Harvestman (Opiliones) fauna associated with Maine lowbush blueberry fields in the major production areas of Washington and Hancock counties

Soil Health and Arthropods: From Complex System to Worthwhile Investigation

The dramatic increase in soil degradation in the last few decades has led to the need to identify methods to define not only soil quality but also, in a holistic approach, soil health. In the past twenty years, indices based on living communities have been proposed alongside the already proven physical-chemical methods. Among them, some soil invertebrates have been included in monitoring programs as bioindicators of soil quality. Being an important portion of soil fauna, soil arthropods are involved in many soil processes such as organic matter decomposition and translocation, nutrient cycling, microflora activity regulation and bioturbation. Many studies have reported the use of soil arthropods to define soil quality; among taxa, some have been explored more in depth, typically Acari and Collembola, while generally less abundant groups, such as Palpigradi or Embioptera, have not been investigated much. This paper aims to evaluate and compare the use of different soil microarthropod taxa in soil degradation/quality studies to highlight which groups are the most reported for soil monitoring and which are the most sensitive to soil degradation. We have decided not to include the two most present and abundant taxa, Acari and Collembola, in this paper in consideration of the vast amount of existing literature and focus the discussion on the other microarthropod groups. We reported some studies for each taxon highlighting the use of the group as soil quality indicator. A brief section reporting some indices based on soil microarthropods is proposed at the end of this specific discussion. This paper can be considered as a reference point in the use of soil arthropods to estimate soil quality and health.

Blueberry IPM: Past Successes and Future Challenges

Blueberry is a crop native to North America with expanding production and consumption worldwide. In the historical regions of production, integrated pest management (IPM) programs have been developed and provided effective control of key insect pests. These have integrated monitoring programs with physical, cultural, biological, behavioral, and chemical controls to meet the intense demands of consumers and modern food systems. Globalization of the blueberry industry has resulted in new pest-crop associations and the introduction of invasive pests into existing and new blueberry-growing areas. Invasive pests-in particular spotted wing drosophila-have been highly disruptive to traditional IPM programs, resulting in increased use of insecticides and the potential to disrupt beneficial insects. Moreover, regulatory agencies have reduced the number of broad-spectrum insecticides available to growers while facilitating registration and adoption of reduced-risk insecticides that have a narrower spectrum of activity. Despite these new tools, increasing international trade has constrained insecticide use because of maximum residue limits, which are often not standardized across countries. Great potential remains for biological, behavioral, cultural, and physical methods to contribute to blueberry IPM, and with more regions investing in blueberry research, we expect regionally relevant IPM programs to develop in the new production regions.

Pupation Behavior and Predation on Drosophila suzukii (Diptera: Drosophilidae) Pupae in Maine Wild Blueberry Fields

Drosophila suzukii (Matsumura; Diptera: Drosophilidae) is an invasive vinegar fly and pest of soft fruits in North America, including wild blueberries (Vaccinium angustifolium Aiton) in Maine. Despite its presence in the continental United States for 9 yr, little is known about its natural enemy complex. Here we report the results of a 3-yr study designed to identify naturally-occurring predators in Maine's wild blueberry fields. Experiments were conducted to determine pupation site and pupation depth to understand D. suzukii's predation vulnerability. Predation rates in the field of fully-exposed, caged, and buried pupae were measured. Pitfall traps were deployed to identify the potential predator assemblage, and laboratory experiments were conducted to determine how many pupae were consumed by commonly occurring ground beetle species (Carabidae) and field crickets (Gryllus pennsylvanicus Burmeister). The most commonly collected predators were ants, ground beetles, harvestmen, and field crickets. Significantly more pupae were found to occur in the soil compared to blueberry fruit, with most pupae in the top 0.5 cm layer of soil. Pupal predation rates in the field were high, with higher rates of predation on exposed pupae compared to buried pupae. Laboratory studies revealed that ground beetles and field crickets are likely predators of D. suzukii pupae.

Predator- and Scavenger-Mediated Ecosystem Services Determined by Distance to Field-Forest Interface in the Maine Lowbush Blueberry Agroecosystem

Predators and scavengers play a vital role in regulating insect pests, weeds, and vertebrate scat in perennial agroecosystems. Understanding how farm management practices and surrounding habitat influence these beneficial ecosystem services contributes to our understanding of these complex ecological systems and guides future management decisions. In a mensurative 2-yr study, we determined how different pest management strategies and surrounding forest composition influenced levels of sentinel insect pupae, weed seeds, and deer scat (feces) removal. Removal of these bioresources was measured within 12 commercial lowbush blueberry fields during 2011 and 2012; farms differed in surrounding landscape composition and farm management strategies. Both the removal of sentinel pupae and scat, was significantly higher within field interiors than at field edges and within adjacent forests. Additionally, farm management strategy interacted with field position to result in significantly higher scat removal in conventional field interiors than organic field interiors. Surrounding forest composition had variable effects on removal of materials. Our results indicate higher levels of activity within field centers as opposed to field edges; this is contrary to what has been observed in other perennial cropping agroecosystems.

A global review of arthropod-mediated ecosystem-services in Vaccinium berry agroecosystems

Native beneficial arthropods, including bees, predators, and parasitoids, provide valuable ecosystem services, which help to maintain agricultural productivity and reduce the need for pesticide inputs.Vacciniumberry species are somewhat unique compared to many of the world’s fruit crops in that, up until recently, most of the harvesting and culture of species for food occurred in the geographic regions of their origin. This suggests that insects involved in many of the ecosystem services for these berries are native species that have a shared co-evolutionary history. Due to the shared phylogenetic origins of theVacciniumspp. agroecosystems, the shared need for efficient pollination, and a number of shared agricultural pests, the potential exists for research from these related systems to closely apply to agroecosystems within the same genus. This review brings together research regarding arthropod-mediated ecosystem services from a number of prominentVacciniumagroecosystems worldwide. In total, thirty-nine ecosystem service studies are discussed. These studies quantified arthropod-mediated ecosystem services being provisioned toVacciniumagroecosystems. Additionally, thirty-nine surveys of arthropods closely associated and/or providing ecosystem services toVacciniumsystems are also reviewed. Studies took place almost exclusively in temperate regions with a heavy emphasis on insect pest biological control and pollination services. It is our hope that by synthesizing this body of literature, researchers and growers might be able to utilize research methods, results, and conservation recommendations despite differences in production practices and local arthropod fauna.

Ant diversity and distribution (Hymenoptera: Formicidae) throughout Maine lowbush blueberry fields in Hancock and Washington Counties

A 6-yr survey (2003-2008) identifying the ant fauna present in Maine lowbush blueberry fields was conducted in Washington and Hancock Counties. Pitfall trapping, leaf litter, and hand collections, as well as protein and sugar baits were used to characterize the resident ant community in this habitat. Estimates of faunal richness as impacted by the blueberry crop stage (pruned or fruit-bearing), methods of pest management (grower standard, reduced-risk, or organic), and location within fields (middle, edge, or forested perimeters) were determined. In total, 42 species were collected from blueberry fields, comprising five subfamilies and 15 genera. Myrmica sculptilis Francoeur, Myrmica americana Weber, and Formica exsectoides Forel were the three most abundant species. Formica ulkei Emery, Myrmecina americana Emery, and Leptothorax canadensis Provancher represent new species records for Maine. Ants were most diverse in organic fields, and along the edge and within the wooded areas surrounding fields. Results suggest insecticide application reduces ant diversity.