Worst Year Ever – Apple Problems – Spring 2025

This year has been one of the worst years ever for Apple problems, and after such a good start with fabulous displays of flowers.

We have been hit with Ermine Moths (Yponomeuta malinellus) and Powdery Mildew (Podosphaera eucotrich). All as a result of the weather, not cold enough to kill off the Ermine Moths, and too hot and dry for the Powdery Mildew.

Ermine Moths (Yponomeuta malinellus) – You do not very often see the moths; what is more noticeable is the webbing around shoots and soft, luscious leaves. As the spring temperatures rise the webbing gets widespread. Some varieties are more affected than others. You can have tree branches from adjacent trees touching each other, and they do not hop over. They also tend to develop around the lower branches. I suppose if they were higher up, the birds would find them more quickly. If you disturb the caterpillars, they are certainly very quick and mobile. As they are so mobile, its amazing how many leaves they can devour. As soon as July comes the caterpillars change into moths, and start mating, and laying the eggs. These eggs developed into Larvae in August time which then overwinter till spring again.

If you only have a small infestation of these, they can be easily controlled by pinching out the webbing and its affected shoot quickly, throw it on the floor and stamp on it.

As with this year the amounts can be excessive, they can defoliate a tree very quickly.

I find we can have more caterpillars than the birds can eat. But we are actively trying to encourage birds to help us out.

Gazelle SG Insecticide is broad spectrum offering additonal control for chewing and sucking pests such as thrips, leafminers (specific species), leaf hoppers, mealybugs, beetles and specific species of weevils. It also controls leafmidge, scale insects, fly species (cherry, sawfly and sciarid), capsids and some caterpillar species.

Powdery Mildew (Podosphaera eucotrich)

Spores overwinter on the buds, and only develop in the absence of rain, and at temperatures above 20°C. Which is why this year its been bad. We have had 2 months with no rain and quite high temperatures. They tend to develop on the terminal buds and then the soft leaves of the terminal shoot.

The only practical control method on small amounts of trees is to prune out the infected terminal buds,or spray with potassium bicarbonate or sulphur or even Lime sulphur (test on varieties first).

Larger orchards will require a spraying regime.

Nimrod® is a systemic fungicide which moves around within a plant as a preventative and curative against powdery mildew on apples, pears, soft fruits, cucurbits, hops and ornamental plant production.

Amistar® contains azoxystrobin, a broad spectrum fungicide from the strobilurin group. It has systemic, translaminar and protectant properties which inhibit fungal respiration.