Under the title of "New Diseases and Pests: Consequences for the Green Sector", IPM ESSEN 2017 will, in cooperation with the Federation of German Nurseries (BdB) and THE GREEN CITY foundation, again offer a top-class information event for nursery gardeners, landscape gardeners and decision takers in local authorities. The event with three brief lectures and a discussion traditionally takes place on the second day of the fair: from 10.30 a.m. to 12.00 noon on Wednesday, January 25, 2017. Because of the construction work, the event will take place in the West Congress Centre West, Berlin Hall, this time.
There are several reasons which, in the past years, have contributed to the fact that new diseases and pests have spread in woody plants time and time again. In part, this is the consequence of globalisation and of the associated transport of goods around the world. Thus, there is a rising probability of undesired organisms being imported unintentionally not only with the goods but also with packaging material, containers or vehicles. One additional factor relates to climate changes which make it easier for foreign species to spread.
A species is designated as invasive if it has become established in the new location and has proliferated to such an extent that it can cause economic or ecological damage. It is also problematical that there are initially no natural enemies or adversaries in most cases. Often, considerable damage has already occurred by the time that concrete combating methods have been developed. The certainly best-known example is the box tree: The cultivated plant which is native to Europe and has been firmly anchored in the European garden culture for centuries has as good as disappeared from the market within just a few years. The box tree moth and the fungal disease called Cylindrocladium buxicola have caused a dramatic decline of the plant not only in public green spaces but also in private gardens: Although combating possibilities are well-known in the meantime, the objective for a foreseeable period seems to be to find and cultivate alternatives to the box.
However, problems are also being shown with other plant species and, in particular, with trees. In part, these are highly specialised diseases and pests (e.g. on sycamore, chestnut, ash, elm and maple trees, hydrangeas, rhododendrons …) but they often extend their spectrum of hosts after spreading and arise on various woody plants. The spread of new diseases and pests restricts the selection possibilities for woody plants (also) in public green spaces. In parallel, there are rising expectations with regard to the public green spaces: Citizens want parks and green spaces for recreation and as compensation areas with impacts on the climate. Under the "Green Infrastructure" term, recommendations for local authorities to use green spaces strategically, also in relation to the urban climate, are coming not only from Brussels but also from the federal government.
All this has long since exerted effects on the green sector: Nurseries are selecting existing ranges and, together with their customers in local authorities and in horticulture and landscaping, are looking for alternatives. Three speakers will supply brief contributions on the conference subject from various perspectives: A representative of the Rhineland Chamber of Agriculture will report on the experience in the plant health service and with regard to import controls, will make an introduction to the subject and will give an overview of the development in recent years. A speaker from the Office for Green Spaces, Environment and Sustainability of the City of Münster will give an insight into the situation of his local authority.
Furthermore, he will present the status of things from the viewpoint of the Working Party on Urban Trees at the German Garden Office Directors Conference in a supraregional form. Thirdly, an employee of a tree care company will explain practical experience from daily work and will present consequences for tree monitoring and care in the green spaces of local authorities. In a final podium discussion, the individual aspects will be exposed even further and questions and suggestions from the public will be absolutely welcome. The event will be compered by Peter Menke, Chairman of THE GREEN CITY foundation.