Late Blight Control – Date and Product Strategy Must be Correct!

Late Blight Control – Date and Product Strategy Must be Correct!

Germany, Bavaria; Bayerische Landesanstalt für Landwirtschaft

Institut für Pflanzenschutz; authors: Michael Zellner, Steffen Wagner, Bernhard Weber, Johann Hofbauer http://www.lfl.bayern.de/ips/landwirtschaft/12990/

 

This article (in English) provides very useful information and tables about the essentials in late blight control concerning the choice of product and the timing of the application. Tables of different fungicides, dates of application, a comparison of systemic and local fungicides are included. It explains the conditions for infestation, the function and modes of action of the fungicides. A selection of fungicides for first and later treatments is provided as well as optimum treatment frequency, dosage and prices.

Control of Colorado potato beetle (Leptinotarsa decemlineata)

This article provides a short overview on existing insecticides to control of Colorado potato beetle (Leptinotarsa decemlineata) in Germany.

For a successful control of Leptinotarsa decemlineata the timing of the treatment and the choice of the right product are essential. Treatment is most efficient at the time of larvae mass emergence (L1/L2) considering temperatures and using forecast models (such as SIMLEP).

In consideration of increasing resistance problems with pyrethroids and first appearance of resistance against neonicotinoids in Northern America strategies for resistance management need to be observed. The core element is using substances with different modes of action. The table displays insecticides and indications against Colorado potato beetle, aphids and aphids as vectors.

Potato late blight control (Phytophthora infestans)

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.