Bordeaux for Fruit Trees
By some miracle it has not rained for twenty four hours now. At the first sign of sunshine yesterday morning I raced outside to spray the stone fruit trees, two nectarines, two peaches. Copper spray, or bordeaux mixture, is an accepted organic treatment for fungal problems of fruit trees. You can see it on my nectarine tree up above. It is a blue powder that you mix up with water and spray - except it always clogs up the sprayer, so I make a watery paste, and paint it on with a paintbrush.
My stone fruit suffer dreadfully from leaf curl, which deforms and curls up the leaves and stunts the growth of the trees, but for the copper spray to kill the fungus, it needs a reasonable dry period, so the spray doesn't get washed off too soon, just at the time that the buds are swelling. By the time the blossom comes right out and the leaves bud, it is too late. Stone fruit is a bit chancy in Northern Tasmania for that very reason - early Spring is so wet, that even if you can keep leaf curl at bay, it often rains the whole time the blossom is out, and the bees have to stay home due to inclement weather. So we gardeners hold our breath, waiting for a week of dry weather, just at the right time.
If you live in the Northern Hemisphere, and get leaf curl, now is also the time to spray your stone fruit, when the leaves drop, because that's when the pesky fungus first gets in.