2015 Wet Spring Leading to Potential Brown Rot Issues

Brown Rot in Gulfking
Brown Rot in Gulfking

I hope that everyone is having a good harvest so far, although I will have to say it’s been challenging with all of the rain we have had here in Central Florida.

One issue that we don’t often have to deal with is Brown Rot.  However, with the afternoon rainshowers that we have had (in some cases over 3 inches over the past couple of weeks), it is showing up in some of the harvested fruit, particularly in the bottom part of the fruit.

We are working on an EDIS publication for future reference; however here are some quick points.

Brown Rot

Brown rot is caused by a fungus, Monilinia fruticola and is often an issue in areas with frequent rainfall during fruit development.

Primary infections occur in the spring and can lead to flower death and reduced yield, but secondary infections affect the fruit.  In addition, abortion of mature fruit, e.g., “mummies” that fall to the orchard floor can serve as inoculum for future infections with later ripening periods.

G. England
Brown Rot in Mature Fruit, G. England

Disease Cycle

The continuous production of spores by mummies, cankers, and apothecia fuel the disease cycle and the infection of blossoms and fruit. Brown rot flourishes under conditions of high humidity (>94%) and optimal temperatures occur around 77°F (25°C). Rain, wind and insect activity lead to the release of spores that initiate the infection.

Secondary infection occurs as blossoms and shoots that have been initially infected begin producing spores, and can continue to do so until early June. If secondary spore production can be prevented by the use of effective management techniques, the disease can be more easily contained. The presence of infected fruit and mummies can also act as a source to spread brown rot.


Management for brown rot should begin before anticipated rain events occur, and guidelines for recommended fungicides are listed in the SE Peach Spray Guide: http://www.ent.uga.edu/peach/PeachGuide.pdf.

Please remember to rotate your fungicide chemical classes (as indicated by the FRAC codes) to avoid resistance risk.  There have been races of brown rot that have been identified as resistant to certain classes of fungicides – although there is a fungicide resistance kit that can be ordered to verify that the fungicide is at fault.

Key Points

As always – if you have any questions or concerned, please let me know!



Freeze Watches/Warnings

Freezing cold weather is set to wash over the state of Florida tonight into tomorrow night, so please be prepared!

A few comments about freeze protection in orchards:

  1. Be sure that your orchard is well-watered – we will be getting sun each day, and wet soil has a greater capacity to absorb heat, and also release it during the night, offering a few degrees of protection.
  2. Watch the weather – and keep your coffee pot going.  For those in Central Florida and to the south, it looks like the temperature will drop to a critical period around 2 a.m. on Friday morning.  However, if the wind is too high, you may induce evaporative cooling rather than protect the fruit, which can do more severe damage.
  3. Know what your irrigation system capabilities are to be able to meet the appropriate water output.
    1. See: http://edis.ifas.ufl.edu/ch182 – this is for citrus, but the principles that they go over, like reading a sling psychrometer are useful to understand.
  4. Hold off on any orchard related activities, like thinning fruit – the cold weather may do a good job of that for you!

Weather Related Resources:

  • The National Weather Service – http://www.noaa.gov/ – just put in your city or zip.  I find that the best resource is a graph like this which gives you the temperature and wind speed which is important:










For those of you that might be stressed – have heart!  It won’t be as cold as it will be in Citra, FL at our research plots for peaches and blueberries!

As always, if you have any questions, please contact me – mercy1@ufl.edu.

Cold Weather Knocking on the Door…

I hope that everyone had a FANTASTIC Christmas vacation (ala Clark Kent style) and is having a great start to their new year.  As we start off this new year, cold weather comes knocking on our door in north central Florida, a normal occurrence.

Freeze warnings/wind chill advisories (1/7/15)

There maybe some of you in north central Florida that are closely watching the weather tonight.  For the following counties, there is a hard freeze warning:

  • Alachua
  • Gilchrist
  • Bradford
  • Union
  • Baker
  • Columbia
  • Suwannee
  • Hamilton

The good news is that hopefully, the peach trees are still resting are not in full bloom.  For a guide to bud stages and their tolerance to cold temperatures – click here.

For counties to the south and east, it’s a freeze warning:

  • Clay
  • Putnum
  • Marion

Again – I don’t think it’s anything to be concerned about unless the wind speed drops down.  However, NOAA is forecasting a blustery night with wind speeds sustained at over 15 mph.  In most cases, frost protection would not be turned on with these advective conditions.   Most all others in the peach growing region of Central Florida will have mid to upper 30s so stay warm!


Freeze Warning and Watches

Well, here we go with the rollercoaster of temperatures in central and south central Florida. So what is going on with the peach trees right now?

Don’t worry!  The peach trees are headed into dormancy, and although the buds have the possibility of suffering a minor amount of damage (<10%), we don’t anticipate any major issues with flower bud damage.  There is NO need to turn on irrigation for frost protection tonight and it is expected to warm slightly tomorrow night, so no frost protection for the next night as well.

The UF Stone Fruit Research/Extension team has a new project in cooperation with Georgia (UGA) for both blueberries and peaches and we will be tracking bud damage as a result of the expected freeze event tonight at our research plots in Citra, FL.  We be looking at flower buds in TropicBeauty peach and Emerald and Jewel blueberry varieties.  When we have the information, we will be posting it here on the blog, as well as on our website, http://hos.ufl.edu/extension/stonefruit.

Freeze Watch/Warning Information:

For a list of current freeze warnings and watches:  http://alerts.weather.gov/cap/fl.php?x=1.


Another Round of Cold Weather!

In January and early February, we all deal with the waves of cold fronts that dip down from the Canadian Arctic.  However, as many growers are in full swing with bloom or have just started, these cold waves keep us all up at night.

At Citra in one of our plots that has some bloom occurring, we have turned on the water on the following dates:

  • Tuesday, January 7th
  • Friday, January 17th
  • Saturday, January 18th
  • Sunday, January 19th
  • Wednesday, January 22nd

We will continue to monitor tonight (Friday, January 24th) for cold weather, since it looks like the wind will be dying down.  The graph below details the actual temperatures for the Gainesville Regional Airport (KGNV) which is a few degrees colder than what we observe in our research plots at Citra.

This graph shows the minimum temperatures for January for Citra – and you can find out this type of information for a FAWN station near you with this link: http://agroclimate.org/tools/climate-risk/.

2014 Citra Minimums


What are some tools that you can use to help decide when to turn the water on?  One thing I can offer – the wind will almost always kick the temperature up a degree, so be on the lookout and carry a good thermometer with you as you are driving around the orchard.  Your car thermometer may not be the most accurate, so don’t count on that.

Good luck tonight, and stay warm!

New Apps for your “Smart”phone

My Florida Farm Weather

FL farmweatherRecently, there were two new apps released that will be helpful to Florida growers of both fruit and vegetables.  Growers can get real-time local weather data from the “My Florida Farm Weather” Program.  The website address is: http://fawn.ifas.ufl.edu/mffw/ – and there is an app for the Android platform at this point, with an iPhone app coming soon (the release of iOS 7 most likely delayed its release).

Key information on rainfall, temperature, humidity, dew point, wind speed and wind direction can be found from both FAWN and grower sites.  Historical data will be added to the site – which will be a useful tool for site selection and variety selection.

Web Soil Survey 3.0

The California Soil Resource Lab has released an iPhone and Android app to navigate the USDA-NRCS web soil survey maps.  This is a handy tool for those evaluating sites and determining irrigation systems and rates for a new planting.  There are also links on the website for linking to Google Earth images and Google Maps images showing soil information.  A neat tool for on-the-go soil information!

For the iPhone App: https://itunes.apple.com/us/app/soilweb-for-the-iphone/id354911787?mt=8
For the Android App: https://play.google.com/store/apps/details?id=casoilresource.apps.soilweb&feature=search_result

Here is an image of our soil types on campus:

soilweb image