Because since the turn of life trees were planted in the East at all corners, there is virtually no corner of the earth more where you can safely plant a pear tree without a very short time to have an infestation of pear rust. Especially young trees grow by a good and not develop bad. Most even die from it. Since I love pears and very much wanted to have some pear trees in the garden, I was very glad to read that there are means to rid the trees of pear rust. After planting I had as expected was in the very first summer, all trees infested with pear rust. At first, I tried again to remove the affected leaves by hand, with the result that the trees were almost bare within weeks. In the second year I have then this means 14-day applied (after I had found the first signs of pear rust). In July, I then stopped it and the trees have retained all the leaves and performed well. A tree has even taken already 5 big pears this year. I can therefore only recommend. For small trees, the package should be enough for several years.