白榆-刺槐混交林叶片养分与光合生理特性

通过田间试验,测定了不同生长时期白榆、刺槐纯林及其不同比例混交林[白榆∶刺槐分别为1∶1(1B1C)、1∶2(1B2C)和2∶1(2B1C)]植物叶片的N、P含量、叶绿素(Chl)含量、光合气体交换参数和叶绿素荧光参数的变化.结果表明:5—9月,2种纯林和3种混交林植物叶片N、P含量均呈减小趋势,到植物生长末期,1B2C混交林中刺槐叶片的N含量和白榆叶片的P含量均较其纯林有明显提高;3种混交林中,白榆叶片的叶绿素含量明显高于刺槐,且1B2C混交的白榆叶片Chl值在7月达到最大;3种混交林刺槐和白榆的光合速率(Pn)均大于其纯林,1B2C混交的刺槐叶片Pn在7月达到18.54μmol.m-2.s-1;不同比例混交林刺槐叶片的蒸腾速率和气孔导度均较其纯林有明显改善,为1B2C1B1C2B1C.至9月,3种混交林中白榆叶片的PSII电子传递量子效率明显大于纯林;2种纯林与3种混交林叶片光化学淬灭系数差异较小,而纯林的非光化学淬灭系数显著高于1B2C混交林.白榆-刺槐混交林可以显著提高植物叶片的养分含量和光合作用能力,其最优混交比例为1B2C.     

间种扁茎黄芪牧草枣园害虫天敌功能团的组成与时空动态

为了有效地管理枣树害虫,2002年在山西省太谷地区对4种不同处理的间作牧草枣园天敌功能团的群落组成、数量时空和多样性的发生动态进行了系统的调查研究.结果表明,间种牧草枣园害虫的天敌明显大于未间种牧草的枣园,种草综合防治园、种草常规防治园和种草不防治园的天敌比未种草常规防治园分别增加187.99%、151.82%和210.03%.种草枣园天敌功能团的恢复与重建速率、时空二维生态位平均宽度与重叠程度,以及平均多样性指数均明显大于未种草枣园;而种草枣园多样性标准误的波动幅度明显小于未种草枣园;不同处理枣园的天敌功能团与物种的优势度、多样性和均匀度的变化趋势均极显著相关.说明枣园种草有利于保护和利用天敌,有利于天敌的扩繁增殖;种草枣园天敌群落比未种草枣园相对稳定;不同时期、不同处理枣园天敌功能团数量和所起的作用不同;在天敌功能团中,瓢虫类恢复能力较强,蜘蛛类与寄生性天敌类较弱.用功能团来代替物种进行枣园害虫天敌群落学研究是可行的.     

外源水杨酸对NaCl胁迫下白榆幼苗光合作用及离子分配的影响

以1年生白榆幼苗为研究对象,设置0、0.5、1.0和2.0 mmol·L^-1水杨酸(SA)与0、50、100和150 mmol·L^-1 NaCl处理组合,考察盐胁迫下白榆幼苗生物量、光合色素含量、光合作用参数及根叶离子含量、分配、运输的情况,探讨外源SA对NaCl胁迫下白榆幼苗耐盐生理特征的影响。结果表明:(1)NaCl胁迫显著抑制了白榆幼苗的生长、光合色素含量及光合能力,并破坏了白榆体内离子平衡。(2)喷施外源SA使盐胁迫下白榆幼苗的干重和根冠比均不同程度升高,0.5和2.0 mmol·L^-1 SA不同程度提高了50和100 mmol·L^-1 NaCl处理组幼苗叶片光合色素含量。(3)0.5 mmol·L^-1 SA显著提升了50 mmol·L^-1 NaCl处理组白榆幼苗的净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr),1.0和2.0 mmol·L^-1 SA对150 mmol·L^-1 NaCl处理组幼苗净光合速率改善效果较好,外源SA对100 mmol·L^-1 NaCl处理组幼苗的光合作用参数无显著影响。(4)NaCl胁迫下,外源SA处理的白榆幼苗叶和根Na^+含量及Na^+/K^+、Na^+/Ca^2+和Na^+/Mg^2+显著降低,离子选择运输系数SK,Na、SCa,Na和SMg,Na升高,从而促进了幼苗K^+、Ca^2+和Mg^2+由根向叶片的转运;隶属函数分析发现对白榆幼苗叶和根中离子含量改善效果最好的SA浓度分别为1.0和2.0 mmol·L^-1。因此,适宜浓度的外源水杨酸能够有效改善NaCl胁迫下白榆幼苗的光合能力,有效调节白榆幼苗体内离子状态,从而增强白榆对NaCl胁迫的抗性。     

桔小实蝇生物防治研究进展

本文综述了国内外桔小实蝇的生物防治研究进展,概括了国内外对桔小实蝇起主要控制作用的主要天敌种类,论述了桔小实蝇寄生性天敌、捕食性天敌的利用;病原微生物中真菌、线虫、共生菌等的利用;对桔小实蝇具有引诱作用的水解蛋白、化学物质和植物次生物利用;桔小实蝇不育技术的应用等方面,并讨论了今后持续控制桔小实蝇中生物防治方面的发展趋势,以期为今后桔小实蝇持续控制提供生物防治方面的参考.     

宽槽胫叶蝉的形态特征和生物学特性

宽槽胫叶蝉Drabescus ogumaeMatsumura主要危害桑、槐、榆等林木,记述了各虫态形态特征、生物学特性、天敌种类,进行了防治试验。在山东商河1年发生2代,以卵在寄主枝条内越冬;天敌主要有螳螂、蜘蛛等,首次报道双距螯蜂Conatopussp.为其寄生性天敌。     

小麦蚜虫的优势天敌及对蚜虫的自然控制

小麦蚜虫天敌资源丰富 ,其优势天敌在甘肃环县有 30余种。各种蚜虫天敌在小麦不同生育期先后衔接、互相配合 ,对小麦蚜虫的发生起着有效的自然控制作用 ;蚜虫与天敌在不同年际间也呈现出一定的规律性变化。保护利用天敌应与测报、防治和改善生态环境相结合     

盐胁迫对朴树和速生白榆幼苗光合特性及叶绿素荧光参数的影响

以1年生的朴树和速生白榆幼苗为试材,采用山东省林业科学研究院东营分院34.6‰的地下天然盐水配制所需盐水浓度,定期定量浇灌,使土壤分别达0（CK）、2‰、2.5‰、3.5‰和5‰的含盐量,各处理胁迫45 d后测定其生长量（地径、苗高）、叶绿素含量、光合参数以及叶绿素荧光特性的变化,研究不同盐胁迫处理对朴树和速生白榆生长及光合作用的影响,探究其耐盐能力。结果显示: （1）整个盐胁迫过程中速生白榆的生长量较朴树高,但随着盐胁迫强度的增加朴树幼苗叶绿素含量呈先升高后降低的变化趋势,速生白榆幼苗则低于CK呈下降趋势。（2）朴树和速生白榆初始荧光（F_o）、最大荧光（F_m）和PSⅡ最大光能转化效率(F_v/F_m)均表现出下降趋势,与朴树相比速生白榆的F_o、F_m和F_v/F_m下降不明显,但在＞2.5‰盐胁迫下速生白榆的非光化学猝灭系数（NPQ）较朴树增加更明显。研究表明,朴树叶绿素含量在每个盐胁迫浓度下均显著高于速生白榆,但在大于2.5‰浓度胁迫下速生白榆的荧光参数变化较朴树占优势;在非环境胁迫及较低盐胁迫条件下（≤2.5‰）,朴树较速生白榆具有更好的光化学性能,但在较高盐胁迫条件下（＞2.5‰）,速生白榆光合参数及荧光参数较朴树变化稳定,能更好的适应盐胁迫环境。     

中稻田三种飞虱的捕食性天敌优势种及农药对天敌的影响

对两优0923非防治的中稻田白背飞虱、灰飞虱和褐飞虱与其天敌间的关系,采用灰色关联度法、生态位分析方法,对盆拍法调查的3种飞虱与其捕食性天敌在数量、时间和空间三方面关系进行分析,对每一种天敌对应的关联度、生态位重叠指数和相似性比例等参数标准化后的密切指数相加,按照密切指数值之和大小排序,评判3种飞虱捕食性天敌优势种.并用同样方法分析常规防治田农药对飞虱捕食性天敌的影响,以期为合理施药,科学保护和利用天敌优势种提供科学依据,其结果是,非防治田白背飞虱前三位天敌是条纹蝇虎、草间小黑蛛和锥腹肖蛸;灰飞虱的是八斑球腹蛛、茶色新园蛛和锥腹肖蛸;褐飞虱的是纵条蝇狮、四点亮腹蛛和黑肩绿盲蝽.防治田白背飞虱前三位天敌是条纹蝇虎、草间小黑蛛和锥腹肖蛸;灰飞虱的是拟水狼蛛、四点亮腹蛛和草间小黑蛛;褐飞虱的是黑肩绿盲蝽、拟水狼蛛和四点亮腹蛛.盆拍法的防治田和非防治田之间3种飞虱前三位的相同天敌,白背飞虱完全相同,灰飞虱没有相同天敌,褐飞虱的是黑肩绿盲蝽和四点亮腹蛛.飞虱与天敌在时间和数量关系上,扫网法的防治田和非防治田之间3种飞虱前三位的相同天敌,白背飞虱的是锥腹肖蛸和四点亮腹蛛,灰飞虱完全相同,褐飞虱的是纵条蝇狮和条纹影虎.两种稻田的差异主要是农药杀伤了飞虱,使飞虱数量减少,并对天敌有一定杀伤力,进而影响到天敌的发生规律.非防治田的盆拍法和扫网法之间,3种飞虱前三位相同的天敌,白背飞虱的是锥腹肖蛸,灰飞虱的也是锥腹肖蛸,褐飞虱的是纵条蝇狮.防治田两调查方法结果之间,白背飞虱的是锥腹肖蛸,灰飞虱和褐飞虱前3位天敌中没有相同天敌,其差异主要是两法调查稻株的部位不同所致.     

不同管理枣林枣粘虫(Ancylis sativa)天敌功能团的组成及动态

枣粘虫(Ancylis sativa)是枣树主要的食叶和蛀果害虫,为了控制其危害,2004年在太谷地区对4种不同处理枣林的枣粘虫天敌发生与态势进行了系统的调查研究,结果表明种草综合防治枣林枣粘虫天敌昆虫的物种数比种草常规防治枣林、未种草综合防治枣林和未种草常规防治枣林分别增加37.2%、84.4%和118.5不%,个体数分别增加39.2%、91.0%和187.4%,枣粘虫幼虫和蛹的寄生率分别增加46.94%和31.27%、35.21%和21.99%、116.42%和60.33%;综合防治枣林区草蛉类和寄生性天敌类的丰盛度明显大于(P<0.05)化学防治的枣林,而瓢虫类与蜘蛛类则明显小于(P<0.05)化学防治的枣林,食虫蝽类与其它捕食性天敌则是种草枣林区大于未种草枣林区;枣林种草后天敌的恢复与重建速率提高了50%~81%;种草枣林多样性的标准误明显减小,相关性测定表明枣粘虫天敌功能团与物种的优势度、多样性、均匀度的变化趋势较为一致,均极显著(P<001)相关。     

松毛虫赤眼蜂对高粱害虫的防效及生态经济效益评估

【目的】高粱是我国重要的食用、饲用、制糖及酿酒用作物,其害虫的绿色防控技术手段的应用和推广非常有限。本研究连续2年在河北省衡水高粱种植区,开展了利用松毛虫赤眼蜂Trichogramma dendrolimiMatsumura防治多种鳞翅目害虫的试验示范,以期为减少化学农药的使用、促进高粱产业的绿色可持续发展,提供一种有效、经济和可靠的害虫防治手段。【方法】赤眼蜂防治试验和化学防治试验分别在两个村子的高粱田内进行。通过统计植株被害率、田间捕食性天敌的丰度及高粱产量等参数,进行成本收益分析,比较两种方法对害虫的防治效果,进一步评价其生态和经济效益。【结果】赤眼蜂防治在减轻植株被害率和提高田间捕食性天敌丰度等方面优于化学防治,同时也实现了高粱的增产增收。与化学防治相比,2019年,赤眼蜂防治显著降低了高粱叶片被害率,田间捕食性天敌的丰度提高了3.96倍,产量略有提高,害虫防治成本相对更低,差额净收入增加了305.47元/hm²;2020年,赤眼蜂防治显著降低了高粱穗部被害率,田间捕食性天敌的丰度提高了2.66倍,产量增加了1 392.5 kg/hm2;2020年,赤眼蜂防治显著降低了高粱穗部被害率,田间捕食性天敌的丰度提高了2.66倍,产量增加了1 392.5 kg/hm²,单位面积防治成本虽略有增高,但综合起来,差额净收入却增加了3 644.05元/hm2,单位面积防治成本虽略有增高,但综合起来,差额净收入却增加了3 644.05元/hm²(19.90%),增收效果显著。【结论】与化学防治相比,松毛虫赤眼蜂不仅防治害虫效果更好,而且增加了田间生物多样性,提高了天敌的丰度,增产、增收效果显著。利用松毛虫赤眼蜂防治高粱害虫是一种可行、高效并极具竞争力的生物防治手段,具有大面积推广应用的前景。     

A meta-analysis of crop pest and natural enemy response to landscape complexity

Many studies in recent years have investigated the relationship between landscape complexity and pests, natural enemies and/or pest control. However, no quantitative synthesis of this literature beyond simple vote-count methods yet exists. We conducted a meta-analysis of 46 landscape-level studies, and found that natural enemies have a strong positive response to landscape complexity. Generalist enemies show consistent positive responses to landscape complexity across all scales measured, while specialist enemies respond more strongly to landscape complexity at smaller scales. Generalist enemy response to natural habitat also tends to occur at larger spatial scales than for specialist enemies, suggesting that land management strategies to enhance natural pest control should differ depending on whether the dominant enemies are generalists or specialists. The positive response of natural enemies does not necessarily translate into pest control, since pest abundances show no significant response to landscape complexity. Very few landscape-scale studies have estimated enemy impact on pest populations, however, limiting our understanding of the effects of landscape on pest control. We suggest focusing future research efforts on measuring population dynamics rather than static counts to better characterise the relationship between landscape complexity and pest control services from natural enemies.     

Adaptive defense of pests and switching predation can improve biological control by multiple natural enemies

One of the most important questions in biological control is whether multiple natural enemies can provide greater suppression of agricultural pests than a single best enemy. Intraguild predation (IGP) among natural enemies has often been invoked to explain failure of biological control by multiple enemies, and classical theoretical studies on IGP have supported this view. However, empirical studies are inconclusive and have yielded both positive and negative results. We extend classical models by considering anti-predator behavior of pests and diet switching of omnivorous natural enemies, and examine their effects on pest control. We assume that the pest can adaptively allocate effort toward the specific defense against each predator, and that the omnivorous natural enemy can consume disproportionately more of the relatively abundant prey (switching predation) by type III functional responses to prey items. The model predicts that adaptive defense augments pests but favors introduction of multiple natural enemies for controlling pests if IGP is weak. In contrast, switching predation does not make pest control by multiple natural enemies advantageous as in classical studies, in the absence of adaptive defense. However, switching predation reduces the necessity of defense by the pest against the omnivore and offsets the effect of adaptive defense. Thus, it makes the introduction of multiple natural enemies advantageous for pest control when the pest employs adaptive defense even if IGP is strong. These results suggest that types and combinations of behavior of prey and predators may greatly affect qualitative outcomes of biological control by multiple natural enemies.     

Constraints to the implementation of biological control in Sri Lanka

Sri Lanka is a tropical island with a rich diversity of arthropods, with many species of indigenous natural enemies of economic pests. However, no extensive island wide surveys have been carried out for natural enemies of major crop ecosystems and only a few of the indigenous natural enemies are reported useful for augmentation biological pest control by massive field releases of laboratory-produced insects. Most successful biological control programs on the island are importation (i.e. classical) biological control programs, where established exotic natural enemies control certain pest populations in valuable crops. There is growing interest in the use of native natural enemies in pest management, thus creating a need for intensive research on the ecology of indigenous natural enemies and development of infrastructure and technology to produce natural enemies for augmentation. This paper examines constraints and opportunities for implementation of biological control in Sri Lanka.     

Connecting scales: Achieving in‐field pest control from areawide and landscape ecology studies

Areawide management has a long history of achieving solutions that target pests, however, there has been little focus on the areawide management of arthropod natural enemies. Landscape ecology studies that show a positive relationship between natural enemy abundance and habitat diversity demonstrate landscape‐dependent pest suppression, but have not yet clearly linked their findings to pest management or to the suite of pests associated with crops that require control. Instead the focus has often been on model systems of single pest species and their natural enemies. We suggest that management actions to capture pest control from natural enemies may be forth coming if: (i) the suite of response and predictor variables focus on pest complexes and specific management actions; (ii) the contribution of “the landscape” is identified by assessing the timing and numbers of natural enemies immigrating and emigrating to and from the target crop, as well as pests; and (iii) pest control thresholds aligned with crop development stages are the benchmark to measure impact of natural enemies on pests, in turn allowing for comparison between study regions, and generalizations. To achieve pest control we will need to incorporate what has been learned from an ecological understanding of model pest and natural enemy systems and integrate areawide landscape management with in‐field pest management.     

橄榄星室木虱的研究

记述橄榄星室木虱Pseudophacopteron canarium Yang et Li的外部形态、生活习性、天敌种类和药剂防治试验。此虫在福州一年发生7～9代,第一代成虫始见于4月下旬,世代重叠明显,一年中的7月上旬至9月上旬先后出现三个成虫高峰,而以9月上旬的成虫数量最多。药剂防治试验表明,20%灭扫利防效最好,喷药后第2d药效达96.5%;其次是10%溴氟菊酯,喷药后第2d药效达到93.8%;此外,2.5%敌杀死、40%氧化乐果与80%敌敌畏等药效也在81%～90%。天敌种类繁多,诸如瓢虫、草蛉、郭公虫、蜘蛛与捕食螨等。尤以瓢虫的种类和数量都相当多,在抑制橄榄星室木虱的种群消长中起了重要的作用。研究工作还包括首次引用绿僵菌属(Metarhizium)于橄榄星室木虱之防治,开辟了该虫防治的新途径。     

不同干扰条件下枸杞园节肢动物群落结构与动态

2008年通过对宁夏银川地区不同干扰条件下枸杞园节肢动物群落的系统调查,共采集节肢动物151628头,鉴定出4纲27目76科167种,其中天敌亚群落61种,化防园23种,有机园30种,自生园61种,天敌总量的比例分别为10.87%、18.78%、70.34%。通过群落结构分析,自生园丰富度、个体数均明显高于化防园和有机园,有机园均匀度、多样性较高,而化防园丰富度、个体数指数都较低,而优势集中度高。通过主分量分析表明潜叶类害虫与刺吸类害虫是不同人工干扰条件下的主要害虫,刺吸类害虫成为发展有机枸杞的重要障碍,食花果类害虫具有较大的危害潜力;寄生类天敌、病原类天敌为自生园优势天敌,捕食类天敌是有机园、化防园的优势天敌,但化防园天敌作用较为微弱。自生园天敌亚群落与害虫亚群落第一对典型变量为V1=0.048x1-0.2533x2+0.5951x3+0.5207x4,W1=0.9021y1+0.0354y2+0.0223y3+0.1847y4-0.0591y5,相关系数为0.8635,化防园、有机园天敌亚群落与害虫亚群落第一对典型变量的相关系数分别为0.6826、0.7332。通过害虫-天敌亚群落的种群消长动态表明,天敌亚群落作为整体对害虫发挥着调控作用,自生园7-9月份寄生性天敌对刺吸式害虫的跟随作用很强,有机园较弱,化防园则不明显。     

天敌昆虫抗药性研究进展

天敌昆虫抗药性研究在协调害虫化学防治和生物防治中有着重要的理论和现实意义,其研究的最终目的在于更好地推进抗性天敌在害虫综合治理(IPM)中的应用。抗药性天敌昆虫具有潜在的巨大价值。鉴于此,本文系统地综述了天敌昆虫抗药性最新研究进展,包括杀虫剂对天敌昆虫的影响、天敌昆虫抗药性现状、抗药性机理和限制天敌昆虫抗药性发展因素等。文章最后还对抗药性天敌昆虫的应用前景进行了展望。     

Mitigating the effects of insecticides on arthropod biological control at field and landscape scales

Integrated pest management (IPM) programs emphasize the combination of tactics, such as chemical and biological control, to maintain pest populations below economic thresholds. Although combining tactics may provide better long-term sustainable pest suppression than one tactic alone, in many cases, insecticides and natural enemies are incompatible. Insecticides can disrupt natural enemies through lethal and sub-lethal means causing pest resurgence or secondary pest outbreaks. Legislative actions such as the Food Quality Protection Act (US) and the Directive on Sustainable Use of Pesticides (EU) have placed greater restrictions on insecticides used in agriculture, potentially enhancing biological control. Here we focus on the effects of insecticides on biological control, and potential mitigation measures that can operate at different scales. At the farm scale, natural enemies can be conserved through the use of selective insecticides, low doses, special formulations, creation of refugia, special application methods, and targeted applications (temporal or spatial). At the landscape scale, habitat quality and composition affect the magnitude of biological control services, and the degree of mitigation against the effects of pesticides on natural enemies. Current research is teasing apart the relative importance of local and landscape effects of pesticides on natural enemies and the ecosystem services they provide, and the further development of this area will ultimately inform the decisions of policy makers and land managers in terms of how to mitigate pesticide effects through habitat manipulation.     

Integrating biological and chemical controls in decision making: European corn borer (Lepidoptera: Crambidae) control in sweet corn as an example

As growers switch to transgenic crops and selective insecticides that are less toxic to natural enemies, natural enemies can become more important in agricultural pest management. Current decision-making guides are generally based on pest abundance and do not address pest and natural enemy toxicity differences among insecticides or the impact of natural enemies on pest survival. A refined approach to making pest management decisions is to include the impact of natural enemies and insecticides, thereby better integrating biological and chemical control. The result of this integration is a dynamic threshold that varies for each product and the level of biological control expected. To demonstrate the significance of conserved biological control in commercial production, a decision-making guide was developed that evaluates control options for European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), in sweet corn, Zea mays L., where the primary natural enemies are generalist predators. Management options are lambda-cyhalothrin (broad-spectrum insecticide), spinosad (selective insecticide), Trichogramma ostriniae (Peng and Chen) (Hymenoptera: Trichogrammatidae) (parasitoid), and Bacillus thuringiensis (Bt) sweet corn (transgenic variety). The key factors influencing thresholds for all treatments are the intended market, predator populations, and the presence of alternative foods for the predators. Treatment cost is the primary factor separating the threshold for each treatment within a common scenario, with the lowest cost treatment having the lowest pest threshold. However, when the impact of a treatment on natural enemies is projected over the 3-wk control period, the impact of the treatment on predators becomes the key factor in determining the threshold, so the lowest thresholds are for broad-spectrum treatments, whereas selective products can have thresholds > 6 times higher by the third week. This decision guide can serve as a framework to help focus future integrated pest management research and to aid in the selection of pest management tools.     

Adaptive Release of Natural Enemies in a Pest-Natural Enemy System with Pesticide Resistance

Integrated pest management options such as combining chemical and biological control are optimal for combating pesticide resistance, but pose questions if a pest is to be controlled to extinction. These questions include (i) what is the relationship between the evolution of pesticide resistance and the number of natural enemies released? (ii) How does the cumulative number of natural enemies dying affect the number of natural enemies to be released? To address these questions, we developed two novel pest-natural enemy interaction models incorporating the evolution of pesticide resistance. We investigated the number of natural enemies to be released when threshold conditions for the extinction of the pest population in two different control tactics are reached. Our results show that the number of natural enemies to be released to ensure pest eradication in the presence of increasing pesticide resistance can be determined analytically and depends on the cumulative number of dead natural enemies before the next scheduled release time.