Residues of carbofuran and 2,3-dihydro-3-hydroxy- 2,2-dimethylbenzofuran-7-yl methylcarbamate in the mushroom,agaricus bisporus,cultivated in casing soils treated with the insecticide

Residues of carbofuran ( 1 ) and 2,3-dihydro-3-hydroxy-2,2-dimethylbenzofuran-7-yl methylcarbamate ( 2 ) in and on mushrooms, cultivated on casing soils containing added carbofuran granular insecticide, were determined. The quantitative estimations in cleaned mushroom extracts were done on thin-layer plates using a cholinesterase inhibition method. Samples were analysed, which had been harvested at different times from cultures, to which different amounts of carbofuran were added. Residues in washed and unwashed mushroom samples were compared. Residues did not exceed 0.5 mg (carbofuran) kg^?1 and 0.25 mg (compound 2 ) kg^?1 for fresh unwashed mushrooms grown on casing soil treated with carbofuran granules 1 g (a.i.) m^?2.     

The effects of helicopter applied adulticides for riverine tsetse control on Simulium populations in a West African savanna habitat. I. introduction,methods and the effect on biting adults and aquatic stages of Simulium damnosum s.l.

Abstract

Helicopter applied insecticides used for tsetse control were investigated for their potential to reduce populations of Simulium damnosum s.l. in riverine forest in the Guinea savanna zone of southwestern Upper Volta. Populations of aquatic stages and biting females were sampled before and after spraying. Deltamethrin applied at 12·5 g a.i./ha to a 30 km length of riverine vegetation almost eliminated adults for a period of about nine days. Residues which fell into the water killed all larvae in the river. Endosulfan at 100 g a.i./ha applied to a similar stretch of vegetation caused a reduction of over 60% in biting adults for 11 days, but residues falling into the river killed only young larvae. Neither dieldrin at 400 g a.i./ha, endosulfan at 10 g a.i./ha nor deltamethrin at 12.5 g a.i./ha applied to a 5 km insecticide barrier between the experimental blocks and the untreated river appeared to have much effect. This suggests that most S. damnosum were traversing the barrier without coming into contact with the insecticides.     

Comparative toxicity of several insecticides to eggs,larvae and adults of the Egyptian cottonworm,Spodoptera littoralis,in laboratory trials

Insecticides commonly used in cotton fields in Israel against lepidopterous pests were tested against eggs, as well as against 2nd-instar larvae and adults raised from eggs ofSpodoptera littoralis (Boisduval) collected in cotton fields in the Bet She’an Valley. Methomyl, chlorpyrifos, methidathion, monocrotophos, ethyl parathion, and methyl parathion were effective against eggs even at low doses, profenofos and phosfolan were less active, and azinphos-methyl was ineffective. The doses needed for 90% kill (LD ₉₀ ) of the 2nd-instar larvae were 8.5, 35, 280, 1300 and 3400 g a.i./1000 m ² for chlorpyrifos, methomyl, profenofos, methyl parathion and ethyl parathion, respectively; monocrotophos was inactive against 2nd-instar larvae even at relatively high doses. The LD ₉₀ of adults was reached with 16, 32, 1700 and 6100 ga.i./l000 m² of chlorpyrifos, methomyl, ethyl parathion and profenofos, respectively. Only chlorpyrifos and methomyl gave successful control of all three stages of the insect tested, at doses close to those generally used with aerial applications.     

江苏溧阳水稻田减量用药研究初探

为尽可能减少稻田农药的使用量,更好地保障稻米品质及保护农田生态环境,通过优化药剂组合和施药次序,综合田间防效、消解动态、最终残留及水稻产量等因素,研究评估了江苏省溧阳市水稻田农药减量施用的可行性。分别设置常规施药组合和减量施药组合2套方案,以水稻主要病虫害稻飞虱、稻纵卷叶螟及纹枯病为例,比较了2种施药方案下对病虫害的防效,分析了相关药剂在水稻中的残留消解动态以及在稻米和谷壳中的最终残留,并对水稻产量进行了考察。结果表明:减量施药方案对水稻上3种典型病虫害的防效均优于或与常规施药方案相当;此外,不同施药次序对水稻病虫害的防治效果差异较大;2种施药方案下,供试药剂在稻米中的最终残留量均未超过其残留限量 (MRL) 标准;与常规施药方案相比,减量施药方案下水稻每公顷产量增加了621 kg,但二者差异不显著。减量方案施用农药总制剂量为4 410 g/hm2 (有效成分1 353 g/hm2), 而常规方案为6 885 g/hm2 (有效成分1 553 g/hm2)。研究表明,在试验期间,该减量施药方案能有效防控水稻病虫害,保证水稻产量,同时还能减少环境中农药及助剂的投入,降低对环境的危害。     

氯虫苯甲酰胺在甘蔗及土壤中的残留消解动态

建立了氯虫苯甲酰胺在甘蔗和土壤中残留的高效液相色谱检测方法,应用该方法对氯虫苯甲酰胺在甘蔗和土壤中的残留消解规律进行了研究。样品用乙腈提取,经Florisil固相萃取柱及N-丙基乙二胺(PSA)净化,紫外检测器检测,外标法定量。结果表明:当添加水平为0.05~2 mg/kg时,氯虫苯甲酰胺在甘蔗植株地上部分(包括茎秆和叶片)、茎秆(去除叶片后的地上至肥厚带部位)和土壤中的平均回收率为77%~97%,相对标准偏差(RSD)为3.4%~11.6%。氯虫苯甲酰胺在3种基质中的最小检出量(LOD)均为0.2 ng,最低检测浓度(LOQ)均为0.05mg/kg。两年两地的田间残留试验结果表明:0.4%氯虫苯甲酰胺颗粒剂在甘蔗下种时一次沟施后覆土,以有效成分用量120和180 g/hm2施药时,在土壤中的原始沉积量在1.18~3.57 mg/kg之间,半衰期为12.4~18.2 d;成熟时采收,甘蔗茎秆中氯虫苯甲酰胺的残留量低于0.05 mg/kg。参照我国制定的甘蔗上氯虫苯甲酰胺的临时最大残留限量(TMRL)值0.05 mg/kg,按照推荐剂量及推荐剂量的1.5倍分别施药1次,成熟时采收甘蔗是安全的。     

Residues of methomyl in strawberries,tomatoes and cucumbers

An accurate and rapid high performance liquid chromatography method was developed to monitor residues of methomyl in plant extracts. The rate of disappearance of foliage-applied methomyl from strawberries, tomatoes and cucumbers was studied. Residues reached levels of 0.55, 0.2 and 0.6 mg kg^?1 seven days after methomyl had been applied to strawberries, tomatoes and cucumbers, respectively. Results also showed that rinsing treated fruits with tap water removed considerable amounts of methomyl. Samples of strawberries, tomatoes and cucumbers were collected from local markets at Ismailia, and checked for methomyl residues. Residues in 12.5% of tomato and 25% of strawberry samples were above 0.2 mg kg^?1.     

几种除草剂对冬麦田杂草的防除效果

通过田间药效试验,比较不同除草剂对当前南疆地区冬麦田播娘蒿、萹蓄、硬草等杂草的防除效果,为科学、安全、高效应用除草剂提供依据。结果表明,药后50 d,10％苯磺隆可湿性粉剂18．0 g a．i．／hm2＋5％唑啉草酯·炔草酯乳油37．5 g a．i．／hm2、75％苯磺隆水分散粒剂18．0 g a．i．／hm2＋10％乙羧氟草醚乳油12．0 g a．i．／hm2＋5％唑啉草酯·炔草酯乳油37．5 g a．i．／hm2、37％炔·苄·唑草酮可湿性粉剂166．5 g a．i．／hm2对播娘蒿的株防效、鲜质量防效均为100％,对萹蓄的鲜质量防效均在92％以上,对硬草的株防效、鲜质量防效均在88％以上,且对小麦生长安全。     

Space Treatment of Warehouses Using Dichlorvos1)

Details are given of the performance of Vapona Pest Strips and of an automatic dichlorvos sprayer developed to prevent infestation of clean or fumigated stored commodities, for infestation control on stored carobs. Air concentrations after spraying a nominal dose of 10 μg/1 of total store space averaged approximately 1.0. μ g/l after 30 minutes and less than 0.3 μ g/l after 3 hours. Residues found on carobs after daily spraying of stores at 10 μ g/1 for 96 days were in the range of 0.2 - 2.0 ppm. Ephestia cautella Walk, and Lasioderma serricorne (F.) become established in carobs after harvest and are the principle pests causing damage during storage. Effective control of E. cautella was obtained by using Shell Vapona Pest Strips at two strips/100 m³ or by daily spraying of dichlorvos at 10g/1,000 m² (10μ g/1). No effect was observed against migrating larvae of E. calidella (Guen.) or E. figulilella Greg, nor against Bracon hebetor Say., the hymenopterous parasite attacking all three Ephestia species. The automatic dichlorvos sprayer is equipped to apply a predetermined dose at time of peak flight activity, 18–20 hours each evening. On stored carobs, no spraying is needed after October because the commodity temperature falls below 20⁰C, too low for active development of the pest species. 23 automatic sprayers are now used in Cyprus to protect the whole carob crop from storage pests.     

Properties of acetolactate synthase from sulfonylurea-resistant Scirpus juncoides Roxb. var. ohwianus T. Koyama

Properties of acetolactate synthase (EC 4.1.3.18; ALS) from sulfonylurea-resistant (SUR) Scirpus juncoides Roxb. var. ohwianus T. Koyama were studied biochemically and physiologically in comparison with those from sulfonylurea-susceptible weed (SUS). GR₅₀ values for growth inhibition and I₅₀ values for ALS inhibition by imazosulfuron were determined for both SUR and SUS. Imazosulfuron controlled the SUS above 80% at the dosage more than 10 g a.i./ha but did not control the SUR at the even great dosage of 1000 g a.i./ha. The rates required for 50% growth inhibition of the SUR relative to the SUS (R/S ratio) were 271-fold. The I₅₀ value for inhibition of ALS from the SUS was 15 nM, compared to I₅₀ of >3000 nM for inhibition of ALS from the SUR. These results suggest that a resistance may due to an altered ALS that is insensitive to imazosulfuron. The K_m (pyruvate) value of ALS from the SUR was similar to the K_m for ALS from the SUS, suggesting that a mutation resulting in resistance does not change the affinity of the enzyme for pyruvate. The specific activity of the SUR ALS was similar to that of the SUS ALS, which indicates that resistance is not an over-expression of the enzyme. ALS activity from both biotypes was inhibited by isoleucine, valine, and leucine in this order. However, the SUR ALS was less sensitive to inhibition by valine than the SUS ALS.     

溴氰虫酰胺对小菜蛾的田间防效及其在花椰菜中的残留与消解动态

通过田间试验研究了溴氰虫酰胺对小菜蛾的田间防效,分析了露地栽培条件下溴氰虫酰胺在花椰菜上的消解动态和最终残留情况。结果表明:田间药效试验中10%溴氰虫酰胺可分散油悬浮剂按推荐高剂量（有效成分21 g/hm2）施药后24 h~7 d对小菜蛾的防效为92.8%~98.3%;按2倍推荐高剂量（有效成分42 g/hm2）施药,溴氰虫酰胺在花椰菜上的消解半衰期为3.86 d,其残留超标风险与田间用药量、用药次数正相关。建议生产中采用10%溴氰虫酰胺可分散油悬浮剂以有效成分21 g/hm2的剂量用药,每季最多施药2次,露地栽培条件下花椰菜上安全间隔期为3 d。     

茶皂素、生石灰等防治稻田福寿螺的效果评估

福寿螺已成为我国南方局部稻区严重危害水稻的有害生物,为解决常用的化学杀螺剂污染环境和农产品的问题,分别在室内和大田环境下研究了生石灰、碳酸氢铵、茶麸和茶皂素4种替代物质防治福寿螺的效果。茶皂素、茶麸和生石灰对稻田福寿螺有很好的防治作用。在室内试验中40 mg/L和50 mg/L茶皂素处理在48 h 即达到了100%的防效;在大田试验中茶皂素6.0 g/m²的处理在第4天、1.5 g/m²的处理在第16天均达到了100%的防治效果,且速效性和持效性也显著优于其它物质。30 g/m²和45 g/m²的茶麸处理以及45 g/m²的生石灰处理在大田试验第16天的防治效果也在80%以上。这3种物质对稻田稗草还有很好的抑制作用。碳酸氢铵对福寿螺防治效果较差,且能促进稻田稗草的发生。研究结果表明,茶皂素、茶麸和生石灰可作为化学杀螺剂的替代物质在大田中推广应用。     

Efficacy of metalaxyl for blue mould control and its persistence on tobacco

Foliar sprays of metalaxyl, benalaxyl, and cymoxanil plus mancozeb gave better control of blue mould (Peronospora tabacina) than mancozeb alone applied as a spray, or metalaxyl applied to the soil. Before flue-curing, the mean values of metalaxyl residues in tobacco leaves were significantly higher from foliar spray treatments (5.09 μg g⁻¹), than from soil treatments (0.93 μg g⁻¹). Residues had decreased after flue-curing (foliar spray treatment 2.51 μg g⁻¹; soil treatment 0.69 μg g⁻¹), especially on samples taken in September. Curing considerably reduced metalaxyl residues in all cases. Residues of mancozeb ranged from 59.5 to 224.2 μg g⁻¹ before flue-curing and from 11.0 to 22.1 μg g⁻¹ after flue-curing. All these residues were calculated on a dry weight basis. Imidazolidine-2-thione (ethylenethiourea) residues from mancozeb were always below the sensitivity limit of the method used.     

Fenvalerate residues in milk following topical treatments to dairy cows

Two mature Holstein cows were treated with 0.1g of fenvalerate each, in six consecutive topical treatments at intervals of 3 or 4 days. Neither of the diastereoisomers of fenvalerate was detected in the milk 6h after the application. After 3 days, the mean fenvalerate residue was 0.46μg litre⁻¹; by day 4, this residue had declined below the detection limit of 0.1μg litre⁻¹ for each of the diastereoisomers. Two Holstein cows were also treated with 0.5g of fenvalerate per cow in three consecutive topical treatments at intervals of 14 days. Residues in whole milk were at a maximum 6h after treatment and declined to less than 0.2μg litre⁻¹ over 21 days. Only 0.03 to 0.06% of the applied fenvalerate appeared in the milk as the intact insecticide.     

Foliar Sprays and Disulfoton Granules for the Control of Aphis gossypii on Okra

Abstract

Monocrotophos, omethoate, formothion, methomyl, pirimicarb and phosphamidon applied as foliar sprays were the most effective of insecticides evaluated in field trials for the control of Aphis gossypii Glov. on okra. Three applications were required to control infestations on plants sown during October to February. Disulfoton granules applied to the soil at sowing remained active for a long period, the duration depending on the method and rate of application. A dosage of 0.1 g a.i./plant hole was effective throughout the season. Residues of disulfoton and its metabolites in the harvested crop were negligible. Using such methods of aphid control, okra yields were increased by 97–119%.     

Effect of air temperature, rain and drought on hot water weed control

The influence of rain and drought before, and air temperature during, weed control with hot water was studied in laboratory experiments on the test weed Sinapis alba (white mustard). The plants were grown in a greenhouse and treated outdoors. There was no difference in weed control effect when S. alba plants at the four‐leaf stage were treated at the air temperatures 7°C and 18^°C. The effective energy dose for a 90% fresh weight reduction was 465 kJ m^?2 for both air temperatures. Weed control of S. alba at the four‐ to six‐leaf stage in rainfall above the rainwater run‐off level increased the required effective energy dose by 20% (i.e. 120 kJ m^?2) compared with dry plants. A short period of drought just before treatment on S. alba at the two‐ to four‐leaf stage increased the plant fresh weight reduction, which was 22% at low energy dose (190 kJ m^?2) and 44% at high energy dose (360 kJ m^?2). Hot water weed control should thus be carried out when the plants are drought stressed and avoided when the plants are wet. The air temperature seems to be of little importance in the range 7–18^°C.     

Response of Sorghum halepense demographic processes to plant density and rimsulfuron dose in maize

In spatially heterogeneous weed infestations, variable dose technologies could be used to minimise herbicide use; high doses could be applied to reduce high‐density patches and low doses to maintain weed populations in low‐density portions of a field. To assess the potential short‐ and long‐term effects of variable herbicide dose and site‐specific management, the major weed demographic processes were described and parameterised in this study. Various doses of rimsulfuron (from 0 to 12.5 g a.i. ha^?1) were applied to different densities of Sorghum halepense (0–100 plants m^?2). Contrary to similar studies with other weed species, higher herbicide efficacy was not observed at low densities, suggesting that the same rimsulfuron dose should be applied regardless of the S. halepense density. The highest percentage of control was obtained with the full rimsulfuron dose. However, it did not guarantee a decrease of the infestation in the following season in the field areas where the initial S. halepense density was lower than 60 plants m^?2. Reduced doses of rimsulfuron to control S. halepense cannot be recommended based on our results.     

The Experimental Application of Insecticides from a Helicopter for the Control of Riverine Populations of Glossina tachinoides in West Africa. IV. Evaluation of Insecticides Applied as Aerosols

Abstract

The effects of aerosol dosages of different categories of insecticide were tested against Glossina tachinoides when applied by helicopter to riverine forest habitats of the River Komoe, Upper Volta, West Africa. The method of application, droplet characteristics of the aerosols and meteorological conditions are described in accompanying papers. Comparative trials based on field dosages calculated initially from dosage mortality curves obtained from topical application studies in the laboratory were carried out. Endosulfan applied at 5.4 g a.i./ha and 9.0 g a.i./ha reduced G. tachinoides populations (determined by Challier/Laveissière traps) by more than 90% in all age and sex categories and evidence is presented which indicates a residual effect at the higher of these dosages. Good results were also obtained with the synthetic pyrethroid decamethrin at a dosage of 0.36 g a.i./ha; another synthetic pyrethroid, permethrin, gave promising results at a dosage of 1.9 g a.i./ha. At the higher dosage of 4.3 g a.i./ha disappointing results were obtained, which were considered to be more attributable to a weakness in the application technique under challenging field conditions, than to a limitation of the insecticide. The organophosphate compounds tested, fenthion, azamethiphos and tetrachlorvinphos although known from laboratory tests to be appreciably toxic to G. tachinoides, performed poorly under field conditions. This was thought to be due to the formulations employed and the authors feel that further small-scale field testing of different formulations of these compounds is warranted. The compounds considered most worthy of larger scale field evaluation were endosulfan and permethrin. Although decamethrin was also very toxic to G. tachinoides it was considered inadvisable to field test this compound on a larger scale, until more information was available on its impact on aquatic food chains. The trials demonstrated that it is not always possible to extrapolate from laboratory-obtained comparative dosage/mortality data (in ng/fly) the field dosages of insecticides (in g a.i./ha) required to produce a certain level of mortality in target populations of G. tachinoides.     

五氟磺草胺在稻田中的消解动态及残留特性

建立了超高效液相色谱-质谱联用检测五氟磺草胺在水稻植株、稻田土壤、田水和糙米中残留的分析方法,结合田间试验研究了五氟磺草胺在稻田环境中的消解及残留特性,并对稻米中五氟磺草胺残留的膳食暴露进行了初步评估。结果表明:在0.005~0.5 mg/L范围内,五氟磺草胺的质量浓度与对应的峰面积间呈良好线性关系,检出限（LOD）为0.001~0.002 mg/kg,定量限（LOQ）为0.003~0.005 mg/kg。在0.005~0.5 mg/kg添加水平下,五氟磺草胺在水稻植株、稻田土壤、田水和糙米中的平均回收率在89%~106%之间,相对标准偏差在2.8%~8.5%之间。浙江、福建和黑龙江2年3地的田间试验表明:0.025%五氟磺草胺颗粒剂在水稻植株、稻田土壤和田水中的消解半衰期分别为1.5~3.3,3.0~4.7和1.6-3.0 d,说明该药剂在稻田环境中消解速率较快。以五氟磺草胺有效成分含量37.5和56.3 g/hm2分别施药1次,于水稻成熟期采样检测,发现其在糙米中的残留量低于0.005 mg/kg,表明其膳食摄入风险很低,该研究结果可为五氟磺草胺风险评估提供一定参考。     

Efficacy of oxolinic acid and other bactericides in suppression ofErwinia amylovora in pear orchards in Israel

The efficacy of oxolinic acid (at 200 and 300 μg a.i./l) and of several antibiotic compounds (streptomycin sulfate at 100 μg a.i./l, glycocide B at 700 μg a.i./l, kasugamycin at 80 μg a.i./l and gentamicin sulfate at 30 and 60 μg a.i./l) againstErwinia amylovora, the causal agent of fire blight in pears, was evaluated in 43 orchard experiments in 1997–2000 in Israel. In addition to the above orchard experiments, the efficacy of the bactericides was tested in live experiments with artificial inoculation. Natural fire blight symptoms were observed in 16 of the 43 experiments; in 13 of them, disease intensity and its distribution among the experimental plots provided a basis for data analysis, leading to reliable conclusions concerning the efficacy of the tested bactericides. Oxolinic acid at 300 μg a.i./l was highly effective againstE. amylovora and reduced disease severity significantly in all experiments, as compared with the untreated plots; however, a concentration of 200 μg a.i./l was not effective in some cases. Among the tested antibiotics, only gentamicin sulfate was as effective as oxolinic acid. Results of the artificial inoculation experiments corroborated those obtained in the naturally infected orchards. The pre-infection activity of oxolinic acid was determined on blossom clusters that were sprayed with the bactericide before inoculation. Control efficacy on blossom clusters sprayed 1–4 days before inoculation ranged from 68% to 80%, a level which did not differ significantly from that observed on blossom clusters sprayed on the day of inoculation (80% control). The postinfection activity of oxolinic acid was determined on blossom clusters that were sprayed with the compound after inoculation. Oxolinic acid was as effective when applied 1 or 2 days after inoculation as when it was applied on the day of inoculation; however, application of the bactericide 3 days after inoculation no longer resulted in significant disease suppression. Oxolinic acid has been used commercially in Israel since 1998 with appreciable success. Contribution No. 533-00 from the Agricultural Research Organization     

Social science input into IPM

Abstract

Metsulfuron methyl (Ally‐Dupont), a sulphonylurea herbicide, was tested at rates of 0.5–2.0 g a.i./ha for the control of Striga hermonthica (Del.) Benth. in two cultivars of sorghum in pot experiments. There was good to excellent Striga control at 1.0–2.0 g a.i./ha applied either pre‐emergence or post‐emergence to CSH‐1 or N‐13 sorghum. The herbicide was unacceptably toxic to the Striga‐susceptible CSH‐1 cultivar when applied pre‐emergence, thus eroding any benefits of Striga control. In the Striga‐tolerant N‐13 cultivar there were considerable increases in the growth of infected plants. The herbicide was better tolerated from post‐emergence applications by both cultivars, and CSH‐1 plants recovered enough growth from Striga infection to produce grain yields at 1–5 and 2.0 g a.i./ha. Herbicide application at 4 weeks after planting sorghum was less damaging than at 2 weeks. Herbicide safening with 1,8‐naphthalic anhydride did not provide any additional benefits with post‐emergence application. The efficacy of the pre‐emergence herbicide was similar with surface or incorporated application.