North American Fruit Explorers mailing list at ibiblio

[Hilborn.E@epamail.epa.gov]

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