ENDURE’s potato case study team has been examining ways to reduce the use of fungicides on one of the world’s most important food crops.
While no Belgian would dream of serving moules without frites and no English Sunday roast dinner is complete without potatoes, the vegetable’s reputation as a tasty, nutritious and above all cheap accompaniment masks the fact that potato production comes with a huge price tag.
In fact, ENDURE’s potato case study team estimates that the combined worldwide cost of crop losses and treatments (mainly fungicides) against the most serious potato disease, late blight, is a staggering €4 billion per year, half of this cost incurred in Europe alone.
Late blight, caused by the pseudo-fungus Phytophthora infestans , has been the focus of the team’s work, and with good reason. First recorded in Europe in the 1840s, late blight destroyed three consecutive potato crops in Ireland leading to the deaths of around one million people and more than 150 years later remains a major problem. In Poland, for example, more than 20% of the potato crop can be lost in bad years, and every year losses of between 15 and 20% occur during storage.
Faced with such a problem, growers (at least in western Europe) have relied on the regular spraying of fungicides, to the extent that more fungicide is used to control blight than is used in any other crop. Such an approach is, obviously, far from ideal, bringing with it both financial and environmental costs, and the team has spent 18 months investigating the combination of techniques that can be used to form an integrated approach to controlling late blight in potatoes.
The team studied the integrated control strategies for early and late blight in Denmark, France, Italy, the Netherlands and Poland, analysing their impacts and considering the possibility of transferring key factors to other European potato growing areas. The result is a series of four guides, part of ENDURE’s From Science to Field series, designed to offer sound, practical advice for agricultural advisory and extension services, though they will be of interest to anyone concerned with late blight.
Guide Number 1 - Reducing Primary Inoculum Sources of Late Blight analyses the first step in an integrated control strategy: identifying the most common sources of late blight and ways to reduce the risk. These include infected plants on dumps (in the Netherlands, for example, growers must cover dumps with black plastic before April 15 each year) and infested seed potatoes. The team recommends that certified seed potatoes be used, but notes that this is no guarantee that the seed will be completely free from blight since the disease can be latently present in the tubers. It says oospores are another threat, especially when short crop rotations are used, and says volunteer potatoes (self-set potatoes from a previous crop growing as weeds in other crops) must be controlled, even though this may be difficult and labour intensive. Early crops covered with perforated polythene are also a threat and the team recommends some practical steps to reducing the risk they pose. Click below to download the guide:
Guide Number 2 - Using Decision Support Systems to Combat Late Blight examines the use of decision support systems (DSS), which integrate all relevant information to generate spray recommendations. The Potato Case Study team believes much can be gained by the wider adoption of DSS, which increase the efficacy of control strategies without increasing risk. They further note that DSS can be a source of advice in situations where the number of sprays or product choice is limited by legislation. The team considered all DSS in Europe, where all potato growing regions have one or more DSS available, and in particular look at the development of these systems in Denmark, France, Italy, the Netherlands and Poland. Click below to download the guide:
Guide Number 3 - Fungicides for Tackling Late Blight notes that fungicides play a crucial role in the integrated control of late blight, with integrated pest management (IPM) strategies balancing a number of factors concerning fungicides, including efficacy and side-effects (both environmental and toxicity) in addition to economic and social factors plus the legislation in place. It says that while control strategies are primarily preventive, when blight enters a crop the strategy must focus on stopping or reducing the epidemic. This means growers and advisors need all the information and tools necessary to control blight efficiently and the guide highlights the important phases of the crop’s development in addition to identifying further sources of information. It also contains a table of fungicides registered for late blight control in five European countries. Click below to download the guide:
Guide Number 4 - Using Cultivar Resistance to Reduce Inputs Against Late Blight says that the late blight resistance of a cultivar offers significant potential in reducing fungicide inputs as part of an integrated control strategy. It says both partial resistance (lower susceptibility) and fungicides can slow the development of late blight, and many reports show that partial resistance in the foliage can be used to complement fungicide applications, cutting fungicide use through reduced application rates or extended intervals between sprays. The team has identified the large differences in the use of resistant cultivars across Europe - in the west they are not grown on a large scale because commercially important characteristics (such as quality and yield) are usually not combined with late blight resistance in the same cultivar, while in countries where fungicides are not widely available or very expensive, the use of resistant cultivars is one of the most important ways of reducing blight damage. The guide examines this situation, looks at the prospects for further progress and offers sources of further information. Click below to download the guide:
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Last update: 24/05/2023 - ENDURE © 2009 - Contact ENDURE - Disclaimer