内蒙古草原主要蝗虫的防治经济阈值

通过取样调查确定内蒙古草原的优势蝗虫种类;根据5种优势蝗虫自然种群的结构和数量,计算了其蝗蝻和成虫的平均寿命;在半自然条件下测定了这5种蝗虫在不同发育阶段的日食量。根据这5种蝗虫蝗蝻和成虫平均寿命及其日食量数据,估算了不同蝗虫造成的牧草损失,提出了其防治经济阈值(3龄蝻,头/m²), 其中：毛足棒角蝗Dasyhippus barbipes为22.7,小蛛蝗Aeropedellus variegates minutus为37.4,亚洲小车蝗 Oedaleus asiaticus为16.9,宽须蚁蝗 Myrmeleotettix palpalis为34.3,狭翅雏蝗Chorthippus dubius为36.7。     

内蒙古农牧交错区草地蝗虫防治对策与技术的研究初报

报道了2005年和2006年在内蒙古农牧交错区应用生物制剂防治蝗虫的试验,并提出其控制策略。草地试验区应用蝗虫微孢子虫(Nosema locustae)3×1010个孢子.hm-2剂量防治蝗虫,25 d后虫口校正死亡率可达60%-80%,2005年微孢子虫所引起宽须蚁蝗感染率第10天为14.4%,第45天为59.6%;2006年混合种群的感染率最高为16.7%。应用绿僵菌(Metarhizium anisopliaevar.acridum)3×1012个孢子.hm-2剂量防治蝗虫,20 d后虫口校正死亡率为40%-60%;将微孢子虫1.5×1010个孢子.hm-2剂量和绿僵菌3×1012个孢子.hm-2剂量协调应用治蝗,10 d后可使防效达到80%以上。在农田周遍草地应用卡死克150 mL.hm-2剂量作为保护带来防治蝗虫,其校正死亡率在75%以上,以阻止蝗虫侵入农田危害。由此提出在农田周围草地建立化学农药保护带,防止蝗虫入侵农田危害;草地蝗虫密度不高时单独使用蝗虫微孢子虫和绿僵菌,或协调应用二者长期控制虫口密度的防治策略。     

蝗虫微孢子虫及其在蝗害治疗中的作用

扼要阐述了蝗虫微孢子虫的生活史,形态特征及其防治蝗虫的原理和方法。指出用蝗虫微孢子虫治蝗具有显著的社会,经济及生态效益。     

蝗虫微孢子虫及其在蝗害治理中的作用

扼要阐述了蝗虫微孢子虫的生活史、形态特征及其防治蝗虫的原理和方法。指出,用蝗虫微孢子虫治蝗具有显著的社会、经济及生态效益。     

我国蝗虫的六大种群的遗传分化分析

我们可以用蝗虫的遗传多样性的变化来检测蝗虫种群的动态变化情况,这有利于研究蝗灾的发生于成为灾害的原理,有利于对蝗灾进行预报,进而有利于蝗灾的防治。对东亚飞蝗、大垫尖翅蝗、中华稻蝗、中华蚱蜢、亚洲小车蝗和黄胫小车蝗这六种蝗虫利用凝胶电泳的技术分析对其进行遗传分化分析,在所研究的12个基因座位中有有3个基因座在蝗虫的六大种群中均成呈单态分布,6个基因在在蝗虫的六大种群中呈多态分布,其余蝗虫的基因座位在这几个种群中至少有一个基因座位存在等位基因。研究表明六种蝗虫的遗传多样化水平均不高,我们可以通过蝗虫基因型和蝗虫等位基因频率的变化情况来对蝗虫种群进行检测,从而为防止蝗灾的发生提供指导和参考,进而提高防治效率。     

蝗虫微孢子虫病对东亚飞蝗聚集行为的影响

采用行为生测法和触角电位法研究了感染蝗虫微孢子虫病的东亚飞蝗对其聚集信息素粗提物的行为反应。在第3龄时部分蝗虫每头接种10^6个蝗虫微孢子虫,与健虫同一条件下饲养。用二氯甲烷从健康蝗虫的粪便、体表或卵囊中抽提聚集信息素,粗提物经纯化和浓缩后保存于冰柜中待用。结果表明,感病飞蝗对其信息素的感受能力下降,聚集行为反应减弱。行为生物测定发现,微孢子虫病对第4龄雌性蝗虫和第5龄蝗虫的聚集行为有明显的抑制作用,而对第4龄雄蝗的影响较小;总的看来,信息素粗提物对感病雄蝗和高龄蝗虫的作用分别高于对感病雌蝗和低龄蝗虫的作用。触角电位(EAG)测定表明,感染了微孢子虫病的东亚飞蝗蝗蝻和成虫,对其信息素粗提物的敏感性降低,且对不同来源的聚集信息素的电生理反应不同,其中对从雄性成熟蝗虫、第4龄蝗蝻及第5龄病虫的粪便中抽提制备的信息素粗提物、第4龄蝗蝻粪便挥发物、第4龄蝗蝻活虫体表挥发物的电生理反应显著下降;但对第5龄雌蝗和第5龄散居型蝗虫的粪便抽提物的电生理活性,病健虫无明显差异。此研究结果证明,施用微孢子虫治蝗时,微孢子虫对蝗虫的聚集行为有明显的影响,为微孢子虫的控害机理提供了新的证据。     

典型草原三种蝗虫成虫期的食物消耗量及其利用的初步研究

为了进一步明确蝗虫类群在草原生态系统内的功能作用,在内蒙古锡林河流域典型草原益和乌拉山地区,依蝗虫发生季节的次序,先后研究了3种优势蝗虫(毛足棒角蝗、宽须蚁蝗、亚州小车蝗)成虫群体在自然变温条件下取食羊草的食物消耗量和利用能力问题。 本文首先提出了群体饲育时,蝗虫个体平均寿命的计算式: (?)=sum from n=i-1 to (?) i·N_i/N_t 式中,i=个体寿命的天数;N_i=寿命为i的个体数,N_t=蝗虫实验种群的个体总数。 据上式计算得出3种蝗虫个体平均寿命,毛足棒角蝗:雄性为38.2±2.8天、雌性为31.4±2.2天;宽须蚁蝗:雄性为40.9±2.3天、雌性为30.2±1.6天、亚洲小车蝗:雄性为52.6±0.7天、雌性为40.6±2.3天。 3种蝗虫在其成虫历期内,平均个体累积食量玩 (干重,克)为:毛足棒角蝗的雄性为0.607±0.059、雌性为0.643±0.084;宽须蚁蝗的雄性为0.303±0.022、雌性为0.340±0.037;亚洲小车蝗的雄性为1.414±0.180、雌性为2.933±0.186。在不同蝗种间,其平均个体累积食量的差异显著(P<0.01)。 3种蝗虫的雌性个体的近似消化力（A.D.）均显著高于同种的雌性个体（p<0.01）;季节发生早的蝗种之近似消化力相对高于较晚期发生的种类（毛足棒角蝗>宽须蚁蚁蝗>亚洲小车蝗）。对摄入食物的转换效率（E.C.I.,E.C.D.）,则同种内的雌性个体均显著高于雄性（p<0.01）;不同蝗种间,以个体最小、在中期发生的宽须蚁蝗对摄入食物的转换效率为最高。     

蝗虫微孢子虫对蝗虫脂肪含量的影响

用东亚飞蝗Locusta migratoria manilensis作为活体寄主,将4龄蝗蝻接种蝗虫微孢子虫Nosema locustae后,对虫体总脂含量和血淋巴中的甘油脂含量、脂肪酶活力进行了测定,结果表明：蝗虫微孢子虫的寄生可导致东亚飞蝗虫体总脂含量和血淋巴甘油酯含量大幅度下降及血淋巴脂肪酶活力大幅度上升。根据病虫生理指标提出了一种新的病级鉴定方法。     

围栏禁牧对羊草草原和大针茅草原蝗虫丰富度的影响

报道了围栏封育后羊草草原和大针茅草原蝗虫丰富度的变化,比较了蝗虫在羊 草草原和大针茅草原的发生特点．结果表明,以毛足棒角蝗为主导种的大针茅草原蝗虫生 物量是以小翅雏蝗为主导种的羊草草原蝗虫生物量的４～５倍;围栏封育后,羊草草原蝗 虫的生物量增加 ２４％,而大针茅蝗虫的生物量略有减少;围栏措施改变蝗虫的结构组成, 使毛足棒角蝗、鼓翅皱膝蝗、宽须蚁蝗、亚洲小车蝗等旱生和中旱生的地栖或兼栖偏地栖 种类的发生减少,条纹鸣蝗、小翅雏蝗、红腹牧草蝗等中生的植栖或兼栖偏植栖种类增加, 短星翅蝗及狭翅雏蝗的生物量在大针茅草原增加而在羊草草原减少．     

白洋淀蝗虫分布调查及其防治

1998～ 2 0 0 2年对白洋淀蝗区的蝗虫种类、分布、优势种群及蝗区水文、植被、土壤、天敌等进行了调查研究。调查表明 ,白洋淀蝗区有蝗总科昆虫 3 0种 ,隶属 6总科、2 2属 ,分布于白洋淀淀内湖泊蝗区、淀边内涝蝗区和淀外河泛蝗区 ;明确以东亚飞蝗Locustamigratoriamanilensis (Meyen)为主的 5个蝗虫优势种群及生活史 ,并根据不同蝗区类型 ,提出了蝗区治理区划、生态治理技术、应急化学防治等 3项防治技术和“两改一加强”防治手段     

Persistence of <Emphasis Type="Italic">Paranosema</Emphasis> (<Emphasis Type="Italic">Nosema</Emphasis>) <Emphasis Type="Italic">locustae</Emphasis> (Microsporidia: Nosematidae) among grasshopper (Orthoptera: Acrididae) populations in the Inner Mongolia Rangeland,China

Paranosema (Nosema) locustae Canning has persisted in grasshopper populations in the Inner Mongolia Rangeland since spore treatment was applied in 1993. In the treatment year, a 58.32–71.43% reduction of grasshoppers was recorded and 59.26–80.36% of surviving grasshoppers of various species were infected. In the years following application, prevalence of P. locustae varied from 13.65% to 60.71%, demonstrating that P. locustae remains in grasshopper populations for many years. Infection prevalence was more than 60.00% for Dasyhippus barbipes (F.-W.), Bryodema luctuosum luctuosoma (Stoll) and Angaracris barabensis (Pall.) in 1993 but was very variable, ranging from 20.00% to 60.71% over the subsequent nine years. Disease prevalence was 43.72–60.71% in 1993 and 1994 for Oedaleus asiaticus B.-Bienko and Myrmeleotettix palpalis (Zub.) but gradually declined to approximately 20%, where it remained. Persistence of P. locustae in grasshopper populations may be important in keeping densities below economic thresholds for a number of years after application. Handling Editor: Helen Roy.     

SEASONAL FLUCTUATIONS IN POPULATION DENSITES OF BULINUS SENEGALENSIS AND B. TRUNCATUS (PLANORBIDAE) IN TEMPORARY POOLS IN A FOCUS OF SCHISTOSOMA HAEMATOBIUM IN NIGER: IMPLICATIONS FOR CONTROL

Annual and seasonal changes in population densities of Bulinussenegalensis Müller 1781 and B. truncatus (Audouin, 1827)were studied in temporary pools of the west sahelian zone inNiger in relation to environmental factors. B. senegalensisis present in the temporary pools whatever their duration, whereasB. truncatus inhabits only the more persistent pools. B. senegalensispopulations develop mostly during the rainy season when thewater temperature is warm. B. truncatus is most abundant afterthe rainy season when the water temperature is cooler, but thissnail may increase when the water temperature is warmer duringunusual rainy seasons with low and intermittent rainfall. Fieldobservations suggest that interspecific competition is exceptionallyoccurring in the pool colonized by both B. senegalensis andB. truncatus. The implications of these observations on treatmentand retreatment schedules for schistosome infection in peopleand on snail control in temporary pools are discussed. (Received 4 May 1993; accepted 22 July 1994)     

Importance of timing,spore concentrations,and levels of spore carrier in applications of Nosema locustae (Microsporida: Nosematidae) for control of grasshoppers

In a study of microbial control of grasshoppers, Nosema locustae was applied to 10-acre plots in 2 replications of 24 treatment combinations in which the factors were (1) times of applications: 4 applications spaced over 22 days; (2) concentrations of spores: 1, 30, and 900 spores/in²; and (3) levels of the spore carrier: 1 and 4 lb wheat bran/acre. The concentrations of spores had the most effect in reducing the densities of grasshoppers and the incidence of infection among the survivors at the last sampling (coincided with the initiation of oviposition), the average reduction in density attributed to application of 1 spore/in² was 21%, that attributed to 30 spores/in² was 46%, and that attributed to 900 spores/in² was 73%. The first and second applications caused the greatest reductions in density; the second, third, and fourth applications produced the highest incidence of infections. Also, a higher incidence of infection was observed among grasshoppers from plots treated with 30 spores/in² on 1 lb bran/acre than from plots treated with 30 spores/in² on 4 lb of bran/acre. Therefore, a ratio of about 0.63–0.94 billion spores/lb bran applied at a rate of 1–1.5 lb/acre (= 100–150 spores/in²) at the time when the principal early summer species are third-instar nymphs would have resulted in overall reductions in density of 50–60%, with 35–50% of the survivors sufficiently infected so that fecundity would probably be affected. The reductions and incidence of infections would be higher in species that readily accept and use wheat bran, among which are some of the more economically important species of grasshoppers.     

Grasshoppers (Orthoptera: Acrididae) select vegetation patches in local‐scale responses to foliar nitrogen but not phosphorus in native grassland

Abstract Key elements such as nitrogen (N) and phosphorus (P) are often limiting relative to the nutritional needs of herbivores that feed on them. While N often limits insect herbivores in natural terrestrial ecosystems, the effect of P is poorly studied in the field, even though compelling hypotheses from the ecological stoichiometry literature predict its importance. We evaluated small‐scale spatial distributions of, and herbivory by, grasshoppers among neighboring plots that vary in foliar‐N and ‐P in tallgrass prairie. Grasshopper densities were 67% greater in N‐fertilized plots but detected no effect to grasshopper densities from P‐fertilizer. Leaf damage to the dominant grass Andropogon gerardii was 32% greater in N‐fertilized plots, but no response to foliar‐P was detected. Herbivore damage to a common forb, goldenrod (Solidago missouriensis), was not strongly linked by fertilizer treatments, although there was increased leaf damage in N‐fertilizer treatments when no P was applied (a significant N × P interaction). Under field conditions at local scales, we conclude that spatially heterogeneous distributions of grasshoppers are primarily affected by foliar‐N in host plants with little evidence that P‐levels contribute to the spatial patterns.     

Experimental control of the Mormon cricket,Anabrus simplex,byNosema locustae [Microspora: Microsporida], a protozoan parasite of grasshoppers [Ort.: Acrididae]

Spores ofNosema locustae Canning were applied with aerial equipment for experimental control of the Mormon cricket,Anabrus simplex Haldeman. The application resulted in infections in crickets during the season of application and the season following application. Spores were observed in cricket feces which indicated probable vertical transmission between generations. Reduced densities of crickets during the second season suggested effective control byN. locustae.     

Prevalence and infection intensity of the biocontrol agent Paranosema locustae (Microsporidia) in field-collected,newly-associated hosts (Orthoptera: Acrididae: Melanoplinae)

Host range, prevalence, and infection intensity of Paranosema locustae in grasshoppers at an establishment site in Patagonia, Argentina, were recorded. Results agreed with earlier observations at other introduction-establishment areas. Affected grasshoppers were melanoplines (Baeacris punctulatus, Dichroplus elongatus, Dichroplus maculipennis). Sporulation was not observed in instars I, II, and III.     

持续治理飞蝗灾害的新对策

该文通过对飞蝗Locusta migratoria为害特性的描述以及本世纪我国飞蝗防治历史的回顾,对各个时期的飞蝗治理策略的特点及不足进行了分析,并在总结我国近几年飞蝗生物治理理论研究与实践的基础上,提出了21世纪我国飞蝗生物治理的对策,即逐步扩大采用生物防治措施,增强如蝗虫微孢子虫生物防治制剂及天敌的控制作用,在飞蝗虫口密度中等或较低时,采用生物防治制剂为主,阻止或延缓中、低密度的飞蝗向高密度群居型的发展进程;在飞蝗虫口密度高时,可采用化防(昆虫生长调节剂等)与生防(如微孢子虫)配合使用,以迅速压低虫口密度,防治其迁飞为害,同时也可使蝗虫微孢子虫疾病长期流行于蝗群中,抑制飞蝗种群数量的增长。并积极探讨信息化合物对飞蝗行为的调控作用。     

Combined field efficacy of <Emphasis Type="Italic">Paranosema locustae</Emphasis> and <Emphasis Type="Italic">Metarhizium anisopliae</Emphasis> var. <Emphasis Type="Italic">acridum</Emphasis> for the control of sahelian grasshoppers

Field trials were conducted to evaluate the efficacy of wheat bran bait formulations of Paranosema locustae and Metarhizium anisopliae for controlling grasshoppers in southeast Niger. Treatments consisted of wheat bran baits mixed with M. anisopliae, P. locustae + M. anisopliae or with P. locustae spores and P. locustae + sugar. Oedaleus senegalensis, Pyrgomorpha cognata and Acrotylus blondeli were the predominant species at the time of application representing ca. 94% of the total population. Bran application was done when O. senegalensis (ca. 75% of the population) was at its early developmental stages, with first, second and third instars accounting for 64–85%. Grasshopper population reduction, P. locustae prevalence and level of infections in the predominant species were monitored. Manual application of P. locustae and M. anisopliae formulated in wheat bran has proven to induce consistent pathogen infection in grasshopper populations. Population density over the three weeks monitoring, typically decreased by 44.7 ± 6.9%, 52.8 ± 8.4%, 73.7 ± 5.5% and 89.1 ± 1.8% in P. locustae, P. locustae + sugar, M. anisopliae and P. locustae + M. anisopliae treated plots respectively. Paranosema locustae prevalence in surviving adult grasshoppers at 28 after application was 48.1 ± 2.3%, 28.9 ± 4.8% and 27.4 ± 3.7%, with infection level of 6.2 ± 0.8 × 10⁶, 2.3 ± 0.3 × 10⁴ and 2.1 ± 0.3 × 10³ spores mg⁻¹ host weight in O. senegalensis, A blondeli and P. cognate respectively. Other species that each accounted for <2% of the community, namely Aiolopus thalassinus, A. simulatrix, Acorypha glaucopsis, Acrotylus patruelis, Anacridium melanorhodon, Diabolocatantops axillaris, Kraussaria angulifera and Schistocerca gregaria were found to show sign of infection. The results from this study suggest that wheat bran application of M. anisopliae and P. locustae alone or in combination, targeting early instars grasshopper could be a valuable option in grasshopper control programs.     

New case of long-term persistence of Paranosema locustae (Microsporidia) in melanopline grasshoppers (Orthoptera: Acrididae: Melanoplinae) of Argentina

We report an additional case of long-term persistence of Paranosema locustae in grasshoppers of Argentina. The pathogen was introduced from North America on rangeland at Loncopué, Neuquén province. Microsporidia were not detected in pre-introduction samples whereas infected grasshoppers were found 11 years after introduction. Affected grasshoppers were the melanoplines Dichroplus elongatus, Dichroplus maculipennis, and Scotussa lemniscata, some of them with high spore loads. The case highlights the ability of P. locustae to recycle in local grasshopper communities by parasitizing susceptible species other than the natural hosts.     

芦芽山亚高山草甸、云杉林土壤有机碳、全氮含量的小尺度空间异质性

分析比较了山西芦芽山不同海拔处分布的亚高山草甸（样地A,海拔2756.3 m;样地B,海拔2542.3 m）和云杉林（样地C,海拔2656.8 m;样地D,海拔2387.2 m）土壤有机碳和全氮的小尺度空间异质性特征。结果表明：相同植被类型下海拔较高的样地有机碳含量较高（A：49.84 g/kg,B：38.33 g/kg,C：47.06 g/kg,D：40.67 g/kg）,而较低海拔的样地土壤有机碳含量的异质性较高;除样地A以外的其他3个样地均表现为高度空间依赖性。亚高山草甸土壤全氮含量的异质性远远高于云杉纯林,四个样地中均表现出强的空间自相关性。亚高山草甸样地土壤有机碳和全氮含量均在较大尺度上空间自相关,云杉纯林样地则表现为较小尺度的空间自相关变异。