by Did67 » 27/11/17, 08:49
Group varieties or species ?????
As said, I am not an expert. But logical reflection would lead me to this:
a) According to the species, there is interest in having in the same orchard, different varieties of the same species; some are known to be good pollinators; and even, such a variety can be the pollinator of such another ... There are tables on the internet. A good nurseryman should know that. But more and more, they are sellers of potted trees, especially in garden centers and are not always able to advise.
That at least is clear.
b) Bees and bumblebees "work" on perimeters of a few kilometers.
However, they tend to go from one tree to the next tree ... So it seems to me that they are more likely to pollinate an apple tree X from the pollen of an apple tree Y if they are contiguous. If in the meantime they pass over pear, quetschier, mirabelle plum trees, that seems less favorable to me ...
c) The "biodiversity" effect on the main "parasites" seems to me to be quite illusory. Codling moth will find apple tree Y from apple tree X even if there is a cherry tree in between. I think there is a lot of "internetic" exaggeration here on the part of permaculture dreamers. We have to come to terms with the idea that a lambda parasite of such a plant has the sensors it needs to spot it (color? Smell? Gas?). Otherwise, he would be long gone. A Colorado beetle spots the potatoes. An aphid beans rich in nitrogen. And a ladybug the aphids! I would be inclined to think (but this is only a conviction) that the codling moth (for example) is just as well "equipped" to spot an apple tree! I can't imagine it being so poorly designed to be fooled by a cherry tree on the way!
Conclusion of my speculation (that's just it, linked to my way of "seeing the living"):
- to have multiple varieties for each species: absolutely (also so that one escapes the frosts early, the other one with the late frosts)
- by zones, grouping varieties of the same species seems to me favorable to pollination; theoretically, this should favor parasitism (but we can also doubt it)
- the opposite will work too !!! And it is not even certain that the difference is measurable!
- in any case, we will have to consider a "soft" fight against parasitism, as soon as we bring together so many fruit trees in such a small space - traps, auxiliaries ...
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