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Peach tree--fruit gets brown spots

Posted by ironhorsedriver Illinois (Chicago) (My Page) on
Sun, May 8, 11 at 22:08

Hey Folks,

I'm not much of a "green thumb", so perhaps I can get some advice and guidance regarding two peach trees that are on my property (I live near Chicago). I have lived in this house since 2008 and the trees, which seem to be older trees, did not produce any decent fruit the first two summers I was here. Last year I pruned a lot of dead branches in the spring and it really seemed to help. I got a lot of blossoms then a lot of fruit started growing. Around the end of June the peaches developed small brownish-grey spots all over the fruit. They kept growing but toward the end of July they just died off and dropped to the ground without ripening.

I was only able to harvest less than 10% of what started growing.

Any suggestions? I had pounded in some Jobes plant spikes for trees a couple of weeks ago, and I see the blossoms starting (it's been a very cold spring in Chicagoland so everything is late in blossoming this year). Can anyone recommend fertilizers or sprays that may prevent this fruit from going bad?

Thanks in advance for your help.


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RE: Peach tree--fruit gets brown spots

  • Posted by olpea zone 6 KS (My Page) on
    Mon, May 9, 11 at 9:46

Ironhorsedriver,

You sound like you need a little fruit growing 101.

First, peach trees should only grow about 10% of their blooms. To put it another way, after the shucks come off the fruitlets, about 90% of the fruitlets need to be removed by hand. This is called fruit thinning.

I know it seems counter-intuitive to manually pull fruit off, but peach trees will set about 10 times the amount of fruit they can realistically carry. If you don't thin, you end up with very small fruit, broken branches, and stressed trees.

If you don't thin, the tree will naturally abort some of it's fruit in June (called June drop) but it won't get rid of enough to eliminate the problems listed above.

Plant spikes are a poor value for the money. Mostly they are a marketing gimmick. If you feel your trees are poorly growing, apply a small amount of a mild fertilizer (something like 10-10-10) under the canopy of the tree.

Now more directly to your pest issues:

Bacterial spot and scab can cause spotty fruit, but neither disease will cause abortions.

The most common insects for peaches in the Midwest are Plum Curculio and Oriental Fruit Moth. Both will cause infected fruit to drop in my area. The best way to tell if this is your problem is to cut the fruit open and look for evidence of a worm or worm tunneling. An good insecticide starting at shuck split will generally control this problem. Triazicide Once and Done liquid concentrate is a good one. You'll probably need to spray it every couple weeks (maybe less). Make sure you follow the label directions.

Olpea

P.S. I've always wanted to blow one of those train whistles.


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RE: Peach tree--fruit gets brown spots

Olpea gives some good advice. Your brown/grey spots sound like brown rot since they brown the flesh and then a grey mold grows over the top, but the peaches often stay on the tree with that. I would look up various pictures of fruit tree diseases and bugs to get a good diagnosis of your problem. If you can't figure it out, post some pictures here. Proper diagnosis is a critical step so then you will apply the right control.

Scott


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RE: Peach tree--fruit gets brown spots

Thank you, Professor, for this little lesson. I am new to fruit growing so I had no idea that I need to remove 90% of the small fruitlets that grow! I will try that as the season wears on. If I experience brown spots again on the fruit I will take pictures and post them to this forum for advice.

BTW, I planted three dwarf apricot trees (2 in the fall of 2009, one in the spring of '10). I don't know if anything will grow this year (no blossoms as of now), but when they start producing fruit, shall I do the same thing as with the fruitlets on the peach trees?

Thanks again for your help. I will give a nice long blast on the locomotive whistle for you :-)


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RE: Peach tree--fruit gets brown spots

  • Posted by olpea zone 6 KS (My Page) on
    Sat, May 14, 11 at 11:54

Ironhorse,

No professor here. I respect many people of learning, but never had the desire to explore theoretical realms professors do.

Most temperate tree fruits require thinning, including apricots. For example, the apple industry uses chemicals to remove fruit from apple trees. They may spray the trees three different times early in the season to adjust to the correct crop load.

There are no effective chemical thinners for peaches and apricots. Those are generally thinned by hand, although there has been experimentation with mechanical thinning on peaches. The newest and most promising is a tractor attachment that spins wires and "whips" the blossoms off trees.

For homegrowers however, thinning by hand is the best method. Apricots are not thinned as aggressively as peaches. If you Google, there are lots of Websites that provide instruction on fruit thinning.


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RE: Peach tree--fruit gets brown spots

Here is the latest saga on my peach trees: I thinned the fruit as suggested (with the exception of branches I cannot reach), and the remaining fruit is growing. However, I have noticed small (about 1/16-1/8 inch) clear crystals growing on the sides of the fruit. If I pick the crystal off there is a tiny brown mark. I now remember seeing the same issue last year. What could that be? Any suggestions?


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RE: Peach tree--fruit gets brown spots

Is the tiny brown mark shaped a bit like the capital letter D?

Stone fruit will ooze pectin like that in response to any injury. Typically, injuries are cause by some insect laying eggs on the fruit. I'm in your area and not aware of the Oriental Fruit Moth being present, so that leaves the plum curculio.

Nothing you can really do about it now, as the season for the curculio should be over. Be sure to pick up those fruits if they fall, which means the larva is ready to leave the infested fruit and pupate in the soil under your tree. Next year, follow the spray recommendations above.


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RE: Peach tree--fruit gets brown spots

Here is the latest saga on my peach trees: I thinned the fruit as suggested (with the exception of branches I cannot reach), and the remaining fruit is growing. However, I have noticed small (about 1/16-1/8 inch) clear crystals growing on the sides of the fruit. If I pick the crystal off there is a tiny brown mark. I now remember seeing the same issue last year. What could that be? Any suggestions?


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