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Summary
This report describes methods to reduce the use of pesticides in field-grown
vegetable crops. The report also reviews existing knowledge of the extent to
which the surrounding environment is affected by pesticides used in Danish
field-grown vegetable crops. The report was prepared for the Kirsten Jensen
Committee for use in their evaluation of the consequences for the Danish
horticulture industry of introducing additional restrictions on the use of
pesticides in plant production.
Danish field-grown vegetables are primarily sold on the domestic market.
Green pea is the vegetable most often exported, mainly as frozen products.
Danish production is insufficient to meet domestic demand. The most
important field-grown vegetable crops are pea, cabbage, carrot, onion, leek
and lettuce. In total, 10,500 ha are cultivated with field-grown vegetables. The
quality of the vegetables is crucial for their market value, regardless of whether
production is sold domestically or exported. EU quality standards stipulate
that first-grade vegetable products must be pest-free and undamaged by pests.
Production and marketing are subject to strong competition from other
countries.
About 10% of the total area is cultivated organically, and carrot is by far the
largest organic crop. Of the remaining 90% with conventionally grown crops,
most is used to produce vegetables in accordance with the principles for
integrated production that the growers have established. For quite some time,
efforts have already been made to reduce pesticide dependence in vegetable
production, as demonstrated by the increased organic production and the
establishment of integrated pest management systems.
This report deals with the possibilities of implementing alternative methods
for the prevention and control of weeds, diseases and insect pests. In
preparing the report, we have drawn on experience gained in organic
cultivation systems, ongoing research projects on alternative methods of weed,
pest and disease control, and documented and published knowledge within
these areas. The report also describes current pesticide use in field-grown
vegetables.
Effects on the environment
Based on pesticide sales figures for the period 1996-99, estimated insecticide
treatment frequency in vegetables varied from 1.1 to 3.0, and fungicide
treatment frequency varied from 1.1 to 2.8. A qualified estimate of herbicide
treatment frequency is that it varied on average for the entire area cultivated
with vegetables from 1.0 to 1.9. There is, however, great variation in pesticide
use among crop species. Seeded onion crops can be treated up to five times
with herbicides, whereas cabbage and lettuce are treated, on average,
considerably less than once.
From available knowledge, row crops (e.g. onion, leek, potato and beet) are
expected to pose a greater risk of pesticide transport to surface and ground
water than broad-sown crops (e.g. peas and cereals). This is because row
crops are more open and have a limited leaf area for a longer period of time,
and the need for weed control is thus greater and herbicide use more intense.
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