Chapter 5 – Dealing with diseases and common pests

There is nothing worse than spending years caring for an orchard or verdant row of berries only to see it attacked by some random fungus or voracious pest.

One of the best ways to prevent disease is by making sure you buy certified plants from a reputable dealer. If you can find and afford virus indexed trees, then it is all the better. The best defense against fungus is proper pruning. While fungus and spores can live through the winter in the soil as well as bark, they travel on the wind and breed wildly in the wet shadows under a plant’s leaves. Proper pruning to allow the wind to ventilate the tree will reduce the amount of time a fungus has to set up shop.

It is also important to think of other plants, especially the plants in your garden that might harbor pests and diseases. For instance raspberries and tomatoes both play host to the dreaded fungus known as early blight and can also be vehicles for fire blight.

Fire blight is a virulent bacteria which loves to attack new growth and tender shoots. The first year it infests a tree it will develop small black cankers on the upper branches. Close attention needs to be paid to the upper branches of mature, standard height trees. The black cankers host the bacteria over the winter. Then it takes off attacking the tree often killing a large number of branches just as the tree comes to life in the spring.

Vigilance is your best defense. Pay attention to the tree during harvest time. Note any tree with black cankers on the upper branches. These trees should have the infected branches pruned in late winter when the snow is on the ground and the tree is still deep in dormancy. Put the pruned branches in an isolated bucket and burn them immediately.

In the spring you should spray the affected area that you pruned with a preventative spray such as streptomycin. Then in the spring avoid applying nitrogen to that tree. While this will reduce the amount of new growth the tree has that year it will also give any surviving bacteria less of a place to call home.

If your fruit trees are under attack from a serious infestation of fungus and you can’t quite manage to identify the source you can always fall back on spraying the tree with sulfur. Organic sulfur spray is to fungus what chemo therapy is to cancer. It can easily damage the entire tree and is especially damaging to new growth.

While you might be tempted to hose down the entire tree with a sulfur spray at the first sign of fungus, it is best to spray a test branch that has some new growth.  Wait a few days to see how the branch reacts before you go in whole hog.