摘要:

AbstractFeeding deterrent activities of twelve clerodane diterpenoids towardsTenebrio molitor(Coleoptera: Tenebrionidae) larvae have been correlated using molecular connectivity indexes (3χc,4χc, °ΔX) and hydrophobicity constants (logK′w) obtained by reverse‐phase liquid chromatography (RPLC). The equations obtained suggest that both the degree of branching and the electronic characteristics of the compounds under study have a dominant role in the observed antifeedant activity. The information obtained from the correlations should be useful in designing more potent an

ISSN:0031-613X    

DOI:10.1002/ps.2780410102

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe ability of ‘waste’ Fe(III)/Cr(III) hydroxide to adsorb paraquat has been investigated. Effects of contact time, initial concentration and pH, adsorption capacity and desorption have been studied. Adsorption followed a first‐order expression. The adsorption rate constant decreased from 1–84 to 0–50 min−1with the increase of paraquat concentration from 10 to 40 mg litre−1. Adsorption obeyed the Freundlich isotherm and theK1value was found to be 0.1995. A maximum removal of 93% was attained at pH 1204. Desorption with water occurred to the extent of 39% indicating that physical sorption was partly responsible in the adsor

ISSN:0031-613X    

DOI:10.1002/ps.2780410103

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract4‐Aminopyridine (4‐AP) is the only pesticide that can be legally used in the US to reduce bird damage in ripening grain fields. Birds that consume grain baits treated with 4‐AP (‘Avitrol’ FC‐99®) exhibit erratic behavior and emit vocalizations that presumably scare away the rest of the flock. Yet the behavior of 4‐A Pintoxicated birds has not been documented, and we do not know how other birds react when observing these intoxicated birds or what these observers learn from their experience. Hence, we examined the behavior of 15 4‐A Pintoxicated red‐winged blackbirds (Agelaius phoeniceus(L.)) and found that initial signs of intoxication occurred 12.5 min after consumption of the bait, with death following 16.3 min later. During this 16‐min intoxication period, birds gradually lost muscular control, making their movements and vocalizations weaker until hardly perceptible. Other captive red‐winged blackbirds (‘observers’) gave more alarm calls while witnessing a 4‐A P‐intoxicated bird in one room of their cage (treatment period) than they did during the pre‐treatment period. Immediately after the intoxicated bird died and was removed from the room, the observers' behaviour returned to pre‐treatment levels. Broadcasting calls of an intoxicated bird or the placement of an untreated bird in one of the rooms had little effect on the observers' behavior. In another experiment, the placement of a 4‐A Pintoxicated or untreated red‐winged blackbird or the broadcast of calls of an intoxicated bird at a feed station did not affect the number of free‐ranging conspecifics feeding, within sight of, or vocalizing at, these feeder stations. These results suggest that red‐winged blackbirds learn lit

ISSN:0031-613X    

DOI:10.1002/ps.2780410104

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe photostability of pirimicarb, (2‐dimethylamino‐5,6‐dimethylpyrimidin‐4‐yl dimethylcarbamate) in aqueous media, under natural and artificial sunlight irradiation conditions, is reported. The pH of the irradiated solutions remained constant during degradation time. The photodegradation mechanism seemed to be similar under both conditions, but the half‐life was found to be about three times longer under natural than under artificial conditions. Four main photo‐products (1,2,3and4) were isolated and identified by spectroscopic methods. It is proposed that a common photodegradation pathway exists for pirimicarb under both irradiation conditions. The results obtained from the photodegradation of pirimicarb and of its four main products isolated on solid phase permit the construction of a possible photodegradation pathway. Photoproduct4(2‐methyl‐formylamino‐5,6‐dimethyl‐4‐hydroxypyrimidine) is here des

ISSN:0031-613X    

DOI:10.1002/ps.2780410105

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe movement of the organophosphate nematicide‐insecticide ethoprophos (ethoprop;O‐ethylS,S‐dipropyl phosphorodithioate) and the carbamate insecticide‐nematicide carbofuran (2,3‐dihydro‐2,2‐dimethylbenzofuran‐7‐yI methylcarbamate) was studied under steady‐state flow in small‐scale laboratory soil columns. Miscible displacement column experiments, mass balance calculations, and batch incubation studies furnished information on insecticide sorption and degradation processes that occur during transport through soil. Miscible displacement studies demonstrated that ethoprophos degradation could be described as first‐order and that both insecticides exhibited non‐equilibrium sorption. Both batch and miscible displacement results showed ethoprophos to be more strongly sorbed by soil than carbofuran. Measured equilibrium sorption coefficients were 1.29 cm3g−1for ethoprophos and 0.29 cm3g−1for carbofuran on a Riverhead soil (0.011 organic carbon fraction); 035 cm3g−1for carbofuran on Valois soil (0.016 organic carbon fraction); and 2.38 cm3g−1for ethoprophos on Rhinebeck soil (0.031 organic carbon fraction). Two solutions to the convection‐dispersion equation, one that incorporated equilibrium sorption and another (bicontinuum model) that included a non‐equilibrium sorption term, allowed quantitative evaluation of transport processes. The bicontinuum model used in conjunction with experimental batch and mass balance techniques provided estimates of insecticid

ISSN:0031-613X    

DOI:10.1002/ps.2780410106

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractImpacts of pH and sorption‐desorption of ‘Pegosperse’ 100‐O (PEG. 100‐O; diethylene glycol monooleate, containing 15% diester) surfactant by apple (Malus pumilaM.) leaf cuticles on surfactant‐enhanced cuticular penetration of 2,4‐D [(2,4‐dichlorophenoxy)acetic acid] were studied. Glass cylinders were affixed to enzymatically isolated adaxial apple leaf cuticles after the cuticle segments had been soaked in 10 ml liter−1PEG 100‐O solution and washed for 20 and 120 min, respectively. Quantities of [14C]2,4‐D in the glass‐cuticle chambers passing through the cuticles at pH values from 1 to 6 5 were determined. PEG 100‐O significantly increased cuticular penetration of dissociated 2,4‐D at pH 4–5; the surfactant had no effect on penetration of undissociated 2,4‐D at pH 10. Surfactant‐enhanced penetration of 2,4‐D occurred only when the surfactant was in the cuticles, while the process of surfactant sorption‐desorption alone had no effect on penetration. These results support a ‘hydrophilic channel’ hypothesis, i.e. that surfactants may create hydrophilic channels or increase the area of the channels in the cuticle and, consequently, enhance the passing of polar molecules l

ISSN:0031-613X    

DOI:10.1002/ps.2780410107

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractIt has been proposed that levels of carbon and nitrogen in soil affect the rate at which triazine herbicides degrade. The present study was designed to investigate the effects of varying the levels of initial soil carbon and nitrogen as well as the effects of a later carbon addition on the mineralization of atrazine and its metabolites in soil. Atrazine degradation in soils amended with carbon as mannitol, and with nitrogen as urea, at levels of 10, 30, 50, or 80 mg kg−1mannitol, urea, or mannitol and urea was similar to degradation in unamended soils. Only 39% of applied atrazine was mineralized after 326 days regardless of the initial carbon or nitrogen treatment. In contrast, a second mannitol amendment of 1 g kg−1soil at day 140 increased [14C]carbon dioxide evolution by an additional 17% as a result of enhancing the mineralization rate of the atrazine metabolites. This conclusion is supported by our finding that periodic extraction of the soil with methanol followed by quantification on HPLC showed complete dissipation of the parent atrazine in 120 days. The metabolites hydroxyatrazine (HA), deisopropylatrazine (DIA), deethylatrazine (DEA), and diaminochlorotriazine (DACT) began to appear in the methanol extract 10 days following atrazine application. The greatest concentrations of HA, DEA, DIA. and DACT in the methanol extracts were 19, 12.4, 10.1, and 6.7% of applied atrazine, respectively. These concentrations were observed at day 95 except for DEA where the concentration continued to increase until day 142. A second soil extraction with hydrochloric acid (1m) + methanol (20 + 80 by volume) recovered additional HA, deethylhydroxyatrazine (DEHA), deisopropylhydroxyatrazine (DIHA), and DACT. When the extraction data were combined, 31.9, 12.4, 10.1. 10.2, 12.0 and 7.8% of applied atrazine was recovered as HA, DEA, DIA, DEHA. DIHA, and DACT, respectively. Combustion of the extracted soil showed 20% of the applied atrazine remained as soil‐bound residues after 326

ISSN:0031-613X    

DOI:10.1002/ps.2780410108

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractWe conducted two‐cup feeding trials to assess the responses of cedar waxwings (Bombycilla cedrorum(Vieillet)), American robins (Turdus migratorius(L.)), and European starlings (Sturnus vulgarisL.) to food adulterated with phosmet 500 g kg−1WP (‘Imidan’®). All species avoided phosmet concentrations ⩾ 100 mg kg−1.Robins avoided food containing 60 mg kg−1phosmet, while food consumption by starlings was reduced by a 30 mg kg−1treatment. All species were indifferent to phosmet at 10 mg kg−1.These findings suggest that fruit‐eating birds will safely avoid ingesting harmful levels of phosmet when the insecticide is applied to small fruit such as blueberries and cherries. Feeding deterrence associated with phosmet might be exploited in management strategies to protect small fruit crops

ISSN:0031-613X    

DOI:10.1002/ps.2780410109

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractExtraction of pesticides from river water samples using the classical liquid‐liquid extraction (LLE) approach is a labour‐intensive procedure that requires relatively large volumes of solvent. With the solid‐phase extraction (SPE) technique using membranes, the volumes of solvent are reduced. However, it is necessary to pre‐filter and often also to acidify the river water to pH<2 to prevent plugging of the capillary pores. This low pH may decompose some pesticides and therefore a fast and inexpensive technique with bulk sorbent and without prefiltration and acidification was developed.To reduce the solvent volumes further, extractions of discs and bulk sorbent were performed with supercritical fluids (SF). Seven pesticides with different polarities were studied. Mean recoveries from the bulk sorbent and the discs were of the same order (61%). However, recoveries from the latter improved to 82% with SFE of the discs, providing results comparable to LLE (94%) r

ISSN:0031-613X    

DOI:10.1002/ps.2780410110

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe putrescine analogue. (E)‐1,4‐diaminobut‐2‐ene (E‐BED), synthesized as the dihydrochloride salt, controlled five economically important crop pathogens,Erysiphe qraminisDC f.sp.hordeiMarchal.Uromyces viciae‐fabae(Pers.) Schroet,Botrytis fabaeSardina,Podosphaera leucotricha(Ell.&Ev.) Salm. andPhytophthora infestans(Mont) De Bary. The Z‐isomer. Z‐BED. was also fungicidal, although less so than E‐BED. Post‐inoculation treatment with E‐BED gave greater control of powdery mildew infection on barley and rust and chocolate spot on broad bean than did pre‐inoculation application. It was also effectivein vitroagainstBotrytis cinereaPers. ex Fr.,Pyricularia oxyzaeBr.&Cav. andPyrenophora avenaeIto&Karibay. WhenP. avenaewas grown in the presence of E‐BED dihydrochloride at 81·5 mg litre−1, growth was reduced by 58% and there were significant reductions in soluble ornithine decarboxylase (ODC) andS‐adenosylmethionine decarboxylase (AdoMetDC) activity. These changes were accompanied by a sevenfold increase in putrescine concentration, a 60% increase in spermine concentration and a 32% reduction in spermidine concentr

ISSN:0031-613X    

DOI:10.1002/ps.2780410111

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY