Pesticide Storage, Handling, and Application - Introduction

Table of Contents

1. Cultural Control
2. Chemical Control
3. Biological Control
4. Physical Control
5. Genetic Improvements
6. Benefits
7. Risks
8. Fate of Pesticides in the Environment
9. How Pesticides Can Contaminate Water Resources
10. Available in Published Version of Pesticide Storage, Handling and Application

Pesticide products are very useful tools in agricultural production. Used correctly, they contribute to higher productivity and higher quality characteristics in crops. By protecting crops from pests, pesticide products also contribute to the economical, safe, and nutritious variety of foods consumers enjoy.

As well as the benefits of pesticide use, there are risks to humans, livestock, wildlife, and the environment. Potential problems can be avoided by understanding these risks and knowing how to manage them.

The intent of this book is to help you learn how to store, handle, and apply pesticides in a safe and cost-effective manner. The next two sections describe the details of storage and handling structures as well as the management practices to make them work. The final section describes the principles of application, how to select and care for application equipment, and the best management practices to keep products on target and out of natural resource areas.

For the purposes of this book, a pest is any harmful or troublesome organism that causes an unacceptable level of loss in crop yield or quality. Pests include weeds, insects, diseases, or even animals such as rodents or deer. A pesticide is any chemical designed to kill or control a pest. The emphasis in this book will be on insecticides, fungicides, and herbicides.

Cultural Control

Figure 1. Crop rotation and the use of disease-resistant varieties of crops are examples of cultural control.

Chemical Control

Figure 2. The application of pesticides by sprayers is a chemical method of pest control. Pesticides are substances used specifically to control pests like insects, weeds or diseases.

Biological Control

Figure 3. Parasites are used to control white-fly in greenhouses. This is a biological method of pest control, where a living organism is being used to kill another living organism (i.e. the target pest). Predators of the pests are introduced to the crop.

Physical Control

Figure 4. Physical control removes the pest from or prevents its entry into the crop. Power vacuuming, propane flaming and plastic-lined trenches (above) have been tested against the Colorado Potato Beetle. Cultivating weeds is another means of physical control.

Genetic Improvements

Figure 5. More modern methods of control involve genetic engineering of the crop to give it natural resistance to a pest. Other examples are the release of sterile insects and breeding disease-resistant and herbicide-resistant plant varieties.

Benefits

When used properly, pesticides provide an economical method of managing pests in just about every crop produced in Ontario. They provide the following benefits:

• crop protection from damage and yield losses due to competing organisms
• moderate- to low-cost control method
• improved product quality
  • blemish-free fruit
  • insect-free vegetables
  • higher-yielding grain crops
• harmful pests, some of which produce human disease and dangerous toxins, prevented from reaching our food supply
• improved harvestability when weeds and other pests are controlled
• improved yields on productive land
• more choices in crop production
• part of an integrated approach to controlling pests.

Consumers expect blemish-free fruit and insect-free vegetables. Pesticides help control damage to high value crops.

Figure 6. Apple crop

The average citizen may not recognize the impact of pests on the food supply. Worldwide, losses due to plant pests are high: field and storage losses are estimated to be as much as 40% - in spite of a multitude of pest control options.

Figure 7. Cabbage

Risks

Certain pesticides, when they are not stored, handled, or applied properly, can lead to:

• human exposure to toxic materials, which may cause injury, death, or long-term health effects (e.g., cancer, asthma)
• contamination of water, air, soil, and habitat
• direct wildlife exposure to toxic materials that may harm natural predators, pollinators, beneficial soil organisms, fish, birds, and other wildlife - particularly with spills, but also with drift and leaching into water bodies
• bio-accumulation of some products in body tissues - this presents a risk to the food chain
• excess residue on food through overuse and/or improper timing of use on food products such as fruits and vegetables - this could lead to seizure of the crop
• pest resistance, which occurs when the same material or products within the same chemical group are used continually
• economic losses due to crop damage or poor pest control
• disruption of natural control agents. Many pesticides are non-selective and upset the predator-parasite balance. The removal of natural pest control increases dependence on chemical pesticides.

Figure 8. Carcass of a Mallard duck

Risk = Toxicity x Exposure

Some pesticides that protect crops can be directly harmful to wildlife. Choose chemicals with less toxicity. This carcass of a Mallard duck was found in a cabbage field treated with insecticides.

Fate of Pesticides in the Environment

Pesticides dissipate at varying rates. Simple chemicals often dissipate more quickly than complex chemicals.

The physical and chemical properties of pesticides influence their potential to harm the environment. The most important properties to know are:

• degradation - ability to break down in the environment
  • the longer a pesticide takes to degrade, the greater the risk for water contamination
  • generally, complex chemicals like some organophosphates last longer since they can't be broken down readily by soil microbes
  • soil conditions that provide excellent habitat for microbial growth may also lead to more rapid rates of degradation
• volatility - ability to move into the air, e.g., hormone herbicides
• solubility in water - ability to leach into groundwater, e.g., metalochlor can leach more readily than atrazine
• adsorption - binding characteristics with soil particles, e.g., triazines bond to soil particles
• absorption - ability to move into organisms or structures
• bio-accumulation - ability to accumulate in body tissues.

These properties, combined with processes such as runoff, leaching, wind and water erosion, and vapour drift, determine what happens to a pesticide and where it ends up after it's released into the environment.

When present in soil, pesticides degrade over time. Dissipation is the lowering of pesticide concentrations in a specified area (soil, plant, atmosphere) due to the combination of biological, physical, and chemical activities such as photodecomposition into other chemicals.

Figure 9. How Pesticides Degrade: at no days after treatment, average concentration is at ~200 ppm; at 1000 days after treatment, concentration is at >50 ppm.

How Pesticides Can Contaminate Water Resources

Potential for Groundwater Contamination

Figure 10. Pesticides or pesticide breakdown products from improperly stored containers can contaminate groundwater resources

Pesticides and their breakdown products can contaminate surface water and groundwater resources by following the pathways of the water cycle or by artificial means. Therefore, care must be taken in areas of porous soil materials, shallow aquifers, poorly protected wells, and concentrated storage or use of pesticides.

Groundwater is recharged by surface water, precipitation, snowmelt, and irrigation waters that percolate through soil and geological materials. The more porous or fractured the materials and the shallower the groundwater resource (aquifer), the higher the rate of recharge.

Ponds and wells, including abandoned ones, not only access aquifers but can also provide direct conduits for infiltrating waters.

For information on safeguarding wells from contamination, see Water Wells, a Best Management Practices book.

Potential for Surface Water Contamination

Figure 11. Surface waters can be contaminated by pesticides through leakage, spills, and surface runoff.

Not all water infiltrates the soil. About 10% runs off. Rates of runoff increase with slope, lower infiltration rates (e.g., clay soils), and higher volumes of water due to snowmelt, rainfall, and storms.

Sometimes, runoff from farmland will reach natural areas such as watercourses, ponds, and wetlands. There is a higher risk to natural areas when the rate of runoff is high, the distance from source is short, and there is no barrier in place to divert the flow. Some pesticides will follow this path of the water cycle: this is particularly a concern in the case of a spill. Some pesticides, like triazines, attach to soil particles and can contaminate natural areas if best management practices are not put in place to control erosion and reduce runoff.

The label instructions reflect all the known properties of the product. Follow the directions carefully to minimize risks to people, livestock, wildlife, and environmental concerns.

Available in Published Version of Pesticide Storage, Handling and Application

• A Century of Development
• Fate of Pesticides in the Environment Flowchart
  

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