Conservation biological control for the management of Diaphorina citri in California (USA)
Diaphorina citri (vector of ‘Candidatus Liberibacter asiaticus’ - Hemiptera: Liviidae, EPPO A1 List) is a pest of citrus and has been present in California (USA) since 2008. Classical biological control agents (e.g. Tamarixia radiata and Diaphorencyrtus aligarhensis Hymenoptera: Encyrtidae) have been released against the pest in California with varying levels of success. Conservation biological control aims to improve the habitat for natural enemies through the manipulation of the habitat/ species within it. For example, the planting and maintenance of floral resources which can provide shelter, nectar or alternative hosts and prey. Studies were conducted to evaluate the potential of Fagopyrum esculentum, Lobularia maritima, Phacelia tanacetifolia and Eschscholzia californica as insectary plants for hoverflies (Diptera: Syrphidae) for conservation biological control of D. citri in California citrus orchards. Field studies were carried out to assess the flowering phenology and attractiveness to hoverflies and hoverfly oviposition on D. citri colonies. F. esculentum and L. maritima attracted more hoverflies due to the short sowing to flowering time and were identified as superior food resources for hoverflies compared to the other plant species. The only hoverfly species that attacked D. citri in the field was Allograpta obliqua. Laboratory studies showed that A. obliqua larvae consume on average 421 D. citri nymphs before pupation. Results demonstrate that A. obliqua is an important and effective predator of D. citri nymphs.
Sources
Irvin NA, Pierce C, Hoddle MS (2021) Evaluating the potential of flowering plants for enhancing predatory hoverflies (Syrphidae) for biological control of Diaphorina citri (Liviidae) in California. Biological Control. https://doi.org/10.1016/j.biocontrol.2021.104574