Bestrijding en beheersing van overmatige groei van de schimmel Leucocoprinus birnbaumii bij de teelt van Phalaenopsis

English. Phalaenopsis is cultivated using mainly bark as a substrate, in some cases additional material is added like sphagnum or foam. During cultivation a sudden fungal growth can be determinated in the substrate. In some cases only primordia are visible but even mushrooms develop on the substrate. Leucocoprinus birnbaumii, the yellow parasol or the flower pot parasol, is observed in Phalaenopsis. Damage is mainly cosmetic. There is no or hardly any interference with Phalaenopsis, plants are vital, develop well and have a long shelf life. An excessive growth of fungal hyphe can turn the bark into a hydrophobic substrate. In this research the biology of L. birnbaumii is studied. Especially the influence of different parameters on the biology of this fungus is studied. On top of this the effect of plan protection products are studied to observe the effect on the fungus directly as well as in growing substrate. The development of this fungus will stop if treated with a fungicide like Ortiva (azoxystrobine) and if a high dosage of the fungicide Switch (fludioxonil en cyprodinil) is used. These results cannot be repeated under practical circumstances. Therefore we are not able to draw any conclusions about the effect of the previously mentioned fungicides in substrate. The outcome of this research, the hypotheses and the experience this gathered during this experiment ask for more research in the near future.

Dutch; Flemish. Referaat Bij de teelt van Phalaenopsis wordt als teeltmedium over het algemeen boombast gebruikt, al dan niet gemengd met verschillende vulstoffen zoals sphagnum of foam. Gedurende de teelt wordt regelmatig een plotselinge groei van schimmelpluis of vruchtlichamen en zelfs paddenstoelen waargenomen. De teelt van Phalaenopsis heeft vooral te maken met de overmatige groei van de schimmel Leucocoprinus birnbaumii, de goudgele plooiparasol. De schade is vooral cosmetisch van aard, de planten zijn vitaal, groeien goed en er is geen effect op de houdbaarheid vast te stellen ondanks de aanwezigheid van de schimmelbolletjes. De schimmels hebben wel de eigenschap dat de boomschors door het mycelium wordt inkapselt, waardoor de schors geen vocht meer opneemt. In dit onderzoek is gekeken naar de levenswijze en op welke manier deze levenswijze kan worden beïnvloed. In het bijzonder is er gekeken naar de omstandigheden op basis waarvan de schimmel groeit, zich ontwikkelt en overgaat tot de vorming van de gele bolletjes, de zogenaamde primordia. Daarnaast is er gekeken naar de effecten van gewasbeschermingsmiddelen op de groei en ontwikkeling van de schimmel. De schimmel stopt met groeien bij een directe toepassing van Ortiva (azoxystrobine) en bij een hoge dosering van Switch (fludioxonil en cyprodinil). De experimenten op praktijkniveau hebben onbevredigende resultaten gegeven. De oorzaak lag niet in de werking of toepassing van de middelen, maar in de kweekomstandigheden van de schimmel. Er is geen conclusie te trekken over de werking van de eerder genoemde middelen op praktijkschaal in bark. De uitkomsten, hypotheses en ervaringen uit dit project vragen om een vervolg. Abstract Phalaenopsis is cultivated using mainly bark as a substrate, in some cases additional material is added like sphagnum or foam. During cultivation a sudden fungal growth can be determinated in the substrate. In some cases only primordia are visible but even mushrooms develop on the substrate. Leucocoprinus birnbaumii, the yellow parasol or the flower pot parasol, is observed in Phalaenopsis. Damage is mainly cosmetic. There is no or hardly any interference with Phalaenopsis, plants are vital, develop well and have a long shelf life. An excessive growth of fungal hyphe can turn the bark into a hydrophobic substrate. In this research the biology of L. birnbaumii is studied. Especially the influence of different parameters on the biology of this fungus is studied. On top of this the effect of plan protection products are studied to observe the effect on the fungus directly as well as in growing substrate. The development of this fungus will stop if treated with a fungicide like Ortiva (azoxystrobine) and if a high dosage of the fungicide Switch (fludioxonil en cyprodinil) is used. These results cannot be repeated under practical circumstances. Therefore we are not able to draw any conclusions about the effect of the previously mentioned fungicides in substrate. The outcome of this research, the hypotheses and the experience this gathered during this experiment ask for more research in the near future.