The use of pesticides can be a hot button issue for those of us who are not involved with agriculture. This presentation will review some definitions and will discuss the risks of pesticide use and how government regulators and growers deal with these risks to protect crops, the public and the environment.
Most people think pests are bugs and pesticides are poisons used to kill them. Actually, bugs, or insects, are only one type of pest. There are many types of pests, the most common in the vineyard setting are:
- Insects and mites - insects have 6 legs and mites are spiders with 8 legs. These pests feed on leaves and fruit. Examples are grape leaf hopper and Glassy Winged Sharpshooter.
- Diseases - include fungus (powdery mildew, botrytis bunch rot), bacteria (Pierce's Disease) and virus (leaf roll).
- Weeds - compete with vines for nutrients and water
- Vertebrates - like birds and gophers, which feed on the fruit and even the vines themselves.
All these pests cause enough damage to produce significant economic loss to the grower. Pesticides are chemicals used with the intent to control these and other pests. Pesticides make up a large group of chemicals, including living pest-destroying organisms like Bacillus thuringiensis as well as household products like toilet bowl cleaners and disinfectants. There are lots of new pesticides coming out that are softer on the environment and attack the specific target pest, without harm to beneficial insects. Pesticides are expensive and hazardous and most growers only use them when necessary. Pest monitoring and other integrated pest management practices aimed at reducing pesticide use are covered by another presentation. Common vineyard pesticides include:
- Insecticides and miticides for insects and mites
- sulfur dust for powdery mildew
- various fungicides for botrytis and other fruit rots
- Roundup and other herbicides for weeds
- Baits for gophers and rabbits.
Because most pesticides are designed to be toxic to their target pest - and because any substance can be harmful if used improperly - pesticide use is strictly controlled. Three groups are at risk from pesticide exposure - those who mix, load and apply pesticides, those who work in the fields that have been treated with pesticides and the rest of us who do not live or work on the farm. In addition, we want to protect the environment from inadvertent exposure to toxic materials. So how is pesticide use controlled?
All pesticides are registered by State and Federal regulatory agencies. A grape grower may not apply a pesticide unless it is registered for use on grapes. Each pesticide comes with a label which contains valuable information about how to apply the material, safety requirements, permitted rates of application, what to do if there is an accident, what crops and pests the material is registered for and EPA registration numbers. The label tells us what protective gear is needed, how much time must pass before workers can reenter the field and how much time must pass before the crop can be harvested. In addition, the label tells us the relative toxicity of the material based on toxicology studies. Caution, Warning and Danger signify the three categories of pesticide toxicity. All this information is contained in the label.
The label contains this information to assure proper application and to protect pesticide loaders, mixers and applicators. In addition, operators are required to train each applicator and field worker on all the pesticides used in that vineyard. Training includes requirements for storing, using and disposing of pesticides and their containers. Symptoms of pesticide poisoning are covered as are do's and don't for avoiding exposure. Protective gear includes gloves, coveralls, respirators and eye protection. For each treatment, the operator must keep detailed records and either post or verbally warn every employee on each treatment, including the blocks treated, materials used and reentry period. Pesticide Use Reports must be turned in monthly to the County Ag Commissioner. Did you know these reports are available to the public?
The public and the environment should also be protected from exposure to pesticides. Proper applications put pesticides on the target plant or pest, while avoiding drift or other contamination. Many growers do their applications at night when the air is still and there is no drift. Mixing and loading of the concentrated chemicals must not be done near waterways or wells where water contamination may take place. Special care is needed when treatments take place near homes or schools. A Department of Pesticide Regulation task force including regulators and growers is finalizing recommended practices to avoid drift of sulfur dust. These practices include buffer zones around homes and other non-farm uses. Increasingly growers are taking responsibility for their pesticide applications. This is due to increased regulation (or the threat of such) and a conservation ethic that wants to protect the environment and the long-term productivity of vineyards in Napa Valley.
Pesticides are toxic and everyone should be concerned by their use in agriculture, as well as parks, schools, railroad tracks, homes and other places were pests must be controlled. Education, regulations and the public's demand for a clean environment and food supply motivate growers to find alternatives to pesticides. Efforts like those of the Napa Sustainable Winegrowing Group are helping growers find ways to prevent and manage pest problems without pesticides. Despite the continued development of Integrated Pest Management, pesticides remain a valuable tool for growers. Armed with modern approaches to pest control, new reduced risk pesticides and adherence to strict government regulations, growers today can control pests while minimizing the risk of exposure to employees, the public and the environment.
For more information on pesticides and their use, see the following references:
- Napa County Agricultural Commissioner,1710 Soscol Ave., Suite 3, Napa, CA 94559-2977, (707) 253-4357; the local regulatory agency; County pesticide use data
- California Department of Pesticide Regulation, 1001 I Street, Sacramento, CA 95814-2828, (916) 445-4300, www.cdpr.ca.gov; contains reports and information about pesticides and their use in California, regulation information and lots of pesticide links
- University of California Statewide Integrated Pest Management Project, www.ipm.ucdavis.edu; contains pesticide use summaries and pesticide registration information as well as lots of information on Integrated Pest Management
- U.S. Department of Food and Agriculture, www.usda.gov; contains pesticide databases
- U.S. Environmental Protection Agency, www.epa.gov; excellent section for kids, students and teachers