The use of surfactants to enhance acaricide control of Phytonemus pallidus (Acari: Tarsonemidae) in strawberry

The tarsonemid mite, Phytonemus (Tarsonemus) pallidus ssp. fragariae (Zimmerman), is a serious pest of strawberry throughout much of Europe and North America. Many of the plant protection products previously effective against the mite, which causes stunting and distorting of leaves and buds, reducing fruit yield and quality, are no longer available. Finding alternative acaricides for control is a priority. In two field trials, we tested 9 foliar applied plant protection products to determine the efficacy for control of Phytonemus pallidus, and to assess their effects on natural enemies. The products tested as foliar applications (dose ha⁻¹) were; abamectin 18 g/l EC (250, 500, 750, 1250 ml), tebufenpyrad 20% WP (500 g), fenpyroximate 51.3 g/l SC (1.0 l), bifenazate > 90% WP (400 ml), spiromesifen 24 g/l SC (500 ml), acequinocyl 15.8% SC (1.0 l), spirodiclofen 240 g/l SC (400 ml), etoxazole 110 g/l SC, and the surfactant, Silwett L-77 (Heptamethyltrisiloxane 0.05% (50 ml)). Effective products were used in admixture with the surfactant to investigate potential increased efficiency against P. pallidus. In each experiment, two applications were applied to plants previously inoculated with P. pallidus.     

蜂螨的种类及蜜蜂主要害螨研究进展

蜂螨是一类危害严重的蜜蜂寄生虫。随着蜂螨抗药性的产生和危害的加重,现已引起各国养蜂业的高度重视。本文从4个方面综述了近年来与蜂螨相关的研究进展:①蜂螨的种类;②重要蜜蜂害螨武氏蜂盾螨(Acarapis woodi),狄氏瓦螨(Varroa destructo)和小蜂螨(Tropilaelaps spp.)的分布、生物学特性、危害和防治方法;③与蜂螨相关的蜜蜂信息素研究;④与蜂螨相关的蜜蜂病害研究;并对今后蜂螨的研究趋势和方向进行了讨论。     

Responses of soil microarthropods to changes in soil water availability in tallgrass prairie

 Changes in precipitation and soil water availability predicted to accompany global climate change would impact grasslands, where many ecosystem processes are influenced by water availability. Soil biota, including microarthropods, also are affected by soil water content, although little is known about how climate change might affect their abundance and distribution. The goal of this study was to examine soil microarthropod responses to altered soil water availability in tallgrass prairie ecosystems. Two separate experiments were done. The first utilized control and irrigated plots along a topographic gradient to examine the effects of soil water content on microarthropod densities. Microarthropods, mainly Acari, were significantly less abundant in irrigated plots and were generally less abundant at the wetter lowland sites. The second study utilized reciprocal core transplants across an east-west regional precipitation gradient. Large, intact cores were transplanted between a more mesic tallgrass site (Konza Prairie) and a more arid mixed-grass site (Hays) to determine the effects of different soil water regimes on microarthropod abundance and vertical distribution. Data from non-transplanted cores indicated greater total microarthropod densities at the drier Hays site, relative to the wetter Konza Prairie site. Data from the transplanted cores indicated significant effects of location on Acari densities in cores originating from Hays, with higher densities in cores remaining at Hays, relative to those transplanted to Konza. Acari densities in cores originating from Konza were not affected by location; however, oribatid mite densities generally were greater in cores remaining at Konza Prairie. These results confirm the importance of soil water content in affecting microarthropod densities and distributions in grasslands, and suggest complex, non-linear responses to changes in water availability. Received: 14 April 1998     

陕西小爪螨属—新种(蜱螨亚纲:叶螨总科)

本文记述小爪螨属一新种——水杉小爪螨 Olionychus melasequoiae sp.nov.,属叶螨科Tetranychidae     

The Rhagidiidae (Acari: Prostigmata) in NW Lapland: Could their assemblages be climate warming monitors related to environmental and habitat patterns?

Fifteen species of Palearctic and Holarctic Rhagidiidae inhabit the polar Fennoscandian mountain birch forest and tundra, but additional taxa are expected to be discovered. Their assemblages comprise 5-10 species. Of these, Rhagidia gigas, R. diversicolor and Poecilophysis pratensis are the most abundant and widely distributed in the forested subalpine (480-600 m a.s.l.) and transitional (500-650 m a.s.l.) altitudinal zones while Poecilophysis pseudoreflexa and Rhagidia longiseta are found in the low-(600-800 m a.s.l.) and mid-(800-960 m a.s.l.), and Rhagidia parvilobata in the high alpine (960-1025 m a.s.l.) zones. Ten species of the rhagidiid mites are common in the Fennoscandian tundra as well as the alpine tundra of the Ötztal Alps, North Tyrol. Patterns of richness and diversity in this group of mites are different in different altitudinal zones in NW Lapland and the Ötztal Alps. In contrast to the Alps, no endemic species were detected in Fennoscandia. The different altitudinal niches of most common mite species overlap, but some species of mites in the subalpine forest and the high alpine zone are altitudinal vegetation belt-specific and occupy different niches. Some species of mites are rare in all altitudinal vegetation belts.Rhagidia diversicolor, R. gigas, Poecilophysis pratensis and P. pseudoreflexa exhibited sufficient abundance, habitat and elevational specificity to be useful as indicator species of the subalpine to transitional as well as the low alpine to middle alpine altitudinal zones, respectively. Rhagidia parvilobata and Poecilophysis saxonica are indicators of the high alpine zone. Abundant species from the low subalpine forested zone as well as the high alpine zone are proposed as potential monitors for direct and indirect impact of climate warming. Summit mite invaders detecting current impact of climate warming were not discovered in the high alpine zone of the Fennoscandian oroboreal tundra.     

巴基斯坦为害芒果树的短须螨属一新种(蜱螨亚纲:细须螨科)

在巴基斯坦,害螨是果园的严重害虫,但此前并未作过广泛的研究。对巴基斯坦芒果种植区苏加堡的芒果树螨类区系进行了调查。记载并描述了短须螨属一新种:杓短须螨B.arystis。     

中国皮刺螨总科名录初报

医学革螨非是昆虫类节肢动物的统称,可以作为多种疾病的传播媒介。皮刺螨总科是医学革螨的重要组成部分,结合国内关于革螨区系研究的诸多文献报道,在《中国经济昆虫志》(第40册)的基础上,新增了9属126个新种,丰富和扩展了皮刺螨总科的内容。     

Effects of long-term soil warming and fertilisation on microarthropod abundances in three sub-arctic ecosystems

Soil microarthropod responses to long-term soil warming and increased fertilisation by addition of NKP or litter were assessed in three subarctic ecosystems. The experiment was carried out at three different field sites, where temperature and fertilisation manipulations had been running for 3–5 years (glade), 11 years (fellfield), and 12 years (heath) at the time of sampling. In the glade soil, warming led to decreases in Collembola and Gamasida, and increases in Oribatida, although effects were inconsistent between years. Actinedida densities were increased by fertilization, while Acaridida had higher densities in the treatment with both fertilisation and warming. In the fellfield, we found increased densities of Oribatida, Gamasida and Actinedida in the fertilised treatments, and some increases in Oribatida and decreases in Collembola and Gamasida in warming treatments. In the heath, there were increased densities of Collembola, Oribatida and Actinedida in the fertilised treatments, but we found no strong effects of warming. We suggest that the responses found in this study comply with the assumption that soil microarthropods are bottom-up controlled, and the observed changes are probably linked to changes in food availability more than direct climatic influences.     

Soil microarthropod response to the application of entomopathogenic nematode-killed insects in maize and flower strip habitats

Insects killed by entomopathogenic nematodes (EPN) represent a resource with which soil arthropods can interact. These interactions can be positive for EPN (e.g., arthropods serve as parasitic or phoretic hosts) or negative (e.g., EPN serve as prey). Plant diversity and soil disturbance may influence these interactions. We investigated the effects of maize and flower strip habitats on microarthropod abundance and community composition in soil surrounding greater wax moth larvae, Galleria mellonella, infected with the EPN Steinernema carpocapsae (Sc). In the first year of the experiment (2005), we compared microarthropod communities responding to burial of Sc-killed insects with a control (no soil disturbance). In 2006, we added two control treatments: burial of freezer-killed insects and sham burial. Soil samples (including G. mellonella) were collected 2 and 20 days (2005) or 2 and 12 days (2006) after application. In 2005, arthropod abundance and community composition were similar between maize and flower strip habitats. In 2006, we detected more arthropods in the maize than the flower strips. In both years, community composition differed between treatments providing resources (Sc-killed and freezer-killed insects) and those without (sham burial and no disturbance), with the greatest difference on the final sampling date. Soil surrounding Sc-killed and freezer-killed insects contained more dipterans, acarid mites, staphylinid beetles, onychiurid and entomobryid collembolans, and immature and male mesostigmatid mites than soil at sham burial and no disturbance sites. Most of these taxa are capable of nematophagy; however, EPN relative abundance was not associated with arthropod community composition.