An Ounce of Prevention…
I had a call from a colleague this morning about his trees. Every year he applies dormant oil / lime sulfur to his trees as a preventative. He is worried it may be too late as we have had such terrific weather this spring.
We are now, April 3, 2020 in Milton Ontario on the very cusp of the end of the season for applying dormant oil. Buds are swelling around here like crazy – the silver and red maples are in full bloom. Arborists will say we are getting near the end of the season as well.
Dormant spray kits are available at your local garden centre. The kit comprises of a bottle of dormant oil and a bottle of liquid lime sulfur. This is an excellent preventative to use in your garden to prevent any “bad” insects from hatching. You simply mix them in an appropriate sprayer – hose end sprayers work well – and spray your woody plants.
The action is quite simple. The Dormant oil is simply an emulsified mineral oil. It covers the branches of the woody plant and smothers any overwintering egg masses. The liquid lime sulfur will kill any exposed insect eggs and will also kill and spores of potentially damaging fungal diseases.
It is important to understand the spray must contact the eggs or spores in order to work as a pesticide. When you are spraying soak all of the bark of the trees and shrubs including the stems. It is best to do this on a cloudy day or late in the afternoon / evening. The longer it takes the water to evaporate from the mixture, the better the oil and sulfur compounds will spread and stick to eggs and spores.
Do not spray any perennial stems that may still be standing and please don’t spray the ground. There are many beneficial insects that overwinter on perennials, on the soil and in leaf litter. We want those fellas in our gardens!
The spray it pretty innocuous but make sure you are wearing all of the protective equipment listed on the package. Sulfur is horrible if you get it in your eyes! Be safe! Follow all of the instructions!
If you have any questions, I’ll be happy to answer them!