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The CATs analysis of chemical use on vineyards revealed widely varying amounts and types of pesticides, even on adjacent properties. vineyards that use huge amounts of pesticide stand next to those which practice organic flirming, and this variability oc~urs throughout wine country.
Sulfur, used by both organic and agrichemical farmers as a fungicide in grape growing, is the one pesticide applied to every vineyard- and thus it can serve as an indicator of the variability of pest management practices. Our survey found that annual rates of sulfur use range from a low of 25 pounds to more than 425 pounds per acre, sometimes within the same microclimate.
Because sulfur-use rates vary radically even among vineyards that are close enough together that weather, types of pests, kinds of soils and other environmental factors are similar, it follows that the extreme divergence in pesticide use in general is almost entirely the result of different approaches to vineyard management. Furthermore, if it is management rather than environinental factors that determine pesticide use, then vintners in many instances can be educated often by their own colleagues - on how to avoid the use of such chemicals.
The following examples illustrate the divergence in pesticide use among vineyard managers who grow grapes in the same vicinity. In preparing these examples we examined vineyards along the Russian River in Sonoma County and in several areas of Napa County, but similar examples can be found in every area of wine country.
The information on which the analysis is based was obtained by painstaking review of public records of pesticide application which are filed by every Califomia farmer with the local county agriculture commissioner.
*Special note: In this report pesticide use is from records for 1995. Pesticide quantities are described in full formulation amounts, grouped together - and identified- by the active ingredient. Chemicals referred to as "adjuvants," those products designed to facilitate the application of pesticides, are listed as a group.
Pesticide quantity is reported by the pound or by the gallon, depending on whethcr the chemicals are packaged in dry or liquid form.
Liquid volumes are reported as gallons although each gallon of pesticide weighs at least seven pounds, and most weigh much more.
Only sulfur, which is analyzed as a benchmark pesticide for the purposes of this report, and pesticides used on established vineyards, are analyzed in the examples which follow Pesticidal soaps are not included in the analysis nor are methyl bromide and chloropicrin, the latter two because their use occurs just once in advance of planting, soap because it's considered low in toxicity although little is known of its health and environmental effects.
Per acre rates of pesticide application describe the combined volume of the non-sulfur analyzed pesticides reported by grape growers in 1995.
Pesticide use data for this report is derived from Pesticide Use Reports which are submitted to each county Agricultural Commissioner under California law. Unfortunately the Napa County database, unlike that of Sonoma County, is ofien incomplete. Because we were unable to link pesticide use to many vineyards located in Napa County information regarding the ainount of pesticides used by some growers could not be reported.
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