Biodynamic Agriculture Course
by Rudolf Steiner
Koberwitz, 14th June, 1924.
The Nature of weeds, animal plagues and the so-called plant diseases before the tribunal of nature
In the lectures that are to follow, I shall base myself to a great extent on what you have heard me say concerning plant growth and also animal forms. We shall have to attempt to put into aphoristic form some of the spiritual scientific concepts concerning the enemies of agriculture, animal and vegetable, and the diseases of plants. These matters can only be studied in concrete cases, they must be dealt with specifically, for there is little that can be said in a general way.
I shall begin with examples which, if they are taken as the starting-point of experiments, may lead to something further. I shall begin with the subject of weeds or noxious plants. What we have to do is not so much to find a definition for what we mean by weeds, as to discover how to remove such plants from a field when we do not wish to have there. Some of us, perhaps, as a habit from our student days, may be inclined to seek for definitions. I have given way — although without much enthusiasm — to such an inclination and have looked up in various books the definitions given of a weed. I found that most authors say: “A weed is that which grows where it is not wanted,” which does not go very deeply into the essence of the matter. Nor can we very successfully apply such a definition to the essential nature of the weed, for the simple reason that before the tribunal of nature the weed has just as much right to grow as plants that are useful to us. Clearly, we must approach the matter from a somewhat different angle. We must ask ourselves how in a particular piece of ground we can get rid of what was not meant by us to grow there, but which nevertheless does so because of the general aspects of nature ruling there.
The answer to this question can only be found by taking account of those things which we have been discussing during the last few days. It was pointed out that we must learn to distinguish those forces which arise in the cosmos but are absorbed by the earth and work upon plant growth from within the earth. These forces come from Mercury, Venus and Moon and act not directly, but through the mediation of the earth. They must be taken into account if we wish to follow up how the mother plant gives rise to a daughter plant, and so on. On the other hand, we must consider the forces taken by the plant from the outer-earthly, and brought to it by way of the atmosphere from the outer planets. Broadly speaking, we may say that the forces coming from the nearer planets (see Lectures 2 and 3) are very much influenced by the workings of lime in the soil, while those coming from the distant planets fall under the influence of silicon. And, in fact, workings of silicon, even though they proceed from the earth, act as mediators of the forces coming from Jupiter, Mars and Saturn, but not for those of Moon, Mercury and Venus. People are quite unaccustomed to take these things into account. Ignorance of the cosmic influences, whether they come through the atmosphere around the earth, or whether they come from below through the medium of the earth, has caused great harm. Let us take a special case to illustrate this. The old instinctive knowledge had disappeared from large areas of the civilised world; the soil was exhausted, and such parts of the old traditions that the peasants had preserved was also worn out. And so the vineyards far and wide were decimated by Phylloxera (or grape-louse). People were powerless to cope with the Phylloxera that was destroying the vineyards. I could tell you of an agricultural paper that used to be published in Vienna in the eighties. Appeals from all sides were made to the editor to supply some remedy for Phylloxera, but to his despair he knew of none and that was at a time when the pestilence was most acute. For the science of today is not able to deal effectively with such evils as these; what is needed is insight into the connections I have been expounding to you here.