IOBC Workshop on Integrated Control in Protected Crops

A joint meeting between the IOBC/NRS (International Organization for Biological Control - Nearctic Regional Section) Working Group 'Greenhouse, Nursery & Ornamental Landscape IPM' and the IOBC/WPRS (Western Palaearctic Regional Section) Working Group 'Integrated Control in Protected Crops, Temperate Climate', held on 6-9 May 2002 in Victoria, British Columbia (BC), Canada, focused on various aspects of biological and integrated control of pests (mainly arthropod pests) in greenhouses. Organized by Kevin Heinz (Texas, USA), Les Shipp (Ontario, Canada), Annie Enkegaard (Denmark), and David Gillespie (BC, Canada), it was attended by some 125 participants (advisors, scientists, beneficial producers) from 25 countries.

The meeting was a mixture of concurrent and plenary sessions designed to allow for ample time for discussion. Numerous strict presentations were therefore not given. Instead moderators and introductory speakers gave brief outlines of the state of the art and/or short presentations of recent work. In addition a few keynote speakers were invited to address specific topics. To facilitate discussions the Bulletin containing the proceedings of the meeting was, as usual, compiled and distributed to participants well in advance of the meeting. This Bulletin* contains 74 contributions by some 150 authors representing 26 countries. Abstracts of the Bulletin articles can be found at:

www.agrsci.dk/plb/iobc/Abstracts-compiled.doc 

The sessions dealt with many and diverse topics: microbial control of pests and diseases; intraguild predation; quality control of beneficials; the biotechnology revolution and its impact on IPM in greenhouses; invasive species; biological and integrated control of thrips, whiteflies, aphids, mites, leafminers, etc.; biological control in vegetables and in ornamentals; environmental risks of biocontrol; regulation of biocontrol agents. A full day excursion to the important greenhouse-growing area in the Fraser Valley on the mainland of British Columbia with visits to a number of premises implementing biological and integrated control gave the opportunity to learn more about the practical use of IPM in this area.

Keynote presentations included: Kevin Heinz (Texas, USA): 'Current challenges in biological control - bringing science into the field'; Willem Ravensberg (Netherlands): 'Status of biological control of diseases in greenhouse crops - a commercial perspective'; Mike Parrella (California, USA): 'Biotechnology revolution and its potential impact on greenhouse IPM'; Roy Van Driesche (Massachusetts, USA): 'Coping with invasive species and how may international collaborations contribute', Joop van Lenteren (Netherlands): 'General overview of new initiatives on regulation'; Peter Mason (Ontario, Canada): 'Regulations are necessary for biological control'; Karel Bolckmans (Netherlands): 'Producers point of view on regulation'; and Antoon Loomans (Netherlands): 'Evaluating environmental risks of biological control'.

Introductory talks were similarly wide-ranging: Mark Goettel (Alberta, Canada) gave a summary of microbial products for arthropod management; Michael de Courcy Williams (UK) talked about the potential of intra- and inter-specific interactions between four species of predatory mites; Jeroen van Schelt (Netherlands) reviewed the evolution of the development of quality control (QC) criteria and guidelines for more than 30 species of commercially available natural enemies in the past decade; Angela Hale (BC, Canada) presented the view of ANBP (Association of Natural Biocontrol Producers) in North America with respect to quality standards of natural enemies; Shimon Steinberg (Israel) presented results of a questionnaire that surveyed the current attitude of potential users towards the existing QC guidelines; Joop van Lenteren (Netherlands) presented the highlights of a new book on quality control of mass produced natural enemies; Jude Bennison (UK) presented 'A push-pull strategy for improving the biological control of the western flower thrips on chrysanthemum'; Antoon Loomans (Netherlands) gave a presentation on the role of hyperparasitoids in biological control of whiteflies and their effect on non-target species; Christine Casey (California, USA) and Sylvia Blümel (Austria) both gave talks on IPM of mites in cut roses; Annie Enkegaard (Denmark) presented 'Resistance' to parasitoids in the shallot aphid, Myzus ascalonicus, on bellflower'; Anna Luczynski (BC, Canada) gave a talk on current control strategies for Lygus spp. and potato psyllids; Barbro Nedstam (Sweden) talked about biocontrol of fungus gnats in Swedish pot plants; Jean-Charles Maisonneuve (France) presented a status report on biocontrol in French greenhouse ornamentals; Graeme Murphy (Ontario, Canada) presented a talk about biological and integrated control in North American ornamentals; Phil Walker (UK) talked about IPM in tomato; Cristina Castane (Spain) outlined the situation re. biocontrol in Spanish vegetables; Renato Ripa (Chile) talked about adoption of biocontrol in Chilean greenhouses; and Dave Gillespie (BC, Canada) presented the biocontrol situation in Canadian greenhouses.

With such a concentration of greenhouse expertise, discussion on key issues was lively and productive. Here is a brief round up of the discussions and conclusions this hothouse atmosphere produced.

Microbial Control of Arthropods and Diseases

The world market for microbial products is less than 1% of the total market for pesticides. Development costs for non-Bt-products are presently 10-20 times the expected yearly turnover, making commercial developments of non-Bt-microbials extremely difficult; the majority of the studies are lab trials evaluating efficacy and interactions; there is a need for standardized methodology for bioassays; the economic thresholds are different from pesticides; there is a need for employment of molecular characterization; mass production of microbials may better follow a cottage industry model.

Intraguild Predation

In this field, theory is ahead of experimental evidence; there is a need to change the experimental approach to include spatial and temporal dimensions as well a need for population level studies; and, intraguild predation seems to be more of an issue with ecologists than with practitioners when making recommendations to growers.

Quality Control

Issues were: how continuous mass rearing might affect the quality of biological control agents (BCAs); there is a potential for diseases in BCAs; it would be nice to have different grades for quality control standards; many factors affect product quality; where does the responsibility of the producer end; and, quality should be a key interaction point between producers and end user.

Enhancing Biological Control Effectiveness

Introduction strategies are driven by ease and cost of product; there is a need for the development of new BCAs and improved strains as well as for good training/support for growers; better identification of the biocontrol needs of greenhouse industry is needed, as is improved integration of different management strategies.

Potential Use of Biotechnology in Greenhouse IPM

Some possibilities can be envisioned, e.g. plants toxic to pests, plants resistant to pathogens, incorporation of lethal genes into pest species, and potential to alter insect sex ratios to favour pest management. Concerns were that these are likely to be feasible only for high value crops; caution is called for to minimize negative impacts on natural fauna and flora; considerable regulatory hurdles are foreseen; loss of return to insectaries may result due to reduced demand (with, e.g. development of non-pollinating and/or resistant varieties).

Invasive Species

A systematic model was proposed for addressing the problem of new invasive pest species in greenhouse crops. This model incorporated a 3-step approach: (1) forecast potential invasions, (2) take steps to prevent such invasions, and (3) implement classical biological control to remedy any invasions.

Biological Control of Whiteflies

Discussion centred on Eretmocerus eremicus and E. mundus (release rates, mass rearing procedures, application methods, field trials and host feeding occurrence); the use of generalist predators with and without banker plants; and the use of Beauveria, screening, UV-absorbing plastic film, potassium phosphate and neem.

Biological Control of Mites

Discussions centred around successful use on roses; on predator/plant adaptation; release methods; production practices and environmental influence on release success; importance of early monitoring; and the effectiveness of Maccrolophus caliginosus against mites and Amblyseius cucumeris against broad mite.

Biological Control of Aphids

Discussion centred on the need for better identification of naturally occurring parasitoids and aphids species; the need for more detailed knowledge on existing and potential specific and generalist predators; the potential use of pathogens; and the possibility of augmenting BCA numbers through the use of banker plants or planting of attractive plants species inside and outside the greenhouse.

Biocontrol of Thrips

Discussion focused on new BCAs or 'new' uses of existing BCAs; on IPM compatible pesticides; on tospovirus management; on pupation sites in different crops; and on the use of the 'push/pull' strategy.

Biocontrol of Leafminers and Other Pests

Here the focus was on some of the many news pests (Lygus, leafminers, potato psyllid, etc.) on Lygus management (antifeedants, Beauveria, trap crops screening, crop/weed management outside the greenhouse); on the potato psyliid; and on the use of new management strategies (SIT, mating disruption and nematodes).

Biological and Integrated Control in Ornamentals

Case stories and discussions revealed that reasons for improved biocontrol are an increased number of BCAs, extensive use of banker plants, the cost of biocontrol equaling chemical control, worker and grower attitudes, biocontrol being more environmentally friendly, and good technical support systems. There is a need to develop whole crop management programmes, though.

Biological and Integrated Control in Vegetables

Case stories and discussions revealed that in warmer climates, the increased use of biocontrol is related to the invasion of indigenous BCAs into the crop, pesticide resistance and pesticide application, availability of BCAs, technical support and consumer demand for 'clean' produce, with the major limiting factors being disease incidence, low winter temperatures, and dynamic and intensive horticultural systems. In temperate climates, good technical support, registration of IPM-compatible chemicals and the increased number of available BCAs has had a dramatic positive impact with limiting factors being the constant invasion of new pests and the complexity of the IPM systems.

Registration/Regulation of Biological Control Agents

From keynote presentations and discussions it can be concluded that current popularity in biocontrol has resulted in a substantial increase in biocontrol projects. Combined with the possible environmental risks associated with the introduction of non-indigenous agents into the ecosystem, this has resulted in many countries reviewing or developing BCA introduction guidelines. Risk assessment encompasses health risks, characterization and identification of BCA, efficacy, and environmental risks. Pro-regulation viewpoints are that regulation is needed to safeguard biodiversity and protect biocontrol as a pest management tool, and that harmonized regulations will help commercial producers by minimizing development costs for new BCAs. Producers' viewpoints on this aspect included: What is risk? Is the precautionary principle necessary for BCAs? Over-regulation will result in fewer BCAs as development will be more time consuming and very expensive. The challenge is to keep the regulations within reasonable limits.

Future Direction of Greenhouse IPM

The overall conclusions from the meeting were that more field trials to improve the understanding of pest/BCA ecosystem relationships should be undertaken; that collaboration should increase to better utilize the global strengths (skills and resources) of greenhouse IPM researchers; that the use of biotechnology should be explored wherever possible in developing improved IPM strategies; and that long term research objectives and milestones for the different pests/crops should be developed.

More detailed summaries from the sessions can be found in Sting 24, which will be issued around August 2002. A net version of Sting 24 will be available under Publications on the WPRS-WG homepage:

www.agrsci.dk/plb/iobc/iobc_home.htm 

The next meeting of the WG will be held in Turku, Finland, 2005. Local organizers are Irene Vänninen, Jan Hulshof and co-workers, AgriFood Research, Finland. Further details will be given in due course on the WPRS WG homepage.

*Enkegaard, A. (ed) (2002) Integrated Control in Protected Crops, Temperate Climate, IOBC/wprs Bulletin 25(1), 308 pp.

By: Annie Enkegaard,
Department of Crop Protection,
Danish Institute of Agricultural Sciences, Denmark
Email: annie.enkegaard@agrsci.dk 

❑