R & L Porter wrote:

I was under the impression that dormant spray was used while
the plant was dormant in order to smother pests (thinking
of apple trees). Am I way off, or am I thinking of something
similarly named?

I can see that most people are thinking the same as you, that 'dormant
oil' as being the spraying of a dilute oil mixture fungicide during
the dormant rose period. In this case you are absolutely correct.

Spraying your roses in order to force them to go dormant and spraying
them in the winter in order to prevent fungal disease and insects are
two different things.

The most common treatment for winter spraying for fungus and insects
is 'lime sulpher' which can be sprayed with a dilute horticultural
oil in order to keep it adhering to the stems and leaves of the plant.
This is commonly referred to as 'dormant oil', but is not necessarily
a plant defoliant although it can be.

There are several other winter treatments for fungus that don't
necessarily defoliate (create dormancy) in the plant. Here are a few
mo Copper Sulphate, Triforine, Chlorothalonil, Propiconazole,
Captan and Methyl Thiophanate.

Don't forget that most of these fungal spores are overwintering in the
fallen leaves and soil in the ground around the plant. So if you
spray, you must also spray the ground around the plant.

Some people do like to remove all of the leaves of their infected
plants in order to help with fungal control it is true. And if most
of the leaves and stems are infected this might help a lot. If the
plant is otherwise OK though, it is not necessary.

Realize also though that some people in some climates actually need to
produce an artificial dormancy period in order for their roses to
bloom well the next year. This is also called dormant spraying and
was what I mistakenly though was meant.

Sorry about the mixup.....

Bob Bauer