Report from the Sub-comittee on the environment and health

Use of warning and
damage threshold models
in agriculture
Conclusion
promote surface predators (spiders and ground beetles), which play a role
in combating pests, and would reduce <strong>the</strong> weed’s possibility of
germinating. It would be possible to mulch after <strong>the</strong> cereal harvest by
cutting <strong>the</strong> straw and leaving it on <strong>the</strong> field. One of <strong>the</strong> problems of
mulching is whe<strong>the</strong>r it is possible to sow <strong>the</strong> crop directly in <strong>the</strong> mulch in
such a way that it can germinate unhindered. The effects of such a
procedure on diseases and pests and on crop growth should also be
investigated.
In recent years, damage thresholds and decision-support systems have
been developed for many of <strong>the</strong> main agricultural crops as support for <strong>the</strong>
farmer in judging <strong>the</strong> need for prevention and control and <strong>the</strong> choice of
pesticides. Although <strong>the</strong> systems are now relatively widely used, not all
farmers have been reached. Damage threshold systems still have to be
developed for a large number of crops and several of <strong>the</strong> existing systems
need improving. It is considered possible to achieve a 20-50% reduction
in <strong>the</strong> use of pesticides in a number of crops by combining decisionsupport
systems with chemical and non-chemical methods. Research has
shown that targeted use of fertiliser, pesticides and o<strong>the</strong>r factors related
to <strong>the</strong> phase-out can contribute to satisfying environmental requirements
and simultaneously optimise production economically. The use of
decision-support systems offers an obvious possibility of reducing <strong>the</strong>
exposure of both <strong>the</strong> environment and people.
The environmental and health benefit <strong>from</strong> <strong>the</strong> use of preventive
cultivation methods would be an obviously reduced consumption of
pesticides and a consequently reduced risk of pollution of groundwater
and <strong>the</strong> surroundings. An added health benefit would be less exposure of
agricultural workers and less pesticide residue in crops.
9.5 Use of genetically modified crops in agriculture
In Denmark, researchers are working on <strong>the</strong> development of genetically
modified plants. Most progress has been made on herbicide-tolerant
plants, which should be ready for marketing in a few years’ time. The
introduction of genetically modified, herbicide-tolerant varieties of beet
is expected to result in a significant reduction in herbicide usage - about
1 kg active ingredient per ha. In <strong>the</strong> case of herbicide-tolerant rape and
maize, <strong>the</strong>re does not seem to be any significant reduction in herbicide
consumption. Intensive research is going on all over <strong>the</strong> world in <strong>the</strong>
field of molecular biology. In time, that will undoubtedly lead to
significant changes in our cultivated plants. Of particular interest is <strong>the</strong>
development of genetically modified disease-resistant plants, which must
be presumed to create a means of reducing losses <strong>from</strong> diseases without
<strong>the</strong> use of pesticides. The use of genetically modified plants with
resistance to pests in maize and o<strong>the</strong>r crops is spreading globally.
However, crops with resistance to pests are unlikely to gain a footing in
Denmark for some years (around 10).
Genetically modified plants provide <strong>the</strong> possibility of reducing <strong>the</strong> use of
pesticides and thus exposure of both <strong>the</strong> environment and people.
However, <strong>the</strong>re could be a risk of some of <strong>the</strong>se crops proliferating and
subsequently harming <strong>the</strong> environment. That applies particularly to
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