VARIABILITY IN PESTICIDE USE AS A FACTOR IN MEASURING AND BRINGING ABOUT REDUCTION IN PESTICIDE USAGE IN APPLE ORCHARDS

摘要

National pesticide reduction targets have largely been based on a percentage reduction in either the number of sprays applied or tonnage of pesticide used or both, These approaches imply a uniformity in pesticide use among the farmers comprising the industry. Data from a three-season integrated pest and disease management study in New South Wales, Australia, showed over 200% variation in the number of both fungicide and insecticide sprays applied by different apple growers in the same season. The total amount of pesticide applied (in kilograms per hectare) also varied between farmers by around 200%. Regression analysis showed no correlation between the number of fungicide sprays applied and the percentage of fruit infected with apple scab or between the number of insecticide sprays and the amount of insect damage recorded. Observations were made in ten orchards where pest and disease levels were monitored and advice given, and in a further ten orchards where no advice was provided. Decisions on fungicide use were left to the farmers in both groups, but advised growers were requested to use reduced rates of protectant fungicides. Pest control recommendations were based on thresholds. Except in the first season, when advised growers used more fungicide treatments, there was no difference in mean pesticide use by the two groups. Anecdotal information suggests that variation in acceptance of risk accounts for a large proportion of the differences in pesticide use in different orchards. The consequences of these findings in establishing pesticide reduction strategies are discussed.