Report from the Sub-comittee on the environment and health

Prevention of pest attack in
agricultural crops through
<strong>the</strong> use of alternative
methods and crops
Mulching
170
thought to have a potential in <strong>the</strong> case of seed-borne diseases and fungi
that affect germination.
Table 9.1
A number of microbiological insecticides and fungicides are at <strong>the</strong>
application stage.
Name Type Extracted <strong>from</strong>
Phlebiopsis giganta Fungicide microorganism
Streptomyces griseovirides Fungicide microorganism
Bacillus thuringiensis ssp. israelensis Insecticide microorganism
Bacillus thuringiensis ssp. kurstaki Insecticide microorganism
Bacillus thuringiensis ssp. tenebrionis Insecticide microorganism
Trichoderma harzianum Fungicide microorganism
Trichoderma harzianum og Trichoderma Fungicide microorganisms
polysporum
Verticillum lecanii Insecticide microorganism
Agrotis segetum granulosis virus Insecticide microorganism
Paecilomyces fumosoroseus Insecticide microorganism
Pseudomonas chloroaphis Fungicide microorganism
Ampelomyces quisqualis Fungicide microorganism
As in <strong>the</strong> case of disease-resistant or insect-resistant varieties, biological
control would result in an obviously reduced consumption of pesticides
and a consequently reduced risk of pollution of groundwater, food
products and <strong>the</strong> surroundings. There would be a corresponding health
benefit of less exposure of agricultural workers and less pesticide residue
in crops.
However, <strong>the</strong> use of beneficial organisms and microbiological products
would involve a serious risk of proliferation of foreign organisms, which
could have a detrimental effect on <strong>the</strong> environment. It should be noted
that <strong>the</strong> beneficial organisms currently used in greenhouses cannot
survive out of doors in Denmark. Theoretically, <strong>the</strong> proliferation of
indigenous species could also upset natural ecological balances. The use
of microbiological products could involve a risk of harmful effects in <strong>the</strong>
form of allergies and bronchial diseases. An authorisation scheme for
<strong>the</strong>se products is under construction and will include an assessment of
possible health effects.
The crop rotation used and <strong>the</strong> crops grown are of great importance for
<strong>the</strong> level of diseases, weeds and pests. Generally speaking, <strong>the</strong> level of
pests can be reduced by means of a varied and diversified crop rotation,
alternating between spring and winter crops, monocotyledonous and
dicotyledonous crops, and annual and perennial crops. As a rule, <strong>the</strong>re
are fewest problems with pests in dairy farm crop rotations with a large
proportion of grass compared with large areas with specialised plant
production. When planning <strong>the</strong> crop rotation it is important to take
account of crop-rotation diseases and ensure a sufficient number of years
between such crops as potatoes, rape, sugar beets, etc. There does not
seem to be any direct possibility of cultivating new, alternative crops or
intercropping.
According to Action Plan II, “Organic Farming in Development”,
mulching could reduce evaporation <strong>from</strong> <strong>the</strong> surface of <strong>the</strong> soil, which
would promote both plant growth and <strong>the</strong> soil fauna, particularly in dry
summers (Directorate for Development 1999). Mulching would also