Subject: Peach fungus

From: [email-masked] (Machiko Hollifield)
Date: Mon, 19 Jun 1995 17:40:00 GMT

This year, for the first time, we had a Peach on our peach
tree.  But most of fruits have light brown fugus like spots.
If left it, it's grow to whole fruits and even the branch will
be killed.  What is this?  And How to treat it?

I'm in South East Alabama.

Thanks very much.

Machiko Hollifield
[email-masked]

Auburn University, Network Support

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From: [email-masked] (Jon Boy384)
Date: 20 Jun 1995 21:51:04 -0400

Hi, 

I grow about 25 acres of peaches in Connecticut. I would disregard the
advice about trying to control your fungus problem with oil. The only
thing oil is good for is insect control, more specifically mites and scale
although it might also suffocate other overwintering insects and eggs
present on the trees.

The major fungus disease which affects peaches and other stone fruits is
brown rot. Infection can begin as soon as the blossoms open in the spring.
It is spread by spores which are ejected from fruiting bodies present in
old fruit mummies in the orchard. If you have not applied a fungicide
after blossoms are open and before a wet period You will have problems.
Brown Rot can infect the wood in severe cases and if it has infected the
wood in your trees I would recommend that you remove the affected
branches. It will continue to spread from the wood making control
difficult. Early season infections cause  blasting of blossoms (they will
appear brown and gummy) and infection of the wood.
I would recommend Bravo or Lime-Sulfur as fungicide choices for early
season.

During the middle of the season if conditions are relatively hot and dry
you can back off a little, but the disease becomes destructive again at
harvest in the fruit rot stage. It is critical to maintain a good
fungicide cover at this stage. If you  are at the harvest stage, and are
experiencing fruit rot, the best you can hope for is to prevent spread to
uninfected fruits. Recommended fungicides for control at this stage are
Orbit or Rovral. 

If you are trying to stay organic you can use sulfur, but under heavy
disease conditions, I wouldn't expect too much.

Good Luck, 

Jon