Predatory mites of the Phytoseiidae family in integrated and ecological pest management systems in orchards in Slovakia

During 2005–2007, 1,332 individuals of predatory mites were found in integrated and ecological orchards in Slovakia. Seven predatory mite species of the family Phytoseiidae, namely Phytoseius echinus, Phytoseiulus macropilis, Euseius finlandicus, Typhlodromus pyri, Paraseiulus triporus, Amblyseius andersoni and Neoseiulella tiliarum, were identified. Out of 1,332 individuals, 519 (39.0%) were found in the apple orchards and 813 (61.0%) in the pear orchards. Out of all predatory mite individuals, 460 (34.5%) were found in the integrated pest management system (IPM) and 872 (65.5%) in the ecological pest management system (EPM). In apple orchards, P. echinus was dominant and constituted 49.3% of the detected mites. In pear orchards, E. finlandicus was dominant and constituted 48.7% of the detected mites. Typhlodromus pyri was also abundant, especially in pear orchards. The other species were less abundant.     

Intra- and interspecific predation by adult female Metaseiulus occidentalis and Typhlodromus pyri (Acari: Phytoseiidae) when provisioned with varying densities and ratios of Tetranychus urticae (Acari: Tetranychidae) and phytoseiid larvae

The phytoseiid mites Metaseiulus occidentalis (Nesbitt) and Typhlodromus pyri Schueten are used together and alone as biological control agents against tetranychid pest mites of apple. Their effectiveness as control agents may be impacted by intraguild predation. The effects of prey species and prey density on the rates of inter- and intraspecific predation and oviposition by these two predators were investigated through a series of experiments. Adult female predators were given prey as mixed populations of phytoseiid larvae and larvae of a more preferred species, the spider mite, Tetranychus urticae Koch, at different densities and ratios. Typhlodromus pyri, more of a generalist predator, showed higher rates of predation and cannibalism on phytoseiid immatures at most prey densities and ratios. Manly preference indices indicated that T. pyri switched to feed on phytoseiid larvae at higher prey levels and ratios of T. urticae than M. occidentalis. This greater ability to use phytoseiid larvae as prey may help stabilize T. pyri populations when more preferred prey is unavailable. This may, in part, explain the observed persistence of T. pyri populations when M. occidentalis populations were decreasing in orchard test plots.     

Biocontrol of Pests of Apples and Pears in Northern and Central Europe: 2. Parasitoids

The parasitoids of arthropod pests of apple and pear in northern and central Europe and their use as biological control agents are reviewed. The review demonstrates that apple and pear pests are host to a large and varied parasitoid fauna. All important pests are known to be host of parasitoids, but many parasitoids play only a minor part in regulating populations of their host. However, many parasitoid species are important natural enemies and some effectively regulate pest populations in unsprayed and/or commercial (insecticide sprayed) apple or pear orchards either individually or as part of parasitoid guilds. Exploitation/fostering of existing populations of parasitoids has been demonstrated to be an effective or partially effective approach for natural control of several important pest species. Important examples include natural regulation of the apple sawfly by Lathrolestes ensator and Aptesis nigrocincta, of the summer fruit tortrix moth by Colpoclypeus florus and Teleutaea striata, of leaf midges by Platygaster demades, of woolly aphid by Aphelinus mali and of leaf mining moths by guilds of parasitoid species. Introduction of parasitoids is an alternative approach to the exploitation of parasitoids already present in the orchard. This approach has been little explored and its success rate has been low, mainly confined to the control of non-indigenous pests by introducing parasitoids from their native region. Mass production methods for parasitoids are difficult and costly and are likely to be economic only where long-term populations can be established. Even where low cost mass culture techniques are developed, the degree of control may not be high enough to prevent economic pest damage as demonstrated by negative results with mass release of Trichogramma egg parasites for control of tortricids in orchards. Suitability of the orchard habitat is recognized as crucial to the success of individual parasitoids. Key requirements are adequate populations of the pest(s) and/or alternative hosts, suitable shelter, overwintering sites or food sources and avoidance of harmful effects of pesticides. Many species are highly sensitive to broad-spectrum insecticides, especially in the adult life-stage. Avoiding the harmful affects of insecticides is crucial to successful exploitation. The use of insecticides needs to be avoided, either altogether or at crucial times in the parasitoids' life cycle, or less harmful alternatives need to be used. Numerous parasitoids could potentially be exploited as biological control agents but hitherto have received little attention because little is known about them and/or because they are sensitive to broad-spectrum pesticides and are thus virtually absent from commercial orchards. The aim of future studies should be to develop effective strategies for establishing equilibria between important pests and their parasitoids, with pest damage rarely exceeding the economic threshold.     

Integrated management of phytoplasma diseases in pome fruit: an overview of efficacy results of IPM insecticides against pear Psylla (Cacopsylla pyri)

Phytoplasmas are plant pathogenic mollicutes that cause devastating diseases in various crops worldwide. The closely related pome fruit tree phytoplasmas Candidatus Phytoplasma mali and Candidatus Phytoplasma pyri are the causal agents of apple proliferation and pear decline, respectively. They can be transmitted from tree to tree by Psyllidae. As pear suckers (Cacopsylla pyri) are widely considered to be the most important pest in pear orchards, a good control of this insect vector is a key element for limiting the natural spread of pear decline. Efficient control relies on a perfect tuning of treatment schedules, taking into account efficacies of (at preferably) low-impact insecticides and side-(repellent)-effects of alternative products (e.g. kaolin, mineral oils and fungicides), the optimal positioning of these crop protection agents, and the best possible presence of beneficial predators. The department of Zoology of the pcfruit vzw research institute (Belgium) has a long tradition of executing insecticide field trials according to EPPO guidelines. Here, we present an overview of the results of a selection of IPM-compatible insecticides (abamectin, spirotetramat, thiacloprid, spinosad, spirodiclofen), tested in efficacy trials against pear Psylla on different life stages during the last decade. Based on these results and monitoring data of pest and beneficial biology, we additionally propose optimal pear Psylla control schedules which allow to reduce the number of (phytoplasma harbouring) psyllids in integrated systems to a minimum.     

More intraguild prey than pest species in arachnid diets may compromise biological control in apple orchards

Understanding the full diet of natural enemies is necessary for evaluating their role as biocontrol agents, because many enemy species do not only feed on pests but also on other natural enemies. Such intraguild predation can compromise pest control if the consumed enemies are actually better for pest control than their predators. In this study, we used gut metabarcoding to quantify diets of all common arachnid species in Swedish and Spanish apple orchards. For this purpose, we designed new primers that reduce amplification of arachnid predators while retaining high amplification of all prey groups. Results suggest that most arachnids consume a large range of putative pest species on apple but also a high proportion of other natural enemies, where the latter constitute almost a third of all prey sequences. Intraguild predation also varied between regions, with a larger content of heteropteran bugs in arachnid guts from Spanish orchards, but not between orchard types. There was also a tendency for cursorial spiders to have more intraguild prey in the gut than web spiders. Two groups that may be overlooked as important biocontrol agents in apple orchards seem to be theridiid web spiders and opilionids, where the latter had several small-bodied pest species in the gut. These results thus provide important guidance for what arachnid groups should be targets of management actions, even though additional information is needed to quantify all direct and indirect interactions occurring in the complex arthropod food webs in fruit orchards.     

Biological control of insect pests in apple orchards in China

Apple is one of the most important fruits in China, and both yield and quality are greatly affected by insect pests. According to surveys, there are more than 200 species of natural enemies in apple orchards. Few, however, have been closely studied. Major natural enemies including parasitoids, predators and pathogens are briefly described in this review, especially focusing on two parasitoids of Trichogramma dendrolimi Matsumura and Aphelinus mali Haldeman, predatory mites and a pathogenic fungus of Beauveria bassiana (Balsamo) Vuillemin as case studies. Augmentation, one important strategy of biological control, supplements the natural control provided by the existing natural enemy community in apple orchards, and greatly increases their efficiency in controlling pests. Conservation biological control is also widely applied in four major apple-producing areas. Based on habitat manipulation, the ground cover planting system helps regulate the microclimate and enhance the biodiversity of apple orchards, effectively conserving the richness and diversity of beneficial insect species. Certain achievements have been made in the main biological control strategies including successful introduction of some exotic natural enemies such as A. mali and Typhlodromus occidentalis Nesbitt, augmentative production and application of biological control agents such as T. dendrolimi, B. bassiana and Bacillus thuringiensis, and further research in conservation of establishing adaptive ground cover planting patterns to local environment. Challenges, however, still exist. Biological control of insect pests in apple orchards is an important part of integrated pest management programs, requiring more research and application in China.     

Review: predatory soil mites as biocontrol agents of above- and below-ground plant pests

Biological pest control is becoming increasingly important for sustainable agriculture. Although many species of natural enemies are already being used commercially, efficient biological control of various pests is still lacking, and there is a need for more biocontrol agents. In this review, we focus on predatory soil mites, their role as natural enemies, and their biocontrol potential, mainly in vegetable and ornamental crops, with an emphasis on greenhouse systems. These predators are still underrepresented in biological control, but have several advantages compared to predators living on above-ground plant parts. For example, predatory soil mites are often easy and affordable to mass rear, as most of them are generalist predators, which also means that they may be used against various pests and can survive periods of pest scarcity by feeding on alternative prey or food. Many of them can also endure unfavourable conditions, making it easier for them to establish in various crops. Based on the current literature, we show that they have potential to control a variety of pests, both in greenhouses and in the field. However, more research is needed to fully understand and appreciate their potential as biocontrol agents. We review and discuss several methods to increase their efficiency, such as supplying them with alternative food and changing soil/litter structure to enable persistence of their populations. We conclude that predatory soil mites deserve more attention in future studies to increase their application in agricultural crops.

     

Biocontrol of Pests of Apples and Pears in Northern and Central Europe: 1. Microbial Agents and Nematodes

The viral, bacterial, fungal and nematode pathogens of arthropod pests of apple and pear in northern and central Europe and their use as biocontrol agents are reviewed. Baculoviruses are important viral pathogens of several lepidopterous pests of apple and pear but other viral pathogens have not been investigated in depth and are little known. The granuloviruses of codling moth, Cydia pomonella (CpGV), and to a lesser extent, of the summer fruit tortrix moth, Adoxophyes orana (AoGV), have been researched extensively and are exploited as biological control agents. Commercial development and use has been limited because of their high costs, slow action, short persistence and specificity relative to broad-spectrum pesticides. The widespread development of strains of codling moth multi-resistant to insecticides and the desire to reduce dependence on pesticides have improved the commercial prospects of CpGV and use is likely to increase. The development of a genetically improved egt-strain of CpGV (lacking the ecdysteroid-UDP glucosyl transferase gene) in the UK is a significant breakthrough, though commercialization in the UK may be difficult due to adverse public attitudes to the release of genetically-modified microorganisms. Future research and development approaches include further genetic manipulation of CpGV and AoGV to improve potency, speed of kill and/or persistence, improvement of formulation (to reduce UV light sensitivity) and development of cheaper mass production techniques and possibly in vitro production. A systematic search for baculoviruses and other viruses of apple and pear pests is likely to reveal important new opportunities. The most important bacterial pathogen used as a biological control agent is Bacillus thuringiensis (Bt). However, Bt products currently available have limited effectiveness against many orchard pests due to the pests' cryptic life habits. The HD-1 Bt strain has been investigated and used extensively for control of leaf-rolling tortricid larvae and is widely used, but efficacy is moderate. Advances in biotechnology and genetic engineering provide opportunity for development of Bt strains designed specifically to control orchard pests, but this has not yet been done for commercial reasons. Other research approaches include the evaluation of new Bt products developed for other markets worldwide and the bioassay of strains from Bt collections against specific apple or pear pests. Entomopathogenic fungi provide good opportunity for development as biological control agents of apple and pear pests. The main factor limiting their effectiveness is the requirement for high humidities and moderate temperatures for spore germination and development. For foliar pests, a useful starting point for research might be the control of sucking pests which excrete honeydew (e.g. Cacopsylla sp. or aphids) or those that inhabit protected microenvironments (e.g. Dasineura sp.). Key areas for research are improved formulation, the selection of low temperature-active strains, field evaluation and avoiding possible adverse effects of fungicides. An alternative approach is to examine the exploitation of entomopathogenic fungi in soil, to which many species of entomopathogenic fungi are adapted ecologically. Apple and pear orchards provide long-term stable habitats where populations of entomopathogenic fungi in soil are likely to be large. There are few important soil pests of apple or pear. However, many species spend part of their life in soil, mainly to pupate or overwinter, where they may be targeted by fungal entomopathogenic biocontrol agents. Entomopathogenic nematodes have many attributes which favour them as biological control agents. However, their requirement for surface moisture for survival and movement means there are only limited prospects for using them as biological control agents for foliar pests. As with entomopathogenic fungi, there are better prospects for control of pests that occur in soil. Microbial pathogens and entomopathogenic nematodes are important components of the natural enemy complex of apple and pear orchards and more effort needs to be devoted to fostering them and exploiting them as biocontrol agents in sustainable, biologically-based Integrated Pest Management programmes. They can in many cases be mass produced at low cost by bulk fermentation processes and applied as sprays (as 'biopesticides') and are, at least potentially, ideal biological control agents for many apple or pear pests. Important general characteristics are their comparative environmental and human safety, compatibility with other control strategies in Integrated Pest Management programmes and reproductive capacity. They tend to be effective in a narrower range of environmental conditions than pesticides, but there is considerable potential to improve their effectiveness by improved formulation, strain selection and genetic manipulation. They are often host-specific and thus, offer restricted marketing opportunities, which is a significant barrier to development and commercialisation. Registration procedures and associated fees for microbial agents are a further significant barrier. Such requirements do not apply currently to nematodes.     

Biological control and sustainable food production

The use of biological control for the management of pest insects pre-dates the modern pesticide era. The first major successes in biological control occurred with exotic pests controlled by natural enemy species collected from the country or area of origin of the pest (classical control). Augmentative control has been successfully applied against a range of open-field and greenhouse pests, and conservation biological control schemes have been developed with indigenous predators and parasitoids. The cost-benefit ratio for classical biological control is highly favourable (1:250) and for augmentative control is similar to that of insecticides (1:2-1:5), with much lower development costs. Over the past 120 years, more than 5000 introductions of approximately 2000 non-native control agents have been made against arthropod pests in 196 countries or islands with remarkably few environmental problems. Biological control is a key component of a 'systems approach' to integrated pest management, to counteract insecticide-resistant pests, withdrawal of chemicals and minimize the usage of pesticides. Current studies indicate that genetically modified insect-resistant Bt crops may have no adverse effects on the activity or function of predators or parasitoids used in biological control. The introduction of rational approaches for the environmental risk assessment of non-native control agents is an essential step in the wider application of biological control, but future success is strongly dependent on a greater level of investment in research and development by governments and related organizations that are committed to a reduced reliance on chemical control.     

Microbial control of arthropod pests of tropical tree fruits

A multitude of insects and mites attack fruit crops throughout the tropics. The traditional method for controlling most of these pests is the application of chemical pesticides. Growing concern on the negative environmental effects has encouraged the development of alternatives. Inundatively and inoculatively applied microbial control agents (virus, bacteria, fungi, and entomopathogenic nematodes) have been developed as alternative control methods of a wide variety of arthropods including tropical fruit pests. The majority of the research and applications in tropical fruit agroecosystems has been conducted in citrus, banana, coconut, and mango. Successful microbial control initiatives of citrus pests and mites have been reported. Microbial control of arthropod pests of banana includes banana weevil, Cosmopolites sordidus Germar (Coleoptera: Curculionidae) (with EPNs and fungi) among others Oryctes rhinoceros (L.) is one of the most important pests of coconut and one of the most successful uses of non-occluded virus for classical biological control. Key pests of mango that have been controlled with microbial control agents include fruit flies (Diptera: Tephritidae) (with EPNs and fungi), and other pests. Also successful is the microbial control of arthropod pests of guava, papaya and pineapple. The challenge towards a broader application of entomopathogens is the development of successful combinations of entomopathogens, predators, and parasitoids along with other interventions to produce effective and sustainable pest management.     

Factors affecting the presence of Typhlodromusspp. (Acarina: Phytoseiidae) in the calyx cavities of apple fruits and implications for integrated pest management

Predatory mites of the family Phytoseiidae include several species of importance as biological control agents of phytophagous mites in various crops including apples. We report on the post-harvest presence of the motiles of two species, Typhlodromus occidentalis and Typhlodromus pyri, in the calyx cavities of apple fruits of three cultivars. The mean numbers of motiles per fruit were as high as 6.10. The phytoseiid densities were lowest in cv. Bonza and tended to be greater in samples taken in late autumn, particularly in cv. Red Delicious. No significant effect (p > 0.05) was observed for different insecticide treatments. Phytoseiids remained present within fruits of cv. Granny Smith left on the orchard floor in winter. Together with an observed reduction in the numbers of T. occidentalis in the early spring, this suggests that fruits constitute an overwintering refuge. The findings are discussed in relation to the implications for biological control, in particular the minimization of the removal of natural enemies from orchards. This revised version was published online in November 2006 with corrections to the Cover Date.     

Habitat functionality for the ecosystem service of pest control: reproduction and feeding sites of pests and natural enemies

• 1 Landscape management for enhanced natural pest control requires knowledge of the ecological function of the habitats present in the landscape mosaic. However, little is known about which habitat types in agricultural landscapes function as reproduction habitats for arthropod pests and predators during different times of the year.
• 2 We studied the arthropod assemblage on six crops and on the seven most abundant native plant species in two landscapes over 1 year in Australia. Densities of immature and adult stages of pests and their predators were assessed using beat sheet sampling.
• 3 The native plants supported a significantly different arthropod assemblage than crops. Native plants had higher predator densities than crops over the course of the year, whereas crops supported higher pest densities than the native plants in two out of four seasonal sampling periods. Crops had higher densities of immature stages of pests than native plants in three of four seasonal sampling periods, implying that crops are more strongly associated with pest reproduction than native plants. Densities of immature predators, excluding spiders, were not different between native plants and crops. Spiders were, however, generally abundant and densities were higher on native plants than on crops but, because some species disperse when immature, there is less certainty in identifying their reproduction habitat.
• 4 Because the predator to pest ratio on native plant species showed little variation, and spatial variation in arthropod assemblages was limited, the predator support function of native vegetation may be a general phenomenon. Incentives that maintain and restore native remnant vegetation can increase the predator to pest ratio at the landscape scale, which could enhance pest suppression in crops.

     

Sampling of Cacopsylla pyri (Hemiptera: Psyllidae) and Pilophorus gallicus (Hemiptera: Miridae) in pear orchards

The psyllid Cacopsylla pyri L. (Hemiptera: Psyllidae), is one of the principal pests of pear (Pyrus spp.) orchards and, along with its natural enemies, needs to be carefully monitored for correct integrate pest management and biological pest control decision making. We compare sampling techniques and develop sampling methods for C. pyri and Pilophorus gallicus Remane (Heteroptera: Miridae). Four pear orchards were sampled periodically from 2007 to 2010 in southern Spain by beating branches into funnels or 45-cm-diameter nets and taking shoot samples. Different sampling techniques were compared, and several sampling methods were assayed for adults and nymphs of C. pyri and P. gallicus. Psylla adult and P. gallicus counts in the nets and funnels were similar and closely correlated. Counts of C. pyri adults in the funnels and nets were higher than on shoots, but all measures were closely correlated. The number of nymphs on shoots and leaves was correlated, as were the counts on leaves within shoots. A guide for choosing the sampling unit in cost/precision terms is given. C. pyri nymphs and adults showed an aggregated distribution, whereas P. gallicus had a less-crowded spatial distribution. Enumerative sequential sampling was evaluated for both insects by using the different sampling techniques by resampling experimental data. The negative binomial distribution fitted the experimental data gathered using the different sampling techniques for C. pyri adults and P. gallicus. The use of binomial sampling is discussed for the two insects and the costs involved are compared with those implied in the sequential enumerative method.     

Are populations of European earwigs,Forficula auricularia,density dependent?

Biocontrol using naturally occurring predators is often limited by population parameters of those predators. Earwigs, Forficula auricularia L. (Dermaptera: Forficulidae), are important predators in fruit orchards. They are capable of suppressing outbreaks of pest species, such as pear psyllid and various apple aphid species. Earwigs therefore play an important role in integrated pest management in fruit orchards and are essential in organic top fruit cultures. However, earwig populations are very unstable, showing large between-year variation in densities, which limits their practical use. Extensive knowledge of regulating processes of populations is therefore crucial for efficient orchard management. A 2-year phenological study in several apple and pear orchards in Belgium showed a significant displacement of third instars during the second brood in relation to the presence of adults. We also observed a yearly population crash at the time of moulting into adults. This population decrease was correlated with earwig numbers at peak density. The crash occurred at lower earwig densities in apple orchards than in pear orchards. Six possible regulating mechanisms for this density-dependent decrease are discussed: (1) migration, (2) pesticides or orchard management, (3) starvation, (4) pathogens, (5) parasites and parasitoids, and (6) predation or cannibalism. If we can identify these regulating processes, specific management activities could be developed to prevent the population crash, hereby increasing population densities in the orchards.     

Overwintering Mite Diversity and Their Habitats in Apple and Pear Orchards of Korea with Emphasis on Phytoseiidae and Tetranychidae

Overwintering mite diversity and their habitats were studied in apple and pear orchards during 2002-2003 winter season. Twospotted spider mite was mostly found under the tree barks and fabric strips. European red mites were from crevices of twigs. Tydeid, tarsonemid and oribatid mites were mostly from soil and ground vegetation. Even in the protected overwintering habitat such as artificial fabric strip, twospotted spider mite suffered 81-91% mortality during winter. Predaceous phytoseiid mites found were Amblyseius womersleyi, A. makuwa, A. orientalis, A. rademacheri A. obtuserellus, and A. eharai. Amblyseius womersleyi was the most dominant species in both apple and pear orchards, followed by A. obtuserrellus in apple orchards and A. makuwa in pear orchards. Most phytoseiid mites were found on ground vegetation while their potential prey items were remained on the tree. Implication of the findings for conservation of beneficial mites and biological control of spider mite during season was further discussed.     

间种牧草杂交杏李园节肢动物群落的结构及动态

对间种牧草杂交杏李园节肢动物群落结构与组成的系统定位观察与分析表明:杂交杏李园害虫种类有蚜虫类、叶螨类、食心虫类、介壳虫类、吮吸类、食叶类等,危害最为严重的是蚜虫类、叶螨类和食心虫类,这三种害虫的数量直接影响果实的产量。蓄草果园的天敌种类主要有蜘蛛类、瓢虫类和草蛉类,这三类天敌对主要害虫具有一定的控制作用,而且对维持果园害虫及其天敌之间平衡起着重要作用。对各功能类群的数量结构、生态优势度和多样性分析表明,间种牧草果园节肢动物群落结构比较稳定,各种群落指标相对平衡,天敌自然控害效果比较明显。分析认为果园有害生物综合治理应坚持大量利用自然天敌为主的生态控制的途径,不断优化果园生物群落结构、提高群落多样性和均匀度,减少群落生态优势度,增强群落自身调节控害能力,辅助使用农药,逐步达到生态控制果园有害生物的目的。     

Die Feinde der Raubmilben als Reduzierender Faktor der Spinnmilben

Summary The relations betweenMetatetranychus ulmi living on apple trees and its different predators are complex. The most important natural enemy of this spider mite is the predacious miteTyphlodromus pyri (= T. tiliae). It destroys more spider mites than the beneficial insects do. In the district of Stuttgart-Hohenheim about 38 species of insects and spiders feed onTyphlodromus mites. For instanceT. pyri is reduced considerably byOrius minutus. This bug is a natural enemy of aphids and spider mites, however it prefers the predatory mites. It attacks the spider mites and aphids only ifTyphlodromus mites are not available.Chrysopa vulgaris andAnthocoris nemorum are similar in their feeding habits. These two destroyTyphlodromus pyri also but they are less important thanO. minutus. The other beneficial insects in our orchards have little effect on spider mites or predacious mites. If we have enough pests on our apple trees to make spraying necessary, we should look forTyphlodromus mites and be careful no to destroy them. We should always examine the composition of the biocoenosis applying chemical agents because the populations of insects and predacious mites may vary from one area to the other.      

Diversity of natural enemies in Central Otago,New Zealand apple orchards: a practical measure of sustainability in pest management?

The diversity of the arthropod fauna in apple orchards in Central Otago was recorded from 1994 to 1999 using beating trays, pitfall traps, and sticky traps and the data analysed by the Shannon–Wiener Index. Three different fruit production systems were compared, conventional (CFP), integrated (IFP), and biological (BFP), to determine whether total arthropod diversity and/or the diversity of natural enemies (predators and parasitoids) could be used to measure the sustainability of their pest management practices. The contribution of natural enemies to the diversity indices was also examined to determine if they reflected the key species essential for sustainable pest management. The diversity of natural enemies in beating trays was found to be the measure most sensitive to changes in pest management. The diversity of both the total arthropod fauna and natural enemies was much lower under CFP than under either IFP or BFP, due to the use of broad-spectrum pesticides. This practice made the CFP programme unsustainable and it is no longer used. During the transition from CFP to IFP, the diversity indices rose to become similar to that in the BFP programme by the third season. The introduction of frequent applications of fungicides in BFP, including lime sulphur, appeared to reduce total arthropod and natural enemy diversity. Falls in the diversity indices for natural enemies were shown to reflect reduced numbers, range, and evenness of natural enemies but not necessarily the key species known to be critical for sustainable pest management. It is proposed that a Shannon–Wiener Index for natural enemies in beating trays of 0.2 or less in summer is strongly indicative of unsustainable pest management in Otago apple orchards. On the other hand, indices of 0.3–0.8, as found under IFP and BFP, do not give unequivocal or quantitative indications of the sustainability of pest management. A suite of other measures of sustainability are more useful, notably combining lower pesticide use, reduced pest damage and presence at harvest, the greater roles of key natural enemies, more effective plant resistance to pests and diseases, and higher profitability.     

A prospective research on the hedgerow's 'source' function

In pear tree, Forficula auricularia and Forficula pubescens are considered as active predators of the pest Cacopsylla pyri, since that their dispersal characteristics are of crucial importance for biological control. We studied their movement using capture-mark-release-recapture techniques. The aim of this study was to underline a hedge effect as source of beneficials spreading through the orchard. Our results show that movements are mainly linked to the C. pyri fluctuations with a food specialisation for the two species when co-occurring.     

Mechanisms for flowering plants to benefit arthropod natural enemies of insect pests： Prospects for enhanced use in agriculture

Reduction of noncrop habitats, intensive use of pesticides and high levels of disturbance associated with intensive crop production simplify the farming landscape and bring about a sharp decline of biodiversity. This, in turn, weakens the biological control ecosystem service provided by arthropod natural enemies. Strategic use of flowering plants to enhance plant biodiversity in a well-targeted manner can provide natural enemies with food sources and shelter to improve biological control and reduce dependence on chemical pesticides. This article reviews the nutritional value of various types of plant-derived food for natural enemies, possible adverse effects on pest management, and the practical application of flowering plants in orchards, vegetables and field crops, agricultural systems where most research has taken place. Prospects for more effective use of flowering plants to maximize biological control of insect pests in agroecosystem are good but depend up on selection of optimal plant species based on information on the ecological mechanisms by which natural enemies are selectively favored over pest species.