was then determined after making the necessary allowance for chemical breakdown. At a given moisture content, the inactivation process was substantially completed during the first 6 weeks after application and loss of effectiveness from 6 weeks onwards resulted mainly from chemical breakdown. At a given time after application, residues were less active at higher moisture content (m.c). Differences in activity between moisture contents were apparent within a few hours of application and continued to increase for up to 3 days, with relatively little change thereafter during storage of 24 weeks. Thus after 24 weeks, residues on maize of 18% m.c. had an activity about 20% that of similarly‐aged residues at 10% m.c. and 4% that of freshly‐applied residues at 10% m.c. These results were in general accord with changes in the proportion of the residue which was collected from the kernels by a surface wash with methanol, this readily‐extractable residue presumably representing the insecticide that may be picked up by insects.
Predicted and observed droplet deposition on tsetse flies (Glossina morsitans) following aerosol application from aircraft
Authors: Johnstone Donald R. , Allsopp Reginald , Cooper Jeremy F. , Dobson Hans M.
Published: November 2006

A non‐toxic formulation containing fluorescent tracer was dispersed as an aerosol over savannah woodland in stable meteorological conditions, with only light wind, shortly after sunrise. Droplet deposition on wild caught tsetse flies (Glossina morsitans) was measured by means of a fluorescent tracer technique and compared with the deposit levels predicted from rotary sampler measurements using droplet collection efficiency data for samplers and flies derived from a laboratory wind tunnel study. Good correlation was found between the predicted and observed dose. An additional comparison, based only on rotary sampler data, between a typical spray (measured v.m.d. 27 μm) and a spray with smaller drop size (measured v.m.d. 21 μm) suggested that the latter might be significantly more effective as a means of control.
Residue levels of three organophosphorus insecticides in sweet pepper grown in commercial greenhouses
Authors: Al‐Samariee Adnan I. , Shaker Khloud A. M. , Al‐Bassomy Mabrouk A.
Published: November 2006

The degradation rates and residue levels of diazinon, pirimiphos‐methyl and chlorpyrifos in the leaves and fruits of pepper plants grown in commercial greenhouses were studied using g.l.c. Analysis of leaves at intervals following application showed that the initial residue of diazinon was higher than that of the other two insecticides, while its dissipation rate was faster.

The dissipation of chlorpyrifos in fruits was faster than diazinon. The maximum residue levels (m.r.l.) of diazinon (0.5 mg kg−;1) and chlorpyrifos (0.1 mg kg−;1) were reached after 13 and 8 days of application respectively.

With diazinon and pirimiphos‐methyl, sprayed 3 weeks before inflorescence, very low concentrations of both insecticides were found in fruits, although these compounds have no systemic behaviour.

Chlorpyrifos residue level of 0‐2 mg kg −;1 in harvested fruits did not drop below m.r.l. after 11 days holding period.
Plant growth regulating properties of 1‐amino‐1‐methylethylphosphonic acid and its derivatives
Authors: Lejczak Barbara , Kafarski Pawel , Gancarz Roman
Published: November 2006

Seventeen derivatives of 1‐amino‐1‐methylethylphosphonic acid were synthesised and evaluated for plant‐growth‐regulating activity using Cucumis sativus and Triticum aestivum. The tested compounds exerted either moderate herbicidal action or stimulated plant growth. The structure‐activity relationships were similar to those observed earlier for the derivatives of 9‐aminofluoren‐9‐ylphosphonic acids (phosphonic analogues of morphactins).
Multiphase photodegradation of quinalphos
Authors: Dureja Prem , Walia Suresh , Mukerjee Sunil K.
Published: November 2006

Photodegradation of the organophosphorous insecticide quinalphos (O, O‐diethyl O‐quinoxalin‐2‐yl phosphorothioate) has been studied. On exposure to natural sunlight, quinalphos was photodegraded with half‐lives of 30 days in distilled water, 20–23 days in tap and rain water and ≤5 days in 2% aqueous acetone. Quinalphos underwent photoisomerisation, oxidation from P=S to the P=O group and de‐esterification. Photoproducts were isolated and characterised by spectroscopic methods. When applied on soil thin‐layer plates quinalphos was promptly dissipated with a half‐life of ≤6 days.
Effects of microbial inhibitors on the degradation rates of metamitron, metazachlor and metribuzin in soil
Authors: Allen Richard , Walker Allan
Published: November 2006

Rates of carbon dioxide evolution and degradation rates of metamitron, metazachlor and metribuzin were measured in two soils in the presence of three microbial inhibitors. The nonselective microbial inhibitor sodium azide reduced both carbon dioxide evolution and the rate of loss of all three herbicides in both soils, although the reduction in degradation rate of metamitron was small. The antibacterial antibiotic novobiocin enhanced carbon dioxide evolution from both soils but had variable effects on the rates of herbicide degradation. It inhibited degradation of metazachlor and metribuzin, and in one of the soils its effects on metazachlor degradation were similar to those of sodium azide. Novobiocin inhibited degradation of metamitron to a small extent in one soil only. The antifungal antibiotic cycloheximide also enhanced carbon dioxide evolution from both soils. In general, its effects on herbicide degradation were similar to those of novobiocin, although the extent of inhibition was usually less pronounced. The results are discussed in terms of the relative involvement of microorganisms in degradation of the three herbicides.
Stabilisation of the carbamate acaricide promacyl in cattle dipping fluid
Authors: McDougall Kerryn W. , Machin Michael V.
Published: November 2006

The concentration of promacyl declined in cattle dipping fluid, and laboratory experiments were undertaken to establish the cause of breakdown and devise ways of overcoming it. Promacyl declined more quickly in dipping fluid at 15–26°C than at 35°C, with concentrations of the metabolite promecarb increasing as the temperature decreased. Promacyl did not break down in distilled water, other than by hydrolysis at 50°C. The degradation rate of promacyl in dipping fluid increased with the addition of ammonium nitrate and by saturation with air, but it remained unchanged with the addition of copper sulphate, magnesium chloride, urea and chlorhexidine diacetate. When samples which were already breaking down were recharged with promacyl the rate of depletion remained unaltered. Samples inoculated with dip solution already showing promacyl breakdown had increased rates of promacyl degradation (P<0.05). Calcium hypochlorite prevented promacyl breakdown, but only for a short time. Breakdown could be prevented by the addition of the bactericides 2,4‐benzisothiazolin‐2‐one or dichlorophen, or by reducing the pH to <5.0. Data indicated that breakdown of promacyl was due to microbial action.
Degradation rates in soil of 1‐benzyltriazoies and two triazole fungicides
Authors: Patil Shantagouda G. , Nicholls Peter H. , Chamberlain Keith , Briggs Geoffrey G. , Bromilow Richard H.
Published: November 2006

The degradation rates in soil of 1‐benzyltriazole together with six analogues having substituents in the phenyl ring and two commercial triazole fungicides, PP450 and triadimefon, were determined at 15°C and 20 % soil water content. The order of degradation rates of the benzyltriazoles was H > 4‐OCH3 > 4‐F>4‐Cl.4‐≥tert‐C4Hg3,4‐diCl>3‐CF3. Thus, in general, persistence was enhanced by electron‐withdrawing substituents and by lipophilic groups that increased sorption by soil.

Of the commercial fungicides, PP450 was degraded very slowly (half‐life 578 days) while triadimefon was quickly converted (half‐life 15 days) to the corresponding alcohol, triadimenol, which in turn was degraded very slowly.

The effects of temperature and soil water content on rate of degradation were studied for 1‐benzyltriazole and 1‐(4‐fluorobenzyl)triazole. The rate of degradation of 1‐benzyltriazole was more sensitive to soil temperature and water content than was that of 1 ‐(4‐fluorobenzyl)triazole. The influence of these results on the input data required by models which simulate persistence in field soil is discussed.
Studies on pesticides based on coumarin. III. Synthesis and antifungal activity of substituted 4‐methyl‐coumarins and related compounds
Authors: Singh Rajvir , Abrol Mrs V. , Gupta Bharat B. , Malik Om P.
Published: November 2006

A series of substituted 4‐methylcoumarins was synthesised and the members tested for their toxicity towards mycelial growth of seven phytopathogenic fungi in culture. Rhizoctonia solani, Alternaria alternata and Fusarium solani exhibited maximum sensitivity to these compounds whereas Pythium aphanidermatum, Colletotrichum falcatum, Drechslera oryzae and Macrophomina phaseolina were relatively less sensitive. 6‐Ethyl‐3‐n‐ propyl‐7‐hydroxy4‐methylcoumarin (I) was relatively toxic towards all fungi except C. falcatum, P. aphanidermatum and M. phaseolina. The 6‐n‐butyl (III) and 6‐(1, 1, 3, 3‐tetramethylbutyl) (VI) derivatives were highly toxic to R. solani with EC50, values of lμg ml−1.
The pyrethrins and related compounds. Part XXXII. Replacement of the central ester link
Authors: Elliott Michael , Farnham Andrew W. , Janes Norman F. , Khambay Bhupinder P. S.
Published: November 2006

This paper, and the two following, report a detailed examination of the effect of replacement of the central link in pyrethroids by isosteric or isoelectronic groups, and how the resulting change in insecticidal activity depends on the particular groups present in the other parts of the molecule. In this first paper, a wide range (42 variations) of central groups in different combinations are synthesised and tested. Results indicate that with conventionally pyrethroidal acid and alcohol fragments in the molecule, some isosteric replacements are tolerated, but most other variations are unsuccessful, Particularly interesting central groups are COCH2 and CHCHCH2(E).
Degradation and movement of aldicarb residues in Florida citrus soils
Authors: Jones Russell L. , Hornsby Arthur G. , Suresh P. , Rao C.
Published: November 2006

The movement and degradation of the pesticide aldicarb was monitored in two Florida citrus groves. One of these was a bedded grove near Oviedo and the other was located in the central ridge near Lake Hamilton. Soil core samples were collected at 0.3 or 0.6 m depth increments six times over an eight‐month period and were analyzed for aldicarb and its two oxidation products aldicarb suljoxide and aldicarb suljone. These analyses showed a relatively rapid decrease of aldicarb accompanied by an increase in aldicarb sulfoxide and aldicarb suljone; the levels of these carbamate metabolites peaked after about 50 days and then began to decline. The dissipation rate of aldicarb carbamate residues in surface soils corresponded to a half‐life of approximately 20 days at both jield sites. The degradation rate in subsoils appeared to be significantly longer (half‐life greater than 60 days), especially at the Lake Hamilton site.

Aldicarb carbamate residue concentrations measured in replicate soil analyses were highly variable, with coeflcients of variation ranging up to 300% for samples collected at the same time and depth. These data point out the need for carefirl design of soil‐sampling strategies (including numbers, timing, and location of samples) in order to obtain statistically valid results from unsaturated zone pesticide monitoring studies.
Promotion of stomatal infiltration of glyphosate by an organosilicone surfactant reduces the critical rainfall period
Authors: Field Roger J. , Bishop Nicholas G.
Published: November 2006

The addition of the organosilicone surfactant ‘Silwet L77’ at 1‐5 ml litre−1 to formulated glyphosate gave complete surface wetting on application to the adaxial leaf surface of perennial ryegrass (Lolium perenne L.). The wetting characteristics of the solution were associated with rapid foliar uptake and near maximal uptake in 3 h compared to greater than 5 h in the absence of ‘Silwet L77’. Evidence is presented showing that solutions containing ‘Silwet L77’ rapidly infiltrate stomata. Rapid uptake did not occur after application to the astomatous abaxial surface of perennial ryegrass leaves.

The rapid rate of glyphosate uptake reduced the critical rainfall period to 2 h or less, compared to up to 10 h in the absence of ‘Silwet L77’. The use of ‘Silwet L77’ has major practical implications for the use of glyphosate in regions with unpredictable rainfall or high rainfall frequency.
The synthesis and biological activity of substituted chlorinated benzenedicarbonitriles
Authors: Clifford David P. , Edamura Fred
Published: November 2006

A number of chlorinated 1,2‐, 1,3‐ and 1,4‐benzodicarbonitriles monosubstituted by either hydroxy, arylamino, alkylthio, sulphinyl or sulphonyl groups were synthesised and assayed against P. viticola, P. oryzae, V. inaequalis, P. parasitica and a number of other fungi and bacteria. The 1,3‐benzodicarbonitriles were the most active compounds and the alkylsulphiyl and sulphonyl groups the most effective substituents.
Estimating buffer zone widths for pesticide applications
Authors: Payne Nicholas J. , Helson Blair V. , Sundaram Kanth M. S. , Fleming Richard A.
Published: November 2006

A technique for estimating the width of buffer zones required around sensitive areas during pesticide applications has been devised and tested. The technique has been used to estimate the buffer width required around water bodies during ground‐based permethrin applications in Canadian forests to prevent significant impact on fish and their food populations. A worst‐ case scenario was developed for environmental impact in water bodies result ing from ground‐based permethrin applications, and a spray application was made under these worst‐case conditions. Permethrin deposit on ground sheets was measured downwind of overlaid crosswind swaths. From these measurements the deposit at various downwind distances from a single crosswind swath was calculated, and a curvilinear regression line fitted to these values. Permethrin deposit downwind of multiple‐swath applications was computed by adding the contributions from individual swaths. Mortality resulting from various permethrin concentrations was measured for Aedes aegypti larvae. Although these larvae are not an important food species for the fish species of interest, salmon and trout, they are more sensitive to permethrin than most aquatic invertebrates. Predicted mortality in populations of this species and Salmo gairdneri, rainbow trout, at various downwind distances from the permethrin application was calculated from the toxicological and spray‐cloud dispersal data. Buffer width was estimated by choosing an acceptably low mortality, and determining the downwind distance at which this value was obtained. For example, a 20 m swath width was found to be adequate to limit mortality in A. aegypti andS. gairdneri populations to 10 and 0.1% during ground‐based permethrin applications.
Molecular properties of the apamin binding protein associated with a calcium activated potassium channel
Authors: Seagar Michael J. , Marqueze Beatrice , Couraud François
Published: November 2006

Apamin, a 2‐kdalton peptide from bee venom, is a potent convulsant. Its neurotoxic action has been attributed to specific blockade, at nanomolar concentrations, of the slow Co2+ activated K+ current (IAHP) that underlies the late afterhyperpolarisation in certain neurons. Mono[125I] iodoapamin binds with high affinity to intact cultured neurons (Kd = 30 PM, Bmax = 500‐1000 sites/cell) and synoptic membranes (Kd = 30 PM, Bmax = 30 fmol mg protein−1). Apamin contains two primary amines (alpha cysl and epsilon lys4) that can be modified to produce photoactivatable arylazide derivatives. Photoaffinity labeling with these derivatives has identified receptor polypeptides of 86 and 59 kdaltons accessible from the alpha cysl position and 33 kdaltons accessible from the epsilon lys4 position of the bound ligand. This suggests that apamin binds at the interface between 3 putative K+ channel subunits. Radiation inactivation studies indicated a target size of 84‐115 kdaltons. The simplest interpret at ion is that the 86 kdalton chain alone carries the neurotoxin binding site.

The apamin binding protein can be extracted from rat brain membranes using sodium cholate. Scatchard analysis of equilibrium binding data revealed a single class of non‐interacting sites with Kd = 40 pm and Bmax = 17 fmol mg protein−1. As in membrane‐inserted receptors, apamin binding is stimulated by occupation of a K+ ion site that saturates at low millimolar concentrations. Other cations can be substituted for K+ with an affinity sequence: K+ = Tl+ = Rb+ > Cs+ > NH+4 > Li+ or Na+. The K+ channel Mockers quinidine and tetraethylammonium + displaced apamin from its solubilised receptor at concentrations similar to those required to block flux through apamin‐sensitive channels. Analysis by sucrose gradient centrifugation showed that the receptor sediments with S20=20, corresponding to a molecular weight of about 700 kdaltons. However, as much as 50%of this could be contributed by the detergent.

Receptor sites for [125I]‐apamin have also been detected and identified by photoaffinity labeling in primary cultured astrocytes and heart cells as well as in membrane preparations from liver and smooth muscle. A 86–87 kdalton componet was was present in all these tissues whereas the 57–59 and 33kdalton polypeptides were revealed in some but not in others, These observations support the hypothesis that the larger chain contains the apamin binding site while the two smaller polypeptides are noncovalently associated perpheral subunits.
Synthesis, insecticidal activity and pyrethroidal mode of action of new tin ether derivatives
Authors: Tsushima Kazunori , Yano Toshihiko , Umeda Kimitoshi , Matsuo Noritada , Hirano Masachika , Ohno Nobuo
Published: November 2006

A novel range of trimethylstanniomethyl ethers of well known pyrethroid alcohols were synthesised, and their insecticidal activities and modes of action as insecticides were investigated. Among them, ethers from three types of alcohol (3‐phenoxybenzyl, 4‐fluoro‐3‐phenoxybenzyl and 6‐phenoxy‐2‐pyridylmethyl) showed remarkable insecticidal activities against rice stem borers, houseflies and German cockroaches.

According to electrophysiological studies on the abdominal nerve cords of German cockroaches, trimethylstanniomethyl 6‐phenoxy‐2‐pyridylmethyl ether induced a rapid decline in spontaneous firing similar to that from tetramethrin. However, insecticidal trimethyltin chloride caused an entirely different response.

These observations suggest that the present tin ether derivatives resemble pyrethroids, rather than the insecticidal tin compounds known so far.
Assessment of canopy and ground deposits of fenitrothion following aerial and ground application in a northern ontario forest
Authors: Sundaram Kanth M. S. , Millikin Rhonda , Sundaram Alam
Published: November 2006

Spray deposit patterns on simulated and live foliage of balsam fir and white birch were determined at different heights and at periphery and interior locations of the tree crown, following aerial and ground applications of fenitrothion formulations over a boreal forest near Searchmont, Ontario. Droplet size spectra and AI deposits were assessed at ground level with ‘Kromekote’ card/glass plate units. Aerial application was made with a Cessna 188 aircraft fitted with ‘Micronair’ AU3000 atomizers. For ground application, a ‘Soloport’ 423 backpack mistblower fitted with an extension tube and a diffuser nozzle at the tip was used.

Deposit data on the ground samplers indicated significantly larger droplets and greater deposits from the aerial spray trial than from the mistblower treatment. However, foliar deposits at tree canopy level were only slightly higher in the former trial than in the latter.

Analysis of spray deposits on simulated and live fir foliage showed definite gradients in deposit levels, decreasing from top to bottom crown, and from periphery to inner tree crown. In the birch tree crown, such gradients were not observed. The simulated leaves generally acted as better collectors of spray droplets than the natural leaves. The overall mean deposit values, expressed in ng cm−2, showed a wide variation, although there was generally a close relationship between the deposits on the simulated and natural surfaces.
Physiological and structural aspects of adipokinetic hormone function in locusts
Authors: Goldsworthy Graham J. , Wheeler Colin H.
Published: November 2006

During trivial flight in locusts, carbohydrates are the main energy source for the flight muscles, but during long‐term (migratory) flight, lipids mobilised from the fat body are utilised. The supply of fuels to the flight muscles, and the balance between fuels, is determined by peptidic adipokinetic hormones, AKH‐I and AKH‐II, released from the corpora cardiaca. These peptides also indirectly effect changes in lipid‐transporting mechanisms in the haemolymph, and regulate a lipoprotein lipase necessary for lipid uptake by the flight muscles. The sequences of the AKHs of locusts are known and they are members of a family of invertebrate neuropeptides. Extensive structure/activity studies for the action of AKHs on lipid mobilisation have been carried out and, together with studies on secondary structure, the structural features necessary for biological activity are being elucidated. Such information will be of great importance in receptor studies for these hormones, and in the development of powerful agonists and antagonists.
Disposal of concentrated solutions of diazinon using organic absorption and chemical and microbial degradation
Authors: Mullins Donald E. , Young Roderick W. , Palmer Christopher P. , Hamilton Robert L. , Sherertz Peter C.
Published: November 2006

Peat moss has been found to be an effective ‘organic matrix’ for the absorption and degradation of diazinon in experimental disposal pits. High concentrations of diazinon sorbed onto nutrient‐enriched commercial grade peat moss were rapidly degraded. Pits treated with diazinon concentrations ranging from 4000 to 32000 mg kg−1 contained less than 1 to 7 mg kg−1 after 18 weeks. Initially, degradation probably was due to hydrolysis resulting from the effects of heat, moisture, low pH and some microbial activity. Further degradation of the hydrolysis product, IMHP, was most likely due to microbial activity. The results obtained suggest that a managed degradation pit, containing a nutrient‐enriched organic matrix (peat moss), might provide a useful means for absorbing and neutralizing waste pesticide formulations because the materials used in this system are readily available and the system may be regenerative so that it can be used repeatedly.
A biopolymer‐based pesticide delivery system for insect suppression in stored grains
Authors: Singh Satish K. , Fan L. T.
Published: November 2006

Degradation of grain quality during storage is mainly caused by insects and microorganisms. To protect against insects, prevailing practices usually require the application of pesticides and fumigants directly to the stored grain; long‐term storage can involve repeated applications. Direct application results in accumulation of chemical residues on the grain, especially from pesticides. A simple delivery system, in which the pesticide (chlorpyrifosmethyl) is incorporated in a biopolymer (xanthan gum), has been formulated with the objective of reducing these residues while increasing the period of effectiveness of a single application. The biopolymer‐based formulation was compared to a conventional formulation on the basis of bioassay tests and residue analysis. The biopolymer‐pesticide formulation was effective over a longer period of time and produced significantly smaller residues than the conventional emulsifiable concentrate formulation.
Toxicity and electrophysiological effects of Spilanthes amella Murr. extracts on Periplaneta americana L.
Authors: Kadir Habsah A. , Zakaria Muhamad B. , Kechil Abdul A. , Azirun Moh D. S.
Published: November 2006

The potential insecticidal activity of Spilanthes acmella Murr. (Compositae) extracts was assessed in this study. The extracts were shown to be toxic against adults of American cockroach, Periplaneta americana L. The active component in S. acmella extract was isolated and identified as N‐isobutyl‐2,6,8‐decatrienamide (spilanthol). The results from topical application of spilanthol show that it has a high acute toxicity and spilanthol was the most potent compound when compared to three conventional insecticides. The potency was found to be 1.3, 2.6 and 3.8 times more toxic than carbaryl, bioresmethrin and lindane, respectively. Electrophysiological studies indicated immediate hyperexcitation followed by complete inhibition of the cockroach cercal nerve activity.
Isolation and characterisation of biologically‐active compounds from some plant extracts
Authors: Peterson Glenn S. , Kandil Mohamed A. , Abdallah Mounir D. , Farag Abdel‐aal A.
Published: November 2006

Of the numerous fractions obtained from the crude plant extracts of Chenopodium ambrosioides, Conyza dioscordisis and Convolvulus arvensis, 11 were found to be active against stored grain pests. The chemical structures of compounds present in the 11 fractions were found by gas chromatography/mass spectrometry to include predominantly long‐chain fatty acid esters of hexadecanoic, arachidonic, and octadecanoic acids.
Photodegradation of the organophosphorus insecticide idofenphos
Authors: Walia Suresh , Dureja Prem , Mukerjee Sunil K.
Published: November 2006

Photodecomposition of the organophosphorus insecticide iodofenphos (O‐2,5‐dichloro‐4‐iodophenyl O,O‐dimethyl phosphorothioate) has been studied in solution and on glass, soil and leaf surfaces. Iodofenphos underwent dehalogenation, oxidation and clearage of the P‐O‐aryl linkage on irradiation in hexane and methanol and produced a mamber of photo‐products which were characterised by 1H‐NMR and mass spectroscopy. It has been observed that, as compared to dark conditions, the degradation of iodofenphos on soil, glass and leaf surface was accelerated under illuminated conditions.
Synthesis and pesticidal activity of some quinazolin‐4(3H)‐one derivatives
Authors: Sen Gupta Anil K. , Pandey Ashok Kumar
Published: November 2006

A number of quinazolin‐4(3H)‐one carbothioamides, pyrazoles, pyrazolones and tetrazole derivatives have been synthesised by the reaction of 2‐hydrazino‐3‐(4‐substituted phenyl)‐quinazolin‐4(3H)‐ones with the appropriate aryl isothiocyanate, acetyl acetone, ethylacetoacetate and nitrous acid. All the compounds were tested in vitro for antibacterial, insecticidal and antifungal activity and found to have some activity.
Mode of action of fixed oils against eggs of Callosobruchus maculatus (F.)
Authors: Don‐Pedro Kio N.
Published: November 2006

Studies on the mode of action of fixed vegetable oils on Callosobruchus maculatus eggs revealed two possible mechanisms of action which may be complementary: (1) that the oils exert lethal action slowly by drastically reducing respiratory activity and elimination of toxic metabolites as a result of the oil ‘barrier effect’, and (2) direct toxic effects of oil or oil constituents that possibly penetrate the eggs.

The slow lethal action of oil was demonstrated by the continuous low level respiratory activity (measured by carbon dioxide emission) of dying eggs over a six‐day monitoring period, and the fact that a significantly higher proportion of the dead eggs found on groundnut or traditional coconut oiltreated grains developed up to the late embryonic stage (first instar larvae) when compared with the control. Furthermore, in an experiment carried out by trapping C. maculatus eggs on oil‐treated and untreated artificial membrane (Sellotape), it was found that oiling did not affect egg development up to the late embryonic stage but prevented hatching of significantly higher numbers of developed first instar larvae.

Eggs that successfully hatch on oily grain surfaces may find it more difficult to penetrate, since egg attachments on such surfaces were found to be significantly less secure than on the control.

The proposed modes of action show that the complete spread of an oil film over the surfaces of a commodity is vital for the successful utilisation of fixed oils as stored‐product protectants.
Structure—activity relationships of organotin biocides and Ceratocystis ulmi
Authors: Eng George , Coddington Stephen P. , Stockton Laura L. , Acholonu Alexander D. W.
Published: November 2006

The effect of organotin compounds on the growth of Ceratocystis ulmi, the causative agent of Dutch elm disease, was studied in shake culture. Triphenyltin, (C6H5)3SnX, tricyclohexyltin, (C6H11)3SnX, and tributyltin, (C4H9)3SnX, compounds were all effective in the inhibition of C. ulmi in vitro. The anionic group, X, did not play a major role in the inhibitory activities of these compounds, suggesting that the species involved in the inhibition is R3Sn+ or the hydrated cation.
Membrane partitioning of organophosphorus and organochlorine insecticides and its implications for mechanisms of toxicity
Authors: Antunes‐Madeira Maria Do Carmo , Madeira Vitor M. C.
Published: November 2006

Partition coefficients of organophosphorus and organochlorine insecticides were determined in several types of membrane. Insecticide partitioning varied among the membranes under study, depending on temperature, cholesterol content and on the physico‐chemical profiles of membrane components and the insecticides themselves. The maximal partitions for DDT, lindane, parathion and malathion in egg phosphatidylcholine bilayers over the temperature range from 10 to 37°C (at which the lipid is in the liquid‐crystalline state) were about 260000, 2000, 1000 and 120, respectively. Incorporation of 50 mol% cholesterol in egg phosphatidylcholine bilayers dramatically decreased the partition and almost abolished the temperature effect. First‐order phase transitions of dimyristoyl‐, dipalmitoyl‐ and distearoylphosphatidylcholines (DMPC, DPPC and DSPC) were accompanied by a sharp increase in insecticide partition. Furthermore, the insecticides under study were more easily accommodated in bilayers of short‐aliphatic‐chain lipids, since higher values of partition were obtained in DMPC bilayers. Partition values in native membranes depended considerably on the membrane type and composition and were higher in sarcoplasmic reticulum (SR) and mitochondria than in brain microsomes, myelin and erythrocytes. Identical results were obtained in related liposomes of total extracted lipids, although the absolute partitions showed decreased values. In general, the incorporation of insecticides correlated reasonably with the cholesterol content of the membranes. The order of partitioning of the above insecticides did not run parallel with their toxicity to mammals and, both in model and in native membranes, followed the sequence: DDT ≫ lindane > parathion > malathion.
Biological effects and metabolism of fenoxycarb after treatment of the fourth and the fifth instars of the tobacco budworm, Heliothis virescens F.
Authors: Mauchamp Bernard , Malosse Christian , Saroglia Patrick
Published: November 2006

Treatment of 4th and 5th instar larvae of Heliothis virescens with different amounts of fenoxycarb induced an increase in weight of the 5th larval instar, prolongation of the 5th larval instar period, or the formation of dauer larvae. No effects were observed during the 4th instar and the moult to the 5th larval instar. To check whether these effects were due to persistence of fenoxycarb in treated larvae, metabolism of this chemical was analysed. Larvae were fed with radio‐labelled fenoxycarb at the first day of the 4th or at the first day of the 5th larval instar. Behaviour of the radio‐labelled compounds was followed during each instar. At the time of gut purge, the whole of the radio‐labelled material was excreted. The effects observed during the 5th instar of 4th‐instar‐treated larvae do not appear to be due to the persistence of fenoxycarb.

The main metabolites of fenoxycarb were identified using coupled gas chromatography and mass spectrometry.
Current insecticide management practices in cotton around the world–short‐term successes or templates for the future?
Authors: Sawicki Roman M.
Published: November 2006

Nationwide Insecticide Resistance Management (IRM) strategies against cotton pests in Zimbabwe, Egypt and Australia to delay build‐up of resistance to insecticides, especially the synthetic pyrethroids (SPs), are critically reviewed. It is concluded that there is a very urgent need to identify key determinants of selection for resistance by both laboratory simulation and field tests to improve knowledge of operational tactics. More reliable and rapid assays to detect resistance and a better understanding of the population dynamics of cotton pests are also needed to assess and predict rapidly and accurately the response of pest populations to countermeasures. Without such research, existing IRM strategies will remain essentially akin to models of population genetics in which scientific input has been replaced by common sense and intuition.
Pyrethroid resistance in Heliothis virescens: Current US management programs
Authors: Riley Steven L.
Published: November 2006

The increasing costs of insect control technology and crop production make it imperative that we clearly understand and attempt to manage insecticide resistance. The cost‐effectiveness of the synthetic pyrethroids for controlling Heliothis spp. and recent reports of resistance in major cotton producing regions around the world underscore this situation. Since 1983, a number of government, university and industry‐based programs have been initiated to monitor the spread of pyrethroid resistance in Heliothis spp. and to manage the use of the pyrethroids. In the US, four major efforts were conducted during 1987 and 1988. These were: (1) a Texas state‐wide management program, (2) a tri‐state management program in the mid‐south, (3) an adult monitoring program conducted by university personnel throughout the cotton belt and (4) an inter‐company monitoring program conducted by PEG‐US. These programs will be reviewed along with recommendations for refining future monitoring and management efforts.
Study of the disappearance of endosulfan, parathion, trichlorfon and pirimicarb from broccoli and portuguese cabbage
Authors: Magalhães Maria João A. , Ferreira Júlia R. , Frutuoso Lúcia , Taínha António A.
Published: November 2006

The influence of surface of exposure of brassicas to insecticide sprays has been assessed in two experiments conducted in small plots where endosulfan, parathion, trichlorfon and pirimicarb were applied to a flowering brassica, broccoli (Brassica oleracea L. var italica Plenck) and to a leafy brassica (Brassica oleracea L. var. tronchuda Bailey).

The differences of surface exposure resulted in much higher deposits and subsequent residue levels in broccoli. The results stress the need to evaluate residue data on groups of brassicas of different surfaces of exposure to pesticide spray when granting registration petitions for brassicas in general in order to establish pre‐harvest intervals.
Potential for exploiting plant genes to genetically engineer insect resistance, exemplified by the cowpea trypsin inhibitor gene
Authors: Hilder Vaughan A. , Gatehouse Angharad M. R. , Boulter Donald
Published: November 2006

Over the 400 million or so years of their co‐evolution, plants have evolved some highly effective strategies to combat herbivorous insects. Amongst these natural defence mechanisms are some which depend on a primary gene product for effect. These are currently suitable for producing insect‐resistant, transgenic crop plants by genetic engineering. One such mechanism involves the protease inhibitors from cowpea (Vigna unguiculata), which are anti‐metabolic to a wide range of insects. Cowpea trypsin inhibitor (CpTI) genes have been cloned and transferred to tobacco plants. Those transgenic tobacco plants which express physiological levels of CpTI have enhanced resistance to a wide range of insect pests. The insecticidal characteristics of these plants compare favourably with those of transgenic plants expressing the B. thuringiensis endotoxin gene. Some possible advantages of, and prospects for, using plant‐derived ‘insect‐resistance’ genes in this way are discussed.
The use of entomogenous fungi for pest control and the role of toxins in pathogenesis
Authors: Gillespie Adrian T. , Claydon Norman
Published: November 2006

Fungi have been suggested as agents for the biological control of insects for over a century, but their use remains extremely limited. This paper examines the biology of entomogenous fungi, highlighting their need for moisture, and reviews studies on the Entomophthoraceae, Beauveria bassiana, Beauveria brongniartii, Metarhizium anisopliae and Verticillium lecanii. It is suggested that current studies should be directed towards the control of pests living in humid micro‐climates and that moisture‐retaining formulations should be developed to reduce the reliance of fungi on moisture.

Many entomogenous fungi produce insecticidal toxins in submerged culture and these compounds are of interest as a source of new toxophores. The most extensively studied toxins are the cyclic depsipeptides from M. anisopliae, termed destruxins, and their possible role in pathogenesis is discussed. Beauveria bassiana also produces the cyclic peptides termed beauvericin, beauverolides, and bassianolide. Toxins produced by V. lecanii, and the Entomophthoraceae are also described.
Multivariate quantitative structure‐activity relationship (QSAR) methods which may be applied to pesticide research
Authors: Livingstone D. J.
Published: November 2006

Regression analysis is the most commonly used technique in QSAR studies. Whilst regression has its advantages, it also suffers from a number of disadvantages. A variety of mathematical and statistical techniques exist which complement or replace regression. These may he classified as ‘supervised’ and ‘unsupervised’ learning methods where supervision refers to the use made of biological data in the analysis. These terms are discussed and examples of three unsupervised and two supervised learning methods are presented. The techniques described are Non‐Linear Mapping, Principal Components Analysis, Cluster Analysis, Canonical Correlation Analysis and Factor Analysis. Although the examples presented are mostly pharmaceutical applications, it is proposed that the extra complexity of pesticide research data, compared with pharmaceutical, makes it very well suited to analysis by these methods.
The pyrethroids: Early discovery, recent advances and the future
Authors: Elliott Michael
Published: November 2006

A brief survey is given of the historical development of some of the more stable synthetic pyrethroids from the starting point of the natural pyrethrins. The main physico‐chemical, biological and toxicological properties of the synthetic pyrethroids are outlined as a background for the following papers. The importance of the pyrethroids in modern agricultural practice is stressed and areas of future application and development are discussed.
A review of the use of synthetic pyrethroids in public health and vector pest control
Authors: Carter S. W.
Published: November 2006

The last 40 years has seen significant evolution of the synthetic pyrethroids from their relatively restricted usage in domestic fly and mosquito control to their adoption in all major areas of public health pest control. The use of the synthetic pyrethroids in national and international control campaigns and in village level self‐help pest‐control schemes for major disease vectors such as mosquitoes, tsetse and blackfly is examined. Their successful introduction into the urban public health sector for control of cockroaches, fleas, bedbugs and lice, etc., is reviewed.
A brief review of the environmental fate and metabolism of pyrethroids
Authors: Demoute Jean‐Pierre
Published: November 2006

Pyrethroids are a class of lipophilic insecticide very easily degraded in the natural environment. The two main routes of degradation, photo‐ and biodegradation, are often superimposed. Pyrethroids developed for use in agriculture are much more photostable than the natural pyrethrins or early synthetic derivatives but they are still sensitive to sunlight, which triggers many alterations such as isomerisation or ester cleavage. The basic pathways of pyrethroid metabolism include hydrolysis of the central ester linkage and oxidation of both acid and alcohol moieties. The rate of these metabolic transformations and the nature of the metabolites depend mainly on the organism involved. Birds and mammals metabolise and excrete more rapidly than insects and fishes. In plants, initial metabolic processes are identical to those known in animals. In soil, pyrethroids undergo the same type of transformation, hydrolysis and oxidation. Neither degradation products nor intact parent compounds are leached.
Fungicidal activity of some alkylthio‐substituted 2‐iodo‐and 2‐methylbenzanilides
Authors: Carmellino Marialuisa , Massolini Gabriella , Pregnolato Massimo , Pagani Giuseppe
Published: November 2006

Some 3′‐ or 4′‐alkylthio‐2‐iodobenzanilides and some 3′‐alkylthio‐2‐methylbenzanilides were tested in vitro and in vivo against fungal plant pathogens of different taxonomic classes and some showed activity, especially in vivo. Among all the tested compounds the 3′‐alkylthio‐2‐iodobenzanilides revealed the highest activities.