苹果园二斑叶螨高效防治药剂筛选

【目的】为解决当前苹果园二斑叶螨Tetranychus urticae抗药性高、防治效果差、用药量大的问题,评价当前登记药剂及果园正在使用的药剂对二斑叶螨的防治效果。【方法】采用室内生测的方法比较了10种登记药剂,9种果园正在使用的药剂对二斑叶螨的毒力效果。【结果】选用的登记药剂中,80%的药剂对二斑叶螨效果差,甚至失去控制作用,防治效果低于66.67%,仅双甲脒、阿维菌素48 h防效在92.68%以上;果园常用药剂螺螨酯、虫酰肼、噻虫啉对二斑叶螨均表现出很好的防治效果,48 h防效达到84.09%-100%。【结论】目前80%以上的登记单剂药剂对二斑叶螨失去了防控效果,这是果园二斑叶螨防效差的主要原因,常用药剂螺螨酯、虫酰肼、噻虫啉等对二斑叶螨防效好。建议增加高效药剂登记或更换防治药剂,保证对二斑叶螨的防效,降低果园用药量,提高果园用药系统的精准性。二斑叶螨防治不能仅依赖化学药剂,要充分发挥果园生态系统的自然控害功能,延缓抗药性发展。     

二斑叶螨危害对棉花应激防御酶活性的影响

探明二斑叶螨取食对棉花叶片内应激防御性酶活性的影响。在棉苗5-6叶期接种不同数量(10-40头)的二斑叶螨雌成虫,取食1-4 d后采摘不同处理的叶片,利用分光光度计测定过氧化氢酶(CAT)、过氧化物酶(POD)、多酚氧化酶(PPO)、脂氧合酶(LOX)和苯丙氨酸解氨酶(PAL)活性。结果表明二斑叶螨取食后,棉花叶片CAT活性显著升高,且随诱导时间的延长其活性变化呈先上升后下降的趋势,为害3 d时,10、20、H(每株接棉蚜跟叶螨各40头)头/叶的CAT活性达到最高峰,显著高于对照(P0.05);POD、PAL活性也随诱导时间的延长和螨口数量的增加呈上升趋势,为害4 d时达到最高峰;而PPO、LOX活性随着时间的增加呈现上升后下降趋势,且为害2 d时达到最高峰,仍显著高于对照(P0.05)。棉叶应激防御酶活性随着二斑叶螨为害时间与螨口密度的增加而增加,表明二斑叶螨的危害胁迫能诱导寄主植物产生一系列应激生化反应,不同的酶活性表现有所不同。     

苹果绵蚜发生危害特点及防治对策

苹果绵蚜主要在我国辽东半岛、胶东半岛和昆明一带局部发生 ,每年 5～ 6月和 9～ 1 0月为害虫发生盛期。近几年来 ,危害逐年加重 ,并不断扩展蔓延 ,对我国苹果的产量和品质构成了严重威胁。该文介绍了苹果绵蚜在我国的危害情况和发生规律 ,分析了其发生与危害的特点 ,并提出了有效防治对策     

苹果园二斑叶螨种群的空间格局

种群空间格局的研究是昆虫生态学的重要内容,它不仅揭示出种群的空间结构特征,而且还是确定抽样技术和资料代换的基础,二斑叶螨是苹果园的重要害螨,应用4种聚集度指标和Iwao法分别考查了该螨在苹果树内的空间格局及动态规律,结果表明,二斑叶螨在树内不同方向和高度上均以个体群的形式存在,个体群的分布为聚集分布,其中上层和南面树冠的聚集度最高,而下层和内部树冠的聚集度最低,造成这种差异与该螨的生物学特性和环境条件的异质性有关,不论螨体在上层,中层或下层树冠,都明显地表现出前期高聚块,6月中旬以后聚集强度逐渐降低的趋势。     

二斑叶螨对六种植物的选择性及生长发育

采用“Y”形嗅觉仪研究二斑叶螨Tetranychus urticae Koch对接骨木(Sambucus williamsii Hance)、苹果(Malus pumila Mill.)、木瓜(Chaenomeles sinensis Koehne)、苦楝(Melia azedarach L.)、火炬树(Rhus typhina Torner)、大叶黄杨(Euonymus japonica Thunb)6种植物的嗅觉选择性差异。结果表明,该螨对苹果叶片的气味表现明显的趋向性,对木瓜叶片的气味表现明显的忌避性,而对其余4种叶片无趋向性或者表现中性。采用海绵水盘法研究在6种植物上的生长发育差异,该螨在接骨木、苹果、苦楝、火炬树上均能正常生长发育至成螨,且具有一定的繁殖力。但在木瓜和大叶黄杨上发育状况较差,繁殖力较差。     

二斑叶螨滞育特性的初步研究

诱导滞育实验表明 :短日照和低温是诱导二斑叶螨发生滞育的主要因子。测定我国天水种群 ,在 15℃条件下 ,诱导其滞育的临界日照长度为 9小时 4 2分 ,在每日 8小时光照条件下 ,诱导其滞育的临界温度为 15.5℃。解除滞育实验表明 :在每日 13小时的光照条件下 ,温度越高 ,解除越冬雌成螨滞育的速度越快 ;低温处理滞育雌成螨的时间越长 ,解除其滞育的速度也越快。     

用葡萄叶饲养的二斑叶螨实验种群生命表

二斑叶螨Tetranychus urticae Koch近几年在葡萄园内暴发为害,通过室内饲养,组建其取食葡萄叶片时的实验种群生命表,结果表明在室温(21～28℃)下,该虫的内禀增长率(rm)、周限增长率(λ)、净增殖率(R0)、种群世代平均周期(T)和种群加倍时间(t)分别为0.2066,1.2295,39.5929,17.8d和3.35d。     

丁氟螨酯对二斑叶螨生长发育的影响

[目的]丁氟螨酯是一种新型酰基乙腈类非内吸性杀螨剂,对害螨的各个螨态都有很高活性,具有较高的应用价值.本文评价了丁氟螨酯对二斑叶螨生长发育的影响,以期为合理用药和二斑叶螨的综合防治提供理论依据.[方法]采用浸叶法测定丁氟螨酯对二斑叶螨成螨与卵的致死中浓度、雌成螨产卵量、各螨态存活率以及各发育历期的影响.[结果]经丁氟螨...     

二斑叶螨为害对菜豆生理指标的影响

二斑叶螨(Tetranychus urticae)是为害菜豆的重要害虫。本文研究了二斑叶螨不同密度和不同时间为害对菜豆各种生理指标的影响。结果表明:在二斑叶螨2头·叶-1的低密度和为害少于5 d的短时期内,菜豆叶片叶绿素a、叶绿素b和叶绿素总含量变化不大,但随着二斑叶螨为害时间的延长和密度的增大,叶绿素含量下降明显增加;总糖和还原糖的含量与二斑叶螨的为害程度关系密切,即为害时间越长、受害程度越严重,还原糖降低幅度越大,总糖的含量则先升高再降低;随着二斑叶螨为害程度的加重,菜豆叶片中全磷、全钾损失显著,全氮含量变化不显著。     

二斑叶螨生物学研究

作者于1994—1995年对生活在花生和苹果叶上的二斑叶螨的生物学进行了研究。研究结果表明,以花生叶片为食科,该螨在25℃、30℃恒温条件和26．5℃-29．1℃变温条件下,其发育历期分别为11．04天,7．96天和8．64天。雌成螨在25℃、30℃恒温条件和23．8℃-30℃变温条件下,寿命分别是13．14天、10．5天和12．43天;产卵量分别是37．75粒、60,42粒和54．62粒。以苹果叶为食科,该螨在25℃、28℃和30℃恒温条件下,其发育历期分别是11．48天、9．56天和8．63天;雌成螨在25℃、30℃恒温条件和24.4℃-28．1℃变温条件下,其寿命分别为16．75天、14．78天和11.56天;产卵量分别是20粒、31.08粒和33．21粒。在花生上,该螨卵发育的起始温度是6．44℃,有效积温是69．79日度;虫期发育的起始温度是14．65℃．有效积温是74.98日度。在苹果上,卵发育的起始温度是4．61℃,有效积温是82,67日度,虫期发育的起始温度是12．41℃,有效积温是93．99日度。     

Effective concentrations of garlic distillate (Allium sativum) for the control of Tetranychus urticae (Tetranychidae)

The two‐spotted spider mite, Tetranychus urticae Koch, is a worldwide pest that feeds on a large variety of plant families. Because its resistance to acaricides is spreading rapidly, the development of new biological control tactics for population management is crucial. Plant extracts, such as garlic extract (Allium sativum Linn.), may represent viable alternatives, because they are currently considered to be minimum‐risk pesticides. Although garlic is known for its acaricidal properties, the extract concentration that provides the most efficient control has not yet been precisely determined. In this study, we conducted a series of laboratory experiments to determine the susceptibility of adult females to different concentrations of garlic extract. Fresh garlic cloves were steam‐distilled and sprayed using a Potter spray tower. Mortality and fecundity were measured upon treatment with garlic extract concentrations ranging from 0.46 to 14.4 mg/l. Female mortality increased with concentration, with LD₅₀ and LD₉₀ values of 7.49 and 13.5 mg/l, respectively. Reduced fecundity was previously observed at concentrations of 0.36 and 0.74 mg/l. The chemical composition of the Allium sativum distillate was characterized by reversed‐phase high‐performance liquid chromatography coupled with photodiode array detection, GC/MS and Fast GC‐FID against an authentic standard (Standard, Bioextract).Vinyl dithiin, diallyl disulphide, diallyl trisulphide and methyl allyl trisulphide were identified based on their mass spectra. Sesquiterpenoids were identified by their retention index.     

二斑叶螨对七种杀螨剂的抗药性测定及其机理研究

室内测定了相对敏感种群(S)和抗性种群(R)对常用7种杀螨剂的敏感性,并测定了羧酸酯酶、谷胱甘肽S-转移酶和乙酰胆碱酯酶3种酶的比活力。结果表明:二斑叶螨Tetranychus urticae Koch R种群已对甲氰菊酯和哒螨灵产生了抗性,抗性倍数分别为5.45和105.47。其中,甲氰菊酯对雌成螨的毒力最低(>3000mg/L),已远远超过田间推荐剂量,不宜继续使用。酶活测定结果表明:谷胱甘肽S-转移酶解毒活性的提高是二斑叶螨对甲氰菊酯产生抗性的原因之一;二斑叶螨对哒螨灵抗性的增强可能与羧酸酯酶有关。     

Field evaluation of Beauveria bassiana efficacy for the control of Tetranychus urticae Koch (Acari: Tetranychidae)

Trials with eggplants were conducted to evaluate field efficacy of Beauveria bassiana (Bb) applications against Tetranychus urticae, during spring of 2006 and 2007. In the 2006‐Trial, a rate of ca. 0.7 × 10¹² conidia/ha was sprayed onto plants at intervals. In the 2007‐Trial, the rates of ca. 0.8 × 10¹² and 1.6 × 10¹² conidia/ha were sprayed at 1‐ or 2‐week intervals. Based on population densities of mites and leaf damage assessed throughout the trial, the Bb sprays with 1‐ or 2‐week interval showed better control than those of 3 or 4 weeks. In both trials there was no statistical difference between 1‐week and 2‐week spray interval for all parameters measured. Furthermore, the higher rate performed significantly better than the lower rate, regardless of the intervals. No interaction was found between the spraying interval and the applied rate. Ultimately, to suppress the population density of T. urticae and prevent the eggplant damage in spring, the higher rate applied at 2‐week interval was effective.     

温度对二斑叶螨实验种群生长的影响

采用大樱桃叶片饲养二斑叶螨Tetranychus urticae Koch,组建其在15,20,25,30和35℃下的实验种群生命表,分析温度对二斑叶螨种群动态的影响。结果表明:在试验的温度范围内,二斑叶螨的发育速率随着温度的升高而加快,并符合Logistic模型。二斑叶螨全世代的发育起点温度和有效积温分别为11.85℃和170.39日.度。计算出在不同温度下的实验种群的内禀增长率(rm)、净增殖率(R0)、周限增长率(λ)、世代平均周期(T)和种群加倍时间(t)等种群参数。     

Functional response of Nesidiocoris tenuis (Hemiptera: Miridae) to the two-spotted spider mite,Tetranychus urticae

We examined the functional response of Nesidiocoris tenuis to varying densities of the two-spotted spider mite, Tetranychus urticae and found that the data fit a Type II response, with the attack rate (a) increasing with increased predator size. N. tenuis can be considered as a potential biological control agent of this pest in tomato.     

Different concentrations of Melia azedarach L. (Meliaceae) ethanolic extract on the developmental time and egg laying of Tetranychus urticae Koch

The use of plant-derived chemicals is a new recommended method to control Tetranychus urticae. According to recent studies, Melia azedarach has several compounds which could be effective on insects and mites. The effect of the extract on the fertility and pre-mature period of the mites were investigated at concentrations of 1, 3, 4 and 5?mg mL^?1 of the extract under laboratory conditions. The effect of chemicals extracted from plants was determined using the spraying bioassay method. The leaves being the location of the mites’activity, were sprayed with ethanol extract, then the mites were placed on the discs. In this experiment, the results show that all concentrations were effective, but extract concentrations 4 and 5?mg mL^?1 caused a reduction of more than 50% in the egg laying of the mites and a significant increase in their pre-mature period.