All of my potatoes have gone down with blight and I have removed all of the foliage and now hope for the best. However, my tomatoes are now showing signs and someone has advised Bordeaux Mixture as an organic treatment. 'Organic' doesn't always mean bee friendly so I need to know if the mixture is safe for bees.
Location: Seattle, WA
posted 4 years ago
Copper sulfate, one of the main ingredients, is used as a herbicide, fungicide and pesticide. It was also used to make pressure treated wood because it is persistent and does not break down. While the bees may not be directly affected by it as long as you do not spray it on the flowers, I would not put those plants in my compost bin at the end of the season as the point of the cooper ions is to disrupt the enzyme process that the fungus uses to reproduce and that would probably have an effect on the fungus in you compost pile.
Also, note that sometimes when bees can't get enough pollen early in the season, they will harvest fungal mycelium as a protein source. If you have persistent copper sulfate in your soil from previous applications, they could be effected by that.
If I were in your situation, I'd see if the tomatoes can recover on their own after laying down some fresh mulch and pinching off any leaves that are having problems. If not, do not grow any plants from the nightshade family near that area for at least three seasons.
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