I live in New England, USA, New Hampshire actually and my question is – what if anything do I spray my Mac Intosh apple trees with in the fall? I was told there are horticultural sprays that are all organic. Is this true? I was also told to spray them in the fall to protect against insects that will live in the tree through the winter, I would really appreciate some good advice. The fruit tree thing is new to me.
Lenny Belanger
The scab fungus, particularly, settles on the leaves of apples in late summer and if they are not removed before they start to shed their ascospores in spring to re-infect the newly formed fruits. In the UK, a common procedure in commercial orchards is to apply a spray of urea, which has a high nitrogen content and is manufactured synthetically, on the leaves a week or so before falling in order to encourage them to rot quickly or be taken below the soil rapidly by earthworms.
The ideal organic substitute is human urine. This is commercially available in Germany and might be in your country, though I do not think it is so in the UK. For a small number of trees, though, it should be possible to collect enough. Alternatively, the leaves can be gathered up and removed for composting. Rapid leaf rotting or removal for composting should also prevent any pest eggs from hatching in spring.