Recent figures from the Federal Office for Agriculture (FOAG) show that sales of synthetic plant protection products, and especially of weed killers, have fallen by 29% since 2008. How was this possible?
On the one hand, I attribute this to the alternative methods that have been developed by research in recent years and are being applied today in farming practice. For example, Swiss farmers are now using mechanical weed control much more often. This is being done not only by hand, but also by robots that make the farmers’ work easier. In addition, farming has adapted its production methods and is increasingly using cultivation systems that reduce weed pressure or contribute to biodiversity by using native weeds. For example: in the past there was virtually no vegetation in between the vines in vineyards. Today we know that certain companion plants enrich biodiversity and – provided the weeds don’t emerge too strongly – can even help to reduce pest pressure by providing new habitat for beneficial insects. On the other hand, public debate has probably led to today’s farmers thinking twice about whether the use of synthetic plant protection products is really necessary.
Back to the sales of synthetic plant protection products: it is striking to note that there has been no reduction in fungicides, bactericides, insecticides or acaricides. What is research doing in these areas?
As part of the development of Integrated Production, Agroscope developed efficient methods of biological and biotechnical control for mites and insects in the 1970s, ’80s and ’90s that are still in use today. Even today, predatory mites still play a crucial role in ensuring that fruit and wine growers hardly need to use any acaricides. Also in fruit and wine growing, the sexual confusion method has shown good effects against certain pests, with the result that – especially in vines – growers need to use very few or even no insecticides. Other pests such as aphids, plant lice and various fly species require further research to guarantee yields and quality without the use of insecticides.
Last year’s summer was hot and very dry. Because fungi and bacteria are less able to reproduce under these conditions, there was less use of fungicides. In warm and wet years, however, fungi and bacteria are able to multiply explosively. The most effective method against fungal and bacterial diseases is the breeding of resistant varieties. In recent years, Agroscope has bred many promising, fungus-resistant varieties such as the grapes Divico and Divona, the apricot variety Lisa, the Rustica and Galiwa apple varieties and many wheat varieties. The apricot variety Mia, the apple Ladina and the pear Fred® are tolerant to bacterial diseases. Agroscope is very efficient in this field of research, thanks in part to multiple collaborations with Swiss universities and foreign institutes such as the French INRA.
According to FOAG statistics, use of the controversial product glyphosate has fallen by 45 percent. Should this active substance be banned?
I am very critical of strategies aimed at banning one active substance after another without effective alternatives being available. From a toxicology perspective, glyphosate is not a high-risk plant protection product. The problem is that it is extremely effective as a herbicide, so farming uses it in phenomenal quantities. If individual active ingredients are used in excessive quantities, resistance develops – as is the case with glyphosate. Synthetic plant protection products should only be used as a last resort in a targeted and site-appropriate manner.
Are there any plant protection products with equivalent effect that could replace glyphosate?
As yet, there is no product that works as broadly as glyphosate. There might be combinations of herbicides with an action equivalent to that of glyphosate. But I doubt that the environmental effects would be any more positive. Thanks to alternative cultivation methods, farming has been able to reduce the use of herbicides in recent years. However, research in this area continues. I doubt we’ll ever be able to manage entirely without herbicides. Climate change is constantly presenting us with new challenges. We will have to deal with plants and animals that are new to Switzerland. It will always take us time to get to grips with these by adapting production systems, and in that time we are likely to be dependent on synthetic plant protection products.