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BIONÆR-Bionæringsprogram

C-IPM IPM2.0 for sustainable control of potato late blight - exploiting pathogen population data for optimized Decisions Support Systems

Alternative title: .

Awarded: NOK 3.1 mill.

During the project period, field trials have been performed, and potato late blight samples have been collected around the country. Late blight development has been monitored in potato cultivars containing different resistance genes, and which cultivars that are attacked give us information about development in the pathogen and breakdown of disease resistance in the host. Which potato cultivars that are attacked tells us something about the characteristics of the attacking pathogen. The same kind of experiments have been performed by all countries in the project. Samples of potato late blight have been collected for molecular analysis during the project. These analyses reveals if the isolate belongs to a certain group (genotype), which again can say something about which traits we can expect (for instance aggressiveness or fungicide resistance). The molecular analysis of the Norwegian isolates has been performed in France, and all results are collected in a database together with data from other European countries (Euroblight). Analysis of isolates from Norway has shown greater variation among the isolates compared to what has been shown in previous collections. The most important result from these experiments is that a new genotype (known as EU_41_A2) previously only found in Denmark has spread to Norway, and has been found all three years. This genotype has not shown any high resistance to any of the fungicides tested, but it has been shown to be very aggressive. All countries involved in the project have collected around 40 isolates each year in 2016 and 2017, and these have been used in several types of experiments to identify traits and possibly tie these to molecular markers. Norway and Estonia have tested all isolates for resistance to 4 different fungicides, while other countries have tested the isolates for aggressiveness and virulence among other things. Our results have shown a relatively high degree of resistance to some fungicides, and there is great variation between the different countries the isolates come from. All isolates that have been collected during the project is stored at NIBIO in Ås, and has been distributed to the project partners when needed. Data from analysis of the isolates (molecular and other traits) will be collected in a common database. In a different part of the project, the modelling of potato late blight attacks is addressed. A system for testing the quality of weather data has been developed and implemented in Matlab. Five European models and one reference model for potato late blight warning have been programmed into a common platform, and have been tested on weather data from 6 European countries, 2 sites in each country. The Nærstad- model, which is developed and used in Norway, is one of the models that are being tested. Statistical analysis of the results have been performed to compare the models and possibly detect effects of time (early or late in the season), region, year and model on estimated risk of potato late blight. Evaluating the precision of the models by comparing the model output to actual disease data from the different countries is also in process, but is delayed because of difficulty in compiling data from several countries. A scientific paper is in writing, and the plan is to submit it in 2019.

Den viktigaste oppdaginga frå dette prosjektet for potetdyrkinga i Noreg er den nye genotypen av tørråte kalla EU_41_A2. Denne genotypen er meir aggressiv og skiller seg klart frå det me har funne i Noreg tidlegare. Prosjektet har vore viktig for forskingsmiljøet ved at det har blitt knytt nye kontaktar, både innan potetforsking, men også innan andre emne som til dømes modellering.

Late blight, caused by Phytophthora infestans, remains the major threat to potato crops in Europe, and a main reason for pesticide use. Despite the release of resistant cultivars and the implementation of modern DSS operated from web platforms or mobile apps, integrated management of late blight still relies heavily on many fungicide applications (up to 25 per season in some regions). The need is thus obvious to develop strategies that take full advantage of alternative options for more sustainable crop protection and better fungicide stewardship. To be sustainable and adopted, such strategies must be tailored to the variability of P. infestans populations and their rapid evolution - the IPM 2.0 concept. This in turn supposes that pathogen populations be monitored for both genotypes and phenotypes, including virulence, aggressiveness and fungicide sensitivity. IPMBlight 2.0 aims at validating the IPM 2.0 concept, with potato late blight as a case study. To this end, it will analyze genotypic (WP1) and phenotypic (WP2) variation in reference collections of the pathogen sampled from sexual and clonal populations collected in partner countries, and develop new DSS models while adjusting existing ones to offer risk assessment based on both epidemiological, weather-driven infection likelihood and pathogen phenotypes (WP3). The new DSS modules will therefore be able to best inform tactical choices (?should I spray now??) and strategic decisions (?can I trust this resistant cultivar? how can I adjust my spraying schedule accordingly?) for improved late blight control. The project builds on the monitoring activities carried out within EuroBlight, and complements them by providing critical, but currently unavailable phenotypic data. EuroBlight is a large collaborative network of scientists, breeders, agrochemical industries, DSS developers and extension specialists dedicated to improved blight Control.

Funding scheme:

BIONÆR-Bionæringsprogram