Use of air-assist sprayers is one tactic to direct sprays onto the desired target and reduce potential for offsite drift.

We Often it is necessary to utilize pesticides as a portion of an integrated pest management program in the nursery. One of the most important considerations in preparing to make a pesticide application is to take all steps necessary to ensure that only the targeted pest and application site are treated during the application. Failure to do so can result in unintended damage to the environment. Following the pesticide label instructions
related to environmental hazards will help prevent any adverse effects on the environment and living things.

Point- and Non-Point Pollution
When one specific area or point is identified to have caused pollution to the environment, it is considered point-source pollution. An example of point-source pollution was when a train wreck in California resulted in the release of a pesticide into a nearby river. If a pesticide is detected in surface water downstream from broadcast applications to fields, the pollution is defined as non-point source. If pesticides applied to a field drift off site into a stream, then the pollution would be considered non-point.

A tactic to reduce potential point-source pollution is mixing and loading pesticides on an impervious surface, such as concrete, and capturing any pesticide, spray mix, or rinsate spills. Applying all sprays in a manner that results in the lowest probability of a pesticide moving off-site and impacting vulnerable species will reduce the potential of non-point source pollution.

Sensitive Areas
As a pesticide handler, you must be aware of the potential for environmental contamination during every phase of an application. Some questions to consider include:

• Are there areas within or near the use site that might be sensitive to the effects of the application?
• Are there environmental conditions at the time of application that may cause the pesticide to move off site?
• Are there procedures in your application techniques or use site that may need to be changed to reduce
  the risk of contamination?

Sensitive areas are sites or living things that may be easily injured by a pesticide. It is important to use information provided on the pesticide label to determine what vulnerable sites are within or adjacent to an area about to receive an application of pesticide.

For outdoor pesticide applications, some sensitive sites that may be encountered are: wells, depressions, or sink holes where groundwater is easily accessible; areas near surface water; schools, playgrounds, hospitals, or other institutions or public places; apiaries, wildlife refuges, parks, or pastures with domestic animals;
and ornamental plantings, food, feed crops, or other sensitive plantings.

If a sensitive area is part of a larger area receiving a treatment, a non-treated buffer left around the sensitive area may be required to avoid injury to it. If sensitive areas are adjacent to permanent pesticide mixing/loading or storage sites, steps such as collection pads made from impervious surfaces to catch and contain leaks, spills, or wastewater are utilized to prevent inadvertent contamination.

A tactic to reduce potential pointsource pollution is mixing and loading pesticides on an impervious surface, such as concrete.

Pesticide Movement
Movement of pesticides away from the intended treatment area has the potential to cause environmental contamination of sensitive areas. Pesticides move from the application in air through action of wind and other air currents, in water as leaching or runoff, and as residues on plants or animals that move or are moved off site.

Pesticide movement away from the intended application site in the air is known as drift. Pesticide formulations containing very lightweight particles such as dusts and wettable powders or those that form a gas or vapor phase have the highest potential to be moved in an air current. In indoor areas like greenhouses, air currents caused by ventilation systems or forced air heating/cooling systems have the potential to cause drift to sensitive areas.

Pesticides in water may move into sensitive areas through leaching to groundwater or runoff in surface water. Pesticides may have been introduced to the water by spills, leaks, or back siphoning into the water source at mixing sites or by improper disposal of pesticide containers and rinsates. Too much irrigation or rainfall after an application can lead to the movement of pesticides from treated surfaces into sensitive areas through both leaching and/or runoff.

It is essential to be aware of any environmental hazard statements on the pesticide labeling related to offsite movement of the product before making the application. Oftentimes the water solubility of a product is so high that it might be prohibited from application in areas where it could be easily leached to groundwater, or non-treated buffers may be required around area ditches, streams, and ponds to prevent runoff-containing pesticide from contaminating surface water.

Gary K. England is a regional specialized Extension agent II – Commercial horticulture in Sumter, Citrus, Hernando, and Pasco counties.