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Issue No. 594

The Vegetarian Newsletter 

A Horticultural Sciences Department Extension Publication on 
Vegetable and Fruit Crops 

Eat your Veggies and Fruits!!!!!

Publish Date: 
September 2014

Is Silicon Fertilization Beneficial to Lettuce Grown on Organic Soils?

Huangjun Lu, Alan L. Wright, and Yigang Luo

Everglades Research and Education Center, Belle Glade, Florida 

Silicon (Si) is the second most common element on earth. Most of the silicon on earth is found in the form of silicon oxides like sand and quartz. Regardless of its abundance, Si has not historically been considered as an essential element for plant growth. However, the beneficial effects of Si on a number of traits were documented in several plant species.

Lettuce, an economically important vegetable crop in Florida, is mainly grown in the Everglades Agricultural Area (EAA) on Histosols (organic soils) (Figure 1) with 85% organic-matter, compared to the 1 to 5% typical range for mineral soils. Because Histosols contain little mineral matter and very little sand, Si is often deficient in these soils. Florida lettuce growers are eager to know if Si has the same beneficial effect on lettuce as it has on many other crops, such as sugarcane and rice that are grown within the EAA. We conducted a research project to evaluate effects of Si fertilizer on the growth of seven lettuce cultivars (‘Gator’, ‘8074’, ‘Raleigh’, ‘Manatee’, ‘70096’, ‘Okeechobee’, ‘Terrapin’). The experiments were conducted at the Everglades Research and Education Center (EREC) and the King Ranch location in Belle Glade, Florida, in the spring of 2012. The original soil plant-available Si contents were 75.4 mg/kg at EREC and 84.2 mg/kg at King Ranch. At each site, silicate slag was broadcast to the plots at a rate of 4,300 lb/ac before planting lettuce seed and the control plots received no silicon amendment. All other fertilizers such as N, P, K, etc., were applied at recommended rates based on soil testing results. The experiments were replicated three times at each location. At maturity, yield data were taken and then leaf tissue samples were collected from each plot for nutrient analysis.

The Si-treated lettuce plants had higher average Si content in leaf tissues than the unamended controls (Table 1). The differences between the Si-treated lettuce plants and the controls were statistically significant at the King Ranch location (P = 0.0203) and were marginally significant at the EREC location (P = 0.0525), indicating that application of Si slag increased the uptake of silicon by lettuce plants. The concentrations of other elements (total N, total P, Ca, Cu, Fe, K, Mg, Mn, Zn) in plant tissues varied between the Si-treated lettuce and the unamended control for different elements but there was a lack of clear trend of the beneficial effects of silicon fertilization on the update of other nutrient elements by lettuce.

Average yield was higher at King Ranch than at EREC. The average yield of Si-treated lettuce was similar to that of the unamended control at both locations, indicating that the Si fertilization of organic soils had no effect on the growth and yield of the lettuce cultivars.

Combining data from EREC and King Ranch, we found little effect of Si fertilization on the organic soils on lettuce. Therefore, application of Si to organic soils may not be profitable for lettuce production as it is for other select crops grown on the organic soils of the EAA.

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Figure 1. Lettuce production on organic soils in Everglades Agricultural Area in Florida.

Table 1. Effect of silicon on mean contents of leaf tissue elements and yield in seven lettuce cultivars.


Fusarium wilt of Watermelon: Things to watch for with this disease.

Dr. Nicholas Dufault
Plant Pathology Department
University of Florida, Gainesville, Florida

Recently, there has been some observational data that suggests North Florida watermelon growers have been experiencing an increased incidence of Fusarium wilt in their production fields. While it is uncertain what may have caused this increase, it is apparent that management of this disease has become important topic for producers throughout region.

Fusarium wilt can be a difficult disease to diagnosis in the field, and often laboratory confirmation of the pathogen in the vascular tissue is needed for identification. A common field symptom of this disease is wilting starting on one side of the plant (Fig. 1) which quickly expands throughout the plant. Whole plants can turn brown and die within a matter of a few days (2-3 days) (Fig. 2). Further confirmation of the disease can be made by cutting the vines, stems or tap roots lengthwise to reveal streaks in the vascular tissue that are brown, orange and/or reddish in color (Fig. 3). In Florida, Fusarium wilt is more likely to occur earlier in the season when temperatures are cooler (< 86°F) which is typically prior to fruit set. However, symptoms can occur after fruit set, especially in cooler growing seasons.

Fusarium wilt is a widespread disease of watermelon in Florida. One of the best management strategies for this disease is the use resistant varieties coupled with crop rotations of 4 to 5 years. Unfortunately, resistance to Fusarium wilt is not complete. Fusarium wilt is caused by the pathogen Fusarium oxysporum f. sp. niveum which has 4 races (Race 0, 1, 2, and 3) that vary in their virulence and aggressiveness on watermelon varieties. Many commercial varieties will have some resistance to races 0 and 1, and various newer varieties can have resistance to race 2. Race 3, however, has only been identified in Maryland, but its potential impact on Florida watermelon production is of great concern. The diversity of this pathogen, along with long term survival periods, has limited the effectiveness of using crop rotation and resistant varieties as a management strategy, and lead to the need of more techniques for the proper management of this pest.

Alternative methods to crop rotation and resistant varieties are being explored for the disease management of this important pathogen. Researchers are the University of Florida are currently examining the use of multiple fungicidal products and grafting as a means for integrated disease control. A recent on-farm trial in Alachua County indicated that some fungicidal compounds are useful in reducing the incidence of the disease when compared to untreated plots (Table 1). The impact of this reduction on yield, however, was not assessed and future work is needed to understand these impacts better.

Table 1. The mean number of plants with Fusarium wilt symptoms from the on-farm watermelon research trial in Alachua County. Each product was applied through the drip tape to 3 separate rows that were 375 ft long. Samples of symptomatic plants were collected from the field and confirmed for the presence of Fusarium wilt in the laboratory.

Treatmenta

Mean Incidenceb

Percent Reductionc

Untreated

33.7

0

Taegro®ECO

19.0

43.6

Proline®

28.7

14.9

Quadris®

26.0

22.8

a All treatments were applied through the drip tape at rates of  5.2 oz, 5.7 fl oz, and 15.4 fl oz per acre for Taegro®ECO, Proline®, and Quadris® respectively.  Treatments were applied once 7 days after transplanting.

b The mean number of plants exhibiting Fusarium wilt symptoms in 3 rows of 375 ft in length

c The percent reduction in incidence compared to the untreated controls. 

Unfortunately, there are no silver bullets for Fusarium wilt. Optimal management of this disease will most likely be achieved by an integrated strategy utilizing many of the tools available. Future studies are being planned to examine more thoroughly the effects of fungicidal products and watermelon grafting on the management of this disease as well as seed treatments, SAR inducers and cover crops. The goal is to improve the management of Fusarium wilt in Florida and throughout all the watermelon producing regions of the U.S.

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Fig. 1: Early wilting symptoms starting on one side of the plant for the disease Fusaruim wilt of watermelon.

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Fig. 2: Final symptoms of Fusarium wilt which include complete wilting of the plants leading to brown and dead plant tissue. 

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Fig. 3: Discoloration of the vascular tissue in a watermelon vine from a severe Fusarium wilt infection.


FARM LABOR SUPERVISOR TRAINING PROGRAM

Article 5 – Transporting Farm workers:  Maintaining safe vehicles.

The condition of farm labor transportation vehicles and of their drivers is critical to ensuring the safe transport of farm workers.  In this article we discuss vehicle inspections.  Next month we will cover responsibilities and requirements of the drivers.  The regulations discussed below apply to both vans and labor buses. 

Daily and periodic inspections are important for several reasons: 

a)    Poorly maintained buses and vans are a hazard to the driver, passengers and the general public.

b)    Regular inspections can catch small problems before they become big problems. 

c)    A bus broken down on the side of the road is bad for business.  Workers stuck on the bus can’t do the work they were hired to do.  

d)    A roadside spot inspection can result in an “Out of Service” designation, which adds further complications beyond fixing the mechanically cited issues.  “Out of Service” means that you may not drive the vehicle until the problem(s) is (are) fixed, documented, and reported back to the agency within 15 days of issuance. 

Agencies that monitor farm labor transport vehicles include the Florida Highway Patrol (FHP) that now enforces what was previously covered by the Florida Department of Transportation (FDOT), specifically the regulations issued by the Federal Motor Carrier Safety Administration (FMCSA).  Two other agencies focused on farm labor transportation are the Federal Department of Labor (DOL), and the Florida Division of Business and Professional Regulations (DBPR).

FLORIDA HIGHWAY PATROL (FHP)

DAILY INSPECTIONS – FMCSA  requires that farm labor vehicles be inspected daily. 

INVESTIGATORS:  In the past, FDOT and FHP were two separate agencies. There were approximately 200 FDOT officers in the state.   Three years ago (2011), FHP absorbed FDOT and thereby increased the number of potential officers who can perform vehicle inspectors to more than 2,000.  All the more reason to be aware!

WHAT:   Items required to be inspected by the FHP are shown below.  No specific form is required but the form must include the following information:  

·         Name of the company

·         Bus number;

·         Odometer readings at start and end of day;

·         Calculation of total mileage;

·         Date, time and location of the driver’s inspection.  

·         Driver’s signature and the signature of the mechanic if repairs have been performed.   

At a minimum, the following items must be inspected every day:  brakes, including parking brake; steering mechanism; lights and reflectors; tires; horn; windshield wipers; rear vision mirrors; wheels and rims; and emergency equipment including road warning devices (at least one red burning fuse and flares, electric lanterns, or red emergency reflectors) and the service date and capacity of the fire extinguisher.

WHEN:  The items listed above must be inspected at the end of every day.  Items needing attention have to be noted and should be fixed before leaving for work the next day.  In the event of an investigation, FHP officers will compare daily inspection forms with repair records, so be sure that each item to be repaired is shown on the inspection form and that repair records are accurately maintained as well.   An inspection should also be done each morning, but does not have to be documented. 

WHO:   Inspections are done by the driver. A helper can assist by standing behind the bus or van to check on  turn signals and brake lights while the driver is inside the vehicle.   

FORMAT AND LANGUAGE:  Preprinted Inspection forms may be purchased from several sources with duplicate or triplicate copies.  You may also create your own form, as long as all the required information listed above is included, and you may translate the form into other languages.

HOW LONG TO KEEP THEM:   FHP regulations require that daily inspection forms be retained and available for review for 90 days.   

PERIODIC INSPECTIONS:  The FMCSA requires all farm labor  vehicles to have an annual inspection by a qualified mechanic.  These records must be retained for 14 months and available for inspection on both the bus and in the office.  In addition, the qualifications of the mechanic doing the inspecting have to be maintained.    

REPAIR AND MAINTENANCE RECORDS:   Identification of the vehicle and the type of repair or maintenance performed must be included on the form, as well as the name and signature of the person performing the work.   These records must be kept where the vehicle is housed for the entire time the vehicle is owned.  If the vehicle is sold or otherwise transferred, the vehicle’s maintenance records must by retained for another 18 months.  Note, as mentioned above, investigators WILL cross-check inspection forms with repair and maintenance records.  

FEDERAL DEPARTMENT OF LABOR (DOL) and FLORIDA DEPARTMENT OF BUSINESS AND PROFESSIONAL REGULATIONS (DBPR) 

The federal DOL and state DBPR officials enforce transportation safety and insurance requirements outlined in The Migrant & Seasonal Agricultural Worker Protection Act (MSPA).  MSPA uses FHP (formerly FDOT) standards and therefore many of the FHP rules and regulations are covered by DOL and DBPR investigators.  These include proper insurance for the vehicle, an annual vehicle inspection record, and continuing compliance with the safety requirements.    The DBPR inspection form says “Transportation vehicle meets all other DOT/MSPA safety requirements.”  

These two agencies will also check the vehicle for other MSPA safety requirements including an annual safety inspection; safe seating; floors smooth and free of holes; proper ventilation; protection from the weather; and unblocked exits.    

In addition, if the vehicle is under the control of an FLC, it must be authorized on   an FLC registration (“TA” or Transportation Authorized.)  DBPR regulations also require the presence of current a Farm Labor Vehicle Sticker issued by the agency, on the back of the transport vehicle.

Authors:   Thissen, C.; T. McQuilken; M. Bayer; and F. Roka.  

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

Tracey McQuilken is a retired Sergeant Investigator with FDOT/FHP.  She is now a DOT Consultant and owner of Ion Drug & Alcohol Testing, Brandon, FL, 813-244-7087, tracey@iondat.com    

Mike Bayer is a former DOL-WHD Investigator, now with Curran, Bayer & Associates, West Palm Beach, 561-371-0126 mtbayer@curranbayer.com  

ABOUT THE FARM LABOR SUPERVISOR TRAINING PROGRAM

The Farm Labor Supervisor (FLS) Training Program is a University of Florida/IFAS Extension program. Begun in 2010, the program is coordinated by Fritz Roka and Carlene Thissen at the Southwest Florida Research & Education Center. Each year from late September through early November a core group of topics are taught at several locations across Florida and in partnership with county extension faculty.  These topics cover laws that keep farm workers safe, fairly paid, and in a working environment free from discrimination and harassment.  The program is offered in both English and Spanish. If there is sufficient interest, individual classes of combinations of classes can be arranged at times and locations convenient for the participants. We also provide training at grower locations that incorporates grower-specific policies and procedures.  For more information, contact Carlene Thissen, 239-658-3449, carlene@ufl.edu.


FARM LABOR SUPERVISOR TRAINING PROGRAM

Article 6 – Transporting Farm workers:  Drivers.

In our last article we talked about the condition of vehicles that transport farm workers, including the importance of inspections.   This month we focus on three regulations that directly apply to drivers of farm labor vehicles:  1) their medical examination;  2) drug and alcohol testing;  and 3) tracking hours of service.  Next month we will discuss driver-related regulations that are primarily the responsibility of the employer, including driver qualification files and the administration of drug and alcohol testing programs.  

AGENCIES:   Agencies that monitor farm labor transport drivers are the same as those that monitor their vehicles, and include the Florida Highway Patrol (FHP) that now enforces what was previously covered by the Florida Department of Transportation (FDOT), specifically the regulations issued by the Federal Motor Carrier Safety Administration (FMCSA).  Prior to 2011, FDOT and FHP were two separate agencies. After FHP absorbed FDOT, the number of potential officers who can stop a driver increased from 200 to more than 2,000.

Two other agencies, the Federal Department of Labor (DOL), and the Florida Division of Business and Professional Regulations (DBPR), require that if a driver is a licensed farm labor contractor, he or she must have Driver Authorized (DA) on the contractor’s license. In addition, the federal DOL and state DBPR officials enforce transportation safety and insurance requirements outlined in The Migrant & Seasonal Agricultural Worker Protection Act (MSPA), plus some of the DOT (FMCSA) regulations have been adopted by both MSPA and in the State of Florida Statutes.

In general, FHP/DOT, DOL and DBPR require that drivers of farm labor vehicles:

  • Carry a Medical Examination Card    
  • Be 21 years old with at least one year of driving experience 
  • Read and speak English well enough to understand traffic signals and converse with officers who may stop them.

If a vehicle’s specifications require that the driver hold a commercial motor vehicle driver’s license (CDL), then FHP/DOT will enforce additional regulations with respect to medical cards, drug and alcohol testing, and hours of service. Operators of crew buses transporting more than 17 passengers typically are required to hold CDLs.

DOT MEDICAL CARD:  The DOT Medical Examination is more rigorous than the Department of Labor’s examination.  In addition, a recent regulation dictates that you must now use a doctor from the National Medical Registry, https://nationalregistry.fmcsa.dot.gov. for this examination.  The stricter requirements are the reason the DOL will accept the DOT’s Medical Examination card, but the DOT will not accept the DOL’s.

The DOT Medical examination form is three pages long and includes driver information, health history, vision and hearing tests, blood pressure/pulse rate and a urinalysis.  The form and detailed instructions can be downloaded by searching for DOT form 649-F or by clicking on this link:   http://www.fmcsa.dot.gov/sites/fmcsa.dot.gov/files/docs/Medical_Examination_Report_for_Commercial_Driver_Fitness_Determination_649-F%286045%29.pdf

To maintain their DOT Medical Card, drivers must be re-examined every 2 years unless the doctor determines the driver requires more frequent monitoring for conditions such as high blood pressure that could worsen over time. 

If the form is checked “qualified only when wearing glasses,” the driver must wear the appropriate glasses whenever operating the vehicle. 

If the form is checked “qualified only when wearing hearing aid,” the driver must wear the hearing aid AND carry spare batteries when operating the vehicle.

Note:  Drivers hauling agriculture or horticultural products are exempt from the DOT Medical Card requirement.

DRUG AND ALCOHOL TESTING:  Any driver with a CDL is required to have Controlled Substances and Alcohol testing.  Please do not confuse this requirement from a company’s designation as a “Drug Free Workplace.”  It is more specific and requires that drivers be tested before they are hired, after an accident, upon “reasonable suspicion,” and randomly throughout the year.  Details for administration of a Controlled Substances and Alcohol Testing program will be covered next month.

HOURS OF SERVICE: CDL drivers are restricted to certain limits on their hours of service. The hours of service regulation is designed to prevent overly tired drivers from operating a motor vehicle, especially when transporting other passengers. Law enforcement considers operating a motor vehicle under sleep deprivation to be a violation and subject to the same penalties as driving under the influence of alcohol.

Hours of service, for either a day or week, is the total time a CDL driver is “on duty.” “On duty” time includes actual driving time as well as any other duties the driver might perform from when he/she begins to work until he or she is completely relieved from work. Many times a crew bus driver serves as a field supervisor and/or drives farm vehicles during the day.   But even if they do nothing but rest in the bus during the day, they are still considered to be “on duty.” 

If drivers never drive beyond 100 “air miles” (about 115 road miles) from their home base (where the bus is parked), they are allowed to be on duty for up to12 hours a day and may drive for up to 10 of those hours.

In this case, time records are sufficient to keep track of the amount of time they worked.  This could be in the form of a sign-in / sign-out sheet, OR electronic payroll records may be used. 

If drivers drive beyond 100 “air miles” (about 115 road miles) even occasionally, they are allowed to be on duty for 15 hours and may drive for 10 of those hours.   After that, they have to be “off duty” for at least 8 hours.  These drivers need more than just time records, however – they are required to keep a logbook.  Logbooks look intimidating, but they are not difficult to use. 

After filling out the information at the top of the form, the driver simply draws a line through the “off duty” section, in this example, from midnight to 6:00 a.m.  When they start work, let’s say to inspect the bus, they draw a line through the “on duty” section and connect it to the first line with a vertical line.  When they start to drive, they draw a line through the “driving” section of the book, etc. all day.   In addition, they should write in their location at each entry.  In the agricultural environment, sleeper berths are not applicable, so that line is not used by agricultural drivers.    

 A completed logbook should look something like this, for each day:

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Logbooks can be purchased from several vendor sources and at truck stops, or you may create your own, as long as all the required information is there. 

IN ADDITION….there are rules about how long drivers may drive within a period of consecutive days, either 7 or 8 days.   You have to pick one or the other and stick to it.  If you choose 7 days, the driver may drive up to 60 hours in 7 days (still bound by the daily restrictions), but then has to be “off duty” for 34 consecutive hours.   If you choose 8 days, they may drive for 70 hours in 8 days before a 34-hour “off duty” period.   It gets a little tricky, because the time frame is a “rolling” time period, looking at the amount of “on duty” time in a row, not just calendar Monday through Saturday or Monday through Sunday.  

FEDERAL DEPARTMENT OF LABOR (DOL) and FLORIDA DEPARTMENT OF BUSINESS AND PROFESSIONAL REGULATIONS (DBPR) 

Drivers of farm labor buses must have “DA” (Driving Authorized) on their Farm Labor Contractor licenses.  In addition, if the vehicle is under the control of an FLC, that person’s DOL registration must be authorized the “TA” (Transportation Authorized).

Farm labor transport drivers who are not subject to DOT requirements (such as small van drivers) still must comply with all the DOL and DBPR regulations pertaining to drivers of vehicles transporting farm workers. This includes being at least 21 years old, having a current doctor's certificate (and carrying it with them while driving), possessing a current and proper driver's license, maintaining a record of the hours they work, being able to speak and understand English, and, if they are not a direct employee of an Agricultural Employer such as a farmer, possessing a federal and state Farm Labor Contractor certificate with Driving Authorization. (DA) 

Authors:   Thissen, C.; T. McQuilken; M. Bayer; and F. Roka.  

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

Tracey McQuilken is a retired Sergeant Investigator with FDOT/FHP.  She is now a DOT Consultant and owner of Ion Drug & Alcohol Testing, Brandon, FL, 813-244-7087, tracey@iondat.com   

Mike Bayer is a former DOL-WHD Investigator, now with Curran, Bayer & Associates, West Palm Beach, 561-371-0126 mtbayer@curranbayer.com  


ABOUT THE FARM LABOR SUPERVISOR TRAINING PROGRAM

The Farm Labor Supervisor (FLS) Training Program is a University of Florida/IFAS Extension program. Begun in 2010, the program is coordinated by Fritz Roka and Carlene Thissen at the Southwest Florida Research & Education Center. Each year from late September through early November a core group of topics are taught at several locations across Florida and in partnership with county extension faculty.  These topics cover laws that keep farm workers safe, fairly paid, and in a working environment free from discrimination and harassment.  The program is offered in both English and Spanish. If there is sufficient interest, individual classes of combinations of classes can be arranged at times and locations convenient for the participants. We also provide training at grower locations that incorporates grower-specific policies and procedures.  For more information, contact Carlene Thissen, 239-658-3449, carlene@ufl.edu.