The phenology, oviposition and feeding rate of Anystis baccarum, a predatory mite in Bramley apple orchards in Northern Ireland

The impact of cover crops on the predatory mite Anystis baccarum (Acari, Anystidae) and the leafhopper pest Empoasca onukii (Hemiptera, Cicadellidae) in a tea plantation

BACKGROUND

Empoasca onukii, the tea green leafhopper, is a key pest of tea whose control often requires the extensive use of insecticides. As a predator of the tea green leafhopper, the mite Anystis baccarum is a potential biological control agent worldwide, though little is known about how intercropping cover crops can impact its suppressing effect on E. onukii. Therefore, we conducted a field experiment to investigate how the relationship of the abundance of the predatory mite and its leafhopper prey is influenced by two different cover crops and a manually weeded inter-row treatment as a contrast to naturally growing vegetation in a tea plantation in China.

RESULTS

The abundance of A. baccarum was significantly higher in tea canopies of intercropped treatments than in canopies over natural ground cover. Litter samples showed higher abundances of A. baccarum when tea was intercropped with Paspalum notatum than with natural ground cover in the first year of treatment. The abundance of E. onukii in tea canopies was higher over the bare ground treatment in the first year but the opposite was observed in the second year.

CONCLUSIONS

Results suggest that the abundance of A. baccarum in a tea plantation is influenced by intercropping and it can affect its leafhopper prey, albeit with varying levels of suppression. For informing biological control and suppression of pests, long-term experiments are needed to investigate the interactions of both pest and predator with cover crop treatments. © 2019 Society of Chemical Industry.

Anystis baccarum: An Important Generalist Predatory Mite to be Considered in Apple Orchard Pest Management Strategies

The increasing concern over the continued use of pesticides is pressurising apple growers to look for alternatives to chemical pest control. The re-discovery, and subsequent conservation, of the beneficial predatory mite, Anystis baccarum (Linnaeus) (Acari: Anystidae), in Bramley apple orchards in Northern Ireland offers a potential alternative control component for incorporation into integrated pest management strategies. Anystis baccarum readily feeds upon economically important invertebrate pest species including European fruit tree red spider mite, Panonychus ulmi (Koch) (Acari: Tetranychidae) and show a level of compatibility with chemical pesticides. Recent mis-identification by apple growers of this beneficial mite species had resulted in unnecessary pesticide applications being applied within Northern Irish apple orchards. However, dissemination of information to the apple growers and promotion of the benefits this mite offers in apple orchards has helped to conserve its populations. Apple growers, across the United Kingdom, must be encouraged to be aware of A. baccarum, and indeed all predatory fauna, within their orchards and seek to conserve populations. In doing so, it will ensure that the British apple market remains an environmentally sustainable production system.

Evaluation of the predatory mite Amblyseius hainanensis (Acari: Phytoseiidae) and artificial rainfall for the management of Brevipalpus obovatus (Acari: Tenuipalpidae)

Brevipalpus obovatus Donnadieu is an important pest mite on tea plants in South China. In the current study, predatory mites of B. obovatus in the tea gardens of Guangzhou were extensively surveyed. In total, 13 species of predatory mites (four families with seven genera) were recorded. The population proportion of Amblyseius hainanensis Wu et Qian was the highest (68.6 %), followed by that of Anystis baccarum (L.) (8.4 %) and A. theae Wu (6.3 %). The effects of starvation time, habitat size and pest population density on the predatory efficiency of the most dominant species, A. hainanensis, feeding on B. obovatus were assessed. In addition, the effectiveness of artificial rainfall in reducing B. obovatus populations was evaluated. After starvation for 48 h, the predatory efficiency of A. hainanensis was significantly higher than those that had been starved for 24 or 72 h when 30-50 B. obovatus eggs were made available. The predation of A. hainanensis on B. obovatus also increased with increasing prey density. The number of prey attacked by A. hainanensis in a 3.2 cm(2) habitat was significantly higher than in a 6.3 cm(2) habitat. The average predation of A. hainanensis was 31.7 eggs per day when offered 100 B. obovatus eggs on a tea leaf. This decreased to 17.8 eggs per day when four A. hainanensis shared 100 B. obovatus eggs. B. obovatus populations can be reduced by artificial rainfall, with the reduction affected by rainfall intensity. With an intensity of 40 mm in 15 min, 90.2 % mortality of B. obovatus occurred; lower mortalities were recorded (13.3 and 29.8 %) when the intensity was 2 or 4 mm in 15 min. Combination of the predatory mite A. hainanensis and artificial rainfall for the integrated pest management of B. obovatus is discussed.

The control of eriophyoid mites: state of the art and future challenges

The superfamily of the Eriophyoidea is a large and diverse group of mites, including a number of species of economic importance, mainly on perennial plants in agriculture and forestry. This review focuses on the economic importance and pest status of this group of mites, with emphasis on some genera. The available acaricide portfolio is reviewed and the influence of EU legislation policy on the sustainable control of Eriophyoidea is investigated. Possible generic guidelines for sustainable control and resistance management with special reference to the European situation are discussed. Recent advances in biological and integrated control of eriophyid mite pests and the implementation of these techniques in crops are explored. Furthermore, the relevance of studies on behaviour, epidemiology and diagnostics in general terms and as a strategic necessity is pointed out.

The impact of eriophyoids on crops: recent issues on Aculus schlechtendali, Calepitrimerus vitis and Aculops lycopersici

The nature of the damage caused by eriophyoid mites and the assessment of yield losses still require detailed studies if appropriate control and risk mitigation strategies are to be planned. The economic importance of eriophyoid mites is increasing worldwide and a lot of species have reached a permanent pest status in certain crops, while others represent a quarantine threat for several countries. Due to their relevant role in Europe and elsewhere, three eriophyoid mites that have been frequently reported in recent research, are here considered as case studies: two of them (the apple rust mite, Aculus schlechtendali, and the grape rust mite, Calepitrimerus vitis) colonise temperate fruits, while one (the tomato russet mite, Aculops lycopersici) affects vegetables. The damage assessment related to the apple rust mite has been evaluated on different apple varieties with implications for pest control. Some factors affecting the spread and economic importance of the grape rust mite have been identified. The complexity and difficulty in controlling the tomato russet mite by chemicals enhances the interest in biological control agents. Considerations on interactions between eriophyoids and host plants (e.g. resistance, varietal susceptibility), on pest management regimes (e.g. impact of fungicides, resistance to acaricides, perspectives on biological control) are presented.