Ingeborg Menzler-Hokkanen

Assessing the Impacts of Metarhizium and Beauveria on Bumblebees

In this chapter we present as an example a specific case study from the ecological safety evaluation of the Hyphomycete fungi Metarhizium anisopliae (Metsch.) Sorokin and Beauveria bassiana (Bals.) Vuill., carried out in Finland during the ERBIC-research project. Only the part concerning the safety to bumblebees is presented here (for a full report see Hokkanen et al., 2003). Metarhizium anisopliae and Beauveria bassiana are two well-studied, commercialised, and commonly used entomopathogenic fungi (EPF), also occurring naturally in Finland. We decided to focus on bumblebees because they are the most important group of natural pollinators of crop plants and wild flowers in the temperate zone. While possible impacts of Metarhizium and Beauveria on the honeybee have been addressed by several authors in many publications, to our knowledge no earlier information exists on the possible impact of these fungal pathogens on bumblebees. These pollinators are also abundant in our model agroecosystem, turnip oilseed rape, which was chosen because both the key pest, the pollen beetle (Meligethes aeneus), and its natural enemy complex have been well studied under Scandinavian conditions. Background information was already available on the occurrence of deuteromycetous EPF in the model system (Va nninen et al. 1989), on the persistence of augmented fungal propagules in cultivated soils of the study area in question (southern Finland) (Vanninen et al. 2000), and on the impact of entomopathogenic fungi on the pollen beetle (Hokkanen 1993). In addition, entomopathogenic fungi and nematodes are a possible future option for managing the soil-dwelling stages of the pollen beetle and other pests in this system via incorporation in the soil (Butt et al. 1994). Fungi can also be used against foliage-dwelling stages of the pest either by spraying, or when vectored by honeybees (Butt et al. 1998). Different application strategies for entomopathogens could therefore be considered, linked to differing non-target risk scenarios based on the impact of the application strategies on key components of the ecosystem.

Multitrophic Interactions: The Entomovector Technology

The entomovector technology (Hokkanen and Menzler-Hokkanen 2007; Mommaerts and Smagghe 2011) utilizes insects as vectors of biological control agents for targeted precision biocontrol towards plant pests and diseases, providing an intriguing example of multitrophic interactions. As the insect vector normally is a pollinator of the crop plant, it adds a further dimension to these interactions. The technology depends on bee management, manipulation of bee behaviour, components of the cropping system, and on the plant-pathogen-vector-antagonist-system. We investigate in this chapter how to exploit and support the natural ecological functions of biocontrol and pollination, and enhance these via innovative management. Recent systematic developments of the entomovector technology are described, with focus on the component technologies such as the dispensers and carrier substances (see Mommaerts and Smagghe 2011; Mommaerts et al. 2011; Hokkanen et al. 2012). With functioning dispensers and improved, new microbiological control agents (MCA) available, excellent results have been obtained, and will be described in two case studies. The first involves open field studies conducted in Finland with honey bees (Apis mellifera Linnaeus (Hymenoptera: Apidae)) as the vector of “Prestop-Mix”, containing Gliocladium catenulatum J1446 (Hypocreales, Bionectriaceae), to control Botrytis cinerea Pers.: Fr. (Helotiales: Sclerotiniaceae) in strawberries, and the second describes the efficiency of bumble bees (Bombus terrestris Linnaeus (Hymenoptera: Apidae)) to vector the commercial product “Prestop-Mix” to control B. cinerea in strawberries in the greenhouse.

Ecosystem services for pollen beetle control in oilseed rape: ethical aspects of ecostacking—lost in translation?

In 2007, the European Plant Protection Agency EPPO organised a workshop on how to control the pollen beetle in Europe. 10 years later, a similar workshop was organised, demonstrating in its presentations the fast advancement of all predictions made 10 years ago. Although in 2007 during the EPPO workshop the increasing problems of pyrethroid resistance in the pollen beetle due to overuse by growers were presented, the control strategies for the major oilseed rape pests did not change in any way. The present special issue contains contributions by European research groups, financed by different sources, proposing solutions to the problem. Characteristic to most contributions is that they are embedded in larger research projects, and the results obtained are of high importance. At the practical level, however, the reader is left with a “bag full of fragmented advice”. In the eye of the practical person (the farmers), the “bag full of fragmented advice” seems unrelated, and not compatible with the economic and management reality on the farm. Concrete guidelines are needed in these complex situations for the practitioner, but are difficult to find. Solid ground on what to build management practices, and on what to build economically sound decisions, has to be provided. Recently, the problems of pest management in conventional agriculture culminate in the decreasing availability of functioning chemical options, due to resistance evolution in target pests. Increasing costs of developing new chemical pesticides, and concerns about negative environmental impacts of the chemical pesticide approach, aggravate the problem. These include the suspected contribution to the declining numbers of pollinators, loss of biocontrol as ecosystem service, and an overall decline in numbers of flying insects with consequent cascading effects throughout the food chain (e.g., insectivorous birds). Abundant biocontrol knowledge and enthusiasm is available in Europe. Many outstanding cases where biocontrol has provided a solution can be presented—but none of these have been spectacular and with large enough impact to place biocontrol as the major option within mainstream agriculture. Overall economic and technical constraints have made it impossible so far. Pest problems in European agriculture that have been solved with the help of biocontrol during the last 50 years include especially the greenhouse environment: greenhouse two-spotted spider mite, greenhouse whitefly, thrips, aphids, leaf-miners, etc. In the open field crops, Bacillus thuringiensis has successfully been used against a number of lepidopteran pests, and entomopathogenic nematodes in some cases, but overall the use of biocontrol in open field cultivations is minimal. Much more needs to be done in this respect.

Urgent need to develop ecostacking techniques to enhance ecosystem services in cropping systems

Improved methods to enhance ecosystem services are urgently needed for being able to maintain or to increase agricultural production, and to keep it at the same time ecologically, economically, and socially sustainable. Ecosystem service providers (ESP), such as biocontrol agents, pollinators, decomposers, and beneficial soil microbial fauna and flora, are key components in securing the sustainability of agricultural production. Functional biodiversity at all its levels has been shown to influence the level and quality of ecosystem services to crops, provided by the ESP. Examples of potential beneficial impacts include the genetic diversity of crop plants (e.g. Grettenberger and Tooker 2017), the composition of soil microbial assemblages (e.g. Pineda et al. 2017; Prieto et al. 2017), botanical diversity within a field (e.g. Balzan 2017; Adhikari and Reddy 2017; Schröder et al. 2017), and diversity of the surrounding landscape (e.g. Steingröver et al. 2010). While there has been intense research effort to investigate the functioning and potential for exploitation of each of the individual mechanisms such as those listed above, combining these beneficial effects in an additive or synergistic manner has not been systematically explored. Hokkanen (2017) proposed the concept of “ecostacking,” where full use of pest control and pollination services in our cropping systems can be achieved by stacking and conserving functional biodiversity. Stacking of ecological traits in a functioning ecosystem is analogous to the well-established concept of stacking genetic traits (functional genes) to produce improved, transgenic crops (see Hokkanen and Menzler-Hokkanen 2017a). For pest management, it implies combining pest control services based on functional biodiversity from all levels and types. All the different types of ecosystem service providers must be functionally and fully integrated with other biotic, abiotic, and management components of the cropping system. The aim of this Forum-article is to encourage the development of integrated cropping systems, where the various components of ecostacking are fully and synergistically employed. The key steps involved in developing sustainable cropping systems based on ecostacking are proposed discussed.

ICE2020Helsinki: it is time to prepare

discipline is very important and relevant. Vector biology, for example, forms a key entomological link to so many diseases plaguing humans and animals. We still have no cure, for example, for leishmaniosis, dengue, or malaria. Millions of humans suffer from such diseases, and also unknown numbers of animals. Let us have a healthy planet. We as entomologists play a key role in solving these challenges. Previous ICE congresses, including those in Brisbane, Durban, Daegu, and in 2016 in Orlando—where the hub was on the zika virus—advanced our knowledge in key areas of research. ICE2020Helsinki will invite and reach out to bordering disciplines, to solve problems, and to help overcome these plagues. APIS is open as a publication venue for scientists and section leaders, who prepare presentations and organize symposia. The book series Progress in Biological Control is inviting proposals—not only to be published after the ICE2020Helsinki event, but if possible, by the time of the congress.

Safety of Prestop® Mix to pollinators: a critical review of its properties and use in entomovectoring. Response to the article by Karise et al. (2015)

Karise et al. (2015) published a study in the Journal of Pest Science on the environmental safety of two biopesticides and a carrier substance, with focus on sublethal effects on pollinators. In the present commentary, I argue that the exposure scenario used by Karise et al. (2015) was unrealistic, and that certain other experimental methods are questionable. The main product in question, Prestop Mix, has been used effectively for management of diseases on berries and fruits, with no reports of harm to vectoring bees or non-target organisms. As entomovectoring is becoming available and popular in many countries (Hokkanen et al. 2015), it is necessary to clarify the safety record of the method.