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Citrus Industry Magazine CEU 2011 Articles Test Series: Article # 4

Pesticide best management practices

By Tim Gaver and Steven H. Futch

Posted Sept. 1, 2011 (expires Sept. 1, 2012)

The Office of Agricultural Water Policy (OAWP) was established by the Florida State Legislature in 2007 to facilitate communications among federal, state and local agencies, and the agricultural industry on water-quantity and water-quality issues involving agriculture. The OAWP is part of the Florida Department of Agriculture and Consumers Services (FDACS) and cooperates with the Florida Department of Environmental Protection, the University of Florida-IFAS, water management districts, agricultural producer groups and industry organizations to develop best management practices (BMPs) that are economically and technically feasible. Correcting existing water quality and quantity problems and enlisting agricultural operations to minimize future problems are the priorities of the voluntary BMP program.

The first citrus BMP manual in Florida was generated by a large working group of interested growers, researchers and regulatory personnel for the Indian River production area and was published in 2000. Since that time, BMP manuals have been developed for the Ridge, Gulf and Peace River citrus-growing areas. Manuals have also been generated for other segments of Florida agriculture, including vegetable and agronomic crops, sod, container nurseries and the Florida specialty fruit and nut crops industry.

Pesticide BMPs are important components of the citrus BMP manuals, as pesticide detections in water bodies are important indicators of water quality. These detections, however small, are of concern because of their potential toxicity to non-target fish, invertebrate, plant and wildlife species in all of our surface water bodies. The pesticide BMPs published in the manuals utilize the information from literally dozens of published sources to provide scientific background and direct agricultural producers to a ready source of information to incorporate into their operations. Providing pesticide application training to employees on a frequent basis is an additional part of the BMP program. Employees who understand how to apply pesticides correctly are more likely to follow the recommended BMP practices and minimize the potential for misapplication of agricultural chemicals.

Virtually all aspects of pesticide application are addressed in the citrus BMPs. Topics include integrated pest management (IPM), storage and transport, calibration of application equipment, mix-load sites, spray drift reduction, calibration of application equipment and other issues. These BMPs are practical recommendations that focus on real problems and solutions that work when conducted in the agricultural operations.

The following paragraphs highlight some of the practices that are recommended in the pesticide BMP topic categories:


An IPM program utilizes all applicable biological, mechanical, cultural and chemical methods to systematically manage pests which can adversely affect people and/or agriculture. IPM does not mean that pesticides cannot be used, but are only used when necessary, which should result in a reduction of the total amounts of pesticides used. Learning to correctly identify both key pests and beneficial organisms, and the factors that influence their populations, is helpful in managing those populations. It is important to know the relationship between pest populations and damage thresholds to avoid unnecessary applications. Selecting pesticides that are “soft” on beneficial organisms may prevent the resurgence of pests that are normally kept in check by the natural predators. Frequent scouting in combination with detailed recordkeeping of scouting results will help to predict pest population trends and perhaps avoid having to treat very high pest populations that are difficult to control.


If it is determined that a pesticide application is needed, selecting an appropriate product should be based on effectiveness on the target pest, effects on non-target organisms and cost, as well as its solubility and persistence. As an example, pre-emergence herbicide products require some measure of persistence in the environment to be effective. However, because many of these products are held by soil particles and organic matter at the soil surface, they will resist leaching if applied correctly. Applications just prior to heavy rainfall events or to very wet soils should be avoided to minimize leaching of the herbicide material into ground or surface water sources.


Drift is defined as spray particles or droplets that do not contact the target (crop) and move off-site to non-target sites. Several factors may contribute to drift, including excessive wind speeds, droplet size or nozzles on the sprayer that are not properly oriented into the target site. Applications should be made when wind is not blowing toward sensitive areas such as homes or surface water bodies, and when wind speeds are less than 10 mph. Nozzles on airblast sprayers should produce droplets that are larger than 150 microns in diameter. Utilizing the lowest pressure setting that results in adequate spray coverage and canopy penetration will help reduce the number of smaller spray droplets produced by the nozzles. Nozzles should be adjusted on the sprayer manifolds to avoid excessive overspray above the tops of the trees. Low-volume equipment that applies as little as 2 gpa for Asian citrus psyllid control should be used on relatively still nights and calibrated to produce spray droplets with a mean droplet size of 100 microns to reduce potential spray drift.


Operators should be trained to turn the sprayer nozzles off at the trunk of the last tree in each row. When spraying is completed within the block, a final pass around the outside of the block with only the inside nozzles on will finish the spray job (wrapping). Valves controlling the flow to each side of the sprayer should close completely when not in use to avoid spray leakage onto non-crop areas.


Pesticide products should be kept in a well-ventilated and locked concrete or metal building that is located at least 50 feet from other structures. Signs should be placed on the building indicating the contents of the building. Plans for pesticide storage structures are readily available. Structures should be designed with concrete floors and internal curbs to prevent any spilled material Pesticide best management practices By Tim Gaver and Stephen H. Futch This is a CEU article that grants one General Standards (CORE) CEU when submitted and approved. from escaping the structure. More elaborate structures may include automatic exhaust fans, an emergency wash area, explosion-proof lighting with external switches and/or other features.

Crop protection products should not be stored with feed, seed or fertilizers. Personal protective equipment (PPE) should also be stored in a separate area away from pesticides. A current inventory of pesticides should be maintained, along with pesticide labels and Material Safety Data Sheets (MSDS) in a separate location.

Pesticides should be stored in their original containers and regularly inspected for leaks and tears. Do not store liquid materials above dry products. Product containers with damaged labels should be used immediately or relabeled with a product label that is securely fastened to the container. Herbicides, fungicides and insecticides should be stored in different areas of the storage facility to avoid mishandling or cross-contamination.


Calibration is defined as the process of measuring and adjusting equipment performance. In the case of the citrus grower, this means working with airblast and concentrate sprayers, herbicide machines, chemigation equipment or perhaps soil-drench injection equipment to apply the proper amount of pesticide to a target area. As a pesticide applicator, you are bound by law to apply the correct amount of pesticide to crop areas as indicated on the pesticide label. Applying pesticides with equipment that is not properly calibrated can result in product failures when less than the correct amount of product is applied or phytotoxicity and excessive costs when too much product is applied. The possibility of pesticide movement off of the target site into water sources is also increased when too much pesticide is applied.

Application equipment should be in good working order and the calibration checked frequently to ensure that the proper amounts are being applied. Equipment operators should be issued written instructions or work orders detailing the correct travel gear, engine rpm and the output pressure of the application equipment used.


Permanent mix/load sites represent an opportunity to very effectively manage the accumulation of pesticides where spill-prone activities are conducted. An impermeable surface such as sealed concrete, surrounded by a raised berm, can direct spilled materials to a sump where it can be collected at the end of the day and then applied at less than labeled rates to a labeled site.

When permanent mix/load sites are not feasible, portable mix/load stations may be utilized. Utilizing portable mix/load pads in combination with these stations can help to reduce the amount of spillage that reaches the soil. Where water is drawn directly from ditches or canals, spills can be prevented from reaching surface water sources by utilizing a containment system or berm. Avoid using the same location to mix or load pesticide application equipment to minimize the risk of pesticides accumulating from repetitive spills. Pumps used to draw water should have at least two backflow devices installed to prevent pesticides from being siphoned back into the water source. These devices may include an air gap at the fill point, check or foot valves and/or vacuum breakers.


Records of the application of all restricted use pesticides (RUPs) must be maintained as required by the Florida Pesticide Law. For restricted use pesticides, these records must be maintained for at least two years after the application date. The federal Worker Protection Standard (WPS) requires that a record of all pesticide applications must be posted at a central location within two days after the application and for at least 30 days after the restricted entry intervals (REIs) for these applications expire.

These recommended practices are only a small portion of those found in the detailed citrus BMP manuals. For those growers who are not currently participating in the BMP process, access to these documents can be found at the IFAS BMP website http://citrusbmp. or the FDACS Office of Agricultural Water Policy website

Tim Gaver is an Extension agent at the St. Lucie County Extension Service, Fort Pierce, and Stephen H. Futch is an Extension agent at the Citrus Research and Education Center, Lake Alfred.