Horticultural Sciences Department

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Issue No. 606

The Vegetarian Newsletter 

A Horticultural Sciences Department Extension Publication on 
Vegetable and Fruit Crops 

Eat your Veggies and Fruits!!!!!

Publish Date: 
October 2015

Extension Faculty Partner with the Mid-Florida Research & Education Center to Present the Mid-Florida Specialty Crops Conference

By Richard Tyson


Image result for mid-florida research and education center


The UF\IFAS Small Farms and Alternative Enterprises Extension Team http://smallfarms.ifas.ufl.edu/ , has partnered with UF & MREC faculty and staff http://mrec.ifas.ufl.edu/ , to present the Mid-Florida Specialty Crops Conference on November 6th at the Apopka research station.  Many other partners will also be there including local growers, marketers and industry suppliers.   How to successfully produce and market vegetable crops, blueberries and grapes will be the main focus of the conference.  For more information about the conference program including the four concurrent breakout sessions or to register online go to: http://midfloridaconference.eventbrite.com        

In 2000, three UF Central Florida Experiment Stations at Leesburg, Sanford and Apopka consolidated into one large horticultural research complex in Apopka.  Historically, the Leesburg station specialized in grapes, watermelons and muskmelons.  The Sanford station specialized in sweet corn, carrots and celery, while the Apopka station focused on ornamental crops and cut foliage.  With the loss of the nearby Zellwood Agricultural Area to a buyout by the state of Florida in 1998, losing 20,000 acres of vegetable crops and $50 million dollars in farm gate value annually, food crops became less important for the new MREC station.  That is beginning to change.

The agricultural industry in Florida is again evolving to adapt to pests, new regulatory rules, economic and market realities, and a shifting mood among consumers who are looking for safer, more sustainable locally grown food. 

  •   The grape program, led by Dr. Dennis Gray at both the Leesburg and Apopka stations, has developed a precision breeding technology that could revolutionize grape production in Florida which has been plagued with disease problems when non-native varieties are grown.
  •   Citrus tree growers adapting to new rules for tree propagation in greenhouses to avoid the greening disease, have turned to MREC, the experts in greenhouse ornamental production, to determine the most efficient way to grow citrus tree transplants under greenhouse conditions.
  •   The recent economic recession resulted in significantly reduced sales of ornamental plants out of the Apopka area.  Many foliage greenhouses became idle with some being put back into production to satisfy the demand for locally produced vegetable crops in the central Florida area.  In 2014, more than 65 million tourists visited the central Florida area creating a lot of demand for local food among wholesale and retail marketers.
  •   With the new market realities in mind, a new greenhouse has been built and a shade house planned at MREC to study best practices and methods for growing vegetable crops in protected agriculture structures in central Florida.
  •   The local food movement  is growing with the formation of grass roots organizations like Good Food Central Florida food policy council http://www.goodfoodcfl.org/ , Slow Food Orlando http://www.slowfoodorlando.org/ and the Simple Living Institute http://www.simplelivinginstitute.org/ .  

Please join us for this exciting event as we move forward into these new opportunities! See information about the conference or to register at: http://midfloridaconference.eventbrite.com



Low winter chill accumulation often presents challenges for Florida blueberry growers.

Jeff Williamson

One of the greatest challenges to growing blueberries in Florida is the mild winter weather which often results in sub-optimal chill accumulation. Chilling is needed for dormant blueberry plants to initiate strong growth in the spring which in turn is necessary for economically viable yields. Without sufficient winter chill accumulation, spring growth may be weak with bloom spread over an extended period of time. Although the University of Florida has developed low-chill blueberry cultivars that are adapted to Florida’s mild winter climate, year-to-year variation in chill accumulation presents challenges for Florida growers. 

The dormancy-breaking compound, hydrogen cyanamide (HC) (Dormex, BudPro, Krop-Max), is widely used on a variety of temperate perennial fruit crops including grape, apples and blackberries in production regions with mild winter weather  to mitigate the negative effects of inadequate chill accumulation.  Hydrogen cyanamide is commonly used in Florida blueberry production due to its ability to stimulate a strong vegetative growth flush as plants emerge from dormancy, and to advance berry ripening date significantly for some cultivars. Several factors should be considered when Florida blueberry growers consider if they should use HC. In Florida, HC is often used with the traditional dormant production system where plants are allowed to enter winter dormancy. However, HC is not approved for organic production, and it is not compatible with the “evergreen” or non-dormant production system which is sometimes used in the southernmost production regions of Florida. With this system, winter dormancy is avoided and leaves from the previous year are carried over into the spring. Southern highbush (SHB) cultivars vary in their sensitivity to spray burn and flower bud injury from HC. ‘Emerald’ is one of the most HC-tolerant SHB cultivars while ‘Primadonna’ is one the least tolerant. Most other commonly grown Florida cultivars fall between these two extremes. If in doubt, cultivars should be tested on a small scale for their HC tolerance before larger-scale use.

Product labels state that HC should be applied only to dormant plants at least 30 days prior to natural budbreak. This usually occurs from mid to late December through early January in most Florida production regions. Winter chill accumulation prior to treatment is desirable but the majority of flower buds should not have progressed past stage 2 (Spiers, 1978) in their development at the time of application. Research has shown that flower buds at developmental stage 3 or greater are significantly more susceptible to HC injury than stage 1 or 2 flower buds.  Research has also shown that chill accumulation prior to HC treatment usually results in a more favorable plant response with less flower bud injury. During particularly warm winters, especially in central and south-central Florida, chill accumulation can be very low. Even so, flower buds may swell during warm periods and rapidly approach a developmental stage (stage 3 or greater) that is no longer safe for HC application. These conditions greatly complicate decisions on whether or not HC will be used and/or on the rate and timing of applications. Given this scenario, growers often opt for lower spray rates if they choose to use HC. Reports of plant injury from HC sprays are more common under conditions of low pretreatment chill accumulation and questionable dormancy.  The current El Nino suggests that Florida’s winter may be cooler and wetter than average which will hopefully translate to higher than average, or at least average, winter chill accumulation. Higher than average winter chill accumulation would generally be welcomed by Florida blueberry growers regardless of whether or not HC is used. For more information on HC use in Florida blueberries see https://edis.ifas.ufl.edu/hs380 and https://edis.ifas.ufl.edu/hs220. Always read and follow the manufacturer’s label directions when applying HC.  


El Niño is back in the tropical Pacific Ocean: How will it impact agriculture in the Southeast?

Date Issued: October 1, 2015

Prepared by Clyde Fraisse

Agricultural and Biological Engineering

University of Florida - IFAS



A mature and strong El Niño is now present in the tropical Pacific Ocean. Most of the climate outlook models suggest that the 2015-16 El Niño is likely to strengthen further before the end of the year. Models and expert opinion suggest that surface water temperatures in the east-central tropical Pacific Ocean are likely to exceed 2° Celsius above average, potentially placing this El Niño event among the four strongest events since 1950 (1972-73, 1982-83, 1997-98).


The El Niño Southern Oscillation (ENSO) is the most important coupled ocean atmosphere phenomenon that causes global climate variability on interannual time scales. It manifests itself as changes in: (1) the sea-surface temperatures in the equatorial Pacific Ocean; (2) the sea level pressure difference between eastern Pacific high pressure and western Pacific low pressure (the “Southern Oscillation”). During El Niño events ocean surface temperatures warm in the central and eastern equatorial Pacific Ocean and easterlies are less strong. El Niño events normally bring cooler and wetter winter and springs to the Southeast USA. More information about ENSO impacts can be found at: http://agroclimate.org/fact-sheets-climate.php


During the winter El Niño causes the Pacific jet stream current to dip into the Southeast. This provides cold fronts with more moisture and energy. El Nino typically leads to 40 to 50% more rainfall than normal for the Florida peninsula. El Niño's impacts on the weather in the Southeast US are usually most prominent in the winter, but given the strength of this year's event, we could begin to see its effects this fall. Many climate models are predicting a wet fall with above-normal temperatures for the Southeast.






The seasonal precipitation forecast for October-November-December of 2015 produced by NOAA indicates increased probabilities for above average rainfall for the Southeast USA, reflecting the effects of El Niño in the region. The shaded areas on the map show the probability (how likely as a %) that precipitation is above normal (A), about average (N), or below normal (B). For each location and month, the driest 10 years from the 30 years of 1981-2010 define the “B” below normal category, the wettest 10 years define the “A” above normal category, and the remaining 10 years define the “N” normal category. Without any forecast, the chance of conditions being in each of the 3 categories is 33.3%. With a forecast, based on ENSO phase and other factors, shading is used to show areas where probability is greater than 33.3%. At any location on the map the probabilities for each of the 3 categories (above normal, near normal, or below normal) adds up to 100%.


Although seasonal forecasts are probabilistic and there is always a chance for weather patterns during the season not to behave as expected, it is well known that the presence of a strong El Niño or La Niña increases the “skill” of the forecast, meaning the ability of climatologists to produce a more accurate forecast.


Winter vegetables such as tomato and green peppers generally yield less during El Niño years than during Neutral or La Niña years. Most soil-borne pathogens and fruit quality problems increase in El Niño years. Fruit quality problems like gray wall and bacterial and fungal diseases that are typically associated with wet climates can be more prevalent during El Niño winters.

Nutrient management can also be affected by wetter cropping seasons as the frequency of leaching rainfall events increases, causing nutrients, mainly Nitrogen, to be washed out of the root zone, especially in fields irrigated by seepage irrigation. Recent studies demonstrated that during El Niño years, at least one leaching rainfall event of 1.0 inch or more in 1 day occurred in most locations where winter vegetables are grown in Florida and two of these events occurred in 9 out of 10 years.

In the case of temperate fruits (peach, nectarine, blueberry, strawberry), El Niño conditions generally result in increased chill accumulation in the early part of the winter (Nov-Jan) and can reduce the need for oil or other dormancy-compensating sprays in peaches and blueberries. Growers can keep track of chill accumulation by checking the AgroClimate chill hours calculator tool on AgroClimate (http://agroclimate.org/tools/Chill-Hours-Calculator/).


Cooler rainy conditions may slow development rates in some perennial fruit crops such as strawberry. Lower levels of solar radiation resulting from cloudy conditions may also affect growth in some cultivars. Additionally, conditions may favor the development of fungal diseases such as Anthracnose and Botrytis fruit rots. Angular leaf spot (Xanthomonas fragariae) is another disease that is favored by cool wet winters (EDIS publication: http://edis.ifas.ufl.edu/PG056). Strawberry growers in Florida can monitor the risk for Anthracnose and Botrytis fruit rot diseases using the Strawberry Advisory System (SAS) available on AgroClimate: http://agroclimate.org/tools/strawberry/. More information about SAS is available in the following EDIS Publication: https://edis.ifas.ufl.edu/ae450. Recently we also released SAS smartphone apps developed with the support of the Florida Strawberry Growers Association. SAS apps are available for Apple iOS operating system (https://itunes.apple.com/us/app/sas-strawberry-advisory-system/id898025106?mt=8) and Google Android operating system (https://play.google.com/store/apps/details?id=org.agroclimate.strawberry).

El Niño may also impact other commodities. In general, El Niño years are good for winter pasture such as rye due to wetter conditions. However, growth may be slower due to increased cloudiness and consequent decrease in solar radiation. In the case of forestry, El Niño plantings (wetter conditions) are generally well established. However, under such conditions, planting in very low lands might be avoided to minimize losses as excessive rains might drown seedlings. Wetter conditions may also have a negative impact on harvest operations.

Food Safety Modernization Act, Preventive Controls for Human Food Final Rule - FDA Expands Farm Definition and Exemptions


Travis K. Chapin1, Keith R. Schneider2, Renée Goodrich Schneider2, Mark Ritenour3, and Michelle D. Danyluk1


1 Citrus Research and Education Center, UF IFAS, Lake Alfred, FL; 2 Food Science and Human Nutrition Department, UF IFAS, Gainesville, FL; 3 Indian River Research and Education Center, UF IFAS, Fort Pierce, FL.


On September 17th, 2015 FDA published the Preventive Controls rules for Human Food in the Code of Federal Regulations (CFR).  There are two major features of the preventive controls rule: (1) requirements for hazard analysis and risk-based preventive controls and (2) revision to the existing Current Good Manufacturing Practice (cGMP) requirements.  All these new features will be placed in the 21 CFR part 117 titled “Current Good Manufacturing Practice and Hazard Analysis and Risk-based Preventive Controls for Human Food.”  For the Florida industry, this rule has the potential to impact fresh fruit packers, fresh-cut operations, and those making any “value-added” products; juice processors who already fall under the Juice HACCP final rule are exempt.


FDA hosted a conference call on September 15th, 2015 for over 1,000 stakeholders to discuss the range of facilities that will be covered by the FSMA Preventive Controls for Human Food final rule.  In the earlier proposal and comment periods, FDA received considerable stakeholder feedback, particularly regarding the regulation of farm operations with activities that overlapped proposed versions of both the Preventive Controls Rule and the Produce Safety Rule.  During the call, representatives from FDA stated their intent to streamline grower compliance by minimizing the number of different regulations that an individual operation needs to follow.  To address these concerns, FDA has expanded the farm definition to reflect the complex reality that many farming operations do undertake activities beyond simply growing and harvesting crops.


Farms are not covered by the final Preventive Controls Rule and thus the regulatory requirements for many producers will be streamlined by their inclusion within the expanded farm definition.  In the proposed rule, there was a distinction made between “on-farm” and “off-farm” packinghouses/facilities.  Thus there were many possible scenarios where growers would need to comply with multiple regulations (e.g., Produce Safety Rule for “on-farm” activities and Preventive Controls for Human Food Rule for “off-farm” activities).  The expanded “farm” definition now includes some of the “off-farm” but “farm-owned” packing facilities that would have previously fallen under the Preventive Controls Rule.


The final Preventive Controls for Human Food Rule expands the farm definition to include i) primary production farms, and ii) secondary activities farms.  Regardless of the distinction made between primary production farms and secondary activities farms, both are considered farms and neither will be covered under the final Preventive Controls Rule or required to register as a food facility.  A primary production farm is defined as an operation under one management in one general, but not necessarily contiguous, location that is devoted to the growing of crops, the harvesting of crops, the raising of animals, or any combination of these activities.  This definition was expanded by replacing ‘facility’ with ‘operation’ and ‘ownership’ with ‘management.’  In previous proposals, stakeholders expressed concern that the definition excluded cooperatives and operations divided by a road, for example.  The revised wording still lacks some clarity regarding what FDA will consider as one general location, which stakeholder participants were quick to point out.  FDA is working to resolve the many nuances in this definition and expects to issue further guidance in the near future but reiterated their desire to streamline regulatory requirements for all farming operations.  In addition to growing and harvesting crops, primary production farms can also pack or hold raw agricultural commodities (RACs) regardless of who grew them.  Primary production farms can also perform limited processing functions such as drying grapes to produce raisins or treating produce with ethylene gas.  Further processing such as slicing is not allowed on a farm and must occur in a registered food facility following the Preventive Controls for Human Food Rule.


A secondary activities farm is an operation not located on a primary production farm (i.e., where crops are grown) that is devoted to harvesting, packing, and/or holding RACs.  In previous iterations, these secondary activities farms would have fallen under the Preventive Controls Rule but this expanded farm definition allows for an exemption for these operations as long as the primary production farm(s) that grow, harvest the majority of those RACs own or jointly own a majority (i.e., 51% or more) interest in the secondary activities farm.  The discrepancy between ownership requirements of RACs on primary production farms vs. secondary activities farms is a nuance that stakeholders are seeking further guidance on, especially considering the vagueness of the “one general location” provision that distinguishes between what even constitutes a secondary activities farm.


The facilities that are covered under the final Preventive Controls Rule, generally, include facilities that manufacture, process, pack, or hold food.  These are the facilities that are required to register with FDA and this does not include farms or retail establishments.  There are some exemptions and modified requirements for certain facilities that are detailed in the final rule.  FDA will issue additional guidance documents.


Read the full final rule online at http://www.fda.gov/fsma


To contact FDA about FSMA and find the new online form for submitting questions directly to FDA, go to http://www.fda.gov/Food/GuidanceRegulation/FSMA/ucm459719.htm


Effective communication between supervisors and farm workers is critical to creating a safe, satisfying and productive work environment.    Management Communications is one of 10 courses being offered this fall (2015) at UF/IFAS locations in Lake Alfred, Sebring, Belle Glade and Immokalee. It is a class that grew out of a conversation with our Farm Labor Supervisor advisory committee. Several members of the advisory committee commented that learning all the farm labor rules and regulations is important, but also important is that supervisors communicate effectively to their crews.  At worst, poor communication could lead to increased workplace conflicts.


One of the goals of the Management Communications class is to appreciate the importance of non-verbal communications.  Body language, facial expressions and tone of voice have a significant influence on messages between supervisors and workers.  At times, people can mean one thing but their body language or tone of voice says something quite different.  


Another section of the class involves a quiz that allows supervisors identify their own personal management styles and explain how those styles can change with different circumstances.   To keep these styles simple, we identify them with commonly recognizable titles:  Dictator; By the Book; Asks for Input; and Trusting.   All those styles have their place, depending on circumstances.  For example, in a situation where decisions have to be made quickly, as in an emergency, the Dictator style will quickly decide what to do and where to go.  


In a different example, the Trusting manager might not be the most effective with new workers who don’t yet know everything they are supposed to do or how it has to be done, but is an excellent style if you run crews with a lot of experience who are used to the tasks and working together as a team.  Recognizing your own dominant management style is key to understanding how you work with others and achieve loyalty among your crews.


Other discussions in the class focus on listening skills; recognizing the difference between threats and consequences, and encouragement and praise; and exploring how people react to being treated with respect and disrespect.


Farm Labor Supervisors can take one or as many classes as he or she desires. If a person completes 8 classes and passes a test in each, then he or she will earn the Certificate of Farm Labor Management.  Three classes are specifically required to earn the Certificate:  Wage & Hour; Human Resource Compliance, and one class in worker safety.   All of the classes are taught concurrently in both English and Spanish.  The classes are $50 each.  


The following is a summary of the scheduled classes being offered during the fall of 2015 at four locations: Lake Alfred, Sebring, Belle Glade and Immokalee.  Additional dates and locations can be added if at least 10 people commit to attend.  Further, the Farm Labor Supervisor Training staff is willing to hold training classes at grower locations.







For more information, contact Fritz Roka, 239-658-3428, fmroka@ufl.edu; Carlene Thissen, 239-658-3449, carlene@ufl.edu; or Primo Garza, 239-658-3463, pgarza08@ufl.edu .   To register, go to http://www.imok.ufl.edu/programs/economics/fls.php

Authors:   C. Thissen, Roka, F.      

Fritz Roka and Carlene Thissen work for the University of Florida at the Southwest Research and Education Center, Immokalee, FL, 239-658-3400.  fmroka@ufl.edu and carlene@ufl.edu.