Occurrence of soil insect pests: insight from classical identification supplemented with DNA barcoding

White grubs are key vegetables soil pests in Rwanda. However, aforementioned insect pests are unknown. We monitored adults with light traps and excavated larvae during cropping seasons of 2014 and 2015. Totally, 42 species were collected. The peak flights of key insect pests occurred from August to October and mid-March. The cytochrome C oxidase I (COI) gene was amplified with polymerase chain reaction (PCR) and used to compare larval DNA against DNA from adults by using MEGA 6, GMYC and ABGD software. The results obtained validate the use of COI gene. The identification results will help to predict critical time for management practices.     

苜蓿田及不同邻作地地表步甲群落多样性及其扩散动态

本研究选取宁夏银川市贺兰山农牧场苜蓿地及苜蓿-玉米、苜蓿-小麦、苜蓿-防护林、苜蓿-休闲地4种邻作边缘带,用陷阱法对步甲科昆虫种类和个体数进行了调查,研究了地表步甲昆虫的物种组成与数量、多样性以及季节迁移动态。调查共采集步甲昆虫9239头,21种。其中毛青步甲(Chlaenius pallipes)、谷婪步甲(Harpaluscal ceatus)、彩角青步甲(Chlaenius touzalini)分别占总个体数的41.17%,18.77%,17.07%,为该地区的优势种类。分析表明,4种邻作型的苜蓿边缘地步甲丰富度为防护林-苜蓿边缘地>小麦-苜蓿边缘地=玉米-苜蓿边缘地>休闲地-苜蓿边缘地;多样性为小麦-苜蓿边缘地>防护林-苜蓿边缘地>玉米-苜蓿边缘地>休闲地-苜蓿边缘地;小麦-苜蓿边缘地的均匀度指数和优势度指数均为最高。苜蓿边缘地与相邻作物边缘地步甲群落多样性比较,前者的步甲多样性指数明显高于后者。地表步甲种群在苜蓿田边缘带与相邻作物田边缘带之间存在着明显的季节迁移,其迁移动态的程度受不同邻作作物类型、苜蓿刈割及灌水等农事操作的显著影响。     

Secondary Ambrosia Beetles in Apparently Healthy Trees: Adaptations, Potential Causes and Suggested Research

Some ambrosia beetles are primary attackers of healthy, living trees, but in recent years normally secondary species have been increasingly observed attacking living trees, either as exotics or in their native geographic ranges. We identified five factors that could underlie an increasing prevalence of attack by secondary ambrosia beetles on living trees: (1) early flight before the host tree has recovered the ability to resist attack in the spring, possibly associated with climate change; (2) nutritional independence from the host that may enable ambrosia beetles to feed on ambrosia fungi that live on dead tissue in a living tree; (3) potentially pathogenic fungi that could become more pathogenic with climate change or through hybridization with exotic strains; (4) cryptic behavior that facilitates international transport and the establishment of exotic species and genotypes; and (5) a complex chemical ecology that enables secondary ambrosia beetles to locate stressed living trees that may temporarily appear to be suitable hosts for secondary beetles. We propose four avenues of research that will lead to an increased understanding of attack of living trees by ambrosia beetles, and may facilitate the implementation of effective pest management strategies and tactics: (1) intensive surveys, particularly for exotic beetle species and associated fungal strains; (2) molecular genetics studies that would facilitate the identification of known and new strains and genotypes, particularly of ambrosia fungi; (3) studies of the pathogenicity of ambrosia fungi as well as other fungi that could predispose trees to attack; and (4) investigations of the chemical ecology of tree-attacking species that could lead to new pest management tools and tactics.     

Stand characteristics and downed woody debris accumulations associated with a mountain pine beetle (Dendroctonus ponderosae Hopkins) outbreak in Colorado

Lodgepole pine (Pinus contorta Dougl. ex Loud.)-dominated ecosystems in north-central Colorado are undergoing rapid and drastic changes associated with overstory tree mortality from a current mountain pine beetle (Dendroctonus ponderosae Hopkins) outbreak. To characterize stand characteristics and downed woody debris loads during the first 7 years of the outbreak, 221 plots (0.02 ha) were randomly established in infested and uninfested stands distributed across the Arapaho National Forest, Colorado. Mountain pine beetle initially attacked stands with higher lodgepole pine basal area, and lower density and basal area of Engelmann spruce (Picea engelmannii [Parry]), and subalpine fir (Abies lasiocarpa (Hook.) Nutt. var. lasiocarpa) compared to uninfested plots. Mountain pine beetle-affected stands had reduced total and lodgepole pine stocking and quadratic mean diameter. The density and basal area of live overstory lodgepole declined by 62% and 71% in infested plots, respectively. The mean diameter of live lodgepole pine was 53% lower than pre-outbreak in infested plots. Downed woody debris loads did not differ between uninfested plots and plots currently infested at the time of sampling to 3 or 4–7 years after initial infestation, but the projected downed coarse wood accumulations when 80% of the mountain pine beetle-killed trees fall indicated a fourfold increase. Depth of the litter layer and maximum height of grass and herbaceous vegetation were greater 4–7 years after initial infestation compared to uninfested plots, though understory plant percent cover was not different. Seedling and sapling density of all species combined was higher in uninfested plots but there was no difference between infested and uninfested plots for lodgepole pine alone. For trees ≥2.5 cm in diameter at breast height, the density of live lodgepole pine trees in mountain pine beetle-affected stands was higher than Engelmann spruce, subalpine fir, and aspen, (Populus tremuloides Michx.), in diameter classes comprised of trees from 2.5 cm to 30 cm in diameter, suggesting that lodgepole pine will remain as a dominant overstory tree after the bark beetle outbreak.     

规模化猪场粪污处理工艺的研究

在国内外猪场粪污处理工艺调研的基础上，通过对粪污粒径分布、沉降性能和气浮工艺适用性的试验研究，确定了一种先进实用、可靠、易行的猪场粪污达标排放的处理工艺。     

引用川硬皮肿腿蜂防治天牛试验

川硬皮肿腿蜂(Scleroderma sichuanensis Xiao)是一种能有效地防治部分天牛、吉丁虫、象甲等林木钻蛀性害虫的优良小型寄生蜂。通过进行室内接种和室外释放试验,结果表明:川硬皮肿腿蜂对锈斑楔天牛的幼虫有寄生,室内寄生率达57.14%;小蜂的释放量越大对天牛的控制效果越好,以放蜂量300头·株-1的防效最佳,校正后的天牛幼虫寄生率达到11.29%。     

四川冶勒自然保护区树皮下的甲虫

作者于2005年7月~9月在冶勒自然保护区对生活在干枯、腐败树皮下的甲虫进行调查研究,共采集到218号标本,初步鉴定出20个科。以隐翅虫科Staphylinidae个体数最多,135头,占总数的61.9%,步甲科Carabidae次之,计29头,占13.3%。     

Aerially applied verbenone-releasing laminated flakes protect Pinus contorta stands from attack by Dendroctonus ponderosae in California and Idaho

We tested a new formulation of verbenone, an antiaggregation pheromone of the mountain pine beetle (Dendroctonus ponderosae Hopkins) (Coleoptera: Curculionidae: Scolytinae), for area-wide protection of lodgepole pine (Pinus contorta Douglas ex Loudon) stands in the western United States. Helicopter applications of verbenone-releasing laminated flakes were made at the rate of 370 g of active ingredient/ha to two sites, one in California and one in Idaho, during summer 2005. Each site consisted of five 20.23-ha treated plots and five matching 20.23-ha untreated plots. We assessed D. ponderosae flight into study plots using traps baited with aggregation pheromones and we tallied D. ponderosae attack rates on P. contorta trees in treated and control plots before and after application. There were no significant differences between numbers of D. ponderosae trapped on treated and control plots. However, a significantly smaller proportion of P. contorta trees was attacked in treated plots than in control plots at both sites; the attack rate in untreated stands was roughly three times that of treated stands in both California and Idaho, even at this low application rate. Furthermore, attack rate in 2004 was a significant explanatory variable for the response in 2005 regardless of treatment in both California and Idaho. There was no significant treatment effect at either site on attraction of Temnochila chlorodia (Coleoptera: Trogositidae) Mannerheim, a key predator of D. ponderosae, to the prey aggregation pheromone.     

2008年河口地区橡胶树寒害后小蠹虫严重危害及防治

2008年,云南河口植胶区继严重寒害后首次发生橡胶树小蠹虫严重为害,经调查证实橡胶树遭严重寒害是诱发小蠹虫大发生的直接原因;通过生产性防治试验,提出新的、有效实用的防治措施。     

利用捕食性天敌大唼蜡甲防治大小蠹属害虫的研究进展

综述云杉大小蠹的重要捕食性天敌昆虫大唼蜡甲在国内外的研究、应用情况,对大唼蜡甲的生物学和习性、化学生态研究情况、人工大量饲养和储存方法进行详细介绍,并对法国、英国等国家运用大唼蜡甲防治云杉大小蠹的实践进行总结.根据其特性及近年来国际生物防治理论的新发展,以引入大唼蜡甲对已传入我国的重大外来入侵害虫--红脂大小蠹进行生物防治的成功实践为例,讨论引入大唼蜡甲防治其他针叶树大小蠹的可能性和必要条件以及应采取的策略.