“Pesticide” is a generic term that includes chemicals used to control arthropods, diseases, weeds, and crop growth. Under federal law, all pesticides are to be classified into restricted-use and general-use categories. Pesticides that are highly toxic and those that are persistent and accumulative are restricted and may be purchased and used only by certified applicators or under the direct supervision of a certified applicator.

All commercial applicators using pesticides in New York State must be certified, even if they use only general-use pesticides. In addition, all private applicators who use restricted-use pesticides must be certified. In most situations, private certification is sufficient for greenhouse operators and their employees. If in doubt, check with the Department of Environmental Conservation.

Certified pesticide applicators are required by regulations of the Department of Environmental Conservation (DEC) to maintain careful records of purchases of restricted-use pesticides, the crops treated, the methods of application, and the dates of application. This information must be maintained annually, retained for a minimum of three years, and made available for inspection on request by the DEC. The list is subject to annual review; consult your Cornell Cooperative Extension agent if you have questions about the status of a pesticide.

4.2 Label Warning Statements

Most pesticide labels have a signal word that alerts the pesticide user to the relative toxicity of the chemical. Signal words in Table 4.1.1 indicate these toxicities.

4.3 Sources of More Information on Pesticides

More information about pesticides is available from your Cornell Cooperative Extension agent, from the Pesticide Handbook published by the Entomological Society of America, P.O. Box AJ, College Park, Md. 20740, and from the Farm Chemicals Handbook, Meister Publishing Co., Willoughby, Ohio 44095.

4.4 Compatibility of Pesticides

Insecticides, miticides, and fungicides recommended in this publication are compatible with each other when mixed for application purposes if these guidelines are followed:

· Read the pesticide label carefully for compatibility statements.

· Avoid mixing different kinds of formulations; for example, do not mix emulsifiable concentrates and wettable powders.

· Do not mix pesticides with oils before compatibility is determined.

· Most pesticides are not compatible with alkaline solutions.

· Never mix herbicides with other pesticides. Apply herbicides with spray equipment reserved for their use only.

Table 4.1.1. Pesticide toxicity levels noted on product labels: their signal words and acute lethal doses (LD₅₀) and concentrations (LC₅₀)
Category	Signal Word Required on the Label	Acute Toxicity of Pesticide
		LD₅₀		LC₅₀	Probable Lethal Dose for a 150-lb. Man
		Oral Mg/Kg	Dermal Mg/Kg	Inhalation Mg/L	Probable Lethal Dose for a 150-lb. Man
I. Highly toxic	DANGER	0–50	0–200	0–2,000	A few drops
	(skull and crossbones)
	POISON
II. Moderately toxic	WARNING	>50 to 500	>200 to 2,000	>2,000 to 20,000	>1 tsp. to 1 oz.
III. Slightly toxic	CAUTION	>500 to 5,000	>2,000 to 20,000		>1 oz. to 1 pt. or 1 lb.
IV. Relatively nontoxic	CAUTION	>5,000	>20,000		>1 pt. or 1 lb.

4.5 Phytotoxicity of Pesticides

Pesticide injury to the crop (phytotoxicity) can be avoided by following the cautions on the pesticide label and by using the recommended concentrations. If you are unsure of the effect of a certain pesticide on a crop or on a particular variety, apply the pesticide to a few trial plants before treating the whole crop.

4.6 Storage of Pesticides

State and local guidelines for the storage of pesticides are subject to change. Get the most current information from your Cornell Cooperative Extension agent. Observe the following guidelines for the safe storage of pesticides:

· Store pesticides in their original containers only. Never store them in soft drink or juice containers.

· Identify pesticide storage areas with prominent waterproof signs over each entrance, including windows, and on all sides of the building.

· Keep the storage area locked.

· Inform police, fire department, and public health officials in writing of the location and layout of the storage area, the types of materials stored, and the hazards involved. Give the telephone numbers of persons responsible for the storage area to the fire chief. The fire company should map the locations of pesticides stored in the area.

· Inform local physicians and hospitals of the hazards. Be sure they know the treatments and have antidotes on hand. The handbook Recognition and Management of Pesticide Poisonings should be readily available (publication no. 055-044-0013-7, U.S. Government Printing Office, Washington, D.C. 20402). See also “Medical Antidotes for Pesticide Poisoning” in this publication.

· Post a list of the chemicals stored (e.g., organophosphates, carbamates, herbicides, chlorinated hydrocarbons, flammable solvents) and the storage plan outside the building. Enclose the list in a waterproof, clear plastic covering.

· Install fire fighting equipment nearby. Familiarize yourself and your workers with its operation. Be sure it works.

· Keep pesticide containers, especially glass, away from windows and out of the sun so they will not be subject to heat and ignition.

· Keep combustibles away from steam lines and heat. Read the labels for information on flammability, and store accordingly.

· Store highly toxic pesticides in one area.

· Store herbicides separately from other pesticides to prevent cross-contamination and to prevent mistakes in choice of materials.

· Dispose of unlabeled pesticides properly. Treat them as highly toxic.

· Keep hydrated lime and sodium hypochlorite (Clorox or similar household bleach) on hand to neutralize pesticide spills.

· Keep absorptive clay, activated charcoal, vermiculite, pet litter, or sawdust available at storage site to soak up spills.

4.7 Shelf Life of Pesticides

Pesticides should be purchased in reasonable quantities so that it is not necessary to store them for considerable periods. Most commercial formulations will retain their effectiveness for two or more years if stored above freezing temperatures under dry conditions with the container properly closed.

The symptoms of ineffectiveness are listed in Table 4.7.1, but they may be useful in determining the value of your pesticide supply. A pesticide may be ineffective without showing these typical symptoms. If you are not sure that a pesticide supply is still effective, dispose of the material properly rather than take a chance.

Table 4.7.1. Typical indicators of deterioration for six types of pesticide formulations
Formulation	General Symptoms of Ineffectiveness
Emulsifiable concentrate (EC)	When a milky formation does not occur with the addition of water; when an insoluble sludge and/or separation or layering of the EC occurs.
Oil spray	When a milky formation does not occur with the addition of water and/or when an oil slick forms on the water surface.
Wettable powder	When lumping occurs and the powder will not suspend in water.
Dust	When excessive lumping occurs.
Granular	When excessive lumping or disintegration occurs.
Aerosol	Generally effective until the opening of the aerosol can becomes obstructed and no longer sprays or until the container is emptied.

4.8 Pesticide Disposal

Proper disposal of surplus pesticides, concentrated or tank mixes, and empty pesticide containers is an important part of proper pesticide use. Improper disposal is a common cause of pesticide hazard and environmental contamination. Remember: Mix only enough for the job. Check with your Cornell Cooperative Extension educator for instructions for proper pesticide disposal.

4.9 Pesticide Formulations and Application Methods

The basic goal of pesticide application is to apply the pesticide to the target in a safe and efficient manner. Before purchasing a pesticide application machine, make critical comparisons of the equipment available. You should observe the equipment in operation and handle it yourself. The application equipment selected should be suited to the size of your operation. No one piece of equipment can adequately handle every situation you may encounter in your greenhouse. Operators should check chemical labels for equipment guidelines or to see if there are any restrictions on equipment use. Pesticide label rates based on dilution in a certain volume of carrier could limit the use of low-volume spray equipment. Current information on equipment is available from your Cornell Cooperative Extension educator.

4.9.1 Hydraulic Sprayers

Hydraulic sprayers operate with dilute sprays and with changeable pressures up to several hundred pounds per square inch. In applying pesticides with a hydraulic sprayer, nozzles should be free of obstruction and have minimal wear on their openings; pressure should be maintained to achieve a fine spray, which will result in uniform coverage and desired canopy penetration.

Research results indicate that it is difficult for hydraulic sprayers to treat both the upper and undersides of leaf surfaces.

Hydraulic sprayers must produce small, fast-moving spray droplets while moving plant leaves to ensure adequate coverage and foliage penetration.

The Cornell multi-orifice nozzle system is a highly effective device for applying dilute sprays on greenhouse crops. This nozzle system is made up of several cone nozzles that direct the spray in several directions, which should improve spray coverage. The Cornell nozzle should be operated at a pressure of at least 300 psi and aimed to provide maximum canopy penetration and coverage. The operator should sweep the Cornell nozzle in a circular motion past the treatment area to ensure adequate coverage of upper and lower leaf surfaces.

Small, hand-held compressed air sprayers that apply sprays at pressures less than 60 psi usually cannot produce drops small enough to ensure thorough coverage. These sprayers are best suited for spot treatments and for the control of weeds in and around the greenhouse.

4.9.1.1 Formulations for Hydraulic Sprayers

The selection of one pesticide formulation over another for use in hydraulic sprayers is usually a matter of personal preference. Several factors, however, should be considered:

Wettable powders (WP) are safer on plants than emulsions because inert diluents are used in the concentrate. A visible white powder residue, which may be objectionable, results from wettable powder sprays but not from emulsions. The addition of a wetting agent or spreader-sticker is often required with wettable powders, especially on hard-to-wet foliage. The use of wetting agents tends to result in the formation of smaller droplets. During treatment, continuous agitation in the spray tank is essential. Because of the abrasive nature of wettable powders, the condition of the spray nozzles should be monitored closely for wear.

Emulsifiable concentrates (EC) should be selected for longest-lasting residual deposits. They are most resistant to washing off. The solvents used may be more likely to cause plant injury than wettable powders. Be cautious; when in doubt, spray small areas on a trial basis before treating an entire area. A xylene-type solvent is safest on most plants. A good emulsion mixture will be uniformly milky white throughout.

Wetters and spreaders need not be added to most spray formulations. If water is so hard that spray powders do not readily mix in it, however, a wetting agent may be needed. Although the use of wetters and spreaders results in smaller droplets, these agents should not be specifically used to decrease the size of spray drops. Many specially prepared materials (DuPont Spreader-Sticker, Triton B-1956, Orvus, and others) are on the market, and most household detergents such as Dreft and Tide are satisfactory. Unfortunately, the specific amount of wetter to use cannot be recommended because the amount needed depends on the hardness of the water, the spray mixture involved, the plant to be sprayed, the pest to be controlled, and other factors.

The approximate amount required for a specific water supply, however, can be determined easily. Make a batch of the mixture without a spreader, and spray 10 feet of the bed. If both the tops and the undersurfaces of leaves of different ages are uniformly wetted with a light film of the spray, no additional wetter is needed. If not, add about 2 ounces of spreader per 100 gallons of spray, then spray another 10 feet of bed and examine the leaves. Continue until the wetting is satisfactory. Once determined, the amount should never need to be varied for that crop and that spray mixture. If, however, another wettable powder insecticide or fungicide is added to the mixture, less spreader may be needed. If a wettable powder is left out of the mixture, more spreader may be required.

4.9.2 Mist Blowers or Mechanical Foggers

Mist blowers carry concentrated pesticide to the plant in a high-volume, high-velocity airstream. Mist blowers generally produce smaller droplets than hydraulic sprayers, thereby improving spray coverage. The airstream carries the spray to the target and provides leaf movement and foliage penetration. Pesticide concentrations used in mist blowers are generally 10 to 20 times as high as those used in hydraulic sprayers, and the volume of the spray mixture is proportionately smaller.

Four factors are critical in mist spraying: the concentration of the spray in the tank, the flow rate at the nozzle, the length of time a group of plants is sprayed, and the uniformity of coverage. This spraying technique is more complicated than hydraulic spraying and requires skilled and careful operators. It is difficult to observe the spray coverage on the plants when using mist blowers, and serious plant injury can result from overspraying.

For effective leaf coverage and canopy penetration, the air-spray stream should be directed into the target area rather than to areas great distances from the nozzles. The nozzle should be continuously moved past the plants to prevent overspraying and to provide adequate leaf movement. Operators will not be able to use leaf wetness as a guide to whether a plant has received adequate spray when using a low-volume sprayer like the mist blower.

4.9.3 Electrostatic Sprayers

Electrostatic sprayers apply an electric charge to the spray cloud as it emerges from the spray nozzle. They commonly require a very small electric power source such as a 9-volt battery to charge the spray, and they are as safe to operate as other sprayers. The charged spray droplets resist colliding with each other and forming larger drops. The electrical attraction between the plants and the spray reduces the amount of spray falling to the ground and may actually cause droplets to travel upwards toward the underside of the foliage.

Electrostatic sprayers are usually used to apply high-concentration sprays. A high-velocity airstream is usually necessary to provide adequate canopy penetration when using these machines. For effective use, the air-spray stream should be directed into the target area rather than across the top of the crop. Directing the high-concentration sprays at the target plants too long can result in an excessive buildup of material on the plants. Under common bench-top production practices, low-volume electrostatic sprayers will be able to treat plants faster than a conventional high-volume hydraulic sprayer. Electrostatic applications are made more effective by reducing liquid flow rates through the nozzle and increasing application times.

4.9.4 Thermal Foggers

Thermal fogging devices or machines produce a dense vapor or smoke for killing insects. In thermal foggers the pesticide and a specially formulated carrier are injected into an extremely hot airstream and propelled into the greenhouse. When liquids are injected, they vaporize and recondense in a cloud of very small droplets that penetrate the greenhouse like an aerosol fog. The method of generating the necessary heat differs somewhat from one kind of machine to another.

Fogging machines vary in size; some are mounted on wheels, some are carried by straps around the shoulder or waist, and small units are carried by hand. The rate of application of the insecticide is about proportional to the size of the machine.

Insecticidal materials are specially formulated for fogging machines. The insecticide is mixed with an oil-based carrier, sometimes in combination with small quantities of other materials, to obtain a satisfactory preparation. Many of the materials for fogging machines are prepared at 10 percent insecticidal strength, such as naled (Dibrom), Kelthane, malathion, nicotine, and dichlorvos (*DDVP, *Vapona). Sulfotepp (*Dithio) is available in 5 percent strength. The materials are generally used at the rate of 1 ounce of formulation per 3,000 cubic feet.

In operation, fogging machines are generally carried or pulled through one or more walks of the greenhouse, depending on the greenhouse width. Although applications can be made from fixed locations in small greenhouses, most effective applications are made by moving around the greenhouse with the machine and aiming the spray outlet slightly above the crop canopy. Pointing the spray outlet directly at the crop can cause damage to the foliage from the heat of the airstream and the deposit of excess spray on the leaves. Foggers cannot usually be used to deposit spray material on the undersides of leaves because they do not drive spray into the canopy and do not stir the canopy.

The effectiveness of fogging machines is also affected by temperature, relative humidity, and air flow in the greenhouse. Under relatively dry air conditions, the droplets tend to settle out more quickly than under relatively wet air conditions if water is used as the carrier. Air movement within a greenhouse can improve the uniformity of spray coverage and foliage penetration.

Venting the greenhouse is extremely important after fogging. The small droplets and pesticide particles can remain suspended in the air for several hours and could present a hazard to workers entering the area after application. If the greenhouse cannot be vented after fogging, the application should not be made.

4.9.5 Aerosol Bombs, Smoke Generators, and Thermodusters

Application of these formulations is based on the air volume of the greenhouse in which the application is made. When using these formulations, the following precautions should be observed:

· Read the label for possible phytotoxicity.

· Eliminate drafts and air leaks in the greenhouse.

· Do not apply during windy weather or when temperatures are above 27° C (80° F) or below 16° C (60° F).

· Make sure the leaves of plants are free of standing water.

· Immediately after application, place a sign on each door of the greenhouse stating that fumigation is in progress. The warning sign should list the pesticide in use and should give the telephone number of a person knowledgeable about the fumigation operation.

4.9.6 Granules

Granular formulations—i.e., pesticide deposited on a granular carrier—usually carry a 10 to 15 percent concentration of pesticide. If large areas are to be treated, spreaders should be used. Extra care should be taken if using rotary spreaders because it is difficult to obtain accurate and uniform distribution of granules from these machines. If individual pots are treated, a volume measure such as a teaspoon should be used and granules should be distributed as evenly as possible across the soil surface. After application of insecticides, the granules should be worked into the soil and watered down. Use care not to float granules off the bench soil surface or out of the pots. Granules should not be applied before steam sterilization.

Note: Granules are registered for soil application only. Do not apply to foliage. Herbicides may be applied over foliage but are not intended to be applied to foliage.

4.10 Care of Equipment

Whether equipment is simple or complex, it must be properly cared for so that it will be both dependable and safe. Nozzles should be inspected regularly for damage or wear. Pressure gauges on hydraulic sprayers should be tested for accuracy. If nozzles are operated at required pressures, the pressure gauges should be placed as close to the nozzle as possible.

Equipment, including hoses, should be flushed out with water after use, drained, and stored under cover. The cleaning agent used will depend on the chemical that was last used. Pumps and other equipment that will be stored in below-freezing weather should be thoroughly drained, or better yet, alcohol should be circulated through the equipment. For long-term storage, nozzles and strainers should be removed, cleaned, and stored.

4.11 Safety Precautions for Handling Highly Toxic Pesticides

Please refer to the pesticide label on the container and the Worker Protection Standard Guidelines for more specific information relative to personal protective equipment (PPE).

4.11.1 Protective Clothing

The most common cause of pesticide poisoning for applicators is skin contact. Some pesticides enter the body through the skin quite readily. Concentrates can be especially dangerous. Most of a pesticide spilled on the skin is absorbed in the first few minutes. If any pesticide is spilled on the skin, wash it off immediately. But it is best to avoid direct contact with pesticides completely by wearing proper protective clothing. The pesticide label will indicate what protective equipment is necessary. Wear it!

4.11.1.1 Gloves

Always wear unlined, elbow-length rubber gloves when handling organophosphates, carbamates, and other chemicals with “Poison” or “Warning” labels. Elbow-length gloves protect the wrists and prevent pesticides from running down sleeves into the gloves. Be sure sleeves are outside the gloves. Check closely for holes by filling the gloves with water and squeezing gently. Discard the gloves if any holes appear. Never use cotton or leather gloves. These can be more hazardous than no protection at all because they hold the pesticide close to the skin for long periods. When using other pesticides, follow the suggestions on the label. After spraying, wash gloves with detergent and water before removing them to avoid contaminating the hands.

4.11.1.2 Coveralls

Wear clean, dry coveralls that cover the entire body from wrists to ankles for ordinary application of highly toxic chemicals. If a mist or spray is to be applied or if coveralls will be wet through for any reason, wear a waterproof suit. If heavy rubber rain suits will be too hot, try the new lightweight waterproof suits. After every use, wash clothes with a detergent and water.

4.11.1.3 Boots

Wear lightweight, unlined rubber boots that cover the ankles when handling or applying highly toxic pesticides. Remember to put pant legs outside the boots; otherwise the pesticide can drain into the boot. The boots should be washed often and dried thoroughly inside and out to remove any pesticide residue. It is wise to keep two pairs of boots on hand in case of accidental contamination.

4.11.1.4 Goggles or Face Shield

Wear tight-fitting, nonfogging goggles or a full-face shield whenever the chemical being handled could contact eyes. Always wear goggles or a face shield when pouring or mixing concentrates or working in a highly toxic spray or dust. Clean it often. Be careful of the headband; it is often made of a material that readily absorbs and holds chemicals. Have several spares and change them often, or use a rubber strap. If possible, wear the strap under the head covering.

4.11.1.5 Head and Neck Coverings

The hair and skin on the neck and head must also be protected. Rubber or plastic rain hats, wide-brimmed hats, bill caps, and hard hats that can be washed are good. In cool weather, waterproof parkas with hoods and bill caps are also effective. Avoid cotton or felt hats; they absorb the pesticide.

4.11.2 Respirators

Respirators prevent the inhalation of toxic chemicals. They should be worn whenever toxic pesticides are applied. The label will indicate if a respirator is needed. Respirators are especially necessary whenever concentrated highly toxic pesticides are handled. Always wear a respirator when mixing or pouring highly toxic pesticides. Applicators who will be constantly exposed to small amounts of less toxic pesticides for a day or several days should also wear a respirator.

4.11.2.1 Cartridge Respirator

The cartridge respirator is usually a half-face mask that covers the nose and mouth only. It contains one or two cartridges that absorb toxic fumes and vapors of chemicals and filter the air breathed. These respirators are used either for relatively short exposure periods to concentrated chemicals or for a long exposure period to low concentrations of toxic chemicals. Goggles, if necessary, are worn separately. The main limitation of this type of respirator is the leakage that usually occurs around the face shield. Make sure the correct replacement cartridge is used.

4.11.2.2 Gas Mask

Gas mask respirators cover the entire face and protect the eyes as well as the nose and mouth. They contain better filters and more absorbing materials to cleanse the air than the cartridge respirators. Gas masks are used when the applicator intends to be exposed to toxic fumes either in heavy concentrations or for long periods of time. Some gas masks are connected to an independent oxygen supply and the contaminated outside air is not used. These are useful when applicators are exposed to unknown vapors as a result of accidents or fires or when they reenter fumigated areas.

4.11.2.3 Use Respirators Correctly

The respirator should fit properly on the face. It should be worn tightly enough to form a seal around the face. If the headband is too tight, however, headaches and/or dizziness may result.

Check the filter (the clothlike outer layer) of the respirator often. Replace it when it looks dirty or if breathing becomes difficult. Cartridges should be changed after every eight hours of use. If a pesticide odor is noticed, first check to be sure the respirator is sealed around the face. If the odor persists, change the cartridge immediately.

After each use, wash the face shield with detergent and warm water. Rinse it thoroughly and wipe it dry with a clean cloth. Store the respirator, filters, and cartridges in a clean dry place away from pesticides. A tightly closed plastic bag works well for storage.

4.12 Commonsense Precautions

Always work in pairs when handling highly toxic chemicals. Watch coworkers carefully for unusual behavior or actions. Remind them (and yourself) to wash face and hands before eating, drinking, or smoking. Never use the toilet before washing your hands. Avoid getting toxic pesticides on any area of the body. At the end of the day, remove contaminated clothing carefully and put it well away from the family laundry. Shower and clean thoroughly from head to toe. Pay particular attention to fingernails and hair where pesticides could remain.

4.12.1 Cholinesterase Tests

Consider having your blood tested to find your normal or base level of a chemical called cholinesterase. This chemical is necessary for the nervous system to operate properly. Both carbamate and organophosphate pesticides attack this chemical in your blood and make it useless. Once your base level of cholinesterase has been determined, a simple blood test will show if you still have the normal amount. If you do not, you have been overexposed to either an organophosphate or carbamate pesticide. You should avoid further contact with these pesticides until your cholinesterase level has returned to normal. In severe cases, antidotes must be given. Follow your doctor’s directions. All applicators working with highly toxic chemicals should have their cholinesterase levels tested at regular intervals.

4.13 Symptoms of Pesticide Poisoning

You should be aware of the early symptoms of pesticide poisoning. It is important to remove the person from the source of exposure quickly. Remove contaminated clothing and wash off any chemical that has soaked through. You may save a life.

4.13.1 Is It Pesticide Poisoning or Not?

The symptoms of pesticide poisoning are similar to those of other types of poisoning and diseases. Heat exhaustion, food poisoning, and asthma are sometimes confused with pesticide poisoning. Just because one becomes ill after using or being around pesticides is not proof that one is poisoned.

The symptoms of poisoning described here may occur in a person who has been suddenly exposed to large quantities of a toxic material, or they may occur in a person who has been continuously exposed to smaller quantities of toxic material over a long period. If symptoms appear, call and tell your doctor what pesticide was involved. If you don’t know whether poisoning has occurred, let a doctor decide.

4.13.2 Kinds of Poisoning

· Acute

Pest Management Guidelines A Cornell Cooperative Extension Publication	Cornell Guide for Pest Management of Greenhouse Floral Crops
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