Soil Fumigation Basics for Tobacco

Module TwoChap. 4, 5, & 6

Chapter 4Soil and Pest Factors ThatInfluence Fumigant Activity

Factors that Influence Soil FumigationPest Factors:What are they (pest identification)?Where are they (how deep)?When to fumigate (application timing) ?How much gas to use (fumigation rate)?3Correct diagnosis is the first step in successful disease management!Factors that Influence Soil Fumigation4

Factors that Influence Soil Fumigation:Application Depth5Fumigating when soil temperatures are higher also catches pest & pathogens at growth stages when pests & pathogens are more active, when they are more susceptible to soil fumigants.Factors that Influence Soil Fumigation:Application TimingThe appropriate fumigant, its application rate, application method, & timing are determined by:The crop to be planted;The target soil-borne organism(s) pests;Level of infestation;Soil characteristics, such as texture;Environmental conditions.7Fumigator Set-up, Repair & MaintenanceCheck fittings and tubing to ensure all are made of materials compatible with the fumigant to be used; never aluminum;Filters in all systems, check valves in pressurized systems.Factors that Influence Soil Fumigation:Soil CharacteristicsSoilParticleSoil ParticleSoil ParticleNematodeSoil Pore Air SpaceSoil Water FilmSoil Water FilmSoil Fumigant9Factors that Influence Soil Fumigation:Soil TemperatureSoilParticleSoil ParticleSoil ParticleNematodeSoil Pore Air SpaceSoil Water FilmSoil Water FilmSoil FumigantSoil temperature influences how fast fumigants change from a liquid into a gas;Gases move through soil faster than liquids;The higher the soil temperature, the faster fumigants vaporize into a gas;10The higher the soil temperature, the further the fumigant often moves through soil, but also potentially into the air above the ground.Acceptable soil temperatures at the point of injection usually between 40o and 90o F.If air temperatures have been above 100o for within 72 hr of application, soil temperatures at application must be recorded.Factors that Influence Soil Fumigation:Soil TemperatureFactors that Influence Soil Fumigation:Soil Texture

12Factors that Influence Soil Fumigation:Soil TextureSoilParticleSoil ParticleSoil ParticleNematodeSoil Pore Air SpaceSoil Water FilmSoil Water FilmSoil FumigantCoarser soils (sands, sandy loams) have larger soil particles & larger spaces between them (pores);Fumigants can move through larger soil pores faster;The coarser the soil, the faster & further fumigants move, both through soil and into the air;13Factors that Influence Soil Fumigation:Soil MoistureSoilParticleSoil ParticleSoil ParticleNematodeSoil Pore Air SpaceSoil Water FilmSoil Water FilmSoil FumigantSoil moisture influences how far & how fast fumigants move;Soil moisture requirements vary for fumigants depending upon their vaporization rate and water solubility;The coarser the soil, the faster & further fumigants move through soil;14SoilParticleSoil ParticleSoil ParticleNematodeSoil Pore Air SpaceSoil Water FilmSoil Water FilmSoil FumigantSoil moisture influences how far & how fast fumigants move;Coarser textured (sandier) soils typically require higher moisture contents than finer-textured soils (clays, silts).Soil moisture requirements vary for fumigants depending upon their vaporization rate and water solubility;Factors that Influence Soil Fumigation:Soil Moisture15SoilParticleSoil ParticleSoil ParticleNematodeSoil Pore Air SpaceSoil Water FilmSoil Water FilmSoil FumigantThe coarser the soil, the faster & further fumigants move through soil;Determine soil moisture with a tensiometer or by the USDA feel & appearance method.Factors that Influence Soil Fumigation:Soil Moisture16USDA Feel & Appearance Methodor Clod Method50-75% Moisture in Fine Sands/Loamy Sands:When darkened soil forms a moist ball with loose & clustered sand grains on fingers, with moderate water staining on fingers; will not ribbon.Photo courtesy USDA-NRCS17USDA Feel & Appearance Methodor Clod Method50-75% Moisture in Sandy Loams: when Darkened soil forms a ball with defined finger marks, very light soil/water staining on fingers, not sticky.Photo courtesy USDA-NRCS18USDA Feel & Appearance Methodor Clod Method50-75% Moisture in Sandy Clays & Clay Loams: when darkened soil forms a ball, very light staining on fingers, pliable, & forms a weak ribbon between thumb & forefinger.Photo courtesy USDA-NRCS19Soil Tilth = the physical condition of soilFactors = clods, moisture content, aeration, water infiltration, & drainage; Clods & hardpans have less pore space, slowing and reducing fumigant movement, but increasing off-gassing;Best soil tilth for fumigation = physical condition that allows the fumigant to diffuse through soil but not escape when the soil surface is sealed properly.Factors that Influence Soil Fumigation:Soil Tilth20Pi = ~844 eggs/500 cc soilFactors that Influence Soil Fumigation:Crop ResiduesSlow fumigant movement by absorbing some fumigants;Break the seal at the soil surface, providing avenues for gas to escape from the soil;Hang-up on fumigator shanks, plugging outlets.21For less volatile fumigants, by compacting soil or irrigation (~1/4 water)

Factors that Influence Soil Fumigation:Soil Sealing22Factors that Influence Soil Fumigation:Soil SealingBy tarping for more volatile fumigants (methyl bromide, some chloropicrin applications).Review QuestionsWhich of the following soil factors has little or no effect on the fumigants movement through the soil?TilthpHTexture

A fumigant handler is intending to apply a 1,3-D/chloropicrin product to a sandy loam field. Soil temperature at the depth of the application is 45F, and the soil forms a weak ball using the feel method. Which of the following may limit the success of this fumigation?Soil textureSoil moistureSoil temperature

Which of the following pest factors has the greatest impact on the timing of a soil fumigant application?Pest densityDifficult-to-control pestsGrowth stage of an insect.

Chapter 5Personal Protective Equipmentand RespiratorsPersonal Protective Equipment (PPE)Fumigants are distinct from other pesticides fumigants are volatile may result in inhalation exposure. Therefore PPE required differs from non-fumigants Check the pesticide label PPE directions in the Precautionary Statements section of the pesticide label. Differences in PPE for FumigantsExamples of how PPE for various fumigants may differ from non-fumigants:Respirators are always required to be kept on siteLoose-fitting work clothesOften no chemical-resistant apron or spray suitMay not allow Chemical-resistant gloves or boots May require wearing cotton glovesOthers may specify chemical-resistant gloves and footwear just for certain tasks.Specific about the type of eye or respiratory protection to wear and when

RespiratorsMedical Evaluation Before Respirator Fit Testingpreliminary screening, a medical practitioner may determine that a physical exam is required.Re-examined if health status, respirator style,use conditions change.RespiratorsMay be required for:Any handling taskTriggered by sensory irritation

Not required:Prior to application of the fumigantWhen transporting unopened cylindersRespirator Fit and CareAfter being cleared for:Air-purifying respirator (APR) Fumigant handlers must be Fit tested and trained on how to use each specific respirator Fit testing is required and repeated annually. Respirator Fit and CareFollow-up fit testing is required if:The style of the face piece has changed.The respirator size, model, or brand has changed.There is a physical change in the persons face due to weight change or dental work. Fit is unacceptable.At request of the user.Employer policy.Fit check before each use (user seal check)Respirator TrainingAdequate training is required before handling a fumigant, including:Fit and use of the respiratorEven if it is for emergency response onlyMust establish a formal respiratory protection program, including:Written operating procedures for maintenance,cleaning, storageRespirator TypesAPR (Air Purifying Respirator)replaceable organic vapor cartridge or canister(gas mask) half-face/fullfacePAPR (powered)SCBA (Self-Contained Breathing Apparatus)

SelectionCarefully review the respirator requirements on the label to determine:Whether you need respiratory protection.Correct type of respirator for that fumigant.Situations when respiratory protection is needed.

Never substitute another type of respiratorCartridge or canister lifeThe type of cartridge.The size of the cartridge.The type and concentration of vapors in the surrounding air.The length of exposure.The rate of breathing. Whether more than one contaminant is present.The temperature and humidity at the time of use.Cartridge Replacement (also a WPS Requirement)At the first indication of odor, taste, or irritation.According to the pesticide label or manufacturer instructions, whichever is more frequent.When the end of service life indicator (ESLI) shows a color change indicating the unit has expired.In absence of any of the above instructions or indications of service life, at the end of each days work period.SCBASCBA respirators are only used For emergency situations and Not permitted for routine handler tasks.

Review QuestionsWho must undergo a medical evaluation before using respiratory equipment?Fumigant handlers with known heart problems. Fumigant handlers who will be removing tarps.Any fumigant handler or certified applicator who might need to wear a respirator.

Which type of respirator may never be worn during routine fumigant handler tasks?Half-face air purifying respirator (APR)Powered air-purifying respirator (PAPR)Self-contained breathing apparatus (SCBA)

How do soil fumigant labels differ from nonfumigant labels regarding personal protective equipment (PPE) statements?Respirators are always required on siteDifferent products have different PPE requirementsPPE requirements will vary depending on the handling task

Chapter 6Protecting PeopleStop Work Trigger Levels and Respiratory ProtectionFumigant labels specify trigger levels which require fumigant handlers toContinue work using a respirator, or Stop work and leave the application block and buffer zone.

Prevents fumigant handlers from being exposed to the maximum-use concentration (MUC) (capacity of the respirator cartridge)

Examples of Label RequirementsAn APR with the appropriate cartridges or canisters must be available for each fumigant handler who may be required to wear a respirator.For methyl bromide formulations with more than 20% chloropicrin, 100% chloropicrin formulations, dazomet, metam sodium, and metam potassium, fumigant handlers only need to wear full-face or gas-mask type respirators when they experience sensory irritation. If this happens, fumigant handlers must either stop work and leave the area, or use a full-face APR to complete the task.Minimum number of fumiganthandlers and respirators that mustbe on site:Methyl bromide, chloropicrin only, and other products with chloropicrin:At least two fumigant handlers must be on site.At least two APRs must be on site.

Metam Sodium & Metam Potassium:One fumigant handler on site.One full-face APR must also be on site.Stop Work TriggersTrigger levels and air-monitoring requirements are found on labels under the Respiratory Protection and Stop Work Triggers section.

Sensory IrritationA physical reaction to a certain fumigant air concentration, includingburning or irritation of the eyes, nose, or mucous membranes. If at any time there is sensory irritation handler must:Use an APR to complete the task, orStop work and leave the application block and buffer zone.Air MonitoringTwo things can initiate the need for air monitoring to start immediately:Whenever a fumigant handler is wearing an APR.Sensory irritation.Air samples must be collected at least every2 hours in the breathing zone of the handler performing a representative taskThe breathing zone is the area within a 10-inch radius of the nose and mouth.Returning to work without APRAfter a trigger level has forced work to stop, handlers cannot re-enter the application site or buffer zone area until:Two consecutive air monitoring samples taken in the fumigant handlers breathing zone and 15 minutes apart are below the specified trigger level.Fumigant handler does not experience sensory irritation.

Monitoring RepresentativeHandler ActivitiesActivities to be sampled must represent each handlers exposure occurring within the application block; i.e.Tractor driverCo-pilotShoveler

Air-Monitoring DevicesGas detector tubesdisposable and can be used only once.Must use pump and tubes from the same manufacturerTubes deteriorate with age. Some tubes have a shelf life of two years when stored at room temperature. Deterioration is more rapid above 86F.Direct sunlight affects the chemical reagents in the tubes.At low temperaturesat or below freezingtubes may not give reliable readings. Warm the tubes to room temperature before use for best performance.Tubes may have crosssensitivity to gases other than their target gas. Seek this information from the manufacturer.

Emergency Preparednessand ResponseIf homes or businesses are near a buffer zone, the certified applicator-in-charge has two options:Option 1: Monitor the buffer zone.Option 2: Provide response information to neighborsCertified applicator may choose the optionIf the buffer zone is 25 feet then emergency preparedness measures are not requiredOption 1 Monitor the Buffer ZoneMonitor between the Buffer Zone and the home or business of concern.Monitor at least four times each day throughout the buffer zone period:1 hour before sunset on the day the application begins,once during the night,once at 1 hour after sunrise, andonce during the day.Over the course of the 48-hour buffer zone period, monitoring will occur eight times.OPTION 2: Provide EmergencyResponse Information to Neighbors.Information to neighbors provided at least one week before the application including:The location of the application block.Basic information about the fumigant product.Contact information for the certified applicator and property owner.When the fumigation and the buffer zone period will occur (must not be more than four weeks away).Early signs and symptoms of exposure, and what to do if exposure is suspected (call 911 in most cases).Method of NotificationProvide this information using any method that effectively communicates the required material to the neighbors.telephone, door hangers,mailings, or email. May not use mass media (radio, TV, Newspaper Ad)It is a good idea to attach a copy of the information provided to the FMP as a record.

Emergency Response PlanPlan must be initiated:If handler experiences sensory irritation, or air monitoring detects concentrations of concern outside of the buffer zone.Fumigant Poisoningand First AidFumigant poisoning can occur from contact with the skin, eyes, or tissues in the mouth or nose. Seek immediate professional medical attention if anyone experiences an exposure to a fumigant.

Review QuestionsIf a fumigant handler who is NOT wearing an air purifying respirator (APR) experiences sensory irritation, he or she has two choices. What are they?Stop working and leave the area or use an APR to complete the task.Use an SCBA or take air-monitoring samples from the breathing zone.Stop working and leave the area or ask the certified applicator-in-charge to finish the task.

The lower trigger level on a fumigant label is 1 ppm and the upper trigger level is 5 ppm. Air-monitoring samples show a fumigant concentration of 2.2 ppm in the area where fumigant handlers are working. Which of the following actions are correct?Continue air monitoring to see whether air concentration levels reach the upper trigger level.Reseal the soil where necessary to prevent further fumigant off-gassing.Require fumigant handlers to either put on a respirator or leave the application block and buffer zone.

Labels typically require how many air-monitoring samples show that air concentrations of the fumigant are below the trigger level, and allow fumigant handlers to remove their APRs?OneTwoFive

How large is the breathing zone around the nose and mouth?1. 6-inch radius.2. 10-inch radius.3. 24-inch radius.

What is the purpose of a trigger level?To determine when respirators must be available on site.To prevent the fumigant handlers from being exposed to maximum-use concentrations (MUCs).To stop the application until the fumigant concentration level falls below the trigger level.