[rimprona] RIMPRO ascospore biofix

[Greg Parzych]

Curious as to what users are entering for the "Biofix Venturia simulation: first dischargeable ascospores" under local parameters.  Marc Trapman reccomended a date of 4/1 but that seems late if we're already looking at 6-8% maturity.  

 

From: RIMproNA [mailto:rimprona-bounces at virtualorchard.com] On Behalf Of David A. Rosenberger
Sent: Monday, March 28, 2016 8:04 PM
To: RIMpro Users North America
Subject: SPAM: [rimprona] Model comparisons

 

Depending on which weather source you believe, we may have our first significant scab infection period in the Hudson Valley with the rains that are forecast for Thursday, March 31. Marc Trapman has given me the opportunity to compare RIMpro this year using two different data input systems, both of which are providing outputs for the orchard at the Hudson Valley Lab. 

 

One data input system uses our NEWA weather station at the Hudson Valley Lab (Highland) for data on what has already happened. This system uses the Norwegian “yr.no” weather forecast system for weather predictions.  I call this model system "Highland-N"

 

The other input system uses only the MeteoBlue data for both past weather and predicted weather; I call this Highland-MB.  Thus this is a virtual station that never accesses any real data from our orchard.

 

In addition, I subscribe to Accuweather for weather forecasts and occasionally check the US Weather Service, which I can access through the NEWA Network. Thus, I can access four different forecasting systems when I want to know what to expect over the next few days.

 

Tonight the output for Highland-MB is suggesting a major scab infection period with a RIM value over 600 will occur April 1-2-3 whereas the Highland-N output suggests that the wetting periods April 1-2-3 will be too short to allow any significant infection, generating a RIM value of only about 40.   Accuweather agrees with the yr.no forecast whereas the US Weather Service forecast agrees with MeteoBlue.

 

Here is the interesting part: The spray window, based on wind conditions as predicted by US Weather Service will be Wednesday,  starting about 2 AM and continuing until about 10 pm.  Accuweather is providing the same wind forecast.

 

So, do we need to spray on Wednesday (as suggested by the MeteoBlue forecast and US weather service), or can we expect to ride through the rains this week-end without getting a scab infection period?  The predicted infection periods are still too far away to get an accurate read (i.e., weather forecasts have a lot of error when they are for more than 48 hr in advance), but we should have a better idea by tomorrow night.  Often the various weather models begin to converge as we get closer to the predicted event.  

 

I pass along this info primarily to help everyone understand how I find value in RIMpro, but also to illustrate that the RIMpro output is no better than the weather forecast that it is using.  If you are using RIMpro, it can give a valuable heads-up about the potential for major infection periods as they approach, but because weather forecasts are often inaccurate, expecially beyond 48 hours, it will predict false-positives at times (as may be the case right now with MeteoBLue and US Weather), or it may give false negatives as may be the case right now with yr.no and Accuweather.  For critical spray decisions such many will be facing later this week, it would always be wise to look at the weather data going into RIMpro  and then compare that with at least one other source of weather forecasts.  If you can wait to start spraying until 48 to 24 hours before the predicted infection event, you will have more accurate predictions because RIMpro will be using more accurate weather forecasts.  However, I know that waiting until 24 to 48 hours before an event to make decisions often is not possible, either because of wind conditions or because of the time required to cover all acreage.

 

Right now, if I had my orchard at risk (i.e., without recent fungicide coverage and warm weather predicted for the next few days), I’d be planning to spray on Wednesday given the risk levels as I see them and the forecast for warm temperatures that will push bud growth.

 

NOTE: This list-serve is not meant to take large messages as occurred when I tried to post screen-shots of my RIMpro outputs.  Therefore I will post this message along with the screen shots of the RIMpro outputon my blog (http://blogs.cornell.edu/plantpathhvl/blog-2014/ ) sometime later tonight or tomorrow morning.

 

********************************************
Dave Rosenberger, Plant Pathologist,
Hudson Valley Lab, P.O. Box 727, Highland, NY 12528
    Cell:     845-594-3060
********************************************

 

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