Scab on an apple leaf. Photo courtesy of keystonetree.com
Taking in consideration the time of year and the current weather conditions, it is now that you can help the trees, in order to improve the crop for next year. Many fungal diseases have been more trouble than usual this season. The problem can be seen, for example, from black spots appearing on the leaves and on the fruit, or premature leaf drop or fruitlets not having made size and stopped growing, or that have dropped on the ground. I am referring to the serious effects of different fungi causing peach leaf curl, canker, scab, mildew, quince blight, walnut blight, coral spot, silver leaf and brown rot of fruit, just to mention the more common troubles. To eliminate or reduce the effect of these fungal diseases next season, the following measures should be taken within the next 10 days.
1) Spray the trees with winter wash now and follow the instructions as stated on the container.
2) Use a good rake or a vacuum blower, which sucks up all the fallen leaves, affected by any of the fungal diseases as mentioned above. Destroy or remove the leaves from the fruit tree area, as fungal spores will overwinter on those leaves and will attack the tree and its fruit next year. Close mowing will pulverize the leaves. Provided the grass clippings and the shredded leaves are removed from the area, well away from the trees, this will also help.
3) Any dead wood in the trees needs to be removed and will have to be burned or shredded.
4) Any sizeable pruning cuts will have to be sealed with a sealing compound.
5) Canker wounds will have to cut out and painted with Arbrex or a similar healing compound.
6) Bacterial canker is not a fungus. However if the cherry and plum trees are not protected now, with the application of the winter wash, the health status of the trees will seriously decline.
7) If you have had trouble with fireblight on pear trees, now is the time to cut out all infected branches cutting well back into healthy tissue, until there is no sign of staining. Burn the wood and seal the wounds.
8) If your peach trees have had serious trouble with the fungus called Peach leaf curl, apart from the measures as stated above, protect the tree with a plastic cover from late January until the middle of May. This will stop the spores already present in the trees from germinating. It is the rain that causes the spores to become active during the winter months.
9) When leaf fall is complete, say in about 10 to 14 days, repeat the application of winter wash on all the trees.
10) Dense tree canopies need to be opened up now by taking out large branches. This will improve the air flow through the tree canopy and reduce the incidence of fungal diseases. If you cannot throw your hat through the tree canopy then there is too much wood in the tree.
Read our month-by-month fruit tree care calendar.