To: "North American Fruit Explorers" <nafex@lists.ibiblio.org>
Subject: Re: [NAFEX] Copper spray timing when plants are not synchronized
Date: Sat, 22 Mar 2008 00:42:32 -0600
Betsy,
Have you ever considered a Bordeaux
mixture? A mild Bordeaux mixture (2-6-100 or 3-3-100) can control
blossom blight also. Bordeaux can be in mixed in various formulas such as
10-10-100 or 8-8-100 plus superior oil. The first number is the copper
sulfate crystals. The second number is hydrated lime. The third
number is water. Superior spray oil can be used with the copper sulfate
crystals only if the lime is also used. The hydrated lime dilutes the
phytotoxicity of the copper sulfate. Under some weather conditions a
mix may damage leaves or cause fruit to turn a russet color. I am including
a mixture table for small quantities that should be suitable for most small
scale uses. The mixture must be agitated continuously. Do not apply mixes
greater than 3-3-100 after 1/4-inch green leaf stage or when drying conditions
are slow, as injury can occur. Here's the recipe:
For 2-6-100 Bordeaux
mixture: (for less severe blight or later in the growth stage of
tree)
4 tsp copper sulfate crystals 12 tsp hydrated
lime 1 gal water 2 Tbsp spray oil
For 3-3-100 Bordeaux mixture: (for
more severe blight or earlier in the growth stage of the
tree)
6 tsp copper sulfate crystals 6 tsp hydrated
lime 1 gal water 2 Tbsp spray oil
Dissolve copper sulfate crystals first. Mix in
hydrated lime, constantly stirring. Finally, agitate the mixture as you add
spray oil.
Subject: [NAFEX] Copper spray timing when plants
are not synchronized
> Hi all, > > I have planned my assault with copper spray
on fireblight in my small > orchard. I have run into a small
snag. > > My information is to spray elemental copper at green tip
stage, and that > it is important to spray the entire orchard for
comprehensive > protection. I understand that copper can be
phytotoxic if I wait too > long. > However, my collection of apples
and pears are all at different stages > of growth. I have a pear
tree in full bloom, another with emerging > flower buds, some apples at
green tip and some pears and apples still > firmly dormant. >
> I managed to spray the early pear by itself a couple of weeks ago as
I > realized the lack of synchronicity, however now it is getting >
complicated. > > Question: do I spray the green tip varieties AND
the dormants or just > the green tips and wait on the dormants? I
understand that the copper > will harm the stages further along so I guess
I need to skip trees. I > also understand that it wears off, so I
expect I will need to spray the > dormants as they become green tip.
Is it harmful to spray multiple > times before bud opening, or should I
just follow the green tip stage > around the orchard and hope there is
enough persistence of copper among > trees? It does not appear that
I can saturate all the trees at each > spraying as generally recommended
as it seems I will harm new growth.... > > Advice
appreciated! > > Betsy Hilborn > 7a NC > >
> >