Many summer residents often complain that walnut trees, grown with love and care on their plots, produce a small harvest of small fruits, which, moreover, quickly turn black.
The cause of poor fruiting is often hidden in a disease known as marsonia or bacterial spot.
This disease primarily attacks the fruits of the walnut tree, as well as its leaves and young shoots.
If you notice small brown spots, it is definitely Marsonia. Such marks usually begin to appear in the second half of summer.
According to experts, copper-based preparations (not the notorious Bordeaux mixture, but something newer) can help to correct the situation: "Oxychom", "Kuproksatom", "Blue Bordeaux", etc.
The treatment should be carried out at the beginning of autumn, and to consolidate the result, the tree should be treated before the onset of real cold weather, when it has already lost almost all its leaves.
For repeated treatment, 3% ferrous sulfate and 1% urea are better suited.
And one more thing: since the disease remains for the winter in fallen leaves and fallen fruit, they should, of course, be removed. If you do not overcome your laziness and leave the leaves and fallen nuts on the plot, in the spring the spores will again affect the walnut - as you understand, you can not count on a harvest.