Report from the Sub-comittee on the environment and health

Prevention of pest attack in
crops through <strong>the</strong> use of
insect-resistant plants
Biological prevention and
control of diseases and
pests in farm and market
garden crops
combination of both diseases and pests. Today, research is in progress on
several alternative methods of combating seed-borne diseases, including
use of resistant varieties, use of biological products and technical
methods involving <strong>the</strong> use of hot water/air or brushes. None of <strong>the</strong>se
methods is yet ready for use and a great deal of research and
development remains to be done.
The environmental benefit <strong>from</strong> developing alternative methods,
including <strong>the</strong> use of resistant varieties, increased assessment of <strong>the</strong> need
and biological protection products, is reduced use of pesticides, although
<strong>the</strong> pesticide consumption is very small. With seed dressing, between 10
and 50 g pesticide per hectare are often used, which is of <strong>the</strong> same order
of magnitude as when spraying with mini-products and pyrethroids.
Since <strong>the</strong> seed is covered with soil, very little pesticide is spread to <strong>the</strong>
air and surface water. However, pesticides in seed-dressing products can
leach in <strong>the</strong> soil in <strong>the</strong> same way as spray products. Seed dressing also
involves a risk to birds and small mammals, which eat <strong>the</strong> seed. The
plants and thus food products made <strong>from</strong> <strong>the</strong>m can also contain residues
of systemic seed-dressing products.
The health benefit of omitting treatment with seed-dressing products
would be no exposure during production, although this is usually in <strong>the</strong>
form of wet-dressing in large, closed dressing plants. Exposure also
occurs during handling of <strong>the</strong> seed in connection with sowing. Lastly,
some residues of <strong>the</strong> systemic pesticides (i.e. <strong>the</strong> pesticides absorbed by
<strong>the</strong> plants) could be present in <strong>the</strong> crops and thus in food products.
9.4 Prevention and control of pests
Very little is known about <strong>the</strong> insect resistance of Danish varieties.
Simple screening for receptivity to pests may reveal an unexploited
potential. Only limited use is at present made of biological control of
pests in fields, so such methods are not yet a realistic alternative to
chemical control. It is a well-known fact that <strong>the</strong> field’s natural fauna
affect <strong>the</strong> pest population, but little is known about how much <strong>the</strong>se
beneficial organisms affect <strong>the</strong> development of, for example, aphids.
The environmental and health benefit <strong>from</strong> developing and using insectresistant
varieties is obviously less use of insecticides with a consequent
reduction in <strong>the</strong> risk of pollution of surface water, groundwater and <strong>the</strong>
surroundings in general.
The health benefit would be less exposure of farm workers and less
pesticide residue in crops.
Biological methods, which include both beneficial organisms and
microbiological products, have a big potential against pests in
greenhouse production. They are already used extensively in greenhouse
vegetable production but not within greenhouse production of
ornamental plants. Effective biological methods of combating diseases in
greenhouses are still limited. In fields, biological methods of controlling
pests are believed to have some potential within special crops, whereas,
in <strong>the</strong> short term, biological methods of combating diseases are only
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