Module 1Chapter 1, 2, and 3

Chapter 1Overview of Soil Fumigants

and Soil Fumigation

Soil-borne Pests Targeted by Soil Fumigants Include:

• Insects (e.g., wireworms)• Nematodes• Fungi• Bacteria• Weed seeds• Germinating weed

seedlings

The Use of Soil Fumigantsin the United States is Heaviest on:

• Potatoes• Strawberries• Tomatoes• Tobacco• Peanuts

Light blue=lower useDark blue=higher use

Fumigant Volatilization

Soil pests are killed if they:• Contact a high enough concentration of the fumigant.• Are exposed to the fumigant for enough time.• As a gas, a fumigant consists of tiny molecules that

move through the soil pores (air spaces between soil particles).

• Some molecules also dissolve in the water film or soil water—surrounding the soil particles.

• Due to the volatility of all fumigants, there is significant concern for gases to escape the soil surfaces.

Effects of Fumigantson Humans

• Fumigants are among the most hazardous of all pesticides and bear the signal words Danger-Poison, Danger, or Warning. Label precautionary statements note specific human exposure concerns.

• Workers, certified applicators, fumigant handlers, and bystanders are at risk to be exposed.

• Very few exposure incidents occur relative to the number of applications.

Exposure Signs and Symptoms

Fumigants are moderately to highly toxic, and overexposure can cause serious injury. General

fumigant exposure symptoms include the following:

• Watering, burning, or irritation of the eyes, nose, or mucous membranes.

• Headache, nausea, or dizziness.• Tremors, slurred speech, or loss of muscle

coordination.• Skin rash, burning, and/or blistering.• Cough.

Certified Applicatorsand Fumigant Handlers

• The term certified applicator includes private applicator and commercial applicator, as defined by federal law.

• A private certified or commercial applicator in charge must supervise the fumigant application and fumigant handlers (WPS + Fumigation Training).

• This supervising certified applicator is considered the certified applicator-in-charge.

• All people that are part of the fumigation process are considered handlers (referred to as “fumigant handlers”).

Certified Applicatorsand Fumigant Handlers

• Fumigant handlers are the most at risk for exposure to fumigants. Some examples of handler tasks where exposure might occur include: product transfer, maintaining and repairing equipment, removing tarps, and assisting in applications.

Bystanders and Field Workers

• Because most soil fumigation occurs in agricultural settings, farm workers in nearby fields are vulnerable to exposure.

• This could include farm or contracted employees doing tasks like planting, pruning, irrigation, thinning, or harvesting, as well as people in adjacent fields.

• Bystanders are most likely to be exposed to fumigants through vapors.

Fumigant Labels Change Over Time

Fumigant labels contain use instructions and mitigation measures. In particular to protect handlers, they provide details on:

• Fumigant handler activities.• Onsite supervision.• Entry-restricted period.• Posting.• PPE.• Tarp perforation and removal procedures.

Fumigant Labels Change Over Time cont’d

• Buffer zones and posting.• Application methods, number of acres treated, and

rate.• Good agricultural practices (GAPs) are addressed on

labels to ensure maximum performance and minimal off-gassing.

• Labels also have requirements for emergency preparedness and response, fumigant management plans (FMPs), and post-application summaries (PASs).

• Each fumigant label may have slightly different requirements, so carefully read and follow label directions.

Review Questions

Which is the primary route of movement through the soil profile for highly volatile

fumigants?

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1. Soil Water

2. Soil Pores

3. Soil Particles

Which is the most common route of human exposure to soil fumigants?

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1. Dermal

2. Oral

3. Inhalation

Soil fumigation labels require that a certified applicator-in-charge do which

of the following?

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1. Provide onsite supervision to other fumigant handlers

2. Provide WPS handler training to other fumigant handlers

3. Provide PPE to field workers before entering a fumigated area

Chapter 2

General Label andRegulatory

Requirements

Restricted-Use Pesticides (RUPs)

• Because of human safety concerns, EPA designated all soil fumigants as restricted-use pesticides. RUPs can only be purchased and/or applied by certified applicators or persons working under their direct supervision.

Fumigant-Specific Certified Applicator-in-Charge Training

• Soil fumigant applicators must be certified applicators AND receive EPA-approved fumigant-specific training.

• In addition, most labels (except 1,3-D only products) require that the certified applicator-in-charge of a soil fumigant application complete an appropriate soil fumigant training program listed on the EPA website :http://www.epa.gov/fumiganttraining.

EPA Approved Training Programs Include:

• Registrant training on a specific soil fumigant active ingredient (every three years), OR

• State Soil Fumigant Training & Exam (Note that not all states will make this option

available)

EPA Soil Fumigant Toolbox

http://www.epa.gov/pesticides/reregistration/soil_fumigants/

The purpose of the training for the certified applicator-in-charge is to

make sure they know how to:

• Apply fumigants correctly.

• Protect handlers and other people.

• Comply with new label requirements.

Fumigant Handler

• Fumigant handler includes any WPS trained person in agricultural settings who performs handler activities. They must also have reviewed the fumigant safe handling information and be supervised by a certified applicator.

Mitigation Summary Safety Information for Handlers

http://www.epa.gov/fumiganttraining

Most labels list fumigant handler activities, such as the following:

• Participating in the application.• Monitoring fumigant air concentrations.• Cleaning up fumigant spills.• Handling or disposing of fumigant containers.• Cleaning, handling, adjusting, or repairing

parts of equipment.• Working with irrigation equipment in an

application block or buffer zone.

Most labels list fumigant handler activities, such as the following (cont’d):

• Entering an application block to perform scouting, crop advising, or monitoring tasks.

• Entering a buffer zone to perform scouting, crop advising, or monitoring tasks.

• Installing, perforating, removing, repairing, or monitoring tarps.

• Performing any handling tasks as defined by the WPS.

Onsite Supervision• For fumigant applications, onsite

supervision means the certified applicator-in-charge must be onsite for the entire application. This is in contrast to direct supervision, which may be done remotely for non-soil fumigant pesticide use.

• Nonwater-run applications (e.g.,shank or rotary tiller): the certified applicator must be at the fumigation site and in the line of sight of the application and fumigant handlers from the start of the application until the application is complete.

Entry-Restricted Period (ERP)

• The entry-restricted period is a specific amount of time during which entry into treated fields by anyone other than a trained and properly PPE equipped fumigant handler is prohibited. The ERP begins when the application starts.

• Labels have a minimum entry-restricted period of five days, or until after tarps are perforated and removed.

• It is important to note that the entry-restricted period is different from a restricted-entry interval (REI), a term more familiar to applicators.

Good Agricultural Practices (GAPs)

• GAPs ensure that fumigant applications are both effective and protective of fumigant handlers, workers and bystanders.

• The GAPs are listed on each fumigant label and are specific to both the product and the application method.

GAPS

• Soil conditions• Weather• Injection depth and application rate• Soil sealing• System requirements for application rigs

More…

Fumigant Application Records

FMP = Fumigant Management Plan

PAS = Post Application Summary

Fumigant Application Records

• Completing the FMP and PAS does not meet all State and Federal Application Recordkeeping requirements.

• Follow USDA Restricted Use Pesticide Recordkeeping Requirements + record end time of application, and remember that each day of application must be a separate record.

• In NC, all fumigant application records must be kept by the applicator and owner for two years.

Review Questions

Of all the soil fumigants, only methyl bromide and chloropicrin are classified

as restricted use pesticides.

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1. True

2. False

To meet the soil fumigant training requirements, both certified applicators

and fumigant handlers must pass a written exam.

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1. True

2. False

Who of the following may apply soil fumigants?

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1. A Trained Field Worker

2. A Trained Handler under WPS

3. A WPS trained fumigant handler supervised by a certified applicator

Which activity requires a person to be a fumigant handler?

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1. Preparing a fumigant management plan

2. Posting warning signs around the perimeter of a buffer zone

3. Monitoring fumigant air concentrations outside the buffer zone

Depending on whether a field is tarped or untarped, how long does an entry-

restricted period last?

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1. A minimum of five days after the application is completed.

2. From the start of the application to the end of the buffer zone period.

3. From the start of the application to at least five days after it is completed.

Chapter 3

Soil Fumigant Chemical

Characteristics

What is a “fumigant”?

A “fumigant” = a gas with pesticidal activity

How Do Soil Fumigants Work?

SoilParticle

Soil Particle

Soil ParticleNematode

Soil Pore Air Space

So

il Fu

mig

ant

Methyl Bromide (MeBr)

• Widest spectrum of pests controlled;• Registered for a wide variety of crops & sites;

Most volatile (high diffusion capability) soil fumigant; moves ≤ 36” from injection site;

• Extremely toxic - ;• Liquified gas: colorless, non-flammable, odorless

– 2% chloropicrin added as a WARNING AGENT;• Shank-applied or hot gas method.

Chloropicrin (Pic, Pic+, Telone C17)

• Controls soil-borne insects, fungi & bacteria. Some nematodes, weeds;

• Combined with MeBr as warning agent or to increase range of pests controlled;

• = Volatile liquid – vaporizes slowly, slightly water-soluble, non-flammable, little or no color;

• Irritant; high concentrations can cause severe symptoms• Tear gas;

• Shank-injected. Moves ~6-12” from injection.

1,3-dichloropropene or 1,3-D (Telone)

• Controls soil-borne insects & nematodes (weeds & fungi?);• Combined with chloropicrin for bacteria & fungi;• = Volatile liquid – vaporizes slowly, water-soluble, highly

flammable, little or no color;• Toxic to organs and tissue, probable human carcinogen;• Shank-injected;

1,3-dichloropropene or 1,3-D (Telone)

• No new Risk-Mitigation Measures (after 2014?):• Certified applicator-in-charge training,

• WPS fumigant handler safety training,

• Weather restrictions

• Buffer zones

• Difficult-to-Evacuate Sites

• Fumigant Management Plans (FMPs) & Post-Application Summaries (PAS)

Metam Sodium or Potassium (Vapam)

• Broad spectrum of target pests;

• Registered on a broad range of crops & sites;

• = MITC generators;

• = Volatile liquid – vaporizes slowly, water-soluble, so only moves a few inches (~3”) from injection; Yellow to orange in color; rotten-egg odor; non-flammable;

• Irritant; can burn skin or cause dermatitis;

• Varied application methods: shank, drip, spray, drench.

Dazomet (Basamid)

• Granular formulation,

• Broad spectrum of target pests (mostly weeds)

• = MITC generator like Vapam, etc.

• Registered on a broad range of crops & sites (not tobacco)

• Non-flammable

Background image from recreational-turf @ wickiespaces.com; 02-14-13

Dazomet (Basamid)

• Does not move far in the soil.

• Soil Water converts dazomet to MITC

• Off gassing smells like rotten eggs.

• Earliest symptoms of MITC inhalation include upper respiratory tract irritation.

Review Questions

Select the pair of soil fumigants listed below in which the first fumigant travels up to 36

inches through the soil and the second travels only a few inches.

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1. (1) Methyl iodide; (2) 1,3-D.

2. (1) Methyl bromide; (2) chloropicrin.

3. (1) Methyl bromide; (2) metam sodium.

A soil fumigant that has a high soil diffusion capability (distance it travels through the soil)

also has high

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1. volatility.

2. water solubility.

3. soil adsorption capability.

A fumigant handler is applying dazomet. Before conversion to MITC occurred, the handler began

noticing some poisoning symptoms. Which of the following symptoms did the handler most likely

experience?

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100%1. Dizziness.

2. Upper respiratory tract irritation.

3. Watering eyes and coughing.