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Botanicals and Phosphonate Show Potential to Replace Copper for Control of Potato Late Blight

Authors :
Tomke Musa
Hans-Rudolf Forrer
Susanne Vogelgsang
Source :
Journal of Fungi, Journal of Fungi, Vol 3, Iss 4, p 65 (2017), Journal of Fungi; Volume 3; Issue 4; Pages: 65
Publication Year :
2017
Publisher :
MDPI AG, 2017.

Abstract

Potato late blight (PLB) caused by Phytophthora infestans (Pi) is the most harmful disease in potato production worldwide. In organic farming, copper is used despite its persistence in soil and toxicity to soil organisms. To replace copper, suspensions of powders from three promising botanicals, including bark of buckthorn (Frangula alnus, FA), roots of medicinal rhubarb (Rheum palmatum) and galls of the nutgall tree (Galla chinensis), were tested in multi-year field experiments. The current study shows for the first time that botanicals could replace copper under field conditions and best PLB reduction on leaves was achieved with FA, reaching a level close to that of 2 to 3 kg copper per hectare and year. Better results than with copper were achieved with Phosfik® (Ph), a phosphonate-based product. For both FA and Ph, the mode of action is based on induced resistance, for Ph also on direct fungicidal effects. A disadvantage of Ph is the accumulation of residues in potato tubers. Nevertheless, two to three applications with 2 to 3 L/ha of Ph would be feasible to not exceed a minimal risk level (MLR) of 20 mg/kg of phosphorous acid as proposed by the European Food Safety Authority. Due to an excellent environmental profile and a complex mode of action counteracting Pi resistance, phosphonate-based products would be most suitable for sustainable PLB management in integrated pest management (IPM) programmes.

Details

ISSN :
2309608X
Volume :
3
Database :
OpenAIRE
Journal :
Journal of Fungi
Accession number :
edsair.doi.dedup.....a3d846c4c4757f0f555541d54ff2f038
Full Text :
https://doi.org/10.3390/jof3040065