Help Requested for Nematode Survey

Hi Everyone,

Ever wonder why we only  have one commercial rootstock that we use for Florida peach production?  It’s because of a type of root-knot nematode found only here in Florida.  In fact, it’s scientific name is Meloidogyne floridensis. 

If you have it in your orchard, you might see short shoot growth, early bloom, and a general delay in fruit development (see below). IMG_0680The tree on the right was found to have nematode galls on the root system that was affecting the tree growth.  Successive years of weak growth can cause tree collapse, and will require removal and replanting.

Help Us Out!

So, what can be done?  First things first, we need some help!  Dr. Janete Brito at FDACS, DPI in Gainesville would like to conduct a survey of growers orchards.

Here is her request:

Scientists of FDACS, Division of Plant Industry, University of Florida, IFAS and other research agencies are joining forces through a cooperative Farm Bill agreement to study and identify plant-parasitic nematodes associated with peach trees in Florida peach orchards. So far, the potential risk posed by these nematodes to the new peach industry in Florida has not been fully assessed because of lack of information on their identity and distribution in the state. Scientists involved in this cooperative project are confident that an intensive nematode survey in Florida peach followed by accurate morphological and molecular analyses of plant-parasitic nematodes found will provide precise information on the species that parasitize peach in Florida. Additionally, an associated survey for detection of plum pox virus (PPV) will be carried out. The results of these surveys will provide information about the incidence of these pathogens in Florida peach.

The sites to be surveyed for nematodes will include existing peach orchards, nurseries and land destined to peach production, including abandoned citrus groves. The support and cooperation of the peach growers in the form of access to orchards, nurseries and other sites to be sampled are much needed for the success of this project. As permission and access to the sites to be surveyed is granted, a timetable and strategy will be developed trying to minimize potential interference with the activity of peach growers involved in the survey. Scientists are hoping that this initiative will receive a favorable reception by the Florida peach industry. Peach growers wishing more information about this cooperative project or willing to provide access to their orchards for the survey should contact Dr. Janete Brito, FDACS nematologist; phone: (352)395-4752; e-mail: janete.brito@freshfromflorida. com.

Thank you in advance for helping to figure out where these nematodes are, so that we can target control methods. If you have any questions, please let Dr. Brito know! Cheers, Mercy

Inking on Peach Fruit

Hello all,

I’ve had a few e-mails and phone calls about inking on peach fruit harvested in the past two weeks. Clemson University has a good publication with pointers to avoid inking – although I have to say, we do not know what causes inking on fruit surfaces.

One cause may the rainfall that we have had – which may have washed chemicals onto the fruit that have high amounts of metals (including micronutrients!).  Also, precipitation/overirrigating near harvest can increase the water pressure (turgor) in cells, but this also makes them more vulnerable to abrasion damage during harvest/transportation and then anthocyanin accumulates causing what we know as “inking” in spots.

Here is a link to the article from Clemson: http://www.clemson.edu/extension/horticulture/fruit_vegetable/peach/diseases/inking.html

Research from California indicate that not only do some chemicals with high metal contents have higher incidences of inking, but so does abrasions on the skin surface.  These might be from harvesting, wind damage, or abrasions in harvesting.

A couple of culprits that might have been issues this year may be Imidan and Elite (tebuconazole), although with Elite, I am watching my own research orchard, as this was my last spray on Saturday. However, we are very far behind everyone else in the throes of harvest and are about 2-3 weeks away from harvest, so we may not see much inking on the skin surface.

Steps to Avoid Inking:

  • Near harvest, choose chemical applications carefully.
    • These chemicals have high metal contents –
      • Foliar nutrients: Micro Plex (Fe)
        Insecticides: Imidan (Al), Delegate (Al)
        Miticides: Vendex (Fe and Al), Acramite (Fe and Al), Omite (Al)
        Fungicides: Elite (AL)
        Additives: none
  • Don’t apply foliar micronutrients within approximately 21 days of harvest to avoid having metals on the fruit surface (e.g., copper, iron, aluminum) that have been implicated in inking.
  • Check the pH of your irrigation/spray water. Water with acidic characteristics (<6.5) can exacerbate inking due to increased iron availability.
  • Don’t overwater near harvest, as this can damage cells in the skin and cause anthocyanin accumulation, leading to inking symptoms.
  • With orchards that have a history of inking, leave harvested fruit in cooler for 48h prior to packing to observe inking symptoms; remove before packing.

As always, call or email me with questions!

Cheers,

Mercy

 

 

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

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!

Cheers,
Mercy

Florida Peach Marketing Order Hearings

Hi Everyone,

As you all know, I have been trying to get a Florida Peach Growers Association up and running. Phil Rucks has taken the reins to investigate the possibility of getting a Statewide Marketing Order for peaches that will help to provide resources for marketing and research.

There must be two public hearings before a vote can go to the growers in the state; and the first one will be on May 12th, 2015 at the next Peach Roundtable to be held in Dade City at 10:00 AM at the Pasco County Extension Office, 36702 State Road 52, Dade City, FL 33525.

The second public hearing will be on Wednesday May 20th, 2015 at 2:00 PM at the Polk County Extension office in the Stuart Center, 1702 Highway 17 S, Bartow, FL 33831.

I hope that you will be able to attend – and Phil would like the name of anyone that is willing to serve on the advisory committee for the marketing order. See Phil’s email for more information. I am also attaching the paperwork that is needed to re-establish the Florida Peach Growers’ Association.

In addition, two contacts at FDACS for marketing orders are:

Marshall Wiseheart – 850-410-2290

Milton Rains – 352-406-0707.

Hope to see you there!