This article refers Potao late blight control in Germany achieved in 2007. A strategy is offered recommending products with different modes of action in order to prevent resistance development.
High infestation pressure occurred in 2007 and occurred mainly on leafs. The recommended strategy is to use first systemic or partial systemic treatment at the beginning of the infestation ensuring the protection of the foliage. Products based on contact activity are well suited if infestation pressure is low.
Intensive treatment (Stoppspritzung) to eliminate infections showed very good results maintaining spraying intervals and recommended dosage. The following should be observed:
- Spraying intervals max.5 days
- Application of full dosage of products local systemic effects combined with a spore killing product (selection): Acrobat plus WG 2 kg/ha + Electis 1,8 kg/ha
Tanos 0,7 l/ha + Shirlan 0,3 l/ha
Valbon 1,6 l/ha + Ranman 0,2 l/ha + 0,15 FHS
Infinito 1,5 l/ha + Shirlan 0,3 l/ha
- For the following treatment a product with good efficiency and rain persistence should be applied
- For the continuing and final treatment (8-10 days before haulm destruction) spore killing products should be applied.
In order to prevent development of resistance alternating use of active ingredients is essential. An alternation of the products Valbon (no spore killing effects) and Infinito (a.I.: Fluopicolide and Propamocarb) with a different mode of action provides a good resistance strategy.
Infinito provides an antisporulant and translaminar effects providing protection to the stem and the growing leafs. Depending on infestation pressure the recommended dosage varies between 1,2 – 1,6 l in 7-10 days.
The table in the original document presents a selection of in Germany approved fungicides.
Column 1= product name; column 2 = recommended (approved) dosage; column 3= active ingredient name; column 4= active ingredient concentration; column 5= mode of action; column 6= distance to surface water (m) and reduction of drift; column 7= sensitive area requirements; column 8= price.
