In our last blog post we mentioned that some of our clients were seeing some yellowing, blotchy leaves falling from their Crab Apple trees. We mentioned that with the spring being as cool, damp and protracted as it was, all types of fungus and blight issues flourish in those conditions. We mentioned that just because we treat your trees against Apple Scab fungus, it does not mean that certain other fungus or blights might not be an issue in some years. Certain fungus and blights are not really treatable, and if they are, they might require different products, treatment timing & even more applications than what is required to treat Apple Scab or Rust issues.
The bottom line is that Apple Scab disease is the most debilitating fungus of all, and even though this may be a tough year for fungal and blight issues, your trees will still look really good if they are being treated by us. They might not be as perfect as they have looked in prior years, but they will be, without a doubt, better than in the years before you started having your trees treated.
That being said, we are also looking into whether the Apple Scab Fungus in some of our treatment areas is developing a certain tolerance to the products that we have used for many years on the Crabs that we treat. Additionally, we are noticing that the pH of the local water supply has been rising increasing from 7.5 to 8.3 pH in recent years. It is well known in our industry that the higher the pH level, the harder it is for insecticides and fungicides to work to their full potential. This is why when homeowners spray their bushes with hose sprayers or those one-gallon pump sprayers, they often claim the products they buy at local nurseries or hardware stores do not seem to work very well. Besides the fact that these are inexpensive products, compared to products we use, the pH also needs to be lowered to get results. The product labels don’t mention the pH level, however, because they don’t want to make it seem so confusing that people will avoid buying the product.
So what does all of this mean going forward?
Tree care is a very, very complex field. Situations and conditions are constantly changing and we do everything we can do to stay up-to-date and adapt to those conditions.
We work in cooperation with another tree company from Wisconsin who takes what they do as seriously as we do. Comparing notes, they determined that the local Apple Scab spores might be developing a tolerance to the product mixture that they used. They had the same issue in Wisconsin years ago, made some changes, and got great results from making those changes. We plan to implement those changes in Illinois in 2017.
First, we are further reducing the pH of the local water that we use by adding water softening products to the water. Additionally, in the case of Apple Scab, we will be adding an additional fungicidal product that works with an additional mode of action.