Good Management Practices for Agricultural Pesticide Use
Pesticides are widely used to protect crops and livestock from losses due to insects, weeds, and diseases. The Environmental Protection Agency (EPA) has estimated that 70% of the total pesticide use is for agricultural production, with the remaining 30% used in the urban, industrial, forest, and public sector. These chemicals have helped to increase agricultural production with reduced labor. However, problems associated with improper pesticide use have led to human illness, wildlife losses, and water quality degradation. The major groups of pesticides include insecticides, herbicides, and fungicides. Herbicides are the most widely used class of agricultural pesticides and subsequently have been the most frequently found in ground and surface water. Until fairly recently, it was thought that pesticides applied to agricultural fields were broken down or tied up before they could reach groundwater. However, the development of extremely sensitive detection methods has led to the discovery that commonly used management practices may lead to small amounts of pesticide contaminating ground and surface water supplies. Since rural residents depend on these water supplies, agricultural producers need to exercise a high level of management to avoid contamination.
Contamination from normal pesticide application is called nonpoint contamination, since a single point of contamination cannot be identified. Point source contamination would include spills of concentrated chemicals at storage, mixing, or loading sites. These point source problems are addressed in the document BMPs for Pesticide and Fertilizer Storage and Handling. Since pesticides are an important tool for most farming operations, and cleaning up contaminated groundwater is extremely difficult, producers need to evaluate their use of pesticides and adopt BMPs that are appropriate for their crops and site. Fortunately, a number of crop management and pesticide application practices are available that can be used to reduce potential contamination of water supplies.
Pesticide Use Practices
Although pesticide use is a standard practice in most agricultural operations, many producers are adopting an Integrated Pest Management (IPM) approach. IPM techniques can reduce pesticide use to the minimum amount necessary to produce high quality food, while maximizing profits.
IPM combines chemical control with cultural and biological practices to form a comprehensive program for managing pests. This approach emphasizes preventive measures to maintain pests below the economic threshold while using the minimum amount of pesticide necessary. However, using the proper pesticide at the time of maximum pest susceptibility is often critical to an effective IPM program.
IPM is the primary BMP for pest management. It includes practices such as:
- Monitoring pest and predator populations selecting crops and varieties that are resistant to pest pressures timing planting and harvest dates to minimize pest damage rotating crops
- Employing beneficial insects and other biological controls.
- Changing your pest management strategy to an IPM program may involve modifying tillage, fertility, cropping sequence, and sanitation practices.
- This may require some experimentation and perhaps even professional help.
Pesticide Application Practices
When pesticides are required to control pests, it is important to use application techniques which lessen potential water quality impacts. All applicators should become certified and remain current in new developments in pest management. Pesticides should be applied at a time when they will be most effective against the crop pest. Pest cycles are influenced by temperature and moisture conditions. In many cases, pests under dormant or stressed conditions may not be susceptible to pesticide treatments.
Apply the lowest labeled pesticide rate that adequately controls pests. Lower rates reduce the total amount of chemical in the environment. Rotate pesticides among chemical families to minimize pest resistance. IPM does not rely on continuous use of a single pesticide or pesticide family. Avoid pesticide applications during adverse weather, especially windy, wet conditions. Do not apply volatile chemicals such as 2, 4-D ester or methyl parathion under high temperature conditions.
- Apply pesticides only when needed and use in a manner that will minimize off-target effects.
- Obtain thorough training and the appropriate certification prior to any pesticide use.
- Read all label instructions prior to chemical mixing.
- All pesticide applications must follow label specifications and must be applied only to the crops for which the product is registered for use.
- Keep precise pest and pesticide records. (See Pesticide Recordkeeping Form for suggested format.)
- Consider the effects of pest control measures on the environment and non-target organisms. Minimize chemical reliance by rotating crops and using mechanical, biological, or cultural pest management measures whenever feasible.
- Avoid the overuse of preventive pesticide treatments.
- Base pesticide application on site-specific pest scouting and indicators of economic return.
- Select least toxic and less persistent pesticides when feasible.
- Consider pesticide and target site characteristics to determine suitability of the pesticide at that location.
- Knowledge of pesticide persistence, mobility, and adsorption should be included in pesticide selection.
- Chemical applicators should know the characteristics of the application site, including soil texture, organic matter, topography, and proximity to ground and surface water.
Pesticide Application GMPs
- Maintain application equipment in good working condition and calibrate equipment frequently to ensure recommended rates are applied. Replace all worn components of pesticide application equipment prior to application.
- Ensure that the pesticide applicator knows the exact field location to be treated. Post warning signs around fields that have been treated, in accordance with local, state, and federal laws. Follow the established re-entry time as stated on the label.
- Employ application techniques which increase efficiency and allow the lowest effective labeled application rate. Use band and spot applications of pesticides where appropriate to reduce environmental hazards and treatment costs.
- Avoid unnecessary and poorly timed application of pesticides. Optimize pesticide rate, timing, and placement to avoid the need for re-treatment.
- Avoid overspray and drift, especially when surface water is in close proximity to treated fields.
- Time pesticide application in relation to soil moisture, anticipated weather conditions, and irrigation schedules to achieve the greatest efficiency and reduce the potential for off-site transport. Avoid pesticide application when soil moisture status or scheduled irrigation increases the possibility of runoff or deep percolation. After application, manage irrigation to reduce the possibility of erosion or leaching which may transport pesticide from the target site.
- Establish buffer zones where pesticide is not applied a safe distance (minimum of 50 to 100 feet recommended) from wells and surface water.
- Avoid repetitive use of the same pesticide, or pesticides of similar chemistry, to reduce the potential for pesticide resistance development and shifts in the pest spectrum.
- Ensure that backflow prevention devices are installed and operating properly on irrigation systems used for applying pesticides.
Pesticide Safety GMPs
- Read and follow label safety directions, maintain appropriate Material Safety Data Sheets (MSDS), and become certified prior to applying restricted use pesticides.
- Wear the appropriate protective equipment specified on the chemical label to minimize unnecessary exposure to pesticide. Be sure to clean protective gear after each day’s use.
- Provide emergency hand and eye wash facilities for personnel who might be accidentally exposed to chemicals, and formulate a safety plan complete with information about locations of emergency treatment centers for personnel exposed to chemicals.
- Know what to do in case of accidental pesticide poisoning. Have a pesticide first aid kit available when handling pesticides. Check the product label for instruction and call the nearest poison center in the event a pesticide is swallowed.
GMP when harvesting surplus cereal straw
Stubble height and residue amount required for erosion control
Tall stubble provides greater protection against wind and water erosion and improves soil moisture conservation through trapping snow and reducing evaporation losses. Tall stubble also helps maintain the surface soil in a moist state, which improves seedbed conditions for shallow seeded crops. Therefore, stubble should be cut as tall as possible without causing problems with plugging of seeding equipment.
Generally, the stubble height can be similar to the row spacing of the seeder. Most air-seeders have row spacing of eight to 12 inches, so stubble height can generally be from eight to 12 inches. With direct seeding equipment that has four ranks of knife openers, some growers successfully manage stubble heights up to 1.5 times the row spacing. Newer direct seeding equipment with coulter or disc openers is able to handle taller stubble with few plugging problems. In most years, shallower seeding results in less soil disturbance and better, more uniform crop emergence.
Slower speeds during seeding disturb less soil and bury fewer residues.
Anchored, standing residue is much more effective for erosion control than loose, unanchored residue.
Where surplus straw is harvested, direct seeding practices provide the Good opportunity to maintain sufficient residue to protect the soil. To consistently maintain adequate residues, zero-till management practices are required.