The use of plant extracts to control the major disease and pest in mushroom cultivation

Dry bubble disease and its spread by insects represents a major problem in the cultivation of mushrooms. Prevention of dry bubble disease and its vectors usually involves chemical crop protection. However, the use of chemical crop protection is becoming less acceptable. We expect that, within a few years, prochloraz will no longer be available for use in mushroom cultivation in the European Union. It is therefore necessary to develop alternative methods to control dry bubble disease. In a number of projects financed by the Dutch Product Board we investigated the efficacy of plant extracts and pure compounds as an alternative to chemical crop protection. We focused on the use of plant extracts to combat dry bubble disease and phorid flies. With respect to dry bubble disease, we identified a plant extract that could reduce the incidence of dry bubbles by 80% after a single application in experimental cultivation of mushrooms. The efficacy of this plant extract compares favourably with the efficacy of prochloraz. With respect to Megaselia halterata phorid flies, we identified plant extracts that (when used in a preventive manner) could reduce the number of flies by 60%. If used curatively, immediately after the flies produced eggs in the compost, some plant extracts could reduce the number of flies by 90%. For both applications further research on plant extracts is aimed at developing crop protection agents that can be used in organic mushroom cultivation.