North American Fruit Explorers mailing list at ibiblio

[Don Yellman <don.yellman@webformation.com>]

Shirley:

Gummosis is a general classification for fungal diseases that attack the 
trunk and limbs of peach trees, although bacterial infections (canker) are 
usually more common on stone fruits.

The little blobs of pectin on your peaches are signs of visits from the 
oriental fruit moth.  This insect is widespread throughout the eastern U.S., 
but there are some places, particularly where there are many untended stone 
fruit trees around, where it is particularly prevalent.  You can minimize the 
OFM hatch on your own territory with dormant spraying and a rigorous orchard 
hygiene program, but you can't stop flying insects from coming in from 
elsewhere.  In my orchard, I have to spray peaches at least four times after 
petal fall with Imidan to get the little peaches up to the size for final 
thinning and bagging in ziplock sandwich bags.  If it were not for the 
ziplocks, I would be spraying chemicals all season long, since the OFM can 
have 5 generations where I live.  Fungicides like sulphur or serenade have no 
effect on this insect, and products like Surround would be of only marginal 
help.  Early damage from plum curculio is also common on peaches, but is not 
normally t
he problem posed by the OFM.

Growing peaches "organically" in much of the eastern U.S. is almost a 
contradiction in terms.  The OFM is such an intractable and persistent insect that even 
a full-blown chemical spray program is barely sufficient in many locations.  I don't 
like chemicals or spraying either, since it is a lot of work and expense I would rather 
avoid.  But, being of a practical mindset, I do it because I want ripe peaches at the 
end of the season.  If it is suspicion of pesticide residues that incline you to strict 
organic practices, consider that by the end of the season after a few early sprays in 
April and May, followed by bagging, they are inconsequential.  After a few days on the 
tree, or a rain, even the insects are unaffected by spray residues, and they are far 
more sensitive to these targeted chemicals than you or I.

Don Yellman, Great Falls, VA