Mike:

Please indicate where you are located when asking a question of this nature. Insects, diseases, and growing conditions vary by location, and having this information will assist anyone trying to help you out.

In most locations, growing peaches without the use of chemical sprays is not possible. Sprays can be used on peaches and still produce healthy and non-toxic fruit. The "stings" on your peaches are probably visits from either the plum curculio, the oriental fruit moth, or both. I have both here in Northern Virginia.

Sprays on peaches should begin right at shuck split, and should be more frequent early in the season while the skins of the fruit are most tender and attractive to egg-laying insects. I use Imidan and/or Permethrin, and begin by spraying at intervals as short as 5-6 days apart, depending on weather. As the fruits grow, I spray less frequently, and in the final month before ripening I have not found it necessary to spray at all.

Spraying Sevin is not the way to thin peaches. Even if it worked (which it does on apples), it would be non-selective and with peaches you want the thinning to be highly selective. So do it with your fingers, and start as soon as you can choose the fastest-growing undamaged peaches to leave behind. As the fruits grow, with some developing insect damage and others growing fast and undamaged, return to the tree to thin again. It may be necessary to repeat this procedure as many as 3-4 times until you have left the number of peaches your tree can reasonably support, and all are perfect and growing quickly. If your fruit develops fungal problems such as mildew or scab, add a fungicide to your spray mix. I would suggest you do this at the outset in most locations.

Keep your tree pruned to an open center, and do not allow heavy top growth to shade the developing peaches. Peaches require direct sunlight to grow and develop. I often prune my peach trees twice during the growing season to let in the sunlight and improve air circulation.

There is always more to learn about growing peaches, and I have by no means covered it all, but if you follow the above suggestions you should see at least some improvement in your peach production.

Don Yellman, Great Falls, VA

Mike,

Don's given you good advice. I would add, you never want to spray blossoms with insecticide, it's lethal to bees, our most beneficial insect.

Sevin is sometimes used to thin apples, but is never sprayed at bloom. Also, the amount of Sevin used as a thinner, is much LESS, not more, than the amount used as an insecticide. Something like 35 parts per million is all that is required to thin apples.

Sevin has no thinning properties on peaches. I suppose it's possible that by spraying a double dose of Sevin on the blossoms, you were able to kill enough bees and pollinators that there was slightly less pollination, and thereby less fruit set. This might might give the appearance of thinning, but I'm sure you recognize this is not what you're really after. Unfortunately, hand (or mechanical) thinning is the only way to thin peaches.

As Don mentions shuck-split is a good time to start spraying for insects. Shuck-split occurs about a week after the petals fall off the blossoms.

I'm in the NE Tenn region. I miss spoke when I said the spray was used at blossom set, it was fruit set. However it was probably as you implied that the fruit was already invaded by pest and started to fall soon after. I believe one of the problems to be the Plum curculio because there are some fruit with a half moon hole. A few of my Asian Pears have the same exit?? hole. However the biggest problem I have with the Asian Pears is that the wasps eat them just before the prime tree ripe time, so I have to pick them a little early and ripen them off the tree. Are there any traps that work effectively for these pest? I have a problem with pesticides of any kind because I have reactions to even the most benign chemicals. I have to get someone else to spray and stay away from the area for a day or two.
You also mentioned fungus and scab. I'm not sure what those would look like. The peaches that I get also get a black speckled look on the skin but I assumed that was due to the insect problem. Are there any insects that hibernate in the tree itself over the winter? I have pruned the tree and it is very open in the center so I don't believe that's a problem. As far as the bees go, I don't like to spray because of them as well. We even grow clover ground cover in our 1 acre vegetable garden to help with pollination, fertilization and keep us out of the mud during the wetter season. And the goats love it after the garden is done. Thank you for the definition of shuck split too, never heard of it. Thank you to both for helping me. As far as the Oriental Fruit moth, I'm not familiar with that particular pest. A little more input on that would be helpful.

Don's advice would be wisely heeded on all counts. I will suggest that an organic approach is not impossible, but certainly more difficult. Surround can be used about every 7 days for as long as there is damaging insect activity. I believe you have 2 generations of PC and Don and others have spoken of major issues with oriental fruit moth (note flagging of young peach shoots).

Here in NY I have had excellent successs with Surround on peaches- the fuzz really helps it to stick. 4 sprays and the trees I manage are fine (only 1 generation of PC, and OFM here is not too bad). The problem is that there is no great organic solution for brown rot. Orbit, Indar or Pristine are so much easier and more affective then sulfur and are relatively non-poisonous to you and me.

Don and others farther south have the experience to guide you on the kind of pest pressure you face. Pest control is extremely regional.

Hi Mike-
If you're not sure about something, like "Peach Scab" simply do a Google Image search on it. You'll see lots of pics showing it and then you'll know if that's what you have or not. When dealing with fungus/diseases/pests Google Image search is invaluable.
-Glenn

Mike,

To answer a few other of your questions.

Most major peach pests don't overwinter on the bark of your peach tree, so trying to do a dormant spray won't help for plum curculio (PC), or Oriental Fruit moth (OFM).

PC and OFM tend to be the biggest insect pests of peach trees. In most locations, if you can control these two, your insect problems are whipped. OFM is a season long pest that has a new generation about once a month. Some folks like Don and Hman don't have as much trouble in their locations, and don't have to battle it all summer. For other folks, like me, it's a season long pest. The larva of the moth tunnel in fruits and new peach shoots causing the end of the new shoots to wilt and die, i.e. flagging.

Black spots on peaches can also be, and frequently are, bacterial spot, for which the best control is to plant resistant cultivars. In your region, the only dormant spray needed would probably be to control peach-leaf curl. Most folks use a copper spray to for it.

On my previous post, I confused Sevin with other apple thinners. Some other thinners use 35-75 ppm, but Sevin requires considerably more chemical, but in most cases, still less than the rate used for insect control. Probably doesn't matter to you, but I wanted to post accurate information.

I love Gardens Alive catalogs not because I can afford to buy much from them but their disease and pest descriptions are excellent. From your description, it sounds like bacterial spot. "symptoms are first visible about 3-5 weeks after petal fall as small water soaked browning lesions." "easily mistaken for insect damage" gum may exude from these lesions" Go to their catalog (lengthy) for a description of possible help. I have this problem not on my pears but plums. I try to keep the trees growing as vigorously as possible but as yet I haven't obtained more than a half dozen edible plums.