Horticultural Sciences Department

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Issue No. 596

The Vegetarian Newsletter 

A Horticultural Sciences Department Extension Publication on 
Vegetable and Fruit Crops 

Eat your Veggies and Fruits!!!!!

Publish Date: 
November 2014

Development of an IPM strategy for management of novel Pseudomonas syringae strains affecting watermelon and other cucurbits

Mathews L. Paret, Plant Pathologist, NFREC, University of Florida

Nicholas S. Dufault, Plant Pathologist, Dept. of Plant Pathology, University of Florida

Joshua H. Freeman, Vegetable Specialist, NFREC, University of Florida

Jeffrey B. Jones, Plant Bacteriologist, Dept. of Plant Pathology, University of Florida

Bob Hochmuth, Multi County Extension Agent, University of Florida

Anthony Drew, Extension Agent, Levy County, University of Florida

Introduction: In 2013, Florida, Georgia, South Carolina, North Carolina, Alabama, Mississippi and Virginia combined produced watermelon on 66,970 acres and squash on 14,500 acres with a farm value of $450 million. A new disease on watermelon and squash was discovered in the spring production season in 2013 from major production areas in Florida including Suwannee, Jackson, Hendry, Levy, Gilchrist, Alachua, and St Johns counties. In 2014, this disease continued to be a major problem on watermelon and squash in Florida, Georgia and other southeastern states. The key symptom on watermelon is circular lesions with black edge and white to tan centers leading to severe leaf blighting  (Fig.1).

596.1.1_0.jpg

Fig. 1. Severe leaf spots and leaf damage caused by the new bacterial disease on watermelon.

This disease has also led to increased cost of production for growers due to additional copper spray applications (3-5 sprays) that were necessary until late in the season due to the extended cool and wet weather conditions which favored disease spread. Under the microscope, cut sections of the lesions from watermelon indicated heavy bacterial streaming. As an immediate response to this bacterial disease outbreak, Florida Watermelon Association and the Southern IPM Center funded projects from 2013-2014 for developing an IPM strategy.

Materials and Methods

In Spring 2014, two field studies were conducted at Quincy and Citra, FL to evaluate the effectiveness of Acibenzolar-S-methyl (ASM; Actigard®), a Systemic Acquired Resistance (SAR) inducer, Copper + Ethylene Bis Dithio Carbamates (EBDC; Mankocide), Copper (Cop-R-Quik/Kocide 3000), biological control agent, Bacillus subtilis (Serenade Optimum) and Aluminum tris (O-ethyl phosphonate) (Aliette) in disease management. This trial mimicked two potential scenarios in pathogen introduction.

1. Seedlings were infected with P. syringae strains before treatment. Use of watermelon seedlings infected with P. syringae strains before transplanting to the field. This was to mimic a scenario of large-scale use of contaminated watermelon transplants, which may be a potential reason for the 2013-2014 disease outbreaks in Florida and Georgia. The product evaluation in this scenario was to test the ability of the materials in reducing the disease and maintaining watermelon yield even with the use of infected transplants to begin with. Three to four week old seedlings (Troubadour - Triploid (Harris Moran, Modesto, CA); Pollen Pro - Diploid Pollenizer (Siegers Seed Co., Holland, MI) were inoculated in the greenhouse with ~107 cfu/mL of a bacterial suspension containing three well-characterized and highly pathogenic strains from the 2013 disease outbreak (13-139A, WM Bac C1, 13-141A) one week before transplanting to the field. The test treatments were initiated 10 days after transplanting to the field and were applied 3 times at weekly intervals.

2. Seedlings were infected with P. syringae strains only after first treatment application.  Use of healthy watermelon seedlings for transplanting but inoculated with P. syringae strains after transplanting. This was to mimic a scenario where the transplants were non-infected, but the infection was due to field level introduction of the pathogen. The product evaluation in this scenario was to test the ability of the materials in preventative management of the disease and maintaining watermelon yield. Seedling inoculation in the field was conducted at 14 days after transplanting. The test treatments were initiated start 4 days before pathogen inoculation and were applied 3 times at weekly intervals.

Results

Quincy, FL, Spring 2014 trial: When watermelon seedlings were infected with P. syringae strains before treatment, Mankocide significantly reduced disease severity compared to non-treated control and all other test treatments as indicated by the AUDPC value (P = 0.0002; Fig. 2A). Actigard (foliar and drip), Cop-R-Quik (foliar), and Cop-R-Quik Injectible (drip) also had significantly less disease than the non-treated control.  There was no statistical difference in disease severity of plants treated with Actigard through foliar or drip, or between Cop-R-Quik through foliar or drip. Plants treated with Mankocide had the highest yield and it was statistically higher than the Cop-R-Quik Injectible (drip) treatment (P = 0.2199; Table 1). However, no statistical differences in yield were noted between the non-treated control, Actigard (foliar and drip) and Cop-R-Quik (foliar).

When seedlings were infected with P. syringae strains only after first treatment application, Mankocide significantly reduced disease compared to non-treated and all other experimental treatments (P = <0.0001; Fig. 2B). Foliar application of Actigard and Serenade Optimum also significantly reduced the disease compared to untreated plots. There was no statistical difference in disease severity of plants treated with Actigard through foliar or drip. Plants treated with Actigard (foliar and drip) and Mankocide had significantly higher yield compared to Serenade Optimum, Aliette and non-treated plots (P = 0.0077; Table 2). Plants treated with Actigard through drip had significantly higher yield than Mankocide, but the yield was not significantly higher than Actigard through foliar application.

Citra, FL, Spring 2014 trial: This trial had a lower disease pressure than the Quincy, FL trial. When seedlings were infected with P. syringae strains before treatment, Actigard (foliar and drip) and Kocide 3000 significantly reduced disease severity compared to non-treated control (P = 0.0066; Fig. 3C). There was no statistical difference in disease severity between the Actigard treatments through foliar and drip and Kocide 3000. Even though all the treatments had a numerically higher yield (13,000-16,000 kg/ha) than non-treated control, it was not statistically different (Table 3). When seedlings were infected with P. syringae strains only after first treatment application also, Actigard (foliar and drip) significantly reduced disease severity compared to non-treated control (P = 0.0011; Fig. 3D). However Kocide 3000 had significantly higher disease severity than Actigard treatments and the disease severity was statistically similar to non-treated control. There was no statistical difference in disease severity between the Actigard drip and foliar treatments. Plants treated with Actigard had significantly higher yield than non-treated plants (P = 0.0894; Table 4).

Fig. 2.  Area under Disease Progress Curve (AUDPC) of plants treated with Actigard through drip/foliar (0.5 oz/A), Mankocide (2 lb/A), Cop-R-Quik (6 oz/A) foliar, Cop-R-Quik Injectible (3 qt/A) drip, Serenade Optimum (0.5 lb/A), Aliette WDG (2 lb/A), and Kocide 3000 (0.5 lb/A). A) Seedlings infected with P. syringae strains before treatment at Quincy, FL trial B) Seedlings infected with P. syringae strains only after first treatment application at Quincy, FL trial C) Seedlings infected with P. syringae strains before treatment at Citra, FL trial and D) Seedlings infected with P. syringae strains only after first treatment application at Citra, FL trial.

Table 1. Average yield (kg/ha) from plants, which were infected with P. syringae strains before treatment at Quincy, FL trial.

 

Treatment

Rate/A

Yield (kg/ha)

1

Actigard (Foliar)

0.75 oz

59,319 ab

2

Actigard (Drip)

0.75 oz

58,444 ab

3

Mankocide (Foliar)

2 lb

68,766 a

4

Cop-R-Quik (Foliar)

6 oz

67,884 a

5

Cop-R-Quik Injectible (Drip)

3 qt

42,956 b

6

Non-treated

 

50,254 ab

 

P = 0.2199

 

LSD = 23,787

Table 2. Average yield (kg/ha) from plants, which were infected with P. syringae strains only after first treatment at Quincy, FL trial.

 

Treatment

Rate/A

Yield (kg/ha)

1

Actigard (Foliar)

0.75 oz

62,073 ab

2

Actigard (Drip)

0.75 oz

73,170 a

3

Mankocide (Foliar)

2 lb

58,702 b

4

Serenade Optimum (Foliar)

0.5 lb

50,193 bc

5

Aliette WDG (Foliar)

2 lb

56,345 bc

6

Non-treated

 

44,768 c

 

P = 0.0077

 

LSD = 13,779

Table 3. Average yield (kg/ha) from plants, which were infected with P. syringae strains before treatment at Citra, FL trial.

 

Treatment

Rate/A

Yield (kg/ha)

1

Actigard (Foliar)

0.75 oz

73,402 a

2

Actigard (Drip)

0.75 oz

75,711 a

3

Kocide 3000 (Foliar)

0.5 lb

76,271 a

4

Non-treated

 

60,082 a

 

P = 0.6858

 

LSD = ns

Table 4. Average yield (kg/ha) from plants, which were infected with P. syringae strains only after first treatment at Citra, FL trial.

 

Treatment

Rate/A

Yield (kg/ha)

1

Actigard (Foliar)

0.75 oz

84,817 a

2

Actigard (Drip)

0.75 oz

85,252 a

3

Kocide 3000 (Foliar)

0.5 lb

65,616 ab

4

Non-treated

 

51,446 b

 

P = 0.0894

 

LSD = 30,442

Future studies

Even though the disease outbreaks in spring 2013 & 2014 seem to have been also associated with the extended cool and wet weather conditions during spring season production in Florida and Georgia, there is currently very little information on the optimum conditions required for disease occurrence and spread. This is of major relevance in determining how many sprays are required for disease control. In our field studies conducted in 2014, we applied test materials 3 times at weekly intervals, but this needs to be further calibrated based on weather conditions, which would be conducive for the P. syringae strains isolated from the 2013-2014 outbreaks and subsequent disease outbreak.

Another aspect, which is of major relevance, is to understand whether these strains are seed-borne in nature. Many of the strains of P. syringae pv. lachrymans affecting cucurbits isolated from many geographical locations in the world have been shown to survive well in seed. However we currently do not have any information pertaining to the seed-borne nature of novel P. syringae strains isolated from the 2013-2014 outbreaks. This is of particular relevance as understanding the origin of the strains and utilizing healthy seeds/transplants will be the first step in any successful disease management program.


FARM LABOR SUPERVISOR TRAINING PROGRAM

ARTICLE 8:   Fair Employment Practices – Definitions

Over the last seven issues, we have discussed Wage & Hour (Department of Labor) and Transportation (Department of Transportation) rules and regulations. This month we start a series of articles on Fair Employment Practices. 

 In 1961, President John F. Kennedy signed an executive order that required government contractors treat their job applicants and employees equally and fairly. The commission overseeing employment practices of government contractors evolved into the Equal Employment Opportunity Commission (EEOC), which was created officially in 1965 to expand equal and fair treatment across all employers.  

Jurisdiction of the EEOC relates strictly to the workplace – the application and hiring process, during the employment period, and/or termination.  “Workplace” includes anywhere an employee is required or expected by the employer to be.  It includes the workplace itself (fields, groves, and office), transportation if provided by the employer, off-site meetings and training sessions, and even company parties at restaurants, private homes, or clubs.  

The federal legislation the EEOC oversees:

·         Title VII of the Civil Rights Act (1964) – Makes it illegal to discriminate against someone on the basis of race, color, religion, national origin or sex.  A 1991 amendment to this act allows civil jury trials to set compensatory and punitive damage awards in discrimination cases.

·         Pregnancy Discrimination Act (1978) – Amended Title VII of the Civil Rights Act to include pregnancy, childbirth or any related medical condition as a protected class.

·         Equal Pay Act (1963) – Amended the Fair Labor Standards Act of 1938 to make it illegal to pay different wages to women and men if they are doing the same work in the same place.

·         Age Discrimination in Employment Act (1967) – protects people 40 or older from age discrimination.  (Note: A Florida Statute protects people of whatever age.)

·         Americans with Disabilities Act (1990) – protects people with disabilities from discrimination or harassment.

·         The Genetic Information Nondiscrimination Act (2008) – Protects applicants or employees against discrimination or harassment based on family traits or inherited characteristics. 

DEFINITIONS

Discrimination and Harassment are broad categories that embody most of what EEOC enforces.  Instructors in the University of Florida’s Farm Labor Supervisor training program have distinguished between discrimination and harassment as follows:

·         Discrimination generally hurts an employee financially by preventing their hire, withholding promotions, salary increases or training opportunities which could lead to advancement.

·         Harassment hurts an employee emotionally, mentally, or sometimes even physically, and often creates an unpleasant environment for other employees.

Prejudice – It is generally accepted that few if any people are free from prejudices against groups of people.  Those prejudices, while sometimes hurtful to targeted groups, are not against the laws enforced by the EEOC, unless they affect decisions made in the workplace or work environment.  

Protected Classes – Protected classes are groups of people identified by the laws listed above as groups that may experience discrimination or harassment.  At this time there are eight protected classes.  In alphabetical order, they are:

1.    Age

2.    Country of Origin

3.    Disability

4.    Genetic Information

5.    Pregnancy

6.    Race and color

7.    Religion

8.    Sex

Reasonable Accommodation – Employers must at least try to “reasonably ccommodate” applicants and employees by making changes in the workplace environment which remove barriers that would otherwise prohibit people within the protected classes from working..

Retaliation – Punishing individuals who report acts of discrimination or harassment or who cooperate with EEOC investigations is called retaliation. It is against the law to retaliate and retaliation can make an initially weak case very strong. 

COMPANY POLICIES AND PROCEDURES

Companies should have policies and procedures that outline acceptable and unacceptable behavior on the part of management and employees.  We will cover these in more detail in an upcoming article on EEOC, but here is a brief overview of what companies should have.  Descriptions of unacceptable behavior should be available and posted for all employees to see, in their language.  It is a good idea to include these descriptions in any employee handbooks.  Unacceptable behavior includes anything that might make any employees uncomfortable or create an undesirable work environment.  These descriptions include behaviors, such as posters of scantily clad women, that might seem harmless to some, but are offensive to others. Foul language, sexual references, racial slurs or demeaning jokes, are other common examples of behavior that might raise objections by some employees.

Job descriptions and productivity standards, applied uniformly to everyone, protect companies from unwarranted employee complaints.  For example, a supervisor refuses to hire women because he believes a woman does not have the physical strength and stamina to lift and stack 45-pound boxes. If in fact a woman has the physical ability to do this job, she would be in a position to file a sex discrimination lawsuit. As long as a job description clearly notes that lifting 45-pound boxes is a requirement, the employer could terminate any individual man or woman who cannot perform up to the job standards. Without a specific job description and productivity standards, this company could lose an EEOC-backed lawsuit. 

Procedures should be in place for employees to safely report complaints of discrimination and harassment.   These procedures should ensure confidentiality.  If someone has a complaint and it is brought to the attention of management, management must investigate the allegations.  

Posting of anti-discrimination and harassment notices is required by statute.  These notices are included in the “EEO IS THE LAW” poster.   Click on this link to download copies in English, Spanish, Chinese, or Arabic: http://www1.eeoc.gov/employers/poster.cfm

Training to prevent harassment, particularly harassment of a sexual nature, should be given to all employees on a regular basis.  This includes the use of videos and/or interactive classes.

Alternative Dispute Resolution is a mediation service offered by the EEOC that allows companies to avoid costly lawsuits and litigation. The EEOC will assign an objective third party to hear the complaint and the company’s defense. In order for this to work, both parties must be willing to participate and to keep the results strictly confidential.   

Authors:   Thissen, C.; 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

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.  In the past, attendees were awarded Certificates of Attendance and of Certificates of Completion if they attended the core classes.  

NEW!   CERTIFICATE OF FARM LABOR MANAGEMENT:  In fall of 2014, a new program was introduced that allows participants to earn a Certificate of Farm Labor Management.   The objective behind this certificate is to enhance the professional stature of those farm labor supervisors who complete the program and successfully manage farm workers in accordance with all associated rules and regulations.   To achieve the Certificate of Farm Labor Management, a total of eight (8) classes are required, and attendees must pass a test administered at the end of each class.  Three (3) of those classes must be Wage & Hour, Human Resource Compliance, and one class related to worker safety.  The remaining five classes will be the choice of the individual.  Times and locations of classes offered in fall, 2014, can be found at www.swfrec.ifas.ufl.edu , along with registration information. 

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.