Abstract
Enhancing the performance of predatory mites is often regarded as the best biological control approach towards the spider mite Tetranychus urticae, the main pest of strawberry plantations. Optimizing the colonization of plantations by predators from adjacent areas such as field margins is seen as an important component of conservation biocontrol. We have investigated the factors contributing to enhancing the numbers of predatory mites (Acari: Phytoseidae), such as management of the field margins, vegetation composition and the effect of the presence of woody species. We also tested the penetration of the phytoseiids from the field margins into the crop. In a study carried out in 14 open-field extensively managed strawberry plantations in Poland we found phytoseiids to be abundant in field margins; 14 taxa were discovered. However, only two species Amblyseius andersoni and Euseius finlandicus dispersed a modest distance into the crop. We found that the diversity and densities of the predatory mites were enhanced somewhat by the management type of the field margins; especially the spontaneous vegetation favoured the presence of phytoseiids. However, despite the predatory mites being rather retained in the field margins also significant reduction in numbers of their prey T. urticae was recorded over the course of the year. The low penetration of predatory mites into the main part of the field, indicates that conservation biological control measures in the field margin might not be sufficient on their own to enhance the impact of predatory mites within the main part of the fields.
Highlights
Integrated pest management (IPM) is increasingly regarded as a workable contribution to meet the challenges of minimising the environmental impacts of chemical pest control, whilst maintaining crop production with a declining list of pesticide alternatives (Wissuwa et al 2012; McMurtry et al 2014)
Whilst the nature of the field margins and the surrounding landscape could enhance the densities of some species of predatory mites, this study found that the changes in the densities were almost entirely limited to the immediate margins of the field, despite the prey available in the entire field
The management type of the field margins was significantly correlated to the general density of predatory mites in the field margins, spontaneous noncrop vegetation being associated most with the presence of the most common phytoseiid, A. andersoni
Summary
Integrated pest management (IPM) is increasingly regarded as a workable contribution to meet the challenges of minimising the environmental impacts of chemical pest control, whilst maintaining crop production with a declining list of pesticide alternatives (Wissuwa et al 2012; McMurtry et al 2014). The natural vegetation of field margins shows a relatively high diversity of beneficial insects and mites (Denys and Tscharntke 2002). IPM is reasserting the importance of sustainable methods of control, including developing genetic resistance (Figueiredo et al 2012) and enhancing favourable conditions for natural enemies (Hajek 2004; Ramsden et al 2015). Field margin vegetation has been shown to provide alternative prey or food resources and refuges for overwintering of beneficial arthropods, including mites (Boller et al 1988; Marshall and Moonen 2002; Romero and Benson 2005; Tixier et al 2000)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
