The aim of decreasing the side-effects of pesticides (on human health and on the environment) is pursued in Denmark through legislation encouraging a decrease in pesticide use, measured both in quantity (of active ingredient and dose per hectare) and quality (by banning those pesticides considered to be most harmful).

The reduction in use of active ingredient has been achieved without great difficulty. However, the reduction in pesticide applications (pesticide treatment index) has not progressed greatly.

No figures were available in Denmark to indicate the contributions of the different aspects which could cause a change in the use of pesticides (such as change in rotations, and kind of pesticides), though some rough estimates have been mentioned.

Current EU policies regarding set-aside land and output prices favour a decrease in cropping. The drop in pesticide use which accompanies this change is estimated at approximately 15 per cent of total pesticide use in 1993. Although the stimulus to reduce cropping helps farmers to achieve the goal of pesticide reduction in the short run, it is not nearly so clear that this decrease will be permanent. Pesticide use can increase as dramatically in the future as it has decreased in the past.

The change in rotations, needed to keep 65 per cent of agricultural land under vegetation, increases the use of pesticides, at least where winter cereals are allowed in the rotation. A rough estimate of the effect of this development is an increase in pesticide use by at least 25 per cent.

The change in rotation practices has brought with it another aspect which could influence pesticide requirements in the future. Haas (1989) reports that the increase in winter grains has meant an increase in certain weeds, especially couch (Elymus repens), which in the longer term are likely to be a problem. While previously mechanical control measures in autumn were possible, the growing of winter cereal has severely restricted this possibility. Together with the fact that climatic conditions in the late 1980s-early 1990s favoured the growth of this and other grass weeds, an increase in need for weedicide was expected. Haas (1991) also reports the appearance of 'new' weeds in Danish agriculture, such as Agrostis spicaventi, Alopecurus myosuroides, Abutilon theophrastis, Echinochloa crus galli, and Amsinckia micrantha. Due to those developments farmers might well feel the need for more intensive spraying in the future. As long as the regulation about a 'green cover' exists, rotations requiring more pesticides than before 1981-85 are likely to continue, with a relatively high need for pesticides. It is also possible that such practices would continue, even if the '65 per cent green cover rule' were to be removed. This is certainly the case where winter cereals are more profitable, as at present.

The change to different kinds of pesticides decreased the active ingredient used. An indication of a change of weedicides on half of the area under grain shows a rough estimate of a drop of approximately 30 per cent on 70 per cent of the cropped area. Technological changes affecting other categories of pesticides will cause an even more dramatic decrease.

More timely applications and better calibrated equipment could well have contributed to a decrease in the use of pesticides, though no lower dosage per hectare is recorded. However, this could be due to the counteracting forces of the change in rotation (towards winter grains from spring grains, requiring a more intense pesticide regime). It can be expected that, as farmers' knowledge about pesticide-reducing practices increases, this will decrease pesticide use.

The requirement of looking into non-chemical control of pests and diseases is considered mainly in the context of conventional agriculture. However, the development of organic agriculture is also stimulated by state (and at present EU) expenditure. For example, DKr.50 million was paid for research over 5 years recently.

The decreasing availability of pesticides does not seem to worry many producers, except in the area of minor crops. There, a decreased interest of (foreign) manufacturers to register specialised pesticides is considered to be likely. Less flexibility in pesticide availability, and a shift in emphasis within the rotation system, are seen as worrying developments.

Although the Danish pesticide reduction scheme was instituted to reduce the risk of degradation in human health and the environment, measures by which to judge pesticides directly are still difficult to work out. There is still the debate about whether the substitution of pesticides with those lower in active ingredient and higher in biological activity is a positive development.

In summary, up until 1993 the reduction in pesticide use in Denmark is only a partial success. The reduction is due in part to real changes such as farmers' perceptions about the possibilities to reduce the use and the risk the changes bring with them. However, part of the reduction is due to factors which have little to do with a permanent change, but with a change in technology (pesticides with low active ingredient content) or policies (resulting in decreased land use).