WPS for Greenhouse Employers: Workers, Handlers and Protections

The majority of the 2015 revisions to EPA’s Worker Protection Standard (WPS) go into effect on January 2, 2017.  To download the complete guide HOW TO COMPLY WITH THE 2015 REVISED WORKER PROTECTION STANDARD FOR AGRICULTURAL PESTICIDES, visit the Pesticide Educational Resources Collaborative (PERC), http://pesticideresources.org//index.html.  Over the next few weeks, we will break down the revised WPS to help wholesale and retail greenhouse employers of workers and handlers comply with WPS. This post provides an overview of WPS protections for agricultural workers, pesticide handlers, and others as provided in the HOW  TO COMPLY manual (pp 4-7).

WPS Definitions

The WPS requires employers to protect two types of agricultural employees: workers and handlers. In addition, the WPS provides certain protections for “other persons” during pesticide applications such as non-worker/handler employees, family members, customers, etc.

Who is a Worker? A worker is anyone who is:

  1. Employed (including self-employed) in exchange for a salary or wages or other monetary compensation, and
  2. Doing tasks directly related to the production of agricultural plants on an agricultural establishment such as harvesting, weeding, carrying nursery stock, repotting plants, pruning or watering.

Who is a handler? A handler is anyone who is:

  1. Employed (including self-employed) in exchange for a salary or wages or other monetary compensation by an agricultural establishment or a commercial pesticide handling establishment that uses pesticides in the production of agricultural plants, and
  2. Doing any of the following tasks:
    • Mixing, loading, transferring, applying or disposing of pesticides,
    • Handling opened containers of pesticides; emptying, triple-rinsing, or cleaning pesticide containers according to pesticide product labeling instructions; or disposing of pesticide containers that have not been cleaned,
    • Acting as a flagger,
    • Cleaning, adjusting, handling or repairing the parts of mixing, loading, or application equipment that may contain pesticide residues,
    • Assisting with the application of pesticides, including incorporating the pesticide into the soil after the application has occurred, or dipping plant cuttings in rooting hormones that are registered pesticides,
    • Entering a greenhouse or other enclosed space after application and before the inhalation exposure level listed on the pesticide product labeling has been reached or any ventilation criteria established by WPS (Chapter 3, Table 1. Entry Restrictions During Enclosed Space Production Pesticide Applications) or on the pesticide product labeling has been met to:
      • Operate ventilation equipment,
      • Adjust or remove coverings, such as tarps used in fumigation, or
      • Check air pesticide concentration levels
    • Entering a treated area outdoors after application of any soil fumigant to adjust or remove soil coverings, such as tarps, or
    • Performing tasks as a crop advisor:
      • During any pesticide application,
      • During any restricted-entry interval, or
      • Before any inhalation exposure level listed on the pesticide product labeling has been reached or any ventilation criteria established by WPS (Chapter 3, Table 1. Entry Restrictions During Enclosed Space Production Pesticide Applications) or on the pesticide product labeling has been met.

Handlers who are currently certified as applicators of restricted-use pesticides must be given all of the WPS handler protections, except that they do not need to receive WPS training.

Who is a Crop Advisor?  A crop advisor is any person who assesses pest numbers, damage, pesticide distribution, or the status or requirements of agricultural plants. A crop advisor may be a worker or handler under the WPS depending on when the crop advising task is done:

  • If crop advising tasks are done during a pesticide application or while the REI is in effect, the crop advisor is a handler under WPS.
  • If crop advising tasks are done after the REI has expired, but is within the 30 days of the expiration of the REI, the crop advisor is a worker under WPS. See Chapter 6: Exemption and Exceptions for additional requirement for crop advisors.

What are the WPS Protections?

WPS ensures that agricultural employees are informed about and protected from exposure to pesticides through the following enhanced protections:

Requirements to inform employees of pesticide exposure:

  • Pesticide safety training for workers and handlers.
  • Pesticide safety information — basic safety concepts (on the poster or otherwise displayed) available at the central location and some decontamination sites.
  • Pesticide application and hazard information (SDS) and access to the information — centrally-located pesticide application information and safety data sheets (SDS) in an area accessible to workers and handlers. This information must be kept for 2 years on the establishment and must be provided to the employee, medical personnel or the employee’s designated representative upon request.
  • Notify workers about treated areas by posting signs or providing oral notification to avoid inadvertent pesticide exposures.
  • Information exchange between commercial pesticide handler employers and agricultural employers.

Requirements to protect employees from pesticide exposure:

  • Exclude workers and others from areas being treated with pesticides.
  • Exclude workers and others from the application exclusion zone (AEZ) within the boundaries of the agricultural establishment during pesticide applications.
  • Exclude workers from areas that remain under a restricted-entry interval (REI), with narrow exceptions.
  • Ensure a pesticide handler or an early-entry worker (one that enters a treated site prior to the expiration of the REI) be a minimum of 18 years old.
  • Prohibit handlers from applying a pesticide in a way that will expose workers or other persons.
  • Protect handlers during handling tasks including monitoring while handling highly toxic pesticides.
  • Provide, maintain and ensure the correct use of personal protective equipment (PPE) including enhanced protections for the use of respirators.
  • Protect early-entry workers who are doing permitted tasks in treated areas during a REI, including special instructions and duties related to correct use of PPE.

In addition, the WPS requires handlers to:

  • Apply pesticides in a way that will not expose workers or other persons.
  • Suspend applications if anyone, other than a trained and equipped handler involved with the application, is in the AEZ during a pesticide application (which may be outside the establishment’s property boundary).
  • Wear PPE specified on the pesticide product labeling.

Requirements to mitigate employee exposure to pesticides:

  • Decontamination supplies such as specific amounts of water for workers and handlers along with soap and towels for routine washing and emergency decontamination.
  • Eyewash water for handlers using pesticides requiring protective eyewear.
  • Emergency assistance by making transportation available to a medical care facility if an agricultural worker or handler may have been poisoned or injured by a pesticide, and providing information about the pesticide(s) to which the person may have been exposed to.

New Worker Protection Compliance Manual Now Available

from Mary Ann Rose
Program Director, Pesticide Safety Education Program

The must-read manual for growers on the 2015 revised Worker Protection Standard (WPS) is now available. Horticultural growers such as greenhouses and nurseries will be most affected by these changes because of the numbers of workers they employ.  Retailers are also affected if pesticides are applied to holding areas. WPS protections for workers are very comprehensive.   The rules include requirements for safety training, posting of application information, application signage and verbal warnings, restrictions during applications, decontamination supplies, and emergency assistance.

WPS protects workers who are exposed to pesticides or pesticide residues on crops.  Worker protections are not indefinite; they extend for 30 days after a pesticide restricted-entry interval expires.  So with minor exceptions, employees not directly involved with handling crops or spraying them aren’t covered by WPS.   WPS also does not apply to livestock production or non-agricultural uses, such as lawn and landscape.

The new rules require employers to train workers and pesticide handlers annually instead of every five years.  New employees must be trained before handling pesticides or working in pesticide-treated areas, and only licensed pesticide applicators or EPA-approved trainers will be able conduct WPS worker training. There is also a first-time-ever age (18) requirement for pesticide handlers and new recordkeeping requirements.

Compliance with most new rules is required by January 2, 2017Compliance with new training content, centrally displayed information, and application exclusion zone restrictions is delayed until January 1, 2018. The Ohio Department of Agriculture has the authority to enforce WPS in Ohio and conducts WPS inspections.

Growers can download a copy of the new WPS compliance manual and other EPA-approved training resources from the Pesticide Educational Resources Collaborative (PERC: http://pesticideresources.org/index.htmll). New WPS worker training videos in English and Spanish also can be downloaded from PERC; worker and handler training manuals are expected to be available in 2017.   All materials are free-of-charge.

Worker Protection Standard Updates will be offered by OSU Extension starting this winter. See the Ohio Pesticide Safety Education WPS page as they become available (http://pested.osu.edu/home/quicklinks/wps).


OARDC Greenhouse Coordinator Position Available

The Department of Horticulture and Crop Science at The Ohio State University/OARDC is currently seeking a Greenhouse Coordinator to manage staff and greenhouse and growth chamber facilities that are used for research in agronomic and horticultural crops. The position is located in Wooster, OH. Interested individuals may apply at http://jobs.osu.edu requisition number 419322. Application deadline is July 17, 2016.

The Ohio State University is an equal opportunity employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation or gender identity, national origin, disability status, or protected veteran status.

For questions about the position, please contact Michelle Jones at 330-263-3885 or by email at jones.1968@osu.edu.

OSU Bioproducts Information Survey is Now Open!

Do you grow ornamental, fruit, or vegetable plants in a greenhouse, high tunnel or other structure? If so, The Ohio State University would like to invite you to participate in an industry-wide survey on bioproducts at http://go.osu.edu/ghbioproducts.  Your responses will provide valuable input to set research priorities and assist in the development of educational materials on bioproducts for the industry.  The survey will take approximately 10 to 15 minutes of your time.  For additional information, questions, or to receive a printed copy of the survey, please contact Beth Scheckelhoff, OSU Extension Educator for Greenhouse Systems at 419-592-0806 or at Scheckelhoff.11@osu.edu.  The electronic survey can also be accessed with your smartphone or other device here: QR CODE

Micronutrient Disorders

By Dr. Claudio Pasian, Department of Horticulture and Crop Science

The Ohio State University

Micronutrient disorders are the fertility problems that I see most often while visiting growers as an Extension Specialist (Figure 1 and 2).  Micronutrients (from the Greek Micro=small and nutrient=nutritive) are mineral elements needed by plants in small quantities.  Small variations from the optimum level required for plant growth can be damaging.  By the same token, levels slightly above those required for good growth can be toxic.  It is very important for growers to have a clear understanding about micronutrient management.  This article is a brief overview of the principles that control the availability of micronutrients in soilless mixes and how to correct imbalances.

Figure 1. Typical iron deficiency symptoms on Streptocarpella. Please, note that the symptoms manifest on young leaves.

Figure 1. Typical iron deficiency symptoms on Streptocarpella. Please, note that the symptoms manifest on young leaves. Photo by Claudio Pasian.

Figure 2. Typical iron-manganese toxicity symptoms on Geranium. Photo by Claudio Pasian.

Figure 2. Typical iron-manganese toxicity symptoms on Geranium. Photo by Claudio Pasian.

Deficiency or Toxicity?  A micronutrient disorder may be a deficiency (when the micronutrient is in deficit) or a toxicity (when the micronutrient is in excess).  Deficiencies can occur either because the nutrients are not present in the growing mix or because the nutrient is present but unavailable to the plant.  (Occasionally, plants with roots damaged by Pythium or other pathogens may show micronutrient deficiency symptoms.)  Some commercially prepared mixes have a fertilizer charge that may include micronutrients.  Growers preparing their own mixes should use one of the many commercially available micronutrient complexes to ensure that the micronutrients are present in the growing mix.

Nutrient Availability.  Sometimes, the micronutrient present in a growing mix is not available to the plant (the plant cannot take it up).  Micronutrient availability is influenced by media pH: except for molybdenum, the availability of micronutrients decreases with increasing media pH and vice versa.  Water alkalinity is an important factor modifying media pH and hence micronutrient availability.  It is important to maintain the pH for soilless media between 5.5 and 6.3.  Some crops are more sensitive to media pH than others:  petunias and gerberas must be maintained at pH levels of 5.5 in order to avoid micronutrient deficiency symptoms.  Other crops are more tolerant of pH changes.  Table 1 shows the minimum and maximum critical foliar levels for floral crops.

Table 1.  General critical foliar ranges for floral crops.  (After J. Biernbaum, Water, growing media, fertilizer, and root zone management.  OFA Short Course, July 1994.)

Nutrient Minimum ppm Maximum ppm
Iron (Fe) 50 ?
Manganese (Mn) 30 500
Zinc (Zn) 20 100-200
Copper (Cu) 5 20-100
Boron (Bo) 25 100-300
Molybdenum (Mo) 0.5 15

Substrate pH.  If the deficiency is due to pH imbalance, the approach is to modify the pH of the mix.  In this case, adding micronutrients can make matters worse because the level of individual micronutrients may affect the level of other micronutrients in the plant through a process called antagonism.  For example, too much iron may produce manganese and zinc deficiencies, while high levels of manganese may result in iron and zinc deficiencies.  Copper and zinc are also antagonistic: too much of one may produce a deficiency of the other (Table 2).

Nutrient Toxicity.  Toxicity on the other hand, can occur when micronutrients are applied in excess (usually more than one application).  Common sources of micronutrients are: the charger in the mix and fertilizers applied during the crop cycle.  Growers MUST have an idea of how much micronutrient they are adding through each of these sources in order to avoid toxicities.  Toxicity symptoms are difficult to recognize visually (only someone with a lot of experience can do it) and are usually mistaken by deficiency symptoms by growers.

Correct Diagnosis.  How do we resolve these problems?  First of all, only a correct diagnosis of the problem will lead to the proper solution.  Do you have a micronutrient deficiency or is it an excess?  Identify the micronutrient causing the problem.  Identify the cause of the deficiency/toxicity: is the nutrient not present or is it present but unavailable? Answering these questions will help you (and your extension agent or consultant) tackle the problem.

Table 2.  Availability of micronutrients as affected by other micronutrients (antagonism) and macronutrients in soilless mixes.

Element Availability reduced by:
Boron Organic nitrogenous fertilizers and high levels of phosphorus.
Manganese High levels of potassium, phosphorus, iron, copper, zinc.
Copper High levels of zinc, nitrogen, and phosphorus
Iron High levels of copper, manganese, zinc, and phosphorus.
Molybdenum High levels of manganese and nitrate-nitrogen fertilizer.
Zinc High levels of copper and phosphorus.

How to Correct the Problem.  If deficiency or toxicity are suspected, soil and foliar analysis are recommended for several reasons.  First, visual identification of the problem is difficult in the absence of information (made available through analysis).  Second, damage may be occurring that is not yet visible and by the time it becomes visible, the damage may be irreversible.

Deficiencies can be corrected by adding the micronutrient that is in deficit or by correcting the factor that makes it unavailable (e.g. high pH).  This second course of action is very common among growers who have high alkalinity irrigation water.  If only one micronutrient is deficient, DO NOT apply a micronutrient complex fertilizer because, as we mentioned above, imbalances can cause antagonism.  Apply a salt that contains only the deficient micronutrient.

Micronutrients can be I) added over time in small amounts with the irrigation water (Table 3); II) applied once with a concentrated solution during a normal watering (Table 4); III) applied as a single foliar spray (Table 5).

Table 3.  Sources, rates, and micronutrient concentration for continuous soil application of one or more micronutrients with every liquid fertilization.    (After D.A. Bailey and P.V. Nelson, Managing micronutrients in the greenhouse.  NCSU Extension, Leaflet No 553, 1991.)

Micronutrient source

Weight of source per 100 gal (oz)

Concentration (ppm)
Iron sulfate–20% iron 0.13 2.00 Iron
Iron chelate (EDTA) — 12% iron 0.22 2.00 Iron
Manganese sulfate — 28% manganese 0.012 0.25 Manganese
Zinc sulfate — 36% zinc 0.0018 0.05 Zinc
Copper sulfate — 25% copper 0.0027 0.05 Copper
Borax — 11% boron 0.030 0.25 Boron
Sodium molybdate — 38% molybdemum 0.00035 0.01 Molybdemum
Ammonium molybdate — 54% molybdenum 0.00025 0.01 Molybdemum

Toxicities are not easily corrected.  The first step is stop adding the micronutrient that is in excess (switching to a fertilizer without the nutrient causing the problem).  Slightly changing (raising, for most Micronutrients) the media pH will decrease the availability of all micronutrients (including the one in excess).  Growers trying to correct a micronutrient excess should raise the pH at the maximum level that the species/cultivar can tolerate for normal growth.  Lastly, use antagonism as a tool: increase slightly the level of a micronutrient that will reduce the availability of another (e.g. if zinc is at high levels, slightly increase the level of copper).

Table 4.  Sources, rates and micronutrient concentrations for a single corrective application of one or more micronutrients applied to the soil*.  (After D.A. Bailey and P.V. Nelson, Managing micronutrients in the greenhouse.  NCSU Extension, Leaflet No 553, 1991.)

Micronutrient source

Weight of source per 100 gal (oz)

Concentration (ppm)
Iron sulfate–20% iron 4.0 62.0 Iron
Iron chelate (EDTA) — 12% iron 4.0 36.4 Iron
Manganese sulfate — 28% manganese 0.5 10.0 Manganese
Zinc sulfate — 36% zinc 0.5 13.9 Zinc
Copper sulfate — 25% copper 0.5 9.3 Copper
Borax — 11% boron 0.75 6.25 Boron
For soil-based media (>20% soil in media)
Sodium molybdate –38% molybdemum 0.027 0.77 Molybdemum
Ammonium molybdate — 54% molybdenum 0.019 0.77 Molybdemum
For soilless media
Sodium molybdate –38% molybdemum 2.7 77 Molybdemum
Ammonium molybdate — 54% molybdenum 1.9 77 Molybdemum

* Do not apply combinations without first testing on a small number of plants.  Wash solution off foliage after application.

Conclusion.  Micronutrient management is complex and difficult.  A more complete treatment of this subject would require more space than we have available here.  I hope, nevertheless, that my description of the problem piqued your curiosity.  At the very least, I hope that you follow this advice: Don’t guess. Test!

Following, is the contact information of some laboratories where you can send your samples for tissue analysis.  Additional labs for media, water, tissue and disease diagnosis can be found here: 2015 Analytical Laboratories for Greenhouse Nursery Fruit and Vegetable Producers. Consult with your local Extension Agent for a local plant testing laboratory.

Brookside Labs
308 S. Main Street
New Knoxville, OH 45871

Calmar Lab
130 S. State Street
Westerville, OH 43081

CLC Labs
325 Venture Dr.
Westerville, OH 43081

421 Leather St.
Marion, OH 44654

Soil and Plant Nutrient Lab
Department of Crop and Soil Sciences
81 Plant & Soil Sciences Building
East Lansing, MI 48824-1325

Soil Testing Laboratory
University of Kentucky
103 Regulatory Service Building
Alumni & Shawneetown Roads
Lexington, KY 40546-0275

Spectrum Analytical Inc.
PO Box 639
Washington Court House, OH 43160

Agricultural Analytical Services Laboratory
Penn State University
University park, PA 16802

A & L Great Lakes lab
3505 Conestoga drive
Ft. Wayne, IN 46808

Brookside Labs
308 S. Main Street
New Knoxville, OH 45871

Calmar Lab
130 S. State Street
Westerville, OH 43081

CLC Labs
325 Venture Dr.
Westerville, OH 43081
This article lists lab references, but such reference should not be considered an endorsement or recommendation by the Ohio State University Extension, nor any agency, officer, or employee at the Ohio State University Extension. No judgement is made either for labs not listed in this article.