摘要:

AbstractUV absorber compounds were tested to reduce the photolytic decomposition of deltamethrin, applied to 100%cotton fabric, to be used as a target screen for tsetse fly control. In the absence of UV absorbers, over 90% of deltamethrin was degraded after 6 h irradiation under an Osram UV‐sun radiation lamp (equivalent to 96 h sunlight) at 35(±1)°C. The degree of protection increased with increase in the proportion of the U V absorber compound. With a mixture of 2,4‐dihydroxybenzophenone (I) and deltamethrin (3 + 1, by mass) 7% of deltamethrin was degraded. Similarly, I protected alpha‐cypermethrin and cyfluthrin against photolysis, I and 2‐hydroxy‐4‐methoxybenzophenone‐5‐sulfonic acid (IV) both protected deltamethrin from “Glossinex 200” SC formulation against photolysis, but I was m

ISSN:0031-613X    

DOI:10.1002/ps.2780280402

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractFlufenoxuron is an acylurea insecticide which inhibits chitin synthesis. Its uptake, excretion and metabolism in larvae ofSpodoptera littoralishave been measured. Larvae fed on a leaf disc sprayed at an application rate equivalent to 50 g ha−1rapidly absorbed a maximum of 20% of ingested flufenoxuron, the remainder being voided in the frass. Excretion of absorbed compound was slow, with a 50% excretion time of approximately 20 h. Flufenoxuron was equally effective as an insecticide by topical application or ingestion. Following topical application, a total of 11% of the dose had penetrated into the body within 24 h. Of this 11%, half had travelled to the gut so that the rest of the body tissues contained no more than 6% of the toxicant dose. The concentration of flufenoxuron in the body tissues was maintained for at least 24 h, the surface residue probably acting as a reservoir. The compound was metabolically quite stable. Following topical application the 6 % of the applied dose which was absorbed into the body was still 92% as unchanged flufenoxuron 24 h after application. The enhanced toxicity of flufenoxuron toS. littoraliscompared with earlier acylureas can probably be attributed to its slower metabolism and reduced excretio

ISSN:0031-613X    

DOI:10.1002/ps.2780280403

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractFlufenoxuron (“Cascade”) is a novel acylurea with acaricidal and insecticidal properties. It acts in a similar manner to diflubenzuron (DFB) by impairing chitin incorporation into insect cuticle.Chitin can be localised cytochemically using the lectin, wheat germ agglutinin (WGA), which binds specifically toN‐acetylglucosamine‐containing polymers. WGA adsorbed to monodisperse colloidal gold (WGA‐gold) was used as an electron‐dense marker for localising chitin in the cuticle of sixth‐instarSpodoptera littoralis.In the cuticle of control insects, the deposition zone and endocuticle were heavily labelled. In flufenoxuron‐ and DFB‐treated insects, only the endocuticle (formed before treatment) was labelled, the deposition zone being devoid of label.These results show that flufenoxuron and DFB act in similar manner in reducing chitin incorporation in the cuticl

ISSN:0031-613X    

DOI:10.1002/ps.2780280404

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe chitin precursor[14C] N‐acetylglucosamine injected into the haemolymph ofSpodoptera littoralis (Boisduval) larva was incorporated into the chitin exponentially with time. When caterpillars were injected with precursor at the commencement of feeding on acylurea‐treated leaf discs, flufenoxuron, teflubenzuron and diflubenzuron were found to be equally effective inhibitors of chitin synthesis, measured after 21 h. The dose response curves by feeding are not parallel, indicating that the relative potency of the compounds will vary across the dose range.When chitin precursor was injected simultaneously with topically applied diflubenzuron, flufenoxuron or teflubenzuron, all three acylureas were found to be equally effective as inhibitors of chitin synthesis when measured after five hours. TheI50values (50% inhibition of chitin synthesis) were not significantly different; average 600 ng, compared with LD50values (50% lethal dose) of∼13 ng for flufenoxuron and teflubenzuron but 130 ng for diflubenzuron (topical application). Injection of precursor 24 h after topical application of insecticide gave an I50value which had dropped 670‐ and 150‐fold for flufenoxuron and teflubenzuron respectively but only 20‐fold for diflubenzuron. It is postulated that the reason for the low increase in diflubenzuron effectiveness with time was due either to less diflubenzuron than flufenoxuron reaching the site of action, or more probably, a faster rate of metabolism and excretion for diflubenzuron.The lower toxicity of diflubenzuron compared with flufenoxuron and teflubenzuron may not be due to any inherent differences in biochemical effectiveness, but rather to different penetration/metabolism

ISSN:0031-613X    

DOI:10.1002/ps.2780280405

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractWhen injected into cockroaches(Periplaneta americana),dihydropyrazoles (pyrazolines), e.g. RH 3421, methyl 1‐(N‐(α,α,α‐trifluoro‐p‐tolyl)carbamoyl‐3‐(4‐chlorophenyl)‐4‐methyl‐2‐pyrazolin‐4‐ylcarboxylate, caused incoordination, followed by prostration and violent tremors. After several hours, prostrate cockroaches became very still, appearing paralyzed, but for several days they retained the ability to produce violent tremors when physically disturbed. The paralysis was associated with block of spontaneous activity in sensory nerves of cockroaches, tobacco hornworm larvae(Manduca sexta)and housefly larvae(Musca domestica).Block of spontaneous central nervous system activity was also seen in some cases.Current‐clamp experiments on the cell body of the crayfish slowly‐adapting stretch receptor neuron revealed that spike initiation in response to injected current was blocked by dihydropyrazoles, with no change in resting potential or input resistance, suggesting that the sodium current was suppressed. Hyperpolarization of blocked stretch receptors could reverse block, and crayfish giant axons, which were not normally sensitive to block by dihydropyrazoles, were rendered sensitive when artificially depolarized by elevation of extracellular potassium ion concentration, leading to the conclusion that the block of sodium current was strongly voltage dependent. The proposed mode of action, while similar to that of local anesthetics, class I anticonvulsants and class I antiarrhyt

ISSN:0031-613X    

DOI:10.1002/ps.2780280406

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractHomodemycine (HDE) is a copper complex of several different amino acids. It is a highly effective, low‐toxic and non‐residual fungicide. Toxicological tests have shown this organo‐copper fungicide to have an oral LD50(Rats) of 1380 mg kg−1, and it is not mutagenic (Ames negative). Field trials over several seasons have shown crop growth stimulation and yield increases in addition to control of cucurbit wilt and other diseases. This paper summarises trials with HDE for the control of cucurb

ISSN:0031-613X    

DOI:10.1002/ps.2780280407

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractSurface 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 discusse

ISSN:0031-613X    

DOI:10.1002/ps.2780280408

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractPartial 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, decreas

ISSN:0031-613X    

DOI:10.1002/ps.2780280409

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractA 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,

ISSN:0031-613X    

DOI:10.1002/ps.2780280410

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

ISSN:0031-613X    

DOI:10.1002/ps.2780280411

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY