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Why use disease model

  Meteobot® helps you control plant diseases. The weather data from your field or orchard can be automatically transmitted to disease models, which can generate forecasts for plant disease risks. The models, used by Meteobot®, are dynamic. They take into account the current climatic conditions, as well as the available pathogens, accumulated as a result of previous … Continue reading Why use disease model

 

Meteobot® helps you control plant diseases. The weather data from your field or orchard can be automatically transmitted to disease models, which can generate forecasts for plant disease risks.

The models, used by Meteobot®, are dynamic. They take into account the current climatic conditions, as well as the available pathogens, accumulated as a result of previous infection events. Under the same climatic conditions, but with a different amount of potential infection, the forecasted disease risk is different. Precise models show you that rain events do not always cause infections, or that a lot of rain does not lead to severe infections.

How do models work?

The models provide forecasts for diseases and pests by taking into account the conditions, which favour their occurrence and development. The models contain rules and algorithms, obtained from scientific research and many field trials. These rules and algorithms take into account rain, temperature, air humidity, leaf wetness, solar radiation, etc. The data comes directly from the weather stations and it is used to automatically calculate a forecast for the expected moment and intensity of the next infection.

As you know, for example, fungus diseases develop when it is warm and humid. In practice, however, the conditions and dependencies between diseases and insects are often much more complex, than we might think. Even if we know them, we can make full use of them only if weather data is obtained each hour and is automatically processed by a computer.

Beside weather data, many other factors are taken into account. Wheat and barley models, for example, contain built-in information about the phenological stages of plant development and the yield risk. The resistance (or tolerance) to diseases of different crop varieties is also incorporated in the models. The previous year crop, the type and amount of the applied fertilizer, etc. are take in mind as well. Other models, such as those for apples, estimate the residual effect of plant protections products on certain pathogens. All of these make the disease forecasts as accurate as possible.

The built-in information in the models has been checked and validated many times through field trials in many countries all over the world. Before being applied in practice, the models have been tested in various climatic zones and situations, under varying disease pressure. Some of them, such as the apple scab model, for example, have been developed in the end of the 1990s and have been validated on several continents since then. The wheat and barley models are based on scientific research and field trials since 1997. Others are more recent and have been introduced into practice after having showed stable results.

Based on all of these features, the models provide a dynamic forecast for the expected moment and the degree of the infection risk.

The purpose is to spray only when necessary and with the most adequate product.

Why use models?

Wheat growers save on average 23 EUR/hectare from fungicides and fuel. For a farm with 500 ha of wheat, this means 11,500 EUR savings – each year!

Have a look at real farmers’ experiences!

RETURN ON INVESTMENT

* The historical data is necessary for the model to work correctly, even if the weather station is installed after the date of seeding or after the start of the growing season.

How do models actually help?

  • Spray only if and when necessary“Calendar sprays”, or spraying according to the term of the plant protection product, are a common practice. For example, if a pesticide’s effective term in two weeks, farmers spray every two weeks. You don’t need to do that anymore! With the models, you can spray if and when there actually is an infection risk. It is most effective to apply a product right before or immediately after an infection event; and in any case before the development of the disease. In this moment the disease agent is most vulnerable and the effect of spraying is the strongest.
  • Choose the most adequate product.You don’t have to spray “blindfolded” or “just in case” any more. The models take into account your individual situation and give you a forecast about the specific disease risk for your crops. This way you can reduce or diversify the use of broad-spectrum plant protection products. Instead, you can use the most effective product, which will have the most adequate action – preventative or curative – in your specific case.
  • Avoid resistance.When a product is used too often against certain disease agents, over time they become resistant to it. This can be the case, for example, with system (curative) fungicides or broad-spectrum products. Resistance can also occur in case of “calendar sprays”. If the infection has occurred towards the end of the product’s term, when its protective effect is weaker, some of the pathogens may survive. The surviving microorganisms may become more resistant against this product during next applications. To avoid resistance, with the help of the models, you can reduce the usage of certain pesticides, or rotate them. This way you can keep a “trump”, which you can use when really necessary. Besides, by spraying in the right moment, you minimize the chance of surviving pathogens, which may have become resistant.
  • Less stress in busy periods.The disease risk forecast gives you additional peace of mind especially in spring, when the staff and machinery are busy with many activities (fertilizing, planting, herbicide application, etc.) If there is no risk at the moment, you can postpone the spraying by several days, in order to finish your other important tasks.
  • Integrated plant protectionThe models help you use the most adequate products and spray only as needed to bring the risk under the harmful threshold.
  • Bio-production.When spraying on time, you can use allowed fungicides and avoid the use of restricted products.
  • Wider use of contact or generic productsThe timely forecast enables you to use more contact (than curative) products, especially on perennials. This way you decrease the probability of resistance and of pesticide residue in the farm produce. Besides, when you know what the risk is in your particular situation, you can make wider use of generic plant protection products.

For an individual advice how to use the models on your farm, please contact us at +359 896 959 628 or info@meteobot.com.

Wheat model

Disease models To help grain growers, Meteobot® has an integration with models for soft and durum wheat. They provide risk forecasts for the following wheat diseases: Yellow stripe rust; Brown leaf rust; Septoria leaf blotch (Septoria tritici); Stagonospora nodorum; Powdery mildew (Oidium); Fusarium head blight; Mycotoxins in grain. The risk level is displayed on a … Continue reading Wheat model

Disease models

To help grain growers, Meteobot® has an integration with models for soft and durum wheat. They provide risk forecasts for the following wheat diseases:

  • Yellow stripe rust;
  • Brown leaf rust;
  • Septoria leaf blotch (Septoria tritici);
  • Stagonospora nodorum;
  • Powdery mildew (Oidium);
  • Fusarium head blight;
  • Mycotoxins in grain.

The risk level is displayed on a dashboard using the “traffic lights” principle – green means that there is no risk and red means that the risk is very high.

Risk level for disease - wheat

When you select a model, you can see detailed information about the infection events and infection pressure during the growing season. This is the first main advantage of the model – it forecasts the infection process even before you can observe any disease symptoms in the field. This way you get reaction time.

On the charts below, you can see real field data about powdery mildew on a tolerant variety.

The first chart shows the infection moments and infection intensity (with red bars). They are calculated using data from the weather station.

Risk of Powdery mildew - wheat

 

In practice, however, disease development depends not only on the weather, but on many other factors as well. This is the second main advantage of the model – it calculates the disease risk taking into consideration crop variety, predecessor, phenological phase, seeding density, fertilization, etc. The infection pressure is shown on the next chart. As you can see, in this case the risk is low, although there had been infection events in the beginning and end of May, as well as in the first half of June. They, however, are not sufficient for disease development; that’s why there is no need to spray.

Risk of Powdery mildew

 

The next chart shows the infection pressure from two other diseases – Septoria leaf blotch (Septoria tritici) and Stagonospora nodorum on a highly sensitive variety. It’s clearly visible that the risk is high and it is necessary to spray against these diseases.

Septoria leaf blotch infection

 

Phenological development model

The system has a built-in growth model for winter wheat, covering all phenological stages:

  • Sowing;
  • Emergence;
  • Tillering;
  • Stem elongation (first node above ground);
  • Booting;
  • Heading;
  • Flowering;
  • Milk ripening;
  • Dough ripening;
  • Senescence ripening.

The model calculates what is the current growth stage of the crop based on weather station data and the date of seeding. It also predicts when the plants will enter the next phenological phase based on the integrated weather forecast. For maximum accuracy, you can calibrate the model. This is quite easy – you just need to enter the date on which the current growth stage has actually started.

Knowing when the next growth stage is expected to begin, you can plan your spraying and fertilization activities much more precisely. That’s why the model is a very useful assistant to all farmers and agronomists.

Phenological development model

 

Database with plant protection products

The system contains a database with registered plant protection products against diseases, which require treatment. You can select one or several products and check the suitable spraying hours. They are displayed using the built-in local weather forecast. The unfavourable periods are marked with red, and the recommended treatments periods – with green.

Database with plant protection products

The models help you make plant protection decisions and plan other activities much more precisely. With their rich database they are useful both for farmers and agronomic consultants.

For an individual advice how to use the models on your farm, please contact us at +359 896 959 628 or info@meteobot.com.

The apple scab model

Effective scab management using RIMpro Marc Trapman Consultant and RIMpro developer, Bio Fruit Advies, the Netherlands Apple Scab is the key disease in apple production. Either measured in potential economic loss or costs and efforts necessary for its control. The apple scab model available on the RIMpro Cloud Service has proven its value over the past … Continue reading The apple scab model

Effective scab management using RIMpro

Marc Trapman

Consultant and RIMpro developer, Bio Fruit Advies, the Netherlands

Apple Scab is the key disease in apple production. Either measured in potential economic loss or costs and efforts necessary for its control. The apple scab model available on the RIMpro Cloud Service has proven its value over the past 20 years. In 2014 every fruit grower and adviser can connect his weather station(s) to this service.

The apple scab fungus rules the life of fruit growers and their advisers. Every rain event has to be judged for its consequences. Mostly there is only one right decision to make, and only one moment for the perfect application. Uncertainty leads to more fungicide treatments than necessary or damage by scab. So in either case to higher costs. RIMpro helps to make the best decisions. The graphs show the current situation and the development in the coming hors and days using local weather forecast. The service offers the possibility to register spray schedules, and estimate the cover remaining from the last fungicide treatment.

Apple scab

 

Inadequate management of the key infections undoubtedly leads to scab damage..

 

How the infection becomes?

The RIMpro graph shows the relative importance of primary scab infections. (Figure 1) Three high peaks mark the major scab infections, followed by a few smaller ones. Infection values under 100 are considered light, till 300 moderate, and over 300 as severe infection risk. Scab infections with RIM values over 600 occur only a few times per year and are the key infections. Inadequate management of these infections undoubtedly leads to scab damage.

Figure 1. RIMpro clearly distinguishes between major and minor infection events. New in the graph is the orange zone after the infection. In this stage the primary stroma is formed and the fungus is still susceptible for materials with limited curative activity like Lime Sulphur and Potassium Bicarbonate.

The RIMpro graph shows the relative importance of primary scab infections.

 

Figure 2 shows an infection event in detail. In the middle graph you see in red the proportion of the ascospore potential ready to be ejected during next rain. The actual spore discharge is presented as yellow bars. The following ‘white cloud’ in the graph represents the spores that try to germinate. Depending on the temperature it takes them up to 40 hours to germinate and infect the leaf. When leaf wetness stops earlier the spores survive for some time, but eventually die without infecting the leaf. This happens to the spores discharged on April 29.

Figure 2. Ascospore discharge is presented in yellow bars. The spores discharged on April 22th die without causing an infection as the leafs dry quickly. The discharge on April 25 causes an infection (red line).

Ascospore-discharge-is-presented-in-yellow-bars-RIMpro

 

When wetness continues the spores germinate and penetrate the leaf. This is the moment of infection. (red line). The more spores infect the leaf, the more severe the infection is, and the higher the RIM value.

Once under the cuticle the fungus starts growing. The first 200-300 Degree Hours (DH) the mycelium is still small and vulnerable. Products like Dodine, Lime Sulphur and Potassium Bicarbonate can still kill the fungus and stop the infection. This stage is the orange zone following the red infection line in the graph.

 

At what stage do fungicides work?

Contact fungicides like captan and sulphur kill spores during the germination process. These are the spores in the white cloud in the graph, which is called the germination window. Contact fungicides can be put on before the rain, but only the residue still present after the rain during the germination window is active. A contact fungicide applied during the germination window is the most effective treatment to stop an infection. Only than you hit the moment of action of these fungicides and bring the full dose of your application to work.

Dodine and Lime Sulfur are both effective during the germination window, and have limited curative efficacy till about 300 DH after start of infection. The mode of action of potassium bicarbonate however is only curative and it is easily washed off by rain. That narrows the window of application for potassium bicarbonate down to the first 300 DH after the infection. Systemic fungicides have no effect on germination but can stop the development of the fungus in the leaf up till 1000 DH post infection.

 

Resistance: game over!

Most commercial important apple varieties are highly susceptible to scab. Organic fruit growers moved to modern Vf scab resistant varieties to realize low input production, and ease their life. Unfortunately scab races breaking the Vf resistance have developed in most European production areas leaving the Vf varieties as susceptible as the standard apple varieties. As it is now, all commercial important apple varieties have to be regarded as susceptible and should be protected well. There is no room for thresholds as failures in spring lead to extra treatments in summer compromising the goal of environmentally friendly and residue low production.

Another unfortunate fact is that the scab fungus develops resistance against fungicides. All over Europe scab populations have developed that are less susceptible to all groups of systemic fungicides. The practical consequence is that scab management should be based on the accurate application of contact fungicides.

When yet even the number of applications of these contact fungicides is limited by label restrictions it is obvious that effective scab management becomes precision work.

 

The power of numbers

We don’t like it, but there is a lot of chance involved in scab control. Eventually the number of spores that escapes our management and successfully infects the tree determines the size our scab problem.

Where there was a lot of scab last year, the potential ascospores dose (PAD) is high. This increases the chance that each infection some spores will escape our control. Therefore sanitation measures to get rid of the leaf litter to reduce PAD make every single infection easier to handle while there are less ascospores involved in the infection process.

Even with the best spraying technique there is a factor 15 in fungicide cover between the best en worst covered leaf. This uneven spray cover makes that at moments of high spore release, there is a high chance that some spores germinate somewhere on the tree were the fungicide cover is not good. A double treatment on key infections is not only necessary while you put on two fungicides, but also because the cover is better in two than in one spray round.

In most apple production areas in Europe relying on systemic curative chemistry has become a complete gamble. Growers have absolutely no guarantee that their local scab population is still susceptible to the systemic product.

 

Curative activity in degree hours

Curative fungicides can stop the growth of the fungus in the leaf until a certain development stage. When it is warm the fungus grows fast, and is out of reach of the curative fungicide earlier than when it is colder. This means that the “kick-back” time of curative fungicides cannot be given in hours but only in Degree Hours. RIMpro presents the kick back of curative fungicides using the actual temperature and the properties of the fungicide.

Curative activity in degree hours - Apple scab

 

Curative fungicides can stop the growth of the fungus in the leaf until a certain development stage.

 

How to do it

Each infection event is different. Weather, orchard history, phenological stage, RIM value, and previous treatments, create a unique situation every time again. RIMpro supports decisions by showing the infection event and how it will develop based on weather forecast. It also estimates what is left of the cover of the previous fungicide treatment. Keeping in mind all written above, the following decision rules apply to practical scab management:

1. Eight-hour reaction time. Equipment and availability of labour should be such that the whole farm can be treated within 8 hours.

2. Build on contact fungicides. Use systemic fungicides only as last resource.

3. No calendar sprays. These have no relation to the infection biology, and make it harder to decide on the real important moments.

4. Pre-rain preventive treatment. When an infection is forecasted, cover as shortly as possible before the rain. This can be an alternate row application if you are capable of treating the other rows during the germination window.

5. Germination window treatment. As soon as an infection is likely to develop, and the remaining cover is less than 30% for a light, or less than 50% for a severe infection. If the previous treatment was alternate row, it should always be repeated now. A germination window treatment is highly effective even when applied during drizzle rain.

6. Stop-curative treatment. If you could not spray during the germination window, or the infection becomes more severe than expected, a stop or curative treatment is necessary. Infections with a RIM-value over 600 should always be treated double! Organic fruit growers use lime sulphur or a combination of sulphur and potassium bicarbonate on wet leaves to stop the infection in the 300 DH post infection window. Integrated fruit growers that still trust modern systemic chemistry would apply a combination of a contact and a systemic fungicide within 1000 DH.

7. Cleaning up during on-going infections. Infections developing from successive days of rain are more complicated to handle. Most spores are released during the first two rainy days. This situation does not need a succession of curative sprays. Keep in mind that a contact fungicide will ‘clean the leaves ‘ from germinating spores, and “zeros” the situation. Don’t hesitate to spray on wet leaves. This is always better than waiting for dry weather and rely on curative chemistry.

 

Decline of cover

RIMpro estimates the decline of the fungicide cover by leaf growth and wash-off by rain. Leaf growth is calculated from temperature, and wash-off is depending on the fungicide. Strobilurins are not washed off as they are fixed in the wax layer of the leaf. Copper en dithianon are quite rain-resistant, while sulphur and especially potassium bicarbonate are washed away by rain lightly.

Figure 3. Users can administrate their fungicide schedule. In this example the first protective treatment is washed away by the rain that is causing the infection. Scab management will fail unless another stop or curative treatment is made. The second treatment provides enough cover throughout the infection event.

RIMpro estimates the decline of the fungicide cover by leaf growth and wash-off by rain.

 

For individual consultations about how to use the models in your farm, you can contact us by phone: +359 896 95 96 28 or email: info@meteobot.com.

Accurate weather forecast for a longer period – how is it possible

The European Center for Medium-Range Weather Forecast (ECMWF) – already outperforming all of the world’s other global forecasting systems – has become even more superior. In 2016, ECMWF launched a new model cycle bringing improved global weather forecasts at a record-breaking resolution. The new grid on which the forecasts are run comprises of up to 904 … Continue reading Accurate weather forecast for a longer period – how is it possible

The European Center for Medium-Range Weather Forecast (ECMWF) – already outperforming all of the world’s other global forecasting systems – has become even more superior.

In 2016, ECMWF launched a new model cycle bringing improved global weather forecasts at a record-breaking resolution. The new grid on which the forecasts are run comprises of up to 904 million prediction points, three times as many as before. Together with other upgrades to ECMWF’s Integrated Forecasting System (IFS), the changes mean that Europe’s weather can now be predicted with more detail, with greater accuracy and, as a result, up to half a day further ahead.

The most overt demonstration of the European model’s superiority came in 2012 and 2015 when only it, out of more than a dozen computer forecasts, precisely predicted the particularly dangerous meteorological phenomena hitting USA – the hurricanes Sandy and Joakin.

The picture below illustrates a comparison of two precipitation forecasts for one and the same location and a period of 24 hours – the left is an output of the old ECMWF’s model and the right is produced using the new. What makes a striking difference in the second forecast is that some spurious storms (red points) have been removed. How amazing!

precipitation forecast comparison

Source: www.ecmwf.int

“What the European modeling community is doing is just amazing,” Ryan Maue, a meteorologist with WeatherBell, shares for Ars Technica. “This is the golden age of weather forecasters. It’s an absolute wonder of computer modeling technology.”

Meteobot® – technological hope in the range of agrometeorological products – also uses the ECMWF’s model. In addition to the real-time weather data it generates for your field, the meteostation delivers a 10-day weather forecast – the first 2 days the information is updated every hour, after that the forecast is produced for 6-hour periods.

The weather forecast includes data about:

  • Air temperature
  • Air humidity
  • Pressure
  • Precipitation
  • Wind speed and direction
  • Fog
  • Cloudiness
  • Dew point

Order your Meteobot® here.


Berger, E. (2017). The European forecast model already kicking America’s butt just improved | Ars Technica. [online]

Ecmwf.int. (2017). New forecast model cycle brings highest-ever resolution | ECMWF. [online]

 

Rainfall – why is it important

How do you understand whether it has rained on a field and how much? The weather forecast, even when it is local, gives us only a general idea. Public weather stations are usually situated in big cities or at airports. And rain is the most uneven weather element – every farmer has seen rain in the … Continue reading Rainfall – why is it important

How do you understand whether it has rained on a field and how much? The weather forecast, even when it is local, gives us only a general idea. Public weather stations are usually situated in big cities or at airports. And rain is the most uneven weather element – every farmer has seen rain in the farmyard and no sign of it in a field, just 1-2 miles away.

Some farmers place rain gauges or simple plastic vessels collecting rainwater in their fields. In order to measure the rainfall before the water has evaporated, and to be able to tell when exactly it rained, farmers need to check these vessels regularly, which wastes a lot of their time. Moreover, it is necessary to keep these manual records without any gaps or omissions, in order to be able to make informed agronomic decisions.

To save you time and make your everyday work easier, we created Meteobot® Mini – an electronic rain gauge, which gives you real-time information about the rain – precisely in your point of interest – your field, vineyard, orchard, etc. Meteobot® Mini is compact-sized, which makes it very suitable to install in the field – among the plants or attached to electric poles. It is no longer necessary to travel kilometers to a field to check if it is muddy and whether the machines can work there. This automatic rain gauge helps you decide much easier whether it is suitable for seeding, fertilizing or cultivation. Your heavy machinery does not need to travel, sometimes many kilometers, only for the operator to see, that he will not be able to work.

Apart from the information about the quantity of rainfall, Meteobot® gives you details about intensity (litres / hour). If the rain is intensive, it is more difficult for water to get absorbed by the soil and sometimes the rain has no agronomic significance. Moreover, some soils types form a sealing top layer which prevents in-depth moisture penetration. In addition to this, if rain’s intensity exceeds 0,2 l/min., the quantity is greater than 10 l/m2  and the field is inclined, there exists a risk of soil erosion.

Real-time rain information helps you assess plant wetness and decide whether to conduct important agronomic activities such as harvesting and spraying. On weather forecasts, we have all seen expected precipitation of 0.2 litres, for example, and have asked ourselves whether it will actually rain, or the meteorologists write it “just to be on the safe side”. 0.2 litres are not significant for the general accuracy of the forecast, however when it comes to plants they are – even a light rain is enough to trigger development of fungal diseases.

The data gathered by Meteobot® is stored and accumulated. This allows calculation of some historical indicators such as annual rain sum and monthly rain distribution.  This way, Meteobot® helps farmers not only with day-to-day planning, but also with agronomic analysis. After harvesting, it is important to find out the causes for this year’s yield and take measures to ensure or improve them next year. For every hybrid, for instance, there is an optimal rainfall quantity that is required to achieve its full potential. If this quantity has been available, but the yield is low, then we have to look for the cause elsewhere – in fertilizing, plant protection, etc.

Total rainfall is of course only the only precondition for high yield. In some development phases (for example grain forming in corn), plants need more water. If there is no precipitation during these periods, grains remain small and the yield is low. Here, to your help comes rainfall distribution by weeks – another historic indicator which is available to you thanks to Meteobot®.

All in all, we cannot influence rain, regardless of how much we would sometimes like to. However, by accurately and timely measuring it, we will be able to make the best possible agronomic decisions in а given situation.