Experiences on integration of biological pest control into IPM-systems in protected ornamental crops

To control aerial pests different methods of releasing beneficials were used. 1. One to several releases of beneficials at the beginning of the pest infestation: Good results were achieved in suppressing population densities of the spider mite, Tetranychus urticae, in Cymbidium of the white fly, Trialeurodes vaporariorum, in Hibiscus by the predatory mite, Phytoseilus persimilis, and the parasitoid Encarsia formosa, respectively. 2. Periodical introduction of antagonists: It was principally possible to control the western flower thrips, Frankliniella occidentalis, on Streptocarpus with the predatory mite, Amblyseius cucumeris, if the mites were released in short periods and in high numbers. It would however be desirable to substitute A. cucumeris by more efficient antagonists, e.g. flower bugs (Anthocoridae) like Orius spp. or Anthocoris spp. 3. Open rearing unit of antagonists: The open rearing unit of the predatory gall midge Aphidoletes aphidimyza on cereal aphids was proved to be a very effective system to control different harmful aphid species occurring in Hibiscus and Streptocarpus, e.g. Myzus persicae, Aphis gossypii. In addition, periodical introductions of cereal aphids (Metopolophium dirhodum, Sitobion avenae, Rhopalosiphum padi) on oats or spring wheat enhanced the occurrence of various other natural enemies, e.g. Aphidius spp., Aphelinus varipes, Praon spp., Anthocoris spp. and spiders, which may obviously have increased stability, efficiency and safety of this control system. Biological control of soil borne pests are currently under experimental stage: Laboratory tests showed that both the bacterium, Pasteuria penetrans, and the newly found predatory mite, Sancassania ultima, were very effective antagonists to control root-knot nematodes (Meloidogyne spp.). After application of entomogenous nematodes, Heterorhabditis heliothidis and Steinernema feltiae, larvae of the ghost moth, Hepialus spp., a dangerous pest in helleborus, died within three and five days, respectively