山楂叶螨经济受害水平的研究

1988～1989年,在北京四季青乡11～12年生红星苹果树上,采用人工接螨的方法建立了山楂叶螨雌成螨螨日MD(mite days)级别与苹果2年联合产量损失率Q关系模型。利用此模型建立了雌成螨、雌成螨螨日、活动螨(雌成螨+幼若螨)、有雌成螨叶率时间动态多指标经济受害水平(EIL)模型EIL(Ⅰ)～EIL(Ⅳ)。并应用Croft提出的方法设计了配合该EIL模型的调查取样方法。     

不同棉花品种对土耳其斯坦叶螨的种群动态和种群参数的影响

土耳其斯坦叶螨Tetranychus turkestani(Vgorag et Nikolski)是新疆棉花害螨的优势种,本试验通过调查土耳其斯坦叶螨对棉田为害程度,研究了土耳其斯坦叶螨对新疆主栽的6个棉花品种(系)的种群动态进行了比较:新海21号、新陆早26号2个棉花品种上叶螨密度水平较低,标杂A1、297-5、81-3、新陆早12号叶螨密度没有显著差异。在此基础上比较了6种品种(系)上土耳其斯坦叶螨的实验种群参数:土耳其斯坦叶螨在新海21号、新陆早12号、新陆早26号品种上各虫态发育历期较长,各虫态存活率较低,每雌产卵量较少,种群趋势指数较低;而在标杂A1、297-5、81-3品种上的发育历期较短,各虫态存活率较高,每雌产卵量较多,种群趋势指数也较高。     

Effects of cotton cultivars on the population dynamics and population parameters of Tetranychus turkestani

土耳其斯坦叶螨Tetranychus turkestani(Vgorag et Nikolski)是新疆棉花害螨的优势种,本试验通过调查土耳其斯坦叶螨对棉田为害程度,研究了土耳其斯坦叶螨对新疆主栽的6个棉花品种(系)的种群动态进行了比较:新海21号、新陆早26号2个棉花品种上叶螨密度水平较低,标杂A1、297-5、81-3、新陆早12号叶螨密度没有显著差异.在此基础上比较了6种品种(系)上土耳其斯坦叶螨的实验种群参数:土耳其斯坦叶螨在新海21号、新陆早12号、新陆早26号品种上各虫态发育历期较长,各虫态存活率较低,每雌产卵量较少,种群趋势指数较低;而在标杂A1、297-5、81-3品种上的发育历期较短,各虫态存活率较高,每雌产卵量较多,种群趋势指数也较高.     

中国(虫穴)螨科二新种记述(蜱螨亚纲:中气门亚目)

记述(虫穴)螨科二新种:花副(虫穴)螨Parazercon floralis sp.nov.和拟重卡(虫穴)螨Caurozercon duplexoideus sp.nov.,副(虫穴)螨属和卡(虫穴)螨属为中国首次发现.     

朱砂叶螨刺吸胁迫对玉米防御信号分子的诱导作用

【目的】探明朱砂叶螨Tetranychus cinnabarinus持续为害对玉米Zea mays叶片内茉莉酸(jasmonic acid,JA)、水杨酸(salicylic acid,SA)、乙烯(ethylene,ET)、一氧化氮(nitricoxide,NO)、脱落酸(abscisic acid,ABA)和过氧化氢(hydrogen peroxide,H2O2)6个防御信号分子的诱导作用。【方法】室内人工接螨(10,20和30头/叶),采用分光光度法(SP)、高效液相色谱法(HPLC)和酶联免疫法(ELISA),测定了朱砂叶螨持续为害0,24,48,72和96 h后,玉米幼苗叶片内6个信号分子的含量。【结果】朱砂叶螨持续刺吸为害玉米幼苗叶片后,JA,ABA和H2O23个信号分子含量在叶螨刺吸为害24 h内迅速上升,在24 h时达高峰值,叶螨密度为30头/叶时其含量分别为同期未接螨对照的4.13,3.84和3.20倍,24-48 h内迅速下降;此后,ABA和H2O2含量维持在较低水平,而JA含量在48-96 h内又上升至次高峰值。NO含量则在24-48 h内上升较快,48 h时达最高,叶螨密度为30头/叶时其含量为同期未接螨对照的5.09倍。SA和ET含量在96 h内均随刺吸时间的延长而增大,96 h时最高,叶螨密度为30头/叶时其含量分别为同期未接螨对照的5.17和2.99倍。叶螨密度为30头/叶时,6个信号分子含量均显著高于同期未接螨对照(P0.05)。【结论】朱砂叶螨为害对玉米叶片内JA,SA,ET,NO,ABA和H2O2均具有诱导作用,且6个信号分子在叶螨持续为害玉米叶片后循序被诱导。     

芬兰真绥螨对苹果全爪螨的捕食作用研究

在实验条件下,系统研究了芬兰真绥螨Euseius finlandicus Oudemans对苹果全爪螨Panony-chus ulmi Koch的控制能力。研究结果表明:(1)在15～32℃的温度条件下,芬兰真绥螨雌成螨的捕食量随着温度的上升呈线型正相关。在15～25℃的温度内芬兰真绥螨的产卵量随温度升高而增加,在15℃下平均单雌产卵0.42粒,25℃时平均单雌产卵2.56粒;当温度升到32℃时单雌产卵下降为1.62粒,雌成螨的产卵量与温度的关系呈抛物线型。(2)在5～15头/叶的猎物密度下,雌成螨的捕食量随着猎物的密度增加呈线型正相关,而当猎物密度达到30头/叶时,芬兰真绥螨雌成螨的捕食量处于平稳状态。在5～15头/叶的猎物密度下,芬兰真绥螨的产卵量和产卵量均与猎物的密度呈线型正相关;当每头雌成螨捕食量为1.8～3.5头时,产卵量为1.0～1.5粒。(3)不同温度下,芬兰真绥螨对猎物的不同密度和虫态的功能反应可用圆盘方程II型进行拟合;在25℃条件下捕食效率最高且喜好捕食的虫态是卵和幼螨。     

二爪螨属和中(虫穴)螨属各一新种(蜱螨亚纲,前爪螨科,(虫穴)螨科)

记述尾足螨股前爪螨科二爪螨属1新种,具齿二爪螨Dinychus dentatus sp.nov.和革螨股(虫穴)螨科中(虫穴)螨属1新种,敦化中(虫穴)螨Mesozercon dunhuaensis sp.nov.,中(虫穴)螨属在中国为首次记录.     

轮伐期前后不同密度巨桉(Eucalyptus grandis)人工林土壤动物群落结构特征

在前期巨桉(E.grandis)人工林土壤生物多样性在轮伐期前(4年左右)降低,此后随林龄显著升高的研究基础上,在四川省丹棱县选择轮伐期前即4年和轮伐期后即8年的不同密度(D1:2000, D2:1600, D3:1200株/hm~2)巨桉人工林,研究了其土壤动物群落结构特征。结果显示:1)共捕获土壤动物2904只,隶属于4门8纲22目70科,其中大型土壤动物541只,以蚁科和康叭科为优势类群;中小型土壤动物2363只,以大翼甲螨科、等节虫兆科和线虫为优势类群。2)土壤动物类群数、个体数和密度随林分密度和林龄具有显著差异,4年生林地大型土壤动物个体数随密度降低显著增加,8年生巨桉人工林中小型土壤动物个体数及类群数随密度降低均显著增加;土壤动物个体数及类群数除D1密度时4年高于8年,其余密度均表现为8年高于4年。3)林分密度对土壤动物多样性指数有显著影响,4年生林地大型土壤动物Margalef丰富度指数随密度降低显著增加,8年巨桉人工林中小型土壤动物Shannon-wiener指数及Margalef丰富度指数随密度降低显著升高。4)巨桉人工林大型土壤动物以杂食性为主,枯食性次之,中小型土壤动物以腐食性为主,杂食性次之。5)RDA分析显示,林分密度、土壤含水量和土壤pH为对土壤动物的主要作用环境因子,4年时对奥甲螨科、长角长虫兆科、寄螨科、隐翅甲科、丽甲螨科等类群影响较大;8年时对线虫、蜚蠊科、康叭科、厉螨科、棘虫兆科等类群影响较大。为此,延长轮伐期、降低林分密度可改善巨桉人工林土壤动物生境、增加土壤动物多样性、促进土壤动物群落结构稳定性。     

不同饥饿程度拟小食螨瓢虫对朱砂叶螨的捕食作用

为明确饥饿程度对拟小食螨瓢虫 Stethorus (Allosstethorus) parapauperculus 控害潜能的影响,本研究通过比较不同饥饿程度下拟小食螨瓢虫对朱砂叶螨 Tetranychus cinnabarinus 的功能反应和自身密度干扰效应,探讨不同饥饿程度拟小食螨瓢虫对朱砂叶螨的捕食作用。结果表明,饥饿程度对拟小食螨瓢虫朱砂叶螨的捕食量有明显的影响,瓢虫的取食量与朱砂叶螨的密度呈正相关,表现为饥饿48 h＞饥饿24 h＞未饥饿;拟小食螨瓢虫对各虫态朱砂叶螨的捕食作用均符合Holling Ⅱ模型。在一定空间范围内,拟小食螨瓢虫个体间存在竞争和相互干扰,Hassell Varley模型能较好地反映拟小食螨瓢虫在捕食各虫态朱砂叶螨时受自身密度的干扰情况。在同样饥饿状态下,随着瓢虫自身密度增加,捕食效率降低,干扰效应增大。     

强度石漠化区不同植被修复模式下土壤螨类群落差异

石漠化治理区不同植被修复模式下的土壤螨类群落差异反映了生态系统的恢复状况,可籍以反映石漠化治理的生态效果。2014年1月、4月、8月和10月,对贵州花江喀斯特峡谷区顶坛小流域强度石漠化区域的"花椒"、"金银花"、"花椒+金银花"3种植被修复生境的土壤螨类进行了调查,共捕获土壤螨类1372头,隶属3目55科89属。采用类群(属)数、个体数量、个体密度、多样性指数(H')、丰富度指数(SR)、均匀性指数(J)、相似性指数(CN)、捕食性螨类成熟度指数(MI)和甲螨MGP类群等参数对土壤螨类群落差异进行了表征。结果显示,花椒林拥有较丰富的螨类属,金银花林拥有较高的的个体数量和个体密度。不同模式下的科、属类群组成呈现差异;属数、个体数量存在一定的季节差异,花椒林的螨类属数、金银花林的螨类个体数量和个体密度呈现一定的表聚性;群落多样性大多存在季节差异;捕食性革螨以r选择型为主,甲螨主要为O型和M型。研究表明,强度石漠化在不同植被修复模式下,土壤螨类生物生态类群存在差异,土壤生态系统仍处于修复之中,其中螨类优势属、具有典型生物学与生态学特性差异的螨类类群对石漠化治理的生态效果具有重要的指示作用。     

Insect economic levels in relation to crop production

Levels of economic insect damage and their effects on crop production are the most often-discussed issue in insect management today. The economic injury level (EIL) concept is the base for decision-making in most integrated pest management (IPM) programs. IPM programs are fundamentally different from control approaches that handle insect problems by focusing on tolerating insect effects. EIL is essential for IPM programs as it indicates which levels of insect populations can be tolerated and which cannot. By increasing our ability to tolerate insects, it is possible to eliminate or reduce the need for management tactics. Scientists can maintain environmental quality through better decisions on the use of those tactics. EILs help maintain environmental quality by reducing unnecessary use of management tactics, especially insecticides. However, including environmental considerations explicitly in the decision-making process could greatly improve the ability of IPM to sustain environmental quality. The EIL components include economic damage, economic thresholds, and the EIL itself. Increased availability of calculated EILs and their related economic thresholds would reduce unnecessary use of management tactics. An environmental EIL evaluates a management tactic based not only on its direct costs and benefits to the user but also on its effects on the environment. There are many factors that can reduce crop yield. One important cause is insects. Insects that cause loss to the fruits are frequently more destructive than those that damage leaves, stems and roots. For example, cotton is infested by Spodoptera littoralis (Boisd.), Pectinophora gossypiella (Saund.), Helicoverpa armigera (Hün.) and Earias insulana (Boisd.) cause the greatest yield losses. The amount of yield loss is dependent upon a number of factors, i.e., plant variety, soil fertility, insect population and skill in handling crop production, etc. Comparatively tolerant varieties, even at the cost of slightly less yield potential, will be more suitable under such conditions.     

The probabilistic economic injury level: incorporating uncertainty into pest management decision-making

Despite the recognition that the economic injury level (EIL) is determined by dynamic biological and economic parameters, which can be highly variable and uncertain, there has been little effort to quantify uncertainty and to use estimates of uncertainty in the determination of EILs. In this paper, we define the probabilistic EIL (PEIL) and develop PEILs for two insect pest scenarios: alfalfa weevil larvae, Hypera postica (Gyllenhal), on early bud-stage alfalfa, and bean leaf beetle adults, Cerotoma trifurcata (Forster), on V1-stage soybean. The PEIL is an EIL that reflects its probability of occurrence. The probability of occurrence is determined by incorporating the uncertainty associated with the input variables used to calculate the EIL. We used Monte Carlo simulation, a random sampling technique in which each input variable in the model was sampled repeatedly from a range of possible values based on probability distributions. Each input variable's probability distribution was sampled such that the distribution's shape was reproduced. Then, the variability for each input was propagated into the output of the model so that the model output reflected the probability of values that could occur. This represents the first use of the Monte Carlo technique to determine EILs.     

Determining an economic injury level for the persea mite,Oligonychus perseae,a new pest of avocado in Israel

The persea mite, Oligonychus perseae Tuttle, Baker & Abbatiello (Acari: Tetranychidae), a pest of avocado, was first discovered in Israel in the autumn of 2001. It has since spread to most avocado growing areas in Israel. To establish an economic injury level (EIL), based on the percentage of leaf area damaged (PLAD), we conducted an extensive field study. For three consecutive seasons we created distinct pest infestation levels on the Hass avocado cv., by applying acaricides (spirodiclofen and abamectin) at 50, 100, and 250 mites per leaf levels, along with non‐sprayed controls in a replicated block design. At harvest time we evaluated the level of leaf damage and fruit yields across treatments. In two out of the 3 years, trees sprayed at 50 and 100 mites per leaf levels had similar PLAD values, differing from trees treated at the 250 mites per leaf level and the non‐treated control, the latter pair also being similar. Over the 3 years, mean yield attained at the two higher infestation levels was reduced by 20% in comparison to the mean yields recorded for plots sprayed at the lower thresholds. Accordingly, we suggest that scouts adopt an action threshold (AT) of 50–100 mites per leaf. Future research is needed to refine this AT. Mean annual cumulative mite days (CMDs) of the two higher levels was ca. 13500 ± 700 per leaf. Using the linear regression equation PLAD = 0.0009CMDs + 2.42, describing leaf damage as a function of CMDs, we estimated an EIL of ca. 15 PLAD.     

Seasonal dynamics of economic injury levels for Tetranychus urticae Koch (Acari, Tetranychidae) on Cucumis sativus L.

Abstract:  Economic injury level (EIL) for Tetranychus urticae Koch on glasshouse cucumbers was established in two ways: EILs based on the number of T. urticae introduced to cucumber early in the growing season and EILs based on mite density and feeding durations (i.e. cumulative mite-days) in each of four growing seasons. The relationship between yield loss and T. urticae infestation level varied among four growing seasons. One mite introduced to cucumber early in the growing season could reduce the cucumber yield by 5.03, 3.20, 1.12 and 2.86 g per plant in spring, summer, autumn and winter, respectively. One mite-day (i.e. one mite feeding in a day) reduced cucumber yield by 0.0123, 0.0074, 0.0035 and 0.0073 g per plant in spring, summer, autumn and winter, respectively. When the seasonal dynamics of market values of cucumber was considered, EILs were the lowest in spring and the highest in autumn. When four seasonal data were combined, EILs can be calculated as EIL = C /(0.00276 ×  K ) for the number of T. urticae introduced early in the growing season and EIL = C /(6.8342 × 10⁻⁶ ×  K ) for cumulative mite-days, where K is efficacy of control measure and C the management cost. This study demonstrated the seasonal dynamics of EILs for T. urticae on glasshouse cucumbers, suggesting that decision making for T. urticae management on cucumber needs to be seasonally different under the glasshouse condition.     

Comparison of insect kinin analogs with cis-peptide bond, type VI-turn motifs identifies optimal stereochemistry for interaction with a recombinant arthropod kinin receptor from the southern cattle tick Boophilus microplus

The multifunctional 'insect kinins' share the evolutionarily conserved C-terminal pentapeptide motif Phe-X1-X2-Trp-Gly-NH2, where X1=His, Asn, Ser, or Tyr and X2=Ser, Pro, or Ala; and are associated with the regulation of diuresis in a variety of species of insects. We previously reported the functional expression of a southern cattle tick (Boophilus microplus) G protein-coupled receptor that is activated by insect kinins. Four different stereochemical variants of each of the 4-aminopyroglutamic acid (APy) and tetrazole moieties, mimics of a cis-peptide bond, type VI beta-turn in insect kinins were now evaluated on the expressed tick receptor using a calcium bioluminescence plate assay. This study represents the first investigation of the interaction of restricted-conformation analogs incorporating components that mimic specific conformations and/or peptide bond orientations in an expressed arthropod neuropeptide receptor. Analog Ac-RF[APy]WGa (2R,4S) was at least 10-fold more active than the other analogs, thus identifying the optimal stereochemistry for tick receptor interaction. The optimal stereochemistry for the tetrazole insect kinin analogs in the tick receptor assay was identified as (D,L). The APy is superior to the tetrazole as a scaffold for the design of mimetic insect kinin analogs. These biostable analogs provide new tools for arthropod endocrinologists and potential leads in the development of selective, environmentally friendly arthropod pest control agents capable of disrupting insect kinin regulated processes.     

Ecological characteristics of insects that affect symbiotic relationships with mites

Parasites and pathogens that begin as symbionts, i.e., organisms living together in the same habitat, are some of the most promising drivers of species evolution. Because insects are highly diverse and important as ecosystem service agents and because mites can exert large effects on insect populations (capable of killing at least juveniles), insect–mite interactions have been analyzed from various perspectives, including evolutionary, ecological and pest‐management perspectives. Here, I review and examine insect–mite symbiotic associations to develop hypotheses concerning the factors that maintain and develop their relationships. Previous studies have hypothesized that insect sociality and mite richness and specificity affect insect–mite interactions. I found that both solitary and social insects, including parasocial and subsocial insects, harbor numbers of symbionts including species‐specific ones but few dangerous mite symbionts in their nests or habitats under natural conditions. Nest size or the amount of food resources in a nest may affect mite richness. On the basis of this review, I hypothesize that the insect characteristics relevant for mite symbiotic hosting are sharing the same habitat with mites and living in a nutrient‐rich habitat. I also suggest that many cases of species‐specific symbiosis began with phoresy. To test these hypotheses, phylogenetic information on mites living with insect groups and quantitative analysis to characterize each insect–mite relationship are necessary.     

蚜虫种群时空分布动态模型

种群空间格局是昆虫种群的重要属性,是为害虫防治提供动态信息的重要前提。关于种群空间格局的时空动态,前人曾建立了富立叶模型和有阻尼自由震荡模型,但忽略了生境资源和空间资源的限制,不能很好地描述昆虫种群在自然界摆布状况的动态行为。因此,在前人研究的基础上,根据蚜虫在自然界的聚集扩散行为逐步建立了描述蚜虫种群聚集扩散规律的变幅、变周期时空分布动态模型,即:y=Ae-nt[sin(w0emtt+φ)+b]+c,并应用该模型对麦长管蚜(Sitobion avenae Fabricius)、麦二叉蚜(Schizaphis graminum Rondani)、禾缢管蚜(Rhopalosiphum padi Linnaeus)和玉米蚜(Rhopalosiphum maidis Fitch)的实验数据进行了拟合。结果表明,麦蚜种群和玉米蚜种群呈现出不同的规律,3种麦蚜均为减幅减周期的变化趋势,玉米蚜则表现为减幅增周期的变化趋势。此外,该模型的拟合效果较好(R20.942,SSE2.6)、生物意义明确,不仅可用于描述蚜虫以及蚜虫以外的其他昆虫和螨类种群的时空动态,还可准确描述不同年龄阶段和不同空间位置上种群的动态,具有普遍适用性。应用该模型考察不同种蚜虫在同一作物上的竞争情况和蚜虫与其天敌的空间分布动态,可为害虫的综合防治奠定基础;对不同小麦抗性品种上同一种蚜虫的聚集扩散行为进行刻画、分析,还可为小麦的抗性育种提供参考依据。     

Economic Injury Level and Economic Threshold as required by Forest Stewardship Council for management of leaf-cutting ants in forest plantations

1. The most commonly used method to control insect pests, such as leaf-cutting ants (LCA) in forest plantations, is the application of chemical insecticides, but their use was forbidden in plantations certified by the Forest Stewardship Council because of their negative effect on the environment.
2. A 5-year derogation of their prohibition was obtained in 2016 in Argentina, on the condition that forestry companies reduce pesticide doses by 5% per year and inform the Economic Injury Level (EIL).
3. The EIL and the Economic Threshold (ET) were estimated for the first time for the Acromyrmex genus in a Salicaceae forestation. As a model, we used the damage caused by the most detrimental LCA species of Argentina (Acromyrmex lundii) in the first, most critical year of a willow plantation (Salix nigra) in the lower basin of the Paraná River.
4. The EIL (8–15 nest/ha) was useful to demonstrate the real magnitude of the damage caused by A. lundii, which justified the need for its control. The ET for profitable production (∼3 nests/ha) would not be operatively applicable in a long-term management program in our study site. This methodology could be extrapolated to other Neotropical forest plantations attacked by Acromyrmex species.

     

Identification of selective and non-selective, biostable beta-amino acid agonists of recombinant insect kinin receptors from the southern cattle tick Boophilus microplus and mosquito Aedes aegypti

The multifunctional arthropod 'insect kinins' share the evolutionarily conserved C-terminal pentapeptide motif Phe-X1-X2-Trp-Gly-NH2, where X1=His, Asn, Ser, or Tyr and X2=Ser, Pro, or Ala. Eight different analogs of the insect kinin C-terminal pentapeptide active core in which the critical residues Phe 1, Pro3 and Trp 4 are replaced with beta 3-amino acid and/or their beta2-amino acid counterparts were evaluated on recombinant insect kinin receptors from the southern cattle tick, Boophilus microplus (Canestrini) and the dengue vector, the mosquito Aedes aegypti (L.). A number of these analogs previously demonstrated enhanced resistance to degradation by peptidases. Single-replacement analog beta 2 Trp 4 and double-replacement analog [beta 3 Phe 2, beta 3 Pro 3] of the insect kinins proved to be selective agonists for the tick receptor, whereas single-replacement analog beta 3 Pro 3 and double-replacement analog [beta 3 Phe, beta 3 Pro 3] were strong agonists on both mosquito and tick receptors. These biostable analogs represent new tools for arthropod endocrinologists and potential leads in the development of selective, environmentally friendly arthropod pest control agents capable of disrupting insect kinin-regulated processes.     

How Predatory Mites Learn to Cope with Variability in Volatile Plant Signals in the Environment of their Herbivorous Prey

When the chemical cues co-occurring with prey vary in time and space, foraging predators profit from an ability to repeatedly associate chemical cues with the presence of their prey. We demonstrate the ability of a predatory arthropod (the plant-inhabiting mite, Phytoseiulus persimilis) to learn the association of a positive stimulus (herbivorous prey, Tetranychus urticae) or a negative stimulus (hunger) with a chemical cue (herbivore-induced plant volatiles or green leaf volatiles). It has been suggested that the rate at which the integration of information becomes manifest as a change in behaviour, differs between categories of natural enemies (parasitoids versus insect predators; specialist versus generalist predators). We argue that these differences do not necessarily reflect differential learning ability, but rather relate to the ecologically relevant time scale at which the biotic environment changes.