灭线磷在3种土壤中移动性的研究

土壤薄层层析法试验结果表明：灭线磷在3种土壤中的Rf值大小为：广东红土＞山东砂壤土＞东北黑土；移动速率m为山东砂壤土＞东北黑土＞广东红土。灭线磷在东北黑土中为不移动农药，在广东红土和山东砂壤土中为不易移动农药。土壤柱法结果与土壤薄层层析法结果相似，在渗透水中有很少量的灭线磷存在。     

Persistence and mobility of tebufenozide in forest litter and soil ecosystems under field and laboratory conditions

A field microcosm study was conducted to determine persistence of tebufenozide, an insect growth regulator, in sandy litter and soil. Litter and soil plots (c. 4·5 m² each) were sprayed with an aqueous suspension concentrate formulation of tebufenozide at rates of 35, 70 and 140 g AI ha^-1. Samples were collected at intervals up to 408 days after spraying, and analyzed for tebufenozide residues. The data were subjected to regression analysis and half-life (DT₅₀, the time required for 50% of the initial residues to disappear) values were computed. The DT₅₀ was c. 62 days for both substrates treated with the two lower dosage rates. At the highest dosage rate, the DT₅₀ was 115 days for the litter and c. 52 days for the soil, indicating irregular variations in persistence. Downward movement in soil occurred only in trace amounts, suggesting strong adsorption. Laboratory microcosm studies were conducted to investigate the relative importance of rainfall, exposure to light and volatilization on persistence. Vertical movement occurred in litter and soil (both sandy and clay types) during rainfall. The amount moved increased with the amount of rainfall, but decreased with the rain-free period. The larger the rain droplets, the greater the downward movement. When the rainwater could move laterally along the surface of the substrate (as would occur on a slope), more lateral movement than vertical movement of tebufenozide occurred. The photolysis study indicated that disappearance of tebufenozide was directly related to the duration of exposure to radiation and radiation intensity. Volatilization of tebufenozide depended upon the ambient temperature and the duration of air passing through the substrates. Nonetheless, the amount lost by volatilization was much lower than the amount lost after rainfall or exposure to radiation, thus indicating the greater influence of rainfall and sunlight on persistence. In the laboratory microcosm studies, more tebufenozide was lost from the sandy substrates than from the clay substrates. This behaviour was attributed to the greater adsorptive capacity of the clay substrates, thus providing a greater protection against downward mobility and loss due to radiation. © 1997 SCI     

Imidacloprid mobility and longevity in soil columns at a termiticidal application rate

The mobility, longevity and termiticidal activity of imidacloprid (Premise 2 termiticide; Bayer Environmental Sciences) at the termiticidal labeled rate for perimeter treatment were tested in vegetated and non-vegetated soil columns in two tests: in cone plots and in polyvinyl chloride (PVC) pipes. Imidacloprid content in the cone plot eluate peaked at 1 month, declined rapidly by the second month and then entered a lagging phase. The concentration of imidacloprid in the cone plot soil declined from 84.5 microg g(-1) initially to 7.5 microg g(-1) (non-vegetated plots) and 8.1 microg g(-1) (vegetated plots) 6 months later. Neither eluate concentration nor soil concentration was affected by the presence of vegetation in the cone plots. In the PVC pipes, the top 15 cm of which was treated with Premise 2 at the perimeter labeled rate, imidacloprid half-life was estimated at 6-9 months for vegetated and non-vegetated soil. Extractable imidacloprid declined more rapidly in the first 15 months than afterwards. Mobility of imidacloprid into lower, untreated soil depths was higher in non-vegetated pipes, and was likely due to the effect of vegetation on soil moisture. The presence of vegetation had little effect on the termiticidal activity of treated soil in the PVC pipes.     

Effect of vegetation on the longevity,mobility and activity of fipronil applied at the termiticidal rate in laboratory soil columns

BACKGROUND: Termiticides are applied at concentrations much higher than those used in agricultural settings. The longevity of fipronil has not yet been examined at the rates used for termite control, nor has the compound's movement in the soil been addressed. RESULTS: Fipronil was detected in the eluates of treated soil cones, increasing initially and then decreasing to a steady concentration of about 1 µg mL^?1. In larger PVC pipe plots, fipronil in the top treated soil depth (0–7.5 cm) dissipated more rapidly (half‐life of 11–13 months) than in treated soil at the next treated depth (7.5–15 cm; half‐life of 20–29 months). The presence of vegetation had no significant effect on the mobility, longevity or movement into untreated depths. Treated soil remained toxic to termites throughout the duration of the study. Fipronil moved into the 15–22.5 cm soil depth in sufficient concentration to cause 100% mortality to eastern subterranean termites in 3 day bioassays. CONCLUSION: Fipronil remains in treated soil at levels toxic to termites for at least 30 months. Movement of the active ingredient was observed in sufficient amounts to kill termites in non‐treated soil directly below the treated soil. Published 2010 by John Wiley & Sons, Ltd.     

Leaching of Alachlor from Alginate-Encapsulated Controlled-Release Formulations

The mobility of alachlor from alginate-encapsulated controlled-release (CR) formulations was investigated in two contrasting soil profiles. Two CR formulations of alachlor were prepared with the following components (1) base—sodium alginate+kaolin+‘Tween’ 20 (1+10+0·5 by mass) and (2) base+40 g kg⁻¹ linseed oil. These were compared to technical grade alachlor and to a commercial alachlor EC formulation (‘Lasso’ 4EC). All herbicide treatments were labeled with [¹⁴C]alachlor and were applied to duplicate soil columns that were composed of a surface and a subsoil horizon. Each horizon was packed to a depth of 12·5 cm, giving a total column length of 25 cm. The columns were leached with 21 cm (420 ml) to 30 cm (600 ml) of 0·01M calcium chloride for a period of 7 to 10 days. Alachlor leaching from the EC formulations was the same as that from the technical material in both soils: 33% in the Evesboro and 10% in the Conover soil. The CR-Oil formulation leached 4 and 2% of the applied [¹⁴C]alachlor, compared to 12 and 3% for the CR-N formulation for the Evesboro and Conover soils, respectively. The CR-Oil formulation also increased the amount of [¹⁴C]alachlor retained in the soil surface horizon (105–114%), compared to CR-N (39–45%), technical material (14–23%) and EC (12–17%).     

Bifenthrin longevity at the termiticidal application rate

BACKGROUND: The longevity, mobility and insecticidal activity of bifenthrin at the termiticidal application rate for perimeter treatment were investigated in packed-soil columns in the laboratory and greenhouse. RESULTS: Bifenthrin was not detected in the eluates of packed-soil cones over a period of 6 months. In larger pipe plots incorporating bifenthrin into the top 15 cm of the soil, the compound degraded in a biphasic fashion. Within the treated soil, the effect of vegetation on the amount of bifenthrin remaining in the soil depended on soil depth and time, and soil half-lives were longer in non-vegetated soil. Bifenthrin residues were higher in the top 7.5 cm of soil and declined over time. Movement of bifenthrin into the top untreated soil depth was observed, but much less was observed in lower depths. The soil remained toxic to termites in 3 day and 7 day forced exposure bioassays for the 30 month duration of the study. CONCLUSIONS: Concentrations of bifenthrin will remain in the soil at levels sufficient to kill termites for more than 30 months. Published 2011 by John Wiley & Sons, Ltd.     

淀粉凝胶电泳在异小杆线虫分类研究中的应用

本文以淀粉凝胶电泳及酶的专一染色方法研究了采自广东、福建及美国、澳大利亚、新西兰的异小杆线虫。线虫同工酶的相对电泳迁移率经平均欧氏距离及UPGMA公式进行聚类分析,结果表明:所研究的7个品系异小杆线虫可分为2～3种;一种被鉴定为Heterorhabdis helicthidis的线虫NZ品系与模式品系不同,而H.bacteriophora与H.heliothidis可能为同种;采自广东和福建的二品系异小杆线虫与已定名的二种线虫差异明显。     

啶虫脒和阿维菌素在4种不同类型土壤中的吸附及迁移

采用薄层层析和平衡振荡法,分别测定了啶虫脒和阿维菌素在紫色土、砖红土、黄壤土和黑土4种不同类型土壤中的迁移率(Rf )和吸附常数(Kd),比较了2种农药在单用及混用下迁移和吸附行为的差异。结果表明:2种农药在单用及混用下的迁移行为几乎不存在差异,在4种土壤中的Rf 值大小顺序均为:黄壤土>紫色土>黑土>砖红土;2种农药的吸附过程均符合经典的Freundlich模型,混用时阿维菌素对啶虫脒的吸附无影响,但啶虫脒的存在会减少土壤对阿维菌素的吸附,表现为竞争吸附作用。     

特丁硫磷在环境中的迁移性研究

采用室内模拟试验方法,研究了有机磷类农药特丁硫磷在不同环境介质中的挥发性以及在3种不同类型土壤中的吸附性、移动性及其影响因素。结果表明:特丁硫磷具有较强的挥发性,其在空气、土壤表面和水中的挥发率分别为87.1%、38.6%和2.51%;在江西红壤、太湖水稻土与东北黑土中的吸附性较好地符合Freundlich方程,3种土壤中的吸附系数Kd值分别为6.56、11.34和15.80;薄层层析试验显示,当溶剂展开至12.0 cm时,特丁硫磷在江西红壤、太湖水稻土与东北黑土中最远可分别移至6~8、4~6和6~8 cm处,土柱试验结果显示,江西红壤、太湖水稻土与东北黑土淋出液中特丁硫磷质量分数分别为5.77%、1.13%和1.22%,表明特丁硫磷具有一定的移动性。影响特丁硫磷在土壤中吸附性和移动性的主要因素为土壤有机质含量,其次为土壤质地。特丁硫磷具有高挥发性及一定的移动性,其对人畜的安全以及地下水的危害应引起高度重视。     

Guttation – the basis of an assay for evaluating formulation behaviour in vivo

Guttation droplets collected from the tips of winter leaves, previously treated with a ¹⁴C version of an experimental xylem-mobile fungicide (ExpF) that was known to elute readily in guttation fluid, were analysed for the presence of radiolabel. The effects of adjuvants on the elution rate was investigated and related to the known biological profile of the fungicide when used in combination with adjuvants. This method, using ExpF as a model molecule, is undergoing further development as a means of investigating formulation behaviour in vivo. Not all xylem-mobile fungicides elute significantly and data are presented to illustrate this.     

毒死蜱和氰戊菊酯在土壤中的吸附与迁移

为评估被用作白蚁预防药剂的毒死蜱和氰戊菊酯在土壤中的移动性,采用平衡吸附法和薄层层析法分别测定了两种农药在浙江宁波地区的东钱湖土(粉砂质壤土)、青岭土(粉砂质壤土)和象山土(粉砂质黏壤土)3种土壤中的吸附常数(Kd)和迁移率(Rf)。结果表明,两种供试药剂在东钱湖土中的吸附等温线线性化程度均较高,而在青岭土和象山土中的吸附等温线均近似于 "L"型。从Kd和有机质吸附常数Koc的数值看,氰戊菊酯在土壤中的吸附作用主要受土壤有机质因素影响,而毒死蜱的吸附并非只受土壤有机质因素的影响。毒死蜱在3种供试土壤中的Kd和Rf值均高于氰戊菊酯。这表明由Kd值推测不同农药在土壤中的相对移动性可能会存在一定偏差。毒死蜱和氰戊菊酯在3种土壤中的Rf值由大到小的顺序为:东钱湖土>青岭土>象山土;而Kd值由大到小顺序为象山土>青岭土>东钱湖土。对Kd和Rf值与土壤理化性质的多元线性回归分析表明:1)土壤有机质含量和阳离子代换量在决定Kd和Rf值中所起的作用相互重叠;2)土壤有机质含量(或土壤阳离子代换量)和土壤黏粒含量是影响Kd和Rf值的关键因素,而土壤pH值对于Kd和Rf值无决定性影响。     

Translocation of Pymetrozine in Plants

Pymetrozine, a pyridine-azomethine, is a selective biocide against aphids, whiteflies and plant hoppers with a high plant systemic activity. By means of bioassays and autoradiographic techniques it has been shown that this systemic behaviour originates not only from xylem but also from phloem mobility. After foliar application the growing points of plants are protected by pymetrozine imports mainly from leaves. This indicates a high importance of phloem mobility for the systemic activity of pymetrozine against plant-sucking insects. © 1997 SCI.     

氟虫腈衍生物-糖基偶合物的合成及其在蓖麻韧皮部的输导性研究

为提高氟虫腈在植物体内的输导性,利用葡萄糖、半乳糖与木糖作为导向基团对其进行了糖基化修饰,设计合成了3个含乙酰保护基的糖基-氟虫腈偶合物(a,b,c)和3个脱保护基的偶合物(d,e,f)。采用液相色谱法测定了其在蓖麻幼苗韧皮部中的输导积累性。结果表明:化合物a、b、c无韧皮部输导性,而d、e、f 则具有良好的韧皮部输导性;培养2 h后,收集的第3 h内韧皮部液中 d、e、f 的浓度分别为21.45、14.14 和14.82 μ mol/L。饲料拌毒法测定结果表明,与母体化合物氟虫腈(LC50为4.49 μ mol/L)相比,6个偶合物对亚洲玉米螟Ostrinia furnacalis的杀虫活性均有所下降,LC50值在47.54~78.00 μ mol/L之间。     

阿维菌素和硫线磷对南方根结线虫的毒力

利用阿维菌素和硫线磷处理南方根结线虫离体卵与幼虫,测试其对线虫卵和卵块孵化以及对2龄幼虫的致死作用、活动能力、侵入能力的影响。结果表明阿维菌素和硫线磷均对线虫卵和卵块的孵化表现很强的抑制作用,阿维菌素5 μg/mL处理24 h对卵孵化抑制率高达82.57%,而硫线磷40 μg/mL处理24 h对卵孵化抑制率为73.05%;阿维菌素和硫线磷处理48 h对2龄幼虫的LD50分别为7.346 1、13.345 6 μg/mL;在阿维菌素2 μg/mL和硫线磷3 μg/mL处理中,2龄幼虫在沙柱中的平均移动距离仅为0.04 cm和0.05 cm,而对照处理的线虫平均移动距离为1.04 cm;在阿维菌素2 μg/mL和硫线磷50 μg/mL处理2龄幼虫48 h后,对番茄根部的侵入率为0.12%和0.45%,而空白对照处理线虫的侵入率达21.85%。     

转crylAh基因玉米花粉对龟纹瓢虫生长发育和成虫移动能力的影响

本文利用花粉饲喂法研究了转crylAh基因玉米花粉对龟纹瓢虫Propyleajaponica生长发育及成虫移动能力的影响。结果显示,与混有适量蚜虫的非转基因亲本对照玉米花粉（花粉与蚜虫重量比为2：1）相比,龟纹瓢虫幼虫取食混有适量蚜虫的转crylAh基因玉米花粉（花粉与蚜虫重量比为2：1）后,幼虫总发育历期、蛹期和成虫寿命均无显著差异,但l、3和4龄幼虫的发育历期显著高于对照,2龄幼虫的发育历期显著低于对照;2龄和4龄幼虫的存活率与对照无显著差异,但3龄幼虫的存活率显著增加;幼虫取食Bt花粉对该虫的蛹重、羽化率和雌雄比与对照无显著差异。幼虫期取食Bt玉米花粉而成虫期取食蚜虫对成虫的日产卵量无不利影响,与对照无显著差异。幼虫取食Bt玉米花粉羽化后雄虫和雌虫的步速和翻跃时间与对照均无显著差异。     

Mobility,longevity and activity of chlorfenapyr in soils treated at a termiticidal rate

BACKGROUND: The mobility, longevity and termiticidal activity of chlorfenapyr applied to soils at the termiticidal labeled rate was evaluated for 30 months after treatment (MAT) in a greenhouse study. RESULTS: There was little dissipation of chlorfenapyr in soil treated at the labeled rate for perimeter treatments for the prevention and control of termite infestations. Chlorfenapyr was detected in soil immediately below the initially treated soil in the packed soil columns. This was likely due to settling of soil. The treated soil remained toxic to subterranean termites in 3 and 7 day bioassays over the duration of the study. The treated soil displayed slow‐acting properties regarding toxicity to termites. Trace amounts of chlorfenapyr were detected in the eluates of packed soil cones. CONCLUSION: The commercial formulation of chlorfenapyr used in this study (21.45% concentrate diluted to 0.125% prior to application) killed 100% of the tested subterranean termites for at least 30 months. Copyright © 2012 Society of Chemical Industry     

Fungicidal activity of N-(2-cyano-2-methoximinoacetyl)amino acids and their derivatives

More than 20 N-(2-cyano-2-methoximinoacetyl)amino acids and derivatives were synthesised and tested for antifungal activity against grape downy mildew, caused by Plasmopara viticola (de Bary) Berl. & de Toni, and rape downy mildew, Peronospora parasitica Fr. Two of the compounds containing a free carboxylic acid group, a moiety which has been shown to confer phloem mobility on compounds, showed high activity, especially against P. parasitica, in protectant tests. These results indicate that there is no incompatibility between the acid function and fungicidal activity. A number of the esters showed activity comparable with that of cymoxanil in the protectant tests, and the tert-butyl esters of the methionine derivative and its sulfone were more than ten times as active as the commercial compound.