Developing strategies for controlling tarsonemid and eriophyoid mites with phytoseiid predatory mites in flower bulbs, Bromeliaceae, gerbera and blackberry

Abstract: Small phytophagous mites of the families Eriophyidae and Tarsonemidae are increasingly causing serious crop damage in various ornamental and fruit crops in the Netherlands. The reduced use of broad spectrum pesticides is probably one of the reasons for this observed increase. A major pest in tulip bulbs is the eriophyid Aceria tulipae. This so-called dry bulb mite is particularly a problem after harvest when tulip bulbs are stored for several months. Another eriophyoid mite, Acalitus essigi, is a serious pest in the culture of blackberry. The mites hide in the buds, leaf axils and bracts. Economic losses occur when they attack the fruit during drupelet ripening. The affected drupelets become hard, inedible and bright red. Tarsonemid mites give serious problems in various ornamental greenhouse crops. A major pest in amaryllis is the bulb scale mite Steneotarsonemus laticeps. Similar to the dry bulb mite, this mite hides deep into the bulbs and is thereby very hard to control with pesticides or biological control agents. Bromeliaceae are mainly attacked by the tarsonemid Steneotarsonemus ananas, whereas the most abundant tarsonemids in gerbera are Tarsonemus violae and the broad mite Polyphagotarsonemus latus. These mites live deep in flower microhabitats and cause flower deformation. Although these various small phytophagous mites all require a specific approach for biological control, there might also be similarities in ways to optimize control. Here we present shortly our plans to enhance biological control of the above mentioned phytophagous mites with phytoseiid predatory mites.