bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of formulation properties on droplet size spectra and ground deposits of aerially‐applied pesticides
Authors: Sundaram Alam , Retnakaran Arthur
Published: November 2006

The influence of the physical properties of the spray liquid on droplet size spectra and ground deposits of aerially‐applied pesticides was studied using heavy (high‐viscosity) oil‐ and water‐based suspensions of wettable powders (w.p.), a clear solution in a light (low‐viscosity) oil, and an emulsion‐suspension containing a bacterial control agent. The heavy oil provided a highly viscous spray medium, 52 to 64 mPa s (at a shear rate of 480 s−1), resulting in large droplet sizes and a high deposit on the ground sampling units. When the spray medium was thickened with petroleum jelly to keep the w.p. in suspension during overnight storage, the viscosity became excessively high (102 mPa s at 480 s−1), and the droplet spectrum was undesirably coarse and resulted in poor coverage of the spray plot and low deposits. The light‐oil‐based solution (ca 4 mPa s), provided a finer droplet spectrum and lower deposits than the heavy‐oil‐based formulations. The water‐based suspensions of the w.p. (ca 2 mPa s), showed Newtonian behaviour, whereas the emulsion‐suspension (ca 240 mPa s at 480 s−1) showed pseudoplastic behaviour. Consequently, the emulsion‐suspension provided a markedly different droplet spectrum from that of the suspensions of the w.p. Nevertheless, all three aqueous media provided deposits comparable to those of the light‐oil‐based solution, markedly lower than the heavy‐oil‐based suspensions. The study indicated that highly viscous Newtonian formulations should be avoided in pesticide applications using Micronair AU3000 atomisers at the volume rate (4–7 litre ha−1) used here if high atomisation efficiency is required.
Broad versus narrow‐spectrum herbicides and the future of mixtures
Authors: Martin Trevor J.
Published: November 2006

The weed flora of cereals is subject to changes in husbandry methods such as cultivations and crop rotations. The herbicide chemist inevitably has to aim at a moving target. Herbicides themselves apply a selection pressure to the weed flora and when newly introduced often give exceptional results. Continued use allows the less‐susceptible species to become dominant and herbicide mixtures may prove necessary. The concept of mixtures is not new; the phenoxy‐acid herbicides were being formulated together in the 1960s. More recently bromoxynil and ioxynil have been added to assist in the control of more difficult species like mayweeds and parsley piert. Grass weeds, which have been encouraged by minimum‐cultivation techniques, can now be controlled, in addition to broad‐leaved weeds, by suitable mixtures.

Completing the weed spectrum is the most obvious reason for mixing two compounds in a formulation or in the spray tank but synergistic interaction, combination of different modes of action, simple convenience and lengthening a product's commercial life may all be involved.

Despite the very large choice of products for use in UK cereal crops there is not a single herbicide that could not be replaced by more effective compounds, safer to the crop, more flexible in application criteria, and with generally more reliable action. The chances of new compound discovery are decreasing and the fluctuations in the weed flora make it difficult to aim at specificity. The development of resistant biotypes within species seems to happen rather slowly and compounds with less specificity or in mixture with others having different sites of action would almost certainly help to avoid the problem.
Fenvalerate wash‐off from cotton plants by rainfall
Authors: McDowell Leslie L. , Willis Guye H. , Southwick Lloyd M. , Smith Sammie
Published: November 2006

Information on rainfall wash‐off of foliar‐applied pesticides is needed in developing mathematical models to predict the transport of pesticides to soil and in run‐off from croplands. Fenvalerate [(RS)‐α‐cyano‐3‐phen‐oxybenzyl (RS)‐2‐(4‐chlorophenyl)‐3‐methylbutyrate] is used extensively for cotton (Gossypium hirsutum L.) insect control in the southern United States during July, August and September, which are months of high‐intensity thunderstorms. Fenvalerate was washed from mature cotton plants by the use of a multiple‐intensity rainfall simulator. Fenvalerate concentration in wash‐off from plants was independent of rain intensity. When 25 mm of rain was applied at 7, 13, 26 and 51 mm h‐1 just2 h after fenvalerate was applied at 0.224 kg ha‐1, 38 (±10)% of the fenvalerate load on the plants was washed off. Fenvalerate concentrations in storm wash‐off decreased with wash‐off volume as hyperbolic functions. Rainfall amount affected the wash‐off of fenvalerate from cotton to a greater extent than did rainfall intensity. This information greatly simplifies modelling the movement of fenvalerate from plant canopy to soil during natural storms.
Effect of formulation properties on ground and foliar deposits of two insecticides in flushed and one year‐old balsam fir needles following aerial application
Authors: Sundaram Kanth M. S. , Raske Arthur G. , Retnakaran Arthur , Sundaram Alam , West Rick J.
Published: November 2006

A study was conducted in 1985 in Newfoundland to investigate the interrelationships between the physical properties of spray formulations, droplet‐size spectra and deposits on ground sampling units, and deposits on flushed and one‐year‐old balsam fir foliage following aerial application of aminocarb and fenitrothion at different dosage rates, but using the same volume rates. The fenitrothion formulations were pseudoplastic, because of the presence of polymeric ingredients, and provided higher deposits on the ground sampling units and on foliage than the aminocarb formulations, which were nearly Newtonian. At similar dosage rates, the ground deposits of fenitrothion were about twice those of aminocarb, whereas the corresponding foliar deposits were about 6 to 8 times higher than those of aminocarb, suggesting possible advantages of pseudoplastic formulations in providing optimum droplet sizes for enhanced deposition on balsam fir needles.

The foliar deposits generally showed an increase when the dosage rates of the two insecticides were increased. Deposits in flushed foliage were slightly higher than those in mature foliage, probably due to the location of the flushed needles at the extreme periphery of the tree canopy.
Effects of the pyrethroid insecticide, WL85871 and phosalone on adults and progeny of the leaf‐cutting bee Megachile rotundata F, pollinator of lucerne
Authors: Tasei Jean‐Noël , Carre Serge , Bosio Pierre Gustave , Debray Philippe , Hariot Jean
Published: November 2006

Experiments have been carried out to compare the effects of phosalone and the pyrethroid insecticide, WL85871 on the alfalfa leaf‐cutting bee. Laboratory trials using male adults exposed to treated filter papers showed that WL85871 at the rate of 15 g ha−1 caused mortality equal to or less than that with phosalone at 1000 g ha−1. At the rate of 10 g ha−1, the pyrethroid was less harmful than phosalone. Populations of about 400 females were reared in 4 flowering lucerne fields. One was the control and was not treated, the three other treatments were: A=phosalone at 1000 g ha−1, B=WL85871 at 10 g ha−1, C=WL85871 at 15 g ha−1. Two days after the treatments, counts of live females in artificial nesting sites showed the losses due to A, B, C to be respectively 31%, 21% and 12%. After hibernation and incubation of the progeny larvae, little effect of the treatments could be observed. No residues were detected in live larvae. The maximum residues found in leaves in nests were 71 mg kg−1 of phosalone and 1 mg kg−1 of WL85871. Much lower residues were found in pollen provisions, where the maximum values were 1 mg kg−1 of phosalone and 0–07 mg kg−1 of WL85871.
Toxicity and mode of action of reductively dechlorinated cyclodiene insecticide analogues on houseflies (Musca domestica L.) and other diptera
Authors: Brooks Gerald T. , Mace David W.
Published: November 2006

The toxicities of reductively dechlorinated analogues of dieldrin and some of its photochemical rearrangement products were compared with those of reductively dechlorinated analogues of endrin, endosulfan and isobenzan, against houseflies (Musca domestica L.), blowflies (Calliphora vicina R‐D) and in some cases, fleshflies (Sarcophaga barbata Parker) by topical application of the compounds in acetone. Some of the known toxic oxidative metabolites of dieldrin and endrin were also included for comparison. The chlorine atoms at C‐1 and C‐8 (bridge‐end) of the hexachlorobicyclo[2.2.1]hept‐2‐ene nucleus were retained in all of the analogues tested, while those at C‐9, C‐10 (ethylenic) and C‐11 (dichloromethane bridge), or their equivalent in the photochemical rearrangement products, were variously replaced by hydrogen atoms. The four‐fold increase in toxicity obtained when both of the C‐9 and C‐10 chlorine atoms in dieldrin were replaced by hydrogen appeared to be unique for this compound. Similar increases in potency also resulted from the selective reductive monodechlorination of the endosulfan isomers but in dechlorinated compounds from other series of analogues, toxicities were either unchanged or reduced. Thus, the effect of reductive dechlorination depends on the structure of the remainder of the molecule. Reductive dechlorination of the C‐11 dichloromethane bridge had the most consistent effect on toxicity; the anti‐C‐11 chlorine atom was generally more important for toxicity than the syn‐C‐11 chlorine atom, with large differences between the toxicities of these isomers in some cases. The results, which support a suggested structural analogy between the cyclodienes, lindane, and convulsant, substituted γ‐butyrolactones such as picrotoxinin, are discussed in relation to current theories of cyclodiene insecticide action.
A rapid and sensitive method for gas‐liquid chromatographic determination of N‐nitrosodimethylamine in formulations of chlormequat chloride
Authors: Wigfield Yuk Y. , Lacroix Mario D.
Published: November 2006

A rapid and sensitive method for the isolation, clean‐up and gas‐liquid chromatographic determination of trace quantities of N‐nitro‐sodimethylamine (NDMA) in an aqueous formulation of 2‐chloroethyltrimethylammonium chloride (chlormequat chloride) is reported. Seventeen samples of two different formulations were collected and analyzed. The levels of NDMA ranged from 0.08 to 0.2 μg g−1 of chlormequat chloride. The minimum detectable amount was 0.01 ng which is equivalent to 0.01 μg g−1 or 0.03 μg g−1 depending on the concentration of the active ingredient in the formulation. Recoveries from the samples spiked with NDMA standard at 0.23, 0.17 and 0.11 μg g−1 were 90–102% with a mean of 98.4% and an overall coefficient of variation of 3.7%. The detector response was found to be linear within the range 0.05 ng to 0.2 ng.
Enhanced degradation of iprodione and vinclozolin in soil: A simple colorimetric test for identification of rapid‐degrading soils
Authors: Walker Allan
Published: November 2006

Measurements by gas‐liquid and high performance liquid chromatography confirmed that 3,5‐dichloroaniline was an important degradation product of iprodione in soil, and demonstrated that it could be extracted in relatively high concentrations when iprodione degradation was rapid. A colorimetric test based on the production of a diazo colour complex was shown to differentiate between amounts of the aniline in the range from 2 to 15 μg. The test was used to examine 3,5‐dichloroaniline production from iprodione incubated at 50 mg kg−1 in 33 soils with previously‐measured iprodione degrading properties. A positive colour reaction in acetone extracts made after 3 days was obtained with those soils in which the time to 90% degradation of iprodione was less than 6 days. A positive reaction after 7 days was obtained when this time was less than 14 days, and a positive reaction after 10 days was associated with a time to 90% degradation of less than 22 days. Preliminary studies with vinclozolin indicated that the test could also be used to identify soils which rapidly degrade this fungicide.
1,2‐Diphenylaziridines as pesticides: Studies on acute toxicity and delayed effects
Authors: Dahlman Douglas L. , Kadaba Pankaja K.
Published: November 2006

The insecticidal activities of 15 different 1,2‐diphenylaziridines were evaluated. These compounds are readily obtained by photolysis of 1,2,3‐triazolines; the latter can be conveniently prepared by the addition of diazomethane to Schiff bases in dioxane in the presence of water. Compounds containing a chloro, bromo or trifluoromethyl group in the para position of the 1‐phenyl and a chloro in the ortho position of the 2‐phenyl caused acute toxicity in 5th‐instar Manduca sexta larvae via both oral and topical routes of exposure. Lower concentrations resulted in delayed effects such as reduced growth rate, pupal and adult malformations and reduced fecundity. When either phenyl group was unsubstituted, the activity was reduced. Unsubstituted 1,2‐diphenylaziridine was inactive. Topical applications of l‐(4‐fluorophenyl)‐2‐(2‐chlorophenyl) aziridine were active against representative species in the insect orders Lepidoptera, Coleoptera and Orthoptera.
An analytical study of formulations containing malathion
Authors: Mason David J. , Crozier Brian
Published: November 2006

A total of sixty‐five samples of eighteen different commercial formulations containing malathion were examined in this study. Twelve formulations were found to have a malathion content which was in general agreement with that declared. However, one of these twelve formulations (an emulsifiable concentrate) contained a high level of isomalathion. Five formulations (all emulsifiable concentrates) had significantly lower malathion contents than those declared and were contaminated with malathion analogues, present at concentrations ranging from c.2 to over 100 % mass/mass of the malathion found. These analogues of malathion appear to have resulted from the transesterification of malathion with alcohols used as formulating agents. One formulation (a dustable powder) was found to contain no malathion above the detection limit. Many of the formulations failed tests of their physical properties.
The pyrethrins and related compounds. Part XXXIII. Effective combinations in the gemdimethyl‐central group region of non‐ester pyrethroids
Authors: Baydar Ahmet E. , Elliott Michael , Farnham Andrew W. , Janes Norman F. , Khambay Bhupinder P. S.
Published: November 2006

Synthesis and testing for insecticidal activity ofa wide range of combinations representing simultaneous variation in the acid or alcohol and central fragments of non‐ester pyrethroids reveals strong interactions between these changes, When the gemdimethyl (CMe2), or the equivalent cyclopropyl, group is present in the central chain rather than in a side chain, a new set of requirements for effective central groups applies; those identified as conferring highest activity in this situation are ; (CH2)3; CH2CO. CH2 and CH2O. CH2. Other variations establish the limits to structural changes within these combinations, for activity to be retained.
Minimum concentration levels of methyl bromide required for full efficacy against seven species of stored‐product beetle at two temperatures
Authors: Bell Christopher H.
Published: November 2006

The dosages of methyl bromide required to control insect pests can be expressed as concentration, time (Ct) products for concentrations down to a certain minimal level, here defined as the efficacy threshold, below which Habers Ct rule (C×t=k,a constant for mortality) no longer applies. Twelve strains of seven species of stored‐product beetle were tested to identify efficacy threshold concentrations at 15°C and 25°C. For each strain the efficacy threshold was higher at 25°C than at 15°C. Different species differed widely in the threshold levels identified. Strains with a higher than usual tolerance to methyl bromide than their standard stock counterparts had slightly higher efficacy thresholds at 25°C but not at 15°C. The order of tolerance of the standard stocks to methyl bromide at 15°C was Tribolium confusum> T. castaneum> Oryzaephilus surinamensis> Rhyzopertha dominica> Sitophilus granarius> S. zeamais> S. oryzae, and at 25°C Tribolium castaneum > T. confusum> R. dominica> O. surinamensis> S. granarius> S. zeamais> S. oryzae. The order of efficacy thresholds largely reflected the order of susceptibility, S. oryzae and S. zeamais having the lowest efficacy thresholds of about 0.6 mg litre−1 at 15°C and 1.3‐2.0 mg litre−1 at 25°C, while Tribolium spp. had the highest, 1.3‐2.0 mg litre−1 at 15°C and 2.5‐4.0 mg litre−1 at 25°C.
Residues of HCH in milk after its oral administration or dermal application to indian buffalo, Bubalus bubalis (L.)
Authors: Kapoor Sudesh K. , Kalra Rajinder L.
Published: November 2006

The excretion of HCH (hexachlorocyclohexane) residues in the milk of Indian buffalo, the main milch cattle of India, after oral or dermal exposure to technical HCH was studied. Following the intake of 10, 25,50 and 100 mg of technical HCH by different groups of buffaloes, HCH residues in milk showed an initial rapid rise but soon attained a dose‐dependent equilibrium. The transfer coefficient of HCH residues in milk fat at 'plateau' showed an average value of about 15%. Half‐life values for the rate of decline of HCH residues during the post‐dosing period were computed according to a two open‐compartment model. Dermal application of technical HCH to buffaloes also resulted in significant residues in milk. The proportions of alpha‐, beta‐, gamma‐ and delta‐isomers of HCH in milk of buffaloes following oral and dermal routes of exposures were different. The significance of these results in the regulation of HCH residues in milk is discussed.
Transformation of barban and analogues by Pseudomonas alcaligenes isolated from soil
Authors: Marty Jean‐Louis , Bastide Jean
Published: November 2006

Chlorbufam and barban are two common herbicides used for the control of weeds. A bacterial strain isolated from soil and identified as Pseudomonas caligenes was able to hydrolyse chlorbufam with the production of 3‐chloroaniline. However, barban was metabolised without production of 3‐chloroaniline. A study has been made of the transformation by Pseudomonas alcaligenes of structural analogues of these two herbicides (but‐2‐ynyl 3‐chlorocarbanilate, butyl 3‐chlorocarbanilate, 4‐hydroxy‐but‐2‐ynyl 3‐chlorocarbanilate) and cinnamyl chloride. It was shown that barban gave a water‐soluble metabolite by reaction of the propargyl chloride group of this compound. The same reaction was obtained with the allyl chloride group of cinnamyl chloride.

The water‐soluble metabolite was identified as a glutathione conjugate. The pH and composition of the medium have a considerable influence on barban metabolism.
Studies on pesticides based on coumarin IV: Synthesis and antifungal activity of twelve 4‐(substituted phenoxy)methyl‐6‐methyl coumarins
Authors: Batra Tushar , Singh Raj V. , Sangwan Naresh K. , Malik Mangel S. , Malik Om. P.
Published: November 2006

Twelve 4‐(substituted phenoxy)methyl‐6‐methyl coumarins were synthesised by the condensation of 4‐chloromethyl‐6‐methyl coumarin with various phenols in the presence of potassium carbonate in dry acetone. The compounds were tested for their toxicity towards the mycelial growth of seven plant pathogenic fungi. Among the tested fungi, Pythium aphanidermatum, Colletotrichum falcatum, Drechslera oryzae, Alternaria alternata and Fusarium solani exhibited maximum sensitivity whereas Macrophomina phaseolina and Rhizoctonia solani were least sensitive to the test compounds. The 4‐(4‐tert‐butylphenoxy)methyl and 4‐(4‐nitrophenoxy)methyl analogues possessed greatest toxicity towards the majority of the tested fungi.
Phosphonate—hydrogen exchange in aqueous solutions of 2H and 3H‐labelled phosphonic acid
Authors: Bompeix Gilbert , Burgada Ramon , Lameta Agnès D'arcy , Soulié Marie‐Christine
Published: November 2006

Phosphonic acid (phosphorous acid), H — PO(OH)2, the active breakdown product in plant tissues of the systemic anti‐oomycete fungicide fosetyl‐aluminium was investigated in order to assay the stability of the labelled compound. There is a strong and fast isotopic exchange in unbuffered aqueous solutions of 2H — PO(OH)2, and therefore 3H — PO(OH)2, so that Fenn and Coffey's experiments must be reinterpreted because these authors used a stock solution of pure labelled phosphonic acid. However, it is possible to use this last compound for biological experiments under the following conditions: (1) Keeping the dry sodium salt 3H — PO(ONa)2. 5H2O in small flasks (100 mg, 37 MBq each) in a vacuum desiccator for individual use without fractionation; (2) using the compound at neutral or slightly acidic pH.
An assessment of methacrifos as a grain protectant and its efficacy against oryzaephilus surinamensis L., Tribolium castaneum herbst, Sitophilus granarius L., Sitophilus oryzae L., Acarus siro L., Glycyphagus destructor schrank and Tyrophagus longior gervais
Authors: Tigar Barbara J. , Pinniger David B.
Published: November 2006

A trial was carried out to investigate the efficacy of methacrifos against susceptible and multi‐resistant strains of four species of insect and three species of mite. Methacrifos was applied to two separate 20‐tonne loads of English wheat which were then stored under ambient conditions for 24 weeks. The efficacy of methacrifos was assessed using established bioassay techniques which showed complete control for 24 weeks of all susceptible insects except S. oryzae, where there were survivors at week 24. Methacrifos also gave 100% mortality of resistant O. surinamensis for 24 weeks. There was >95% mortality for 16 weeks of resistant strains of T. castaneum and of resistant S. granarius and S. oryzae for 20 weeks. After S. granarius and S. oryzae were removed, the grain was incubated for 10 weeks. Subsequent F1 emergence was considerably less from the treatments than from the controls. Methacrifos produced 100% mortality for T. longior for 24 weeks, but control of G. destructor fluctuated and was <100% at week 24. There were survivors of A. siro from week 4.
Field test of a mathematical model for non‐equilibrium transport of pesticides in soil
Authors: Boesten Jos J. T. I. , Van Der Pas Leo J. T. , Smelt Johan H.
Published: November 2006

A model for the transport of pesticides in non‐structured arable soil has been tested under field conditions. Three classes of sorption site are distinguished in the model. Sorption at class 1 sites is assumed to be at equilibrium whereas sorption at class 2 and class 3 sites is calculated using rate equations. Class 2 sites equilibrate on a time scale of days and class 3 sites equilibrate on a time scale of hundreds of days. In the model, the liquid phase is assumed to be homogeneous and completely mobile. The model was validated in two field experiments on a loamy sand soil using the herbicides cyanazine and metribuzin and using bromide ion as a tracer of liquid flow in soil. Ignoring sorption at class 3 sites resulted in large discrepancies between calculated and measured concentration profiles. Calculated concentration profiles were sensitive to the desorption rate constant for class 3 sites.
Synthesis of new 7H‐1,3,4‐thiadiazolo[3,2‐a] [1,3,5] triazine‐7‐thiones as potential fungicides
Authors: Yadav Lal Dhar Singh , Misra Atma Ram , Singh Harendra
Published: November 2006

A number of 2‐aryl‐ and 2‐aryloxymethyl‐5‐aryl‐7H‐1,3,4‐thiadiazolo[3,2‐a][1,3,5]triazine‐7‐thiones have been synthesised and their fungitoxicities determined in vitro against Aspergillus niger and Fusarium oxysporum. Two alternative routes for synthesis of the title compounds are described. Some of the compounds had activities comparable with that of the commercial fungicide mancozeb. Structure/activity relationships for the compounds are discussed.
Products from the sensitised photo‐oxidation of 2‐dimethylamino‐5,6‐dimethylpyrimidin‐4‐ol
Authors: Dixon Stephen R. , Wells Clifford H. J.
Published: November 2006

The products from the methylene blue sensitised photo‐oxidation of 2‐dimethylamino‐5,6‐dimethylpyrimidin‐4‐ol (I) in deuterochloroform/deuteroacetone have been investigated. A zwitterion and a hydroperoxide are formed initially, with the zwitterion predominating. The zwitterion compound degrades or reacts in the solid state on silica gel to give further products.
Accelerated degradation of thiocarbamate herbicides in Israeli soils following repeated use of vernolate
Authors: Tal Abraham , Rubin Baruch , Katan Jacob , Aharonson Nadav
Published: November 2006

Accelerated degradation of vernolate, EPTC and butylate but not of cycloate was detected in soils from three locations in Israel which were treated annually with vernolate. Repeated application of EPTC to soils with and without a history of vernolate application, under laboratory conditions, resulted in a progressive increase in its rate of dissipation with each application. Accelerated degradation of EPTC was also rapidly induced by mixing small amounts (5%) of soil with a history of vernolate treatment with soil that had never received vernolate. Liberation of 14CO2 from [14C]EPTC was more rapid in vernolate‐treated soils than in untreated soils, indicating a development of microbial populations in soil capable of rapidly degrading the EPTC. Degradation of [14C]EPTC was faster in soil previously cropped with maize than in non‐cropped soil, but slower in soils cropped with cotton or peanuts.
Synthesis and insecticidal activity of lipophilic amides. Part 7. Alternative aromatic groups for phenyl in 6‐phenylhexa‐2,4‐dienamides
Authors: Elliott Michael , Farnham Andrew W. , Janes Norman F. , Johnson Diana M. , Pulman David A.
Published: November 2006

Synthesis of a wide range of analogues of the lead compound, N‐2‐methylpropyl‐6‐phenylhexa‐2,4‐dienamide, in which phenyl was replaced by other aromatic systems is reported. In cases where rearrangement rendered the N‐2‐methylpropyl compound less accessible, N‐2,2‐dimethylpropyl substitution was used, because rearrangement was then suppressed. Several of the groups examined, for instance 2‐naphthyl, enhanced insecticidal activity, and when appropriately substituted, particularly with halogen, led to the most active compounds discovered in this series.
Problems in the control of insecticide‐resistant rice plant‐ and leafhoppers
Authors: Miyata Tadashi
Published: November 2006

Several species of rice plant‐ and leafhoppers cause serious yield loss by sucking the plant sap and/or by transmitting diseases. Rice plant‐ and leafhoppers show resistance to various organochlorine, organophosphorus, carbamate and pyrethroid insecticides and may also be resistant to compounds of two or more different chemical groups. Thus, it is important to monitor the levels of resistance in field populations, to control resistant populations and to retard the development of further resistance by appropriate tactics. The merits and shortcomings of the various tactical and monitoring techniques are discussed.
Use of immunochemical techniques for the analysis of pesticides
Authors: Jung Freia , Gee Shirley J. , Harrison Robert O. , Goodrow Marvin H. , Karu Alexander E. , Braun Adolf L. , Li Qing Xiao , Hammock Bruce D.
Published: November 2006

Immunochemical assays for small molecules such as pesticides are rapidly gaining acceptance among analytical chemists. These techniques are rapid, sensitive, cost effective and can easily cope with large sample loads. This review lists the advantages and disadvantages of the technique and describes the steps in assay development using examples from this laboratory, particularly the thiocarbamate herbicide molinate and the triazine herbicides. The focus is primarily on hapten synthesis strategies, assay format considerations, sample preparation and assay validation.
Insecticide resistance in Myzus persicae: From field to gene and back again
Authors: Devonshire Alan L.
Published: November 2006

This review of our work on resistance in Myzus persicae over the past 20 years is divided into three sections. After a brief introduction, the biochemistry of the resistance mechanism is discussed, followed by a description of how the understanding of this has been used to develop sensitive and reliable methods for monitoring resistance in field populations. Finally, recent work on the molecular genetic basis of the resistance mechanism is described, and its practical implications for understanding the build‐up of resistance in populations are discussed.
The role of behavior in insecticide resistance
Authors: Sparks Thomas C. , Lockwood Jeffrey A. , Byford Ronnie L. , Graves Jerry B. , Leonard B. Roger
Published: November 2006

Although behavioral resistance remains enigmatic, an examination of the literature firmly supports the existence of behavioral resistance in both the presence and absence of the better understood and accepted physiological and biochemical mechanisms. Studies of pyrethroid resistance in the horn fly and the tobacco budworm have identified several resistance mechanisms, including behavioral adaptations, in addition to target‐site insensitivity and enhanced detoxification. The coexistence of physiological and behavioral responses neither precludes a common mechanism nor requires one. Even if a common mechanism such as knockdown resistance or enhanced detoxification is involved, this does not negate the survival benefit of either avoiding the toxicant or reducing movement to avoid exposure. Thus, behavioral resistance may be much more ubiquitous and important than previous interpretation of the literature suggests.
Designing resistance management programs: How can you choose?
Authors: Roush Richard T.
Published: November 2006

A list of often‐discussed resistance management tactics is critically reviewed. Alteration of insecticides across generations, non‐persistent formulations, and the use of pesticides conferring only low magnitudes of resistance seem to be among the most promising tactics for general use in resistance management. Justifying the first two choices usually requires little more than data on product persistence in terms of toxic effect on susceptible individuals under field conditions. The last tactic requires additional information on resistance ratios for resistant and susceptible genotypes under field exposure. The efficacy of pesticide mixtures is highly dependent on equal persistence of both compounds used in the mixture. The number of genes involved in resistance and the fitness disadvantages they may confer in the absence of use appear to be of relatively little significance in choosing management tactics.
A comparison of permethrin and methomyl insecticides for the control of a multiresistant strain of houseflies (Musca domestica)
Authors: Webb D. P. , Wildey K. B. , Chapman P. A.
Published: November 2006

A methomyl sugar bait formulation and permethrin residual spray were compared for the control of a multi‐insecticide resistant strain of housefly in a UK pig farm. The methomyl was applied as a granular scatter bait at the manufacturer's recommended rate of 25 mg m−2 active ingredient (a.i.) to the treated floor area. Permethrin was applied at 32, 64 and 128 mg m−2 a.i. to structural surfaces. The highest deposit rate of permethrin used was four times that recommended by the manufacturer for the control of flying insects. The methomyl bait gave effective control but the permethrin spray failed at all deposit rates tested. The use of permethrin increased resistance to this compound at the KD50 level from x 13 to x 560 within 10 weeks and significantly increased the proportion of flies resistant to natural pyrethrins synergised with piperonyl butoxide (P<0.01).
A molecular graphics study of factors influencing herbicidal activity of oximes of 3‐acyl‐tetrahydro‐2H‐pyran‐2,4‐diones
Authors: Winkler David A. , Liepa Andris J. , Anderson‐McKay Janet E. , Hart Noel K.
Published: November 2006

Structure‐activity relationships in oximes of a series of sixteen 3‐acyltetrahydro‐2H‐pyran‐2,4‐diones, exhibiting a variety of pre‐ and postemergent herbicidal activities, have been studied by means of computer graphics methods. The most active compounds are potent grass‐killers. This graminicidal activity appears to depend strongly on the size and shape of the substituent at the 6‐position of the pyran. The activity correlates with both molar refractivity and fit to a hypothetical ‘receptor’ probably the active site of acetyl coenzyme A carboxylase. The herbicide sethoxydim and the pyrandione herbicides appear to mimic the transition state of the reaction catalyzed by acetyl‐CoA carboxylase.

The study has yielded a receptor model which defines clearly the three‐dimensional binding reguirements of the pyran ring and the substituents at the 6 position. It is not capable of providing information on the structural requirements of the 3‐acyl moiety. The model is capable of discriminating between active and inactive herbicidal compounds and provides a basis for the design of new herbicidal compounds with enhanced graminicidal activity.
Symbiotic micro‐organisms of insects: A potential new source for biologically active substances
Authors: Kenny Peter T. M. , Tamura Susan Y. , Fredenhagen Andreas , Naya Yoko , Nakanishi Koji , Nishiyama Koushi , Sugiura Miyoji , Kita Hiroshi , Komura Hajime
Published: November 2006

Symbiotic micro‐organisms isolated from insects have been shown to be a potential new source for antimicrobial substances. Diacetylphloroglucinol and pyoluteorin were produced by a bacterial symbiont of the white‐backed planthopper, Sogatella furcifera. Diacetylphloroglucinol was also produced by a fungal ectosymbiont of an ambrosia beetle, Scolytoplatypus mikado. A peptide antibiotic, polymyxin E1, was isolated from the cultured broth of an intracellular symbiont identified as Bacillus polymyxa, isolated from an oriental stinkbug, Plautia stali. An Enterobacter sp. bacterial symbiont of the brown planthopper, Nilaparvata lugens, produced a novel antibacterial substance, andrimid, whose antibacterial spectrum is unique, displaying potent activity only against the bacterial blight pathogen of the rice plant, Xanthomonas campestris pv. oryzae, and a few other bacteria.
Extended summaries pesticides group symposium natural products as a source for new agricultural chemicals
Authors: McGowan Christine M. , Willms Lothar , Ayer S. W. , Isaac B. G. , Krupa D. M. , Crosby K. E. , Letendre L. J. , Stonard Richard J. , Phillipson J. David , Powell Richard G. , Nair M. G. , Putam A. R.
Published: November 2006

The following are extended abstracts of six of the papers presented at the above meeting and, as so presented, they are entirely the responsibility of the authors and do not reflect the views of the Editorial Board of Pesticide Science.
Use of insect antifeedants against aphid vectors of plant virus disease
Authors: Griffiths David C. , Pickett John A. , Smart Lesley E. , Woodcock Christine M.
Published: November 2006

The probing and feeding behaviour of aphids can result in uptake of viruses from infected plants and subsequent transmission to healthy plants. It is possible to interfere with virus acquisition and transmission by influencing aphid host‐selection and feeding behaviour with antifeedant chemicals. Published work is reviewed and new work is presented in this paper. The two most successful classes of antifeedants against aphids are (a) compounds derived from the aphid alarm pheromone and (b) plant‐derived antifeedants such as the sesquiterpene (‐)‐polygodial. Results with these and other compounds are discussed in terms of antifeedant activity against Myzus persicae, their effects on resistant aphids and the evidence for decŕease in virus spread by aphids in laboratory and field.
A note on simple biochemical methods for resistance detection and their field application in Sri Lanka
Authors: Hemingway Janet
Published: November 2006

Insecticide resistance is conferred by a limited number of clearly defined mechanisms. Previously, resistance detection in field populations of insects was confined to bioassays, which gave information limited to the presence of resistance to the insecticide tested. Biochemical tests have now been introduced into the field in Sri Lanka, which give information on the underlying mechanism of resistance. These tests, as well as being cheap and easy, work at the level of the individual insect and hence give information on the spectrum of resistance, the level of resistance and the frequency of resistance genes in field populations. In Sri Lanka, a malathion‐specific carboxylesterase has been detected in Anopheles culicifacies, an altered acetylcholinesterase in Anopheles nigerrimus and oxidase and glutathione S‐transferase based mechanisms in Anopheles subpictus. The selective advantage of resistant individuals under field insecticide spraying regimes has been estimated, and the relative importance of larval and adult insecticide selection assessed.
The structure/activity relationships of pyrethroid insecticides. 1. A Novel Approach Based upon the Use of Multivariate QSAR and Computational Chemistry
Authors: Ford Martyn G. , Greenwood Richard , Turner Christopher H. , Hudson Brian , Livingstone David J.
Published: November 2006

The structure/activity relationships of substituted benzyl (1RS)‐transcyclopropane‐1‐carboxylate insectieides have been investigated by a combination of multivariate statistical techniques and molecular modelling. Quantum and molecular mechanics were used to calculate a set of seventy descriptors to represent the molecular properties of the series. These can be summarised by eight uncorrelated factors which describe the associations between the seventy descriptors with little loss of information. The neurotoxicities, knockdown and killing activities of the compounds are associated with the same three physicochemical factors, suggesting that common molecular features are required for these different responses. In this series, high biological potency is conferred by the presence of a partial positive charge at a meta carbon in the benzyl ring of the alcohol moiety, small nucleophilic superdelocalisabilities on the carbonyl carbon and oxygen atoms of the ester linkage, and chlorosubstituents subtended by the terminal carbon atom of the vinyl side chain at C3 of the cyclopropane ring. An additional property related to the nucleophilic superdelocalisabilities of the ortho and meta carbons of the benzyl ring is required for knockdown activity.
Pyrethroids and terrestrial non‐target organisms
Authors: Inglesfield Christopher
Published: November 2006

The discovery and development of the pyrethroid insecticides represents a major advance in the techniques of crop protection and disease vector control. These compounds combine outstanding efficacy against a broad spectrum of noxious insects with low toxicity to birds and mammals. This paper considers the effects of pyrethroids on other components of the terrestrial non‐target fauna, with particular reference to effects on ‘beneficial’ organisms, including natural pest‐control agents, pollinators, and organisms responsible for the maintenance of soil structure and fertility. This paper uses laboratory and field data to identify which groups of organisms may be potentially at risk from the use of pyrethroids, and draws on extensive field data to consider the significance of such hazards under conditions of normal use. Emphasis will be placed throughout on the evaluation of these compounds under practical conditions, including both crop and non‐crop usages. Limitations to, and opportunities for, the use of pyrethroids are discussed, and the potential for further development is considered.
The origins of selectivity and performance of a new pre‐emergence bleaching herbicide, WL 110547. Part II: Plant and environmental factors influencing biological activity
Authors: Blackman Peter G. , Deveson Malcolm R.
Published: November 2006

Pre‐emergence applications of the novel tetrazole herbicide WL 110547 control a number of economically important grass and broad‐leaved weed species in small grain cereals. To assess the influence of plant and environmental factors on the biological performance of WL 110547, a series of tests were carried out under controlled conditions and, where appropriate, comparisons were made with field observations.

When presented with the maximum opportunity for compound uptake in the absence of soil, differences in the degree of susceptibility to WL 110547 were observed amongst both monocotyledonous and dicotyledonous species, although the latter group generally showed higher levels of phytotoxicity. This species susceptibility to WL 110547 was unaffected by temperature.

Increasing the sowing depth in soil decreased the level of effect of WL 110547 on a number of monocotyledonous species, although small‐seeded species (e.g. blackgrass, annual meadow grass), emerging from deep in the soil profile, subsequently developed levels of phytotoxicity comparable to, or even greater than, shallow‐planted seedlings. This was attributed to less vigorous seedlings, emerging from depth, that were unable to regenerate new tissue and grow away from a treated soil layer. Reduced growth rates of wild oat, blackgrass and speedwell, induced by low temperatures, also increased the phytotoxicity of WL 110547. Furthermore, applications of WL 110547 during seedling emergence maximised herbicide effect, as did seedling emergence through moist rather than dry soil.

The results are discussed in relation to the mobility of the herbicide in soil, the mode of action of WL 110547, its availability to the plant and the duration of contact between emerging shoot and treated soil layer.
New pesticide metal complexes for controlled release
Authors: Prasad B. Prabhu , Kantam M. Lakshmi , Choudary B. M. , Sukumar K. , Satyanarayana K.
Published: November 2006

Six new pesticide metal complexes were synthesised, characterised and evaluated for controlled release by chemical and bioassay methods. Chemical assay and bioassay data demonstrate the increased persistence and increased shelf life of the pesticides upon complexation.
Stability of emulsifiable concentrate pesticide formulations in liquid fertilizers
Authors: Saltzman Sarina , Brates Nelly
Published: November 2006

The stability of some diluted emulsifiable concentrate formulations in clear liquid fertilizers, as affected by the nature and concentration of the salt solutions, was checked by a static test. The time‐induced changes in the concentration of the dispersed phase were estimated by visual observations and turbidity measurements. For each formulation a specific relationship between the electrical conductivity of all the fertilizer solutions and the emulsion stability was found. This was valid for a pH range between 4.6–6.3; in alkaline conditions the emulsion stability was relatively lower. A critical electrical conductivity range, above which irreversible destabilization occurred, was observed for each formulation: 100‐120 dS m−1 for fenamiphos, 60‐70 dS m−1 for metolachlor, 30‐50 dS m−1 for chlorpyrifos, and about 45 dS m−1 for S‐ethyl dipropylthiocarbamate (EPTC).

The correlation observed between the emulsion stability and the electrical conductivity could be used in a simple and rapid qualitative test to estimate the physical compatibility between emulsifiable concentrate formulations and liquid fertilizers.
Genetic analysis and effect of synergists on diazinon resistance in the bulb mite, rhizoglyphus rohini claparède (acari:Acaridae)
Authors: Chen Jeng‐Shong
Published: November 2006

A genetic analysis revealed that the resistance to diazinon of the bulb mite, Rhizoglyphus robini Claparède. lacked sex linkage, and was based on the operation of a dominant allele. Synergism of diazinon by eight inhibitors of detoxifying enzymes in susceptible and resistant strains of the bulb mite was determined. Esterases were shown to play an important role in detoxification against diazinon. S.S.S‐tributyl phosphorotrithioate, an esterase inhibitor, was the only synergist which obviously synergized diazinon. The others, including the inhibitors of glutathione‐S‐transferases, carboxylesterase and mixed function oxidases, showed obscure or even antagonistic effect.
Organosilane insecticides. Part II: Chemistry and structure—activity relationships
Authors: Sieburth Scott McN. , Langevine Charles N. , Dardaris David M.
Published: November 2006

Silicon effectively substitutes for quaternary carbon in etofenpr ox‐type insecticides; the resulting dimethyl‐4‐ethoxyphenyl‐3‐(4‐fluoro‐3‐phenoxyphenyl)propylsilane is a broad‐spectrum insecticide with extremely low toxicity to fish. Four regions of this new silane insecticide have been systematically altered. The methyl groups on silicon appear to be critical for activity. Replacement of the fluorine with hydrogen results in a substantial loss of activity. The aromatic rings of the phenoxyphenyl fragment are best tethered by oxygen or carbonyl, the methylene and nitrogen analogs being of very low toxicity to the test species. The activity ranking of the methylene and carbonyl tethers is opposite to that found for ester pyrethroids. The relationship of insecticidal activity to the aromatic substituent para to the silicon atom has been found to correlate with the molar refractivity of the substituent. Replacement of a tetra‐substituted carbon atom with a silicon atom can simplify construction of test compounds and thus be advantageously used in the exploration of structure—activity relationships. A novel method for preparing allylbenzenes from aromatic aldehydes was also developed.
Spreading of spray mixtures on leaf surfaces: I. relative effectiveness of various physico‐chemical predictors
Authors: Abbott Henry A. , Van Dyk Louis P. , Grobbelaar Nathanaël
Published: November 2006

Surface tension, contact angles and critical micelle concentration were not effective as practical predictors of spreading. Contact angles could not quantify spreading past the point where the angles became zero, although differences could be discerned by eye. Measurement of diameter of spread allowed quantification of these differences. Hansen parameters, used instead of surface tension, underlined the importance of hydrogen‐bonding and charge effects, but could not explain all the observed phenomena. The results emphasise the complexity of spreading on leaf surfaces, and problems experienced with several approaches encountered in the literature are discussed.
Spreading of spray mixtures on leaf surfaces: II. cohesive interaction parameters as predictors of spreading and the effect of molar volume and roughness on spreading
Authors: Abbott Henry A. , Van Dyk Louis P. , Grobbelaar Nathanaël
Published: November 2006

Partial cohesive interaction parameters as predictors of the spreading of spray mixtures were investigated. Multiple linear regression of the inverse of the area of spread, 1/A, for leaf surfaces on the partial cohesive interaction parameters of pure liquids gave a good fit (r2 > 0–90) on virtually all tested surfaces. The coefficients obtained from the regression analysis could be used to describe the spreading properties of each surface uniquely. Regression of 1/Afor an unknown liquid on the coefficients of known surfaces could, conversely, be used to obtain the cohesive interaction parameters of the unknown liquid. A linear relationship was observed between the calculated energy of adsorption and the inverse of the area of spread. An increase in molar volume caused a decrease in the slope of the regression line and an increase in roughness caused a similar, but more pronounced, decrease.
Fungitoxicity of 6H‐pyrazolo[3,4‐c][l,2,5]thiadiazine‐2,2‐dioxides
Authors: Vicentini Chiara B. , Brandolini Vincenzo , Poli Tiziana , Veronese Augusto C. , Guarneri Mario , Giori Paolo
Published: November 2006

A base‐promoted cyclisation of 4‐nitroso‐5‐benzylsulphonamidopyrazoles (VII) afforded 6H‐pyrazolo[3,4‐c][1,2,5]thiadiazine‐2,2‐dioxides (VIII). They were testedin vitrofor antifungal activity against a series of phytopathogenic fungi of different taxonomic classes. Five of the compounds had noteworthy activity; in particular 6H‐3‐phenyl‐5‐methyl‐7–(3,4‐dichlorophenyl) pyrazolo[3,4‐c][1,2,5]thiadiazine‐2,2‐dioxide (VIIIc) at the concentration of 200 mg litre−1completely inhibited the growth ofPythium ultimum, Corticium solaniandSclerotinia minor.