On 1/20/2008 12:40 PM, Zootal wrote:
I have a copper based fungicide, and a sulfur based fungicide. Both claim to
be the definitive cure for peach leaf curl. Does anyone know which works
better, or if both are equally effective? Last year my peaches had peach
leaf curl quite severly. I'd like to prevent it from happening this year.

I use a dormant spray that combines a light oil (to kill over-wintering
insects and their eggs) with copper sulfate (a fungicide that is both
copper and sulfur). This mix is no longer available in combination, but
can be obtained with the oil separate from the copper sulfate and with
instructions on how to combine them. The mix is diluted in water, about
1 tablespoon of mix to 1 gallon of water. I add some liquid soap to
ensure that the spray sticks to the plant and does not bead up and run
off.

I apply this right after pruning (weather permitting) and again at the
"pink bud" stage (when flower buds just start to show some color but are
not yet open). At the time of the first spraying, I mix extra spray and
apply it to my roses and grapes to prevent early mildew; if there is any
left over, I spray the ground under my camellias to prevent blossom rot.

I finished pruning my peach tree on Friday. However, the weather was
not permitting: The wind was too strong for spraying. Other
commitments prevented me from spraying yesterday or today. Drizzles and
showers are now expected through this coming week. Since any rain
within 48 hours after applying copper sulfate generally means
respraying, I won't be doing the post-pruning spraying until next weekend.

In addition to spraying, cleaning up old fruit is important for
controlling fungus.

--
David E. Ross
Climate: California Mediterranean
Sunset Zone: 21 -- interior Santa Monica Mountains with some ocean
influence (USDA 10a, very close to Sunset Zone 19)
Gardening pages at http://www.rossde.com/garden/