Best Practice – Fusarium, Pythium and Rhizoctonia Root Rots in Vegetables
This 20-page booklet presents an Integrated Crop Management (ICM) and Integrated Pest Management (IPM) approach to the control of Fusarium, Rhizoctonia and Pythium root rot diseases in vegetables. This approach aims to minimise the development of fungicide resistance, minimise pesticide residues in food, reduce environmental impacts and limit possible restrictions in trade (domestic and international). Non-chemical management options are discussed such as irrigation management, limiting the movement of machinery and personnel from infected paddocks to non-infected properties, crop rotation, site selection, seed treatments and in the case of Fusarium, the use of resistant varieties and resistant rootstocks for grafting. Information presented on chemical options (including rates, chemical groups, maximum number of applications and withholding periods) was current as at 30/09/09. It is up to users to make sure the chemicals are still registered or that “minor use” permits are current before using the fungicides mentioned in this publication. Each fungicide is rated according to its impact on the person applying it, other field workers (eg pickers), birds, bees, fish and beneficials, whether it leaches and the “consumer effects” in terms of possible residues in food. These ratings are combined into an Environmental Impact Quotient (EIQ) that allows comparison between fungicide options. Background information on these three types of root rot organisms is presented. They often appear together in “complexes” and an important aspect of their control is reducing or eliminating root damage including the control of damaging pests such as nematodes. Fungicide resistance management guidelines are also included. Because of the nature of Fusarium, Pythium and Rhizoctonia, most fungicides (except for fumigants) are used as either seed dressings (applied to seed prior to planting) or post harvest dips.