Despite the sometimes intense cold of Quebec winters, it is possible that some eggs, larvae, harmful insects, or mites have managed to withstand the weather conditions to attack your trees. A good way to protect them is to apply a 100% natural insecticide early in the spring: dormant oil. Also known as dormant stage oil or horticultural oil, this spray product clogs the insect's pores, preventing it from breathing and causing damage to your plants. Since they have many enemies and the product has no effect on humans, animals, and birds, horticultural oil is often used on fruit trees. It is suitable for all fruits, but some varieties of apple trees are more sensitive to it, so consult a gardening advisor.
When to apply dormant oil
It is in the spring that you should spray the dormant stage oil when the temperature exceeds 4 degrees. Ideally, wait until it reaches 10 degrees for better results. You should apply the product before the buds open since the oil could damage the young leaves. Choose a day without wind, where it hasn't rained the day before, and where no precipitation or risk of frost is expected within 48 hours.
And what about diseases?
Horticultural oil has no effect on diseases and fungi. However, it can be combined with another 100% natural product: sulfur lime, a biological fungicide. Some may say that the oil alone can destroy spores and prevent fungal diseases such as black spot and powdery mildew... the combination of the two will certainly give you better results. You can also find both products pre-mixed at your favorite Passion Jardins® garden center. Take the opportunity to get a sprayer for application, it will be useful for several tasks in the garden.
Attention!
Dormant oil is not recommended for all trees. In fact, it destroys the wax that gives the bluish color to spruces and blue junipers. Rhododendrons, azaleas, holly, and yews are particularly sensitive to the oil, so it's best not to use it on these plants.
Tips and advice
