Investigating the effects of crop type, fertility management and crop protection on the activity of beneficial invertebrates in an extensive farm management comparison trial

The activity of 11 groups of invertebrates, mainly predators and parasites, was investigated in 2005 and 2006 in a plot trial system on a farm in northern England, where the effects of organic and conventional fertility and crop protection management were separated within different crop types. Invertebrate activity was assessed using pitfall traps and suction sampling. Mixed effects models indicated that crop type significantly affected activity in all 11 groups. Crop protection applications had only a limited impact on activity but fertility management had considerable effects in some crops. Most differences were in barley, wheat and grass/clover, with less in vegetable and bean plots. Carabidae, Lycosidae, Staphylinidae, Linyphiidae and Braconidae gave consistent responses to fertility management, with more activity of the first two groups in organic plots and more of the other three in conventional plots. However, Coccinellidae and Ichneumonidae were not consistent in their activity between crops. After the effects of crop type had been partialled out, a constrained ordination showed that the novel combination of organic fertility and conventional crop protection had the most influence on group activity, with the combination of organic fertility and organic crop protection also significant. Maximising the activity of beneficial invertebrates in organic and sustainable farming systems requires a basic understanding of the effects of both crop type and fertility management, as well as crop protection.     

Effects of ground cover (straw and compost) on the abundance of natural enemies and soil macro invertebrates in vineyards

1 Herbicides are commonly applied under grapevines in Australia to remove weeds and thereby to avoid water loss through transpiration. 2 Interest in sustainability promotes a reduction in chemical inputs, including herbicides, leading to trials with surface mulches to suppress weeds. 3 Surface mulches may also influence the abundance of a range of invertebrates. Potentially, an increase in natural enemies will contribute to pest control and encourage a reduction in pesticide application. 4 We used three trapping methods and direct soil sampling to assess invertebrates at ground level, in the canopy and in the soil to determine the influence of mulch on natural enemies, potential pests and soil macroinvertebrates, including earthworms. 5 Collections sorted to family demonstrated that the addition of straw or compost mulches increased natural enemies collected with pitfall traps and soil organisms. However, there was no clear indication of the overall superiority of either mulch. 6 Abundance of ground beetles, parasitoid Hymenoptera and spiders collected with pitfall traps were increased by the addition of mulches. In the canopy, predatory and parasitic Diptera and predatory Hemiptera increased after mulching. 7 Earthworms collected by hand sorting soil increased with straw mulching. 8 No influence on pests was detected. Although Lepidoptera and Sigmurethra, collected in pitfall traps, increased with straw mulching, neither included pest species. 9 The results are discussed with reference to the potential economic impact of mulches.     

Interaction effects between local flower richness and distance to natural woodland on pest and beneficial insects in apple orchards

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Potential biocontrol agents for biofouling on artificial structures

The accumulation of biofouling on coastal structures can lead to operational impacts and may harbour problematic organisms, including non-indigenous species. Benthic predators and grazers that can supress biofouling, and which are able to be artificially enhanced, have potential value as augmentative biocontrol agents. The ability of New Zealand native invertebrates to control biofouling on marina pontoons and wharf piles was tested. Caging experiments evaluated the ability of biocontrol to mitigate established biofouling, and to prevent fouling accumulation on defouled surfaces. On pontoons, the gastropods Haliotis iris and Cookia sulcata reduced established biofouling cover by >55% and largely prevented the accumulation of new biofouling over three months. On wharf piles C. sulcata removed 65% of biofouling biomass and reduced its cover by 73%. C. sulcata also had better retention and survival rates than other agents. Augmentative biocontrol has the potential to be an effective method to mitigate biofouling on marine structures.     

Styrofoam boxes used for shipping mass-reared beneficial arthropods: Internal temperature responds rapidly to ambient temperature

Styrofoam boxes are thought to provide protection for natural enemies by buffering changes in ambient temperature during shipment. Boxes (40×24×13 cm L/W/H; wall thickness 1.8 cm) from a commercial insectary, equipped with temperature loggers, were shipped back to the insectary where they were packed and returned by courier. Internal box temperature and ambient fluctuated in a synchronized manner, differing by <3°C and remaining above 20°C for most of the shipping period. Under controlled conditions, internal box temperature was not effectively regulated by a frozen gel pack, even when boxes were encased in cardboard. Styrofoam boxes of the type and size tested should be refrigerated during shipment.     

Sown wildflowers between vines increase beneficial insect abundance and richness in a British vineyard

1. Traditional vineyards are generally intensive monocultures with high pesticide usage. Viticulture is one of the fastest-growing sectors of English agriculture, although there is currently limited research on habitat management practices.
2. In a vineyard in East Sussex, England, we tested five inter-row ground cover treatments on their potential in supporting beneficial insects: two commercially available seed mixes (meadow mix and pollen and nectar mix), a wild bee seed mix (formulated based on pollinator foraging preferences), natural regeneration, and regularly mowed grass.
3. Over two years, from May to August, we conducted monthly floral surveys and insect surveys using transect walks and pan traps.
4. The abundance and richness of flowers in the natural regeneration treatment were twice that of the regularly mown inter-row treatment. By year 2, the abundance of “total insects” sampled was significantly higher in the wild bee mix compared to mown. Likewise, there was a significant effect of treatment type on pollinator richness, with a higher mean richness found in wild bee mix. Solitary wasp family richness was highest in the natural regeneration treatment and lowest in the mown treatment.
5. Given the rapid growth and lack of specific environmental recommendations for British viticulture, we demonstrate a simple and effective approach for supporting beneficial insects and ecosystem services. Promotion of perennial wildflowers through sowing or allowing natural regeneration in inter-row ground cover in vineyards has the potential to boost biodiversity in vineyards on a large scale if widely adopted.

     

土壤微生物生物量在团聚体中的分布以及耕作影响

了解土壤微生物在土壤结构体内部的分布对于预测相关的土壤生物化学过程具有重要意义。由于气候、土壤以及耕作的影响,该领域的研究结果存在很大的空间和时间变异,因此有待进行更多的在不同气候和土壤类型下的研究。首次报道亚热带紫色水稻土中微生物生物量在长期不同耕作方式的土壤中不同水稳性团聚体中的分布特征。结果表明微生物生物量在紫色水稻土水稳定性团聚体中的分布模式决定于土壤结构本身,而耕作方式的影响不显著;微生物生物量碳在不同粒级土壤团聚体中无显著性差异,微生物生物量氮与可溶性有机碳在0．25～0．053mm微团聚体中含量最高;垄作免耕显著提高土壤团聚体中的微生物生物量及可溶性有机碳含量,而对微生物生物量及可溶性有机碳在土壤团聚体中的分布模式无显著影响。     

美国白蛾防控技术研究进展

美国白蛾Hyphantria cunea(Drury)原产于北美,是重要的国际性检疫害虫。自1979年我国首次发现该虫以来,已经对我国农林业生态系统特别是园林植物造成了严重危害。防控技术一直是美国白蛾研究领域的热点之一,利用性信息素、现代通讯技术和遥感技术,能够更精准地监测美国白蛾的发生危害情况。美国白蛾的防治措施主要以人工、物理、生物和化学防治为主,其中人工防治主要采取剪除网幕和草把诱集化蛹的方法,化学防治以飞机和机器人进行喷药,生物防治主要在美国白蛾幼虫期施用核型多角体病毒HcNPV,老熟幼虫和蛹期释放白蛾周氏啮小蜂Chouioia cunea Yang,可持续控制美国白蛾种群数量。该技术取得了良好的效果并大面积推广使用。尽管对美国白蛾防控技术的研究已经取得了重大进展,但仍存在一些问题需要进一步研究解决。如防治措施持续控制效果的科学评价方法、美国白蛾原产地天敌的引进利用、美国白蛾灾害分布特征与人类活动和生态环境的关系等。此外,随着害虫防治新技术的出现,如基因重组技术以及RNAi技术在多种害虫防治中的应用,均可为美国白蛾防治提供新的借鉴。本文还列出了国内外美国白蛾部分天敌昆虫名录,并对美国白蛾防控技术的未来发展趋势进行了展望,以期为美国白蛾及同类入侵生物的治理策略有所启示。     

Arthropod abundance in an Australian apple orchard under mating disruption and supplementary insecticide treatments for codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae)

The impacts of three codling moth management strategies (i, mating disruption alone; ii, mating disruption plus azinphos-methyl; iii, mating disruption plus fenoxycarb) on some secondary pests and their natural enemies in an apple orchard were compared over two growing seasons: 1993/1994 and 1994/1995. In the absence of azinphos-methyl (strategies i and iii), two-spotted mite ( Tetranychus urticae ) was controlled by Typhlodromus occidentalis and populations of generalist predators (e.g. ladybirds, lacewings and earwigs) increased. The populations of a parasitoid of woolly aphid ( Eriosoma lanigerum ), Aphelinus mali, also increased but not enough to provide adequate control of the aphid. Combined damage caused by lightbrown apple moth ( Epiphyas postvittana ), budworms ( Helicoverpa spp.) and San José scale ( Quadraspidiotus perniciosus ) was significantly higher in the absence of azinphos-methyl in 1994/1995. Beneficial insect populations were not suppressed by fenoxycarb. In 1994/1995, mating disruption plus fenoxycarb produced better control of E. postvittana than mating disruption alone. During transition to an apple integrated pest management program based on codling moth mating disruption, fenoxycarb was shown to be less disruptive to any natural control of secondary pests than azinphos-methyl.     

Do natural enemies really make a difference? Field scale impacts of parasitoid wasps and hoverfly larvae on cereal aphid populations

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Hedgerows surrounding organic apple orchards in north‐west Spain: potential to conserve beneficial insects

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Insecticide odour interference with food-searching behaviour of Microplitis croceipes (Hymenoptera: Braconidae) in a laboratory arena

Response to odours plays an important role in resource location by natural enemies, particularly by parasitoid wasps. While a considerable research effort has been dedicated to studying the effects of insecticide intoxication on natural enemy search behaviour, it is yet unknown if the odours themselves interfere with distant chemoreception. We investigated this issue using the food-searching behaviour of Microplitis croceipes (Cresson)(Hymenoptera: Braconidae) in laboratory arenas as a model system. Odours of imidacloprid (Genesis®), spinosad (Entrust®), esfenvalerate (Asana®), methamidophos (Monitor®), and vanilla were tested for their ability to interfere with wasp response to the odour of honey. The wasps did not contact the chemicals. Honey odour was generally effective in triggering food-searching behaviour in both honey-fed (and thus conditioned to associate honey odour with food) and unfed, naïve wasps. Mixing honey with imidacloprid and spinosad did not affect wasp responses. The remaining compounds (esfenvalerate, methamidophos, and vanilla) significantly reduced the proportion of positively responding fed wasps, but only methamidophos had such an effect on the unfed wasps. Negative methamidophos effects became completely reversed when wasps were forced to feed on honey in the presence of methamidophos odour. Our results suggest that odours and provision of food may potentially be used to keep beneficial natural enemies away from insecticide-treated areas.     

Bibionids (Diptera: Bibionidae) in agricultural land: a review of damage, benefits, natural enemies and control

Records of crop damage caused by Bibionidae are reviewed together with evidence for their beneficial activities, natural enemies and control methods. Bibionids are sporadic and infrequent pests. Although grass and cereals are most vulnerable, a wide range of crops is attacked. Damage is most severe after grass or when plants are under stress. The presence of organic matter during oviposition increases the likelihood of damaging populations. Many natural enemies exist but their impact on adult or larval populations has not been quantified. Given the pattern of attacks and lack of approved insecticides, cultural control methods are more appropriate than chemical. The role of adult bibionids in pollination and of larvae involved in soil processes could be of greater importance than any damage caused by the group.     

Above- and below-ground assessment of carabid community responses to crop type and tillage

1. Carabid beetles are major predators in agro-ecosystems. The composition of their communities within crop environments governs the pest control services they provide. An understudied aspect is the distribution of predacious carabid larvae in the soil.
2. We used novel subterranean trapping with standard pitfall trapping, within a multi-crop rotation experiment, to assess the responses of above- and below-ground carabid communities to management practices.
3. Crop and trap type significantly affected pooled carabid abundance with an interaction of the two, the highest numbers of carabids were caught in subterranean traps in barley under sown with grass.
4. Trap type accounted for the most variance observed in carabid community composition, followed by crop.
5. Tillage responses were only apparent at the species level for three of the eight species modelled.
6. Responses to crop type varied by species. Most species had higher abundance in under-sown barley, than grass, wheat and barley. Crop differences were greater in the subterranean trap data. For predaceous larvae, standard pitfalls showed lowest abundances in under-sown barley, yet subterranean traps revealed abundances to be highest in this crop.
7. Comprehensive estimation of ecosystem services should incorporate both above- and below-ground community appraisal, to inform appropriate management.

     

蜜源食物对节肢动物天敌寿命、繁殖力和控害能力的影响

大多数节肢动物天敌除了寄生或捕食寄主或猎物外,也会取食蜜源食物,特别是包括植物花蜜、花外蜜和昆虫蜜露等富含糖分的食物。这些蜜源食物对于提高寄生性和捕食性天敌的飞行和寄主搜索能力、延长寿命、提高繁殖力和增强控害能力都能发挥重要作用。本文重点介绍了农田生态系统中3类常见的非猎物性蜜源食物即植物花蜜、花外蜜和昆虫蜜露。其中,花蜜和花外蜜能够显著延长天敌寿命,提高天敌繁殖力和控害能力;蜜露的作用虽次于花蜜和花外蜜,但仍能促进某些天敌的生态功能。还进一步综述了显花植物和蜜源食物投放在生物防治中的应用,并从筛选适宜的蜜源植物、蜜源食物中糖成分作用分析和天敌对蜜源食物的搜索和定位等方向开展对蜜源食物的研究利用进行了展望。     

Spiders (Araneae) in the biological and integrated pest management of apple in the Czech Republic

Abstract:  Two management systems, biological and integrated, were compared to control the major pest, codling moth ( Cydia pomonella ) in apple orchards. The aim of the study was to assess the effect of these two systems on arboreal spiders. The biological system was based on the use of biological preparations, whereas in the integrated system selective pesticides were employed. The control plot had no pesticide treatment. The abundance of spiders was similar in all study plots during 3 years of study. Diversity, however, was higher in the biological plot than in the control and the integrated plots, suggesting that the response of spiders to management was guild-specific. Four spider families dominanted in all plots: Araneidae (orb weavers), Theridiidae (space-web weavers), and Philodromidae and Thomisidae (ambushers). While Araneidae and Thomisidae were similarly abundant on all plots, the density of Theridiidae and Philodromidae differed. In the integrated plot there were significantly more theridiid spiders, whereas in the control plot philodromid spiders were significantly more abundant. On the biological plot, the two families were similarly abundant. These differences were attributed to different age of trees in the control and treated plots, different prey spectrum, different susceptibility of the two families to applied chemicals and intraguild predation of theridiids by philodromids.     

我国烟粉虱主要捕食和寄生性天敌控制能力研究进展

烟粉虱Bemisia tabaci Gennadius是一种广泛分布于世界各地的多食性害虫,对我国多个省市区的农作物和观赏植物造成了严重的危害。化学杀虫剂的大量使用在杀伤天敌的同时使烟粉虱产生了不同程度的抗性,防治越来越困难;相较于化学防治,在不同地区筛选有效的天敌对烟粉虱进行生物防治是对烟粉虱进行有效控制的重要方法。我国报道的捕食性天敌共计26科109种,寄生性天敌共计2科59种。烟粉虱防治过程中由于单一的防治效果不理想,联合多个天敌资源的利用是增加对烟粉虱的生物防治效果的重要手段。本文通过对我国烟粉虱捕食性和寄生性天敌种类系统全面的整理,同时对烟粉虱优势种天敌中的单种或者多种组合利用后对烟粉虱的的控害潜能进行综述,以期为烟粉虱天敌昆虫种类的筛选和实现高效的生物防治提供科学依据。     

Dreyfusia nordmannianae in Northern and Central Europe: potential for biological control and comments on its taxonomy

The silver fir woolly adelgid, Dreyfusia nordmannianae, is the most severe pest occurring on Abies nordmanniana in Central and Northern Europe. The adelgid is particularly damaging to trees in Christmas tree plantations. Dreyfusia nordmannianae is native to the Caucasus region and alien to Europe, where its natural enemy complex is less diverse compared to its area of origin. Mitochondrial and nuclear DNA sequence data from the samples of D. nordmannianae collected in its native range and Europe and from the samples of Dreyfusia piceae and Dreyfusia prelli collected in Europe and North America were examined for phylogenetic structure. There was no evidence of differentiation, suggesting that these Dreyfusia species have recently diverged or require taxonomic revision. All existing published and unpublished reports on natural enemies of D. nordmannianae in its place of origin were reviewed, with the purpose of selecting agents for classical biological control in Europe. The literature review suggested that the most promising agent was the Chamaemyiidae fly, Leucopis hennigrata. A new survey in D. nordmannianae's area of origin – Turkey, Georgia and Russia – showed that L. hennigrata was present in all localities. It was particularly abundant in Turkey, where its impact on populations of D. nordmannianae appears to be high. Its use as a biological control agent is discussed, as well as other biological control strategies.     

Insect-resistant biotech crops and their impacts on beneficial arthropods

With a projected population of 10 billion by 2050, an immediate priority for agriculture is to achieve increased crop yields in a sustainable and cost-effective way. The concept of using a transgenic approach was realized in the mid-1990s with the commercial introduction of genetically modified (GM) crops. By 2010, the global value of the seed alone was US $11.2 billion, with commercial biotech maize, soya bean grain and cotton valued at approximately US $150 billion. In recent years, it has become evident that insect-resistant crops expressing δ-endotoxin genes from Bacillus thuringiensis have made a significant beneficial impact on global agriculture, not least in terms of pest reduction and improved quality. However, because of the potential for pest populations to evolve resistance, and owing to lack of effective control of homopteran pests, alternative strategies are being developed. Some of these are based on Bacillus spp. or other insect pathogens, while others are based on the use of plant- and animal-derived genes. However, if such approaches are to play a useful role in crop protection, it is desirable that they do not have a negative impact on beneficial organisms at higher trophic levels thus affecting the functioning of the agro-ecosystem. This widely held concern over the ecological impacts of GM crops has led to the extensive examination of the potential effects of a range of transgene proteins on non-target and beneficial insects. The findings to date with respect to both commercial and experimental GM crops expressing anti-insect genes are discussed here, with particular emphasis on insect predators and parasitoids.     

Parasitoid diversity and impact on populations of the diamondback moth Plutella xylostella (L.) on Brassica crops in central México

Three experimental plots were established and maintained during one year at two sites in the state of Querétaro, México, in order to identify species of parasitoids attacking the diamondback moth (DBM) Plutella xylostella (L.) (Lepidoptera: Plutellidae), and to gather information concerning their relative importance and patterns of population fluctuation. At both sites, the plots were planted with broccoli, cabbage and cauliflower during three cropping seasons. Parasitoid species identified were: Diadegma insulare Cresson, Diadromus (= Thyraeella) collaris Gravenhorst (Hymenoptera: Ichneumonidae); Habrobracon sp. (Hymenoptera: Braconidae); Oomyzus (= Tetrastichus) sokolowoskii Kurdjumov (Hymenoptera: Eulophidae); and Spilochalcis (= Conura) sp. (Hymenoptera: Chalcididae). This last species is a hyperparasitoid of D. insulare. The most abundant and frequently occurring species was D. insulare, it occurred in both localities during all three cropping seasons. The highest levels of parasitism caused by D. insulare on DBM were registered in the spring-summer season of 1996 at `La Soledad' farm with averages of 42.7, 45.0 and 44.5% on cabbage, broccoli, and cauliflower, respectively. Because D. insulare was detected attacking the pest at very low population densities during the initial stages of the crop cycle, it is assumed that the parasitoid has a high searching capacity. Correlation (r) between DBM and D. insulare population numbers was positive and significant. The other species identified occurred sporadically and had little impact on pest populations. The identification of D. collaris represents the first record of this species in North America.