Residual activity of abamectin and spinosad against the predatory bugOrius laevigatus

The residual effect of two biopesticides, abamectin and spinosad, on the predatory bugOrius laevigatus (Fieber) (Hemiptera: Anthocoridae) was tested using a laboratory and an extended laboratory method. Experiments were conducted in the spring and summer 2000. The LD₅₀s on the 2nd and 5th nymphal instar and the adult stage, were lower for abamectin than for spinosad. The toxicity of each product on the 2nd instar and adults was significantly greater than on the 5th nymphal instar. Abamectin was much more persistent in spring than in summer. Spray deposits (at the recommended rate of 10 ppm a.i. for leafminer control) were toxic for 1 month in spring, whereas in summer they were no longer toxic after 2 weeks. Spinosad summer spray deposits (recommended rate of 250 ppm a.i. for leafminer and caterpillar control) were not toxic after 5 residual days. http://www.phytoparasitica.org posting Aug. 26, 2002.     

Effects of dp-B on ATPase activity of insect plasma membrane

Inhibition of ATPase from aphid plasma membrane, sarcoplasmic reticulum (SR), and brain synaptosomal plasma membrane of locust, by 1,5-diphenyl-2-penten-1-one (dp-B), was studied. Results demonstrated that dp-B exhibited the similar effects on ATPase found in the three membranes amongst which the plasma membrane Ca²⁺–Mg²⁺-ATPase is the primary target. The effects of dp-B on Ca²⁺–Mg²⁺-ATPase activity were bi-directional: the enzyme enhanced hydrolyzation when dp-B or Ca²⁺ concentrations were low but inhibited significantly when at high concentrations. The inhibition of Ca²⁺–Mg²⁺-ATPase by dp-B from brain synaptosomal plasma membrane of insect is higher than that from other organizational plasma membranes of the insect. Dp-B inhibiting Ca²⁺- and CaM-requiring ATPase activity may be an important mechanism by which the insect gets poisoned (for example aphid).     

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%。     

添加Silwet 408对3%阿维菌素微乳剂药液表面张力和接触角及其对两种害虫作用效果的影响

通过室内测定和田间防治试验,研究了在3%阿维菌素微乳剂中添加不同量的有机硅表面活性剂Silwet 408后,对药液的表面张力及在苹果叶片上接触角的影响,以及添加助剂后药剂对苹果红蜘蛛Panonychus ulmi和苹果绣线菊蚜Aphis citricola毒力及防效的变化。结果表明:Silwet 408能有效降低3%阿维菌素微乳剂药液的表面张力及其在苹果叶片上的接触角,且在试验添加量(质量分数)3%~10%范围内,表面张力和接触角均随助剂添加量的增加而不断降低。生物测定结果表明:添加Silwet 408可显著提高3%阿维菌素微乳剂对苹果红蜘蛛的毒力及田间防效,但对苹果绣线菊蚜的毒力和田间防效则无明显影响。研究表明,在杀虫剂中添加增效助剂以提高药效时,除了需考察该助剂能否显著降低药液的表面张力及在靶标上的接触角外,害虫种类也是需考虑的因素之一。     

亚致死浓度阿维菌素对荔枝叶螨种群发育的影响

于室内条件下研究了亚致死浓度阿维菌素对荔枝叶螨种群发育的影响。采用Potter喷雾法测得阿维菌素对荔枝叶螨成螨的亚致死浓度（LC10和LC30）,并通过生命表方法研究了阿维菌素LC10和LC30浓度处理荔枝叶螨对其生长和繁殖的影响。结果表明:用阿维菌素LC10和LC30浓度处理荔枝叶螨后,与对照相比,其F0代产卵量分别减少79.16%和71.83%,雌成螨寿命亦均明显缩短。F1代幼螨期、产卵前期与对照相比均无显著差异,但卵孵化期、前若螨期、后若螨期均显著延长,其中LC30浓度处理后分别延长41.4%、39.4%和36.1%;F1代产卵量降低、产卵期缩短,其子代雌性比提高;F1代内禀增长率均降低,分别为0.127 3和0.075 8,而对照为0.132 3;世代平均历期缩短,种群倍增时间延长;净生殖率和周限增长率均降低。表明亚致死浓度阿维菌素对荔枝叶螨种群增长有一定的抑制作用。     

阿维菌素和温度胁迫对朱砂叶螨自由基及保护酶活性的影响

应用酶活力测定的方法,研究朱砂叶螨经阿维菌素和高(低)温处理后对其体内自由基(O2.-)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性的影响。结果表明,朱砂叶螨经阿维菌素处理后,两种群体内的O2.-含量急剧升高,药后4h抗性种群和敏感种群O2.-含量分别是对照的3.42、3.54倍,同时SOD、CAT活性也明显高于对照;处理组中抗性种群体内O2.-含量低于敏感种群,SOD、CAT活性高于敏感种群。不适宜的高温和低温均能使朱砂叶螨体内的O2.-、SOD、CAT、POD活力升高,敏感种群在42℃的热激下SOD、CAT、POD的活性达到最大,分别是对照的4.25、2.06、1.81倍,与其它温度处理差异显著(P<0.05),其后呈下降趋势,而抗性种群酶活性在实验温度下,始终保持平稳上升的趋势;酶活性变化率分析结果显示,SOD对热胁迫的应激性最强,CAT次之,POD最小,抗性种群三种酶活性的变化率均大于敏感种群。     

二斑叶螨抗阿维菌素品系选育及其解毒酶系活力变化

采用室内生物测定和生化分析方法, 以采自甘肃兰州国家级森林公园兴隆山的二斑叶螨为敏感品系(SS), 研究二斑叶螨对阿维菌素的抗药性及抗性生化机理。结果表明：在室内用阿维菌素强化筛选24代, 获得了二斑叶螨抗阿维菌素品系(Ab-R24), 抗性指数(resistance index, RI)为321.5。对SS和Ab-R24解毒酶活性的分析表明, Ab-R24品系体内羧酸酯酶(CarE)、乙酰胆碱酯酶(AchE)、酸性磷酸酯酶(ACP)、碱性磷酸酯酶(ALP)、谷胱甘肽S-转移酶(GSTs)和多功能氧化酶(MFO)活性分别是SS品系的1.43、1.18、1.56、1.48、1.55倍和4.02倍, 差异达到显著水平(P < 0.05), 其中MFO的活性上升最为显著。对SS和Ab-R-24解毒酶动力学常数的分析表明, Ab-R-24品系体内AchE、GSTs和MFO的 Km分别是SS品系的1.14、2.31倍和2.58倍; Vmax分别是SS品系的1.19、2.34倍和1.76倍, 差异均达到显著水平(P <0.05)。说明二斑叶螨对阿维菌素抗性增高与MFO活性快速升高有关, AchE和GSTs也参与阿维菌素抗性的形成。     

Effect of abamectin on root-knot nematodes and tomato yield

BACKGROUND: Tomato growers in Shandong Province, China, commonly face heavy root‐knot nematode infestations. Current methods of control include cadusafos and methyl bromide (MeBr), but alternative methods are required because of the high toxicity of these pesticides and the ecological risk of their use. Therefore, abamectin soil applications were evaluated for their potential to control soil nematodes in a series of laboratory tests, greenhouse pot experiments and field trials. RESULTS: Laboratory tests showed that abamectin exhibited rapid knockdown of Meloidogyne incognita, with LC₅₀ and LC₉₀ values that were superior to those of cadusafos and averaged 7.06 and 21.81 mg L^?1. In the greenhouse pot experiment, soil applications of abamectin provided significant M. incognita control similar to that provided by cadusafos while maintaining excellent plant height and vigour. In the field trials, abamectin exhibited excellent control effects to nematodes while giving a higher tomato yield. There was a 19.3–39.0% yield increase from the various treatments compared with the control, and the best results were obtained from the highest dose of abamectin. CONCLUSION: The results of this study demonstrated that abamectin has the potential to be used as an effective alternative to MeBr and cadusafos for nematode control in tomato production in Shandong Province. Copyright © 2012 Society of Chemical Industry     

生物菌肥和钾肥配施对苹果钾素吸收及果实品质的影响

为了研究生物菌肥和钾肥对苹果果实品质及生长发育的协同作用,以7 a生'瓦里短枝'(Vallee spur Del)为研究对象,设置T1(K2O 420 kg·hm-2)、T2(生物菌肥2520 kg·hm-2)、T3(生物菌肥2520 kg·hm-2+K2O 294 kg·hm-2)、T4(生物菌肥2520 kg·hm...     

Differential inhibition of potassium ion absorption by difenzoquat in wild oat and cereals

Over a concentration range of 5.0 × 10^?6?7.5 × 10^?4M, the selective herbicide difenzoquat (1,2-dimethyl-3,5-diphenyl-1H-pyrazolium) caused more pronounced inhibition of potassium ion (K⁺) absorption by excised seedling roots of susceptible wild oat (Avena fatua L.) compared to those of tolerant barley (Hordeum vulgare L. cv. Bonanza) or wheat (Triticum aestivum L. cv. Neepawa). At 2.5 × 10^?5M difenzoquat, the relative inhibition of K⁺ (⁸⁶Rb) absorption by wild oat root segments inceased from 30% with a 10-min uptake period to 75% with an uptake period of 90 min, whereas no inhibition at all was evident for wheat root segments even after a 90-min exposure to the herbicide. An ion efflux compartmental analysis procedure demonstrated that difenzoquat did not affect the passive permeability properties of the plasma membrane of wild oat root cells. The experimental findings indicated that difenzoquat interfered directly with the process of active ion transport across the plasma membrane of root cells.     

阿维菌素对苹果绣线菊蚜的防治作用及对果园天敌的影响

以1.8%阿维菌素乳油为代表品种,开展了阿维菌素对苹果树绣线菊蚜Aphis citricola田间防治效果试验。结果表明,1.8%阿维菌素乳油1000~3000倍液药后2d、7d、14d对绣线菊蚜的防治效果为64.9%~87.6%。此外,研究了阿维菌素乳油对果园捕食性天敌幼虫种群的影响。田间调查结果表明,施药14d后药剂处理区食蚜蝇Chrysopa septempunctata种群难以恢复,七星瓢虫Epistrophc baltcata种群恢复至喷药前的65%以上,大草蛉Coccinella septempunctate种群基本恢复正常;室内实验结果与田间基本相同,对食蚜蝇影响最大,大草蛉影响最小。但枝条喷药后,在太阳光下放置4h后接虫,则天敌幼虫的死亡率均有明显下降。     

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。     

美洲斑潜蝇对阿维菌素的抗性筛选和遗传方式

在室内对美洲斑潜蝇进行了阿维菌素的抗性筛选和抗性遗传方式分析.经过1年的筛选,抗性水平从起初的13.05倍提高到36.05倍,遗传分析结果表明,抗性基因位于常染色体上,抗性为不完全显性遗传,受多基因控制.     

混合盐胁迫对油葵保护性酶活性、细胞膜透性及其主要农艺性状的影响

研究了不同浓度混合盐NaCl和NaHCO3对油葵苗期叶片、根系细胞膜透性,SOD、POD酶活性,油葵物候期、成熟期主要农艺性状的影响,目的在于对其耐盐性进行初步鉴定。结果表明:随着土壤混合盐浓度增大,叶片和根系的细胞膜透性,SOD、POD酶活性均呈现上升的趋势,差异显著,其中叶片SOD酶活性明显高于根系,并与盐浓度呈极显著的正相关。油葵的整个生育期明显受土壤盐浓度的影响,生育期延长,百粒重、单株产量、盘径、株高、干物质、鲜重有较大幅度下降。     

低钾胁迫下干旱对烤烟幼苗生理特性及钾含量的影响

为探究低钾胁迫下不同干旱程度对烤烟幼苗生理特性及烟株钾含量的影响,以烤烟品种‘K326’为试验材料,采用室内水培法,分别设置不同钾水平(低钾0.15 mmol·L^-1,常钾5.00 mmol·L^-1)和模拟干旱程度(PEG-6000浓度分别为0、5%、10%、15%、20%)双因素处理,对烟株生理指标、光合特性及烟株各部位钾含量进行测定。结果表明：相同PEG-6000浓度下,低钾水平处理的烟株地上部及根系干质量、鲜质量、根系活力、烟叶光合指标(除胞间CO₂浓度和水汽压饱和亏外)和各部位钾含量均低于常钾水平,其中低钾水平下烟株地上部及根系钾含量较常钾水平分别降低了10.62%～21.70%和35.96%～58.82%。常钾水平下,随着PEG-6000浓度的升高,烟株根系干质量、根系活力、叶片净光合速率、气孔导度、水分利用率、叶片可溶性蛋白含量、叶片POD、CAT活性均表现为先升高后降低,且均在PEG-6000浓度为10%时达到最大值,与PEG 0处理相比,各指标分别增加了16.01%、131.66%、27.87%、73.6...     

Effects of chlordimeform on vascular smooth muscle

The effects of chlordimeform on agonist-induced contractions of rabbit aortic strips and on calcium flux in the deadventitiated strips have been studied. Chlordimeform antagonizes contractions induced by several vasoactive agents, with the order of antagonism being potassium . histamine > serotonin > norepinephrine, and decreases the rate of contraction of strips exposed to each of the four agonists. Muscles contracted by each of the agonists are rapidly relaxed by application of chlordimeform, although in the case of norepinephrine the relaxation only proceeds to approximately one-half of the maximal tension. The rate of washout of ⁴⁵Ca from the media-intimal layer of the rabbit aorta was increased by chlordimeform, but the norepinephrine-induced decrease in the rate of washout of ⁴⁵Ca was not affected by chlordimeform. Chlordimeform did not affect ⁴⁵Ca uptake by the media-intimal strips. The results of this study indicate that chlordimeform probably interferes with loosely bound calcium to a greater extent than it does with more tightly bound stores.     

茄子叶螨种群消长动态及阿维菌素防治研究

连续2年调查了北京地区春茬塑料棚和露地茄子叶螨的种群消长动态,并评价了施用阿维菌素对棚内叶螨的防治效果。结果表明,北京地区春茬塑料棚内茄子叶螨的种群消长有明显的初现、上升、高峰和下降阶段,而露地叶螨的种群动态则随着气象条件的变化呈现明显波动趋势;露地和塑料棚内茄子叶螨均于5月底初现,6月上旬种群数量开始上升,此时是预防的最佳时机。1.8%阿维菌素乳油稀释2 500倍于种群高峰期前对棚内茄子植株进行均匀喷雾,药后7 d和14 d对叶螨的防效分别达84.11%和97.67%,表明喷施阿维菌素对茄子叶螨具有良好的控制作用,同时对蓟马和粉虱类害虫也有一定的兼治效果。     

不同钾肥品种对甘肃中部地区马铃薯产量及品质的影响

为了确定甘肃中部马铃薯主产区马铃薯生产过程合理施用钾肥品种及其用量,于2009年在甘肃省漳县进行了硫酸钾和氯化钾两种钾肥的不同用量试验,测定了马铃薯植株地上部分株高、分枝数以及经济性状和薯块产量,分析了不同用量下马铃薯品质和经济效益。结果表明,施用钾肥能有效提高马铃薯地上部分株高、分枝以及薯块产量和品质;同一钾肥下K₂O施用量105 kg·hm^-2时单株薯块、大中薯率、产量以及干物质、粗淀粉、Vc最高,而烂薯率和薯块还原糖含量最低,K₂O 60 kg·hm^-2时马铃薯粗蛋白含量最高;同一钾水平下施用硫酸钾马铃薯植株分枝数以及烂薯率明显低于施用氯化钾,单株结薯个数、大中薯鲜重、大中薯率及产量明显高于氯化钾,同时薯块干物质、粗淀粉、Vc、粗蛋白含量高于氯化钾,还原糖含量低于氯化钾,而株高差异不明显。研究得知,甘肃中部马铃薯主产区马铃薯生产过程中施用硫酸钾优于氯化钾,在施纯N120 kg·hm^-2、P₂O₅ 60 kg·hm_-2条件下,K₂O施用量105 kg·hm_-2时可有效提高马铃薯产量和品质,且纯收益最高。     

Effect of abamectin on electrophysiological activity in the ventral nerve cord of Periplaneta americana L.: Correlation with symptoms of poisoning and levels of toxicant in vivo

Twenty-four hours after injection of adult male Periplaneta americana with 36 ng [5-³H]abamectin, when symptoms of poisoning were apparent in most individuals, similar levels of radioactivity were found in tissue samples from the ventral nerve cord, metathoracic muscle, fat body and testis of randomly-selected insects. When insects injected with [5-³H]abamectin (36 ng) were separated after 24 h into three groups showing varying symptoms, the level of radioactivity in the ventral nerve cord was found to be significantly greater in partially-paralysed and paralysed groups (4- and 7-fold respectively) than in a treated but non- paralysed group. The mean levels of abamectin in the nerve cords of unaffected, ‘partially-paralysed’ and ‘paralysed’ insects were estimated to be 4, 23 and 37 nM respectively. Extracellular studies of the in-vitro action of abamectin (10 nM and 1 μM) on the spontaneous activity of a picrotoxin-sensitive, partially desheathed, ventral nerve cord preparation of adult male P. americana found the mean response time to be relatively slow (77 and 38 min respectively). In sheathed nerve cords, the mean response time to abamectin (1 μM) was 117 min. In all cases, treatment with abamectin increased the stimulus voltage required to evoke a response. Spontaneous activity was found to be progressively reduced in ventral nerve cord preparations from ‘partially-paralysed’ and ‘paralysed’ insects compared with ‘non-paralysed’ and untreated insects following dissection 24 h after injection of P. americana with unlabelled or labelled abamectin (36 ng), while the stimulus required to evoke activity in the ventral nerve cord showed the reverse trend. These differences in electrophysiological activity could be correlated directly with varying levels of abamectin in the nerve cords of ‘paralysed’ and ‘partially-paralysed’ insects.     

Effects of nitrogen, phosphorus, potassium and calcium nutrition on strawberry anthracnose

The effects of a range of concentrations of four nutrients – nitrogen, phosphorus, potassium and calcium – in fertilizer solutions on the severity of anthracnose on strawberry cv. Nyoho cultivated under a noncirculation hydroponics system were determined after inoculation with Colletotrichum gloeosporioides . Crop growth and tissue nitrogen, phosphorus, potassium and calcium contents of the entire above-ground parts of the plant were also investigated. Elevated nitrogen and potassium concentrations in the fertilizer solution increased disease severity in contrast to phosphorus and calcium. Treatment with either NH₄ or NO₃ nitrogen was not significantly different. The dry weight of the strawberry plants increased significantly with elevated concentrations of nitrogen ( R ² = 0·9078) and phosphorus ( R ² = 0·8842), but was not influenced by the elevated amounts of potassium ( R ² = 0·8587) and calcium ( R ² = 0·6526) concentrations.