Approaches to conserving natural enemy populations in greenhouse crops: current methods and future prospects

Abstract

Biological pest control in greenhouse crops is usually based on periodical releases of mass-produced natural enemies, and this method has been successfully applied for decades. However, in some cases there are shortcomings in pest control efficacy, which often can be attributed to the poor establishment of natural enemies. Their establishment and population numbers can be enhanced by providing additional resources, such as alternative food, prey, hosts, oviposition sites or shelters. Furthermore, natural enemy efficacy can be enhanced by using volatiles, adapting the greenhouse climate, avoiding pesticide side-effects and minimizing disrupting food web complexities. The special case of high value crops in a protected greenhouse environment offers tremendous opportunities to design and manage the system in ways that increase crop resilience to pest infestations. While we have outlined opportunities and tools to develop such systems, this review also identifies knowledge gaps, where additional research is needed to optimize these tools.

Biological control using invertebrates and microorganisms: plenty of new opportunities

“…Almost 40% of the income of the European companies originates from invertebrate biological control agents sold for control of thrips, another 30% for control of whitefly, 12% for control of spider mites, 8% for control of aphids, and the remaining 10% for control of various other pests (Bolckmans K, personal communication 2016). Since 2005, predatory mites have contributed enormously to the growth of the market for invertebrate biological control agents as a result of: the (re)discovery of their use for control of whiteflies (Nomikou et al 2001), finding more efficient species for thrips control (Messelink et al 2006), the development of techniques to enhance dispersal and establishment of predatory mites in crops (Messelink et al 2014), and the development of new highly economic production technologies (Bolckmans et al 2005).…”

“…They review societal challenges and options for innovation, and conclude that such a policy should not concentrate on agriculture only, but needs to be developed with participation of all stakeholders, and will help ''the entire food chain-from farm to fork, from animal breeding to human food production-to cope with the challenges of the coming decades''. Within conscious agriculture, the first line of crop protection consists of strictly enforced quarantine regulations, prevention of pest development by cultural methods, host-plant resistance, classical and conservation biological control, preventative releases of natural enemies (an aspect of ABC) and use of banker plants to establish natural enemy populations before pests establish (Messelink et al 2014). When pests exceed acceptable population levels, i.e.…”

Protocol for the evaluation of data concerning the necessity of the application of insecticide† active substances to control a serious danger to plant health which cannot be contained by other available means, including non‐chemical methods

“…habitat management to favour local natural enemies, e.g. by the use of banker plants for the provision of alternative food (nectar, pollen, alternative hosts or prey), the provision of nesting or overwintering sites (Landis et al 2000;Messelink et al 2014  Inundative biological control by massive releases of natural enemies that are expected to achieve control in one or two generations. An example is mass releases of Trichogramma spp.…”

Geïntegreerde bestrijding van plagen in de sierteelt onder glas : een systeembenadering met preventieve biologische bestrijding als basis

“…Voorafgaand aan dit project is een aantal experimenten gedaan met toplagen bestaande uit zemelen, gist, bark en schimmel-etende mijten (Grosman et al 2014 (Wade et al 2008;Messelink et al 2014). Dit is vooral een goede methode om generalistische predatoren vroegtijdig te laten vestigen wanneer plagen nog niet, of in zeer lage dichtheden aanwezig zijn.…”