Search the Archives
The following thread was started by Paul W on November 06, 2002 at 1:46 am PST
I've sprayed & sprayed (at all the right times!) and i disposed of all affected leaves & fruit last year. My nectarine tree is a lot healthier this year, with heaps of fruit, BUT it still has a bit of leaf curl AND about 30% of the fruit has this raised rough leaf curl look on the skin (please see image). Also a lot of the fruit hasn't developed, it remains small & drops off.
please help - it's spreading to my peaches!!!
The above followup was added by dave harris on November 06, 2002 at 11:20 pm PST.
This is a problem I need to find a cure for, our peach and nectarine trees get this so bad that they are almost at the stage of dying from it, the silly thing is that in town near the beach on the sand soil no single peach tree gets curly leaf but out in the red acid dirt outside of town you can hardly grow them because the curly leaf is so bad. This year I sprayed them at the right time and it made no difference and it's driving me insane, I'm sure it's a nutricional problem that's causing the tree's to loose their resistance to disesase but I don't know what they need
The above followup was added by Jason on November 06, 2002 at 11:29 pm PST.
found some info here, http://www.au.gardenweb.com/forums/load/cornucop/msg1018462423889.html?5
not sure how reliable it is!?
did my picture show on the above mail? these "free" web hosters are shockers!
the address is http://djharris5.tripod.com/nectarine.jpg
The above followup was added by dave harris on November 06, 2002 at 11:46 pm PST.
There are claims of resistant varieties, I know of no reliable substantiation.
http://www.organicgardening.com/library/peaches.html gives a couple supposed resistant varieties, which I have never heard of, and I saw another reference that Redhaven derived cultivars have some resistance while Redskin shows more susceptibility. I personally doubt it.
Every time I ask the bareroot growers, they just shake their head and say they don't see any differences, and they should know. It is mostly just wishful thinking.
Here is the story, as discovered by one university in a very good, large study done back in the early eighties, so listen closely:
lime sulfur and oil, applied as per label in December or late November when leaves are about 90% off the tree, gives about 95% control with a single spray. Follow up with another spray about mid February just before they break leaf and you can get about 99%.
Everything else is pretty much a waste of time. Bordeaux gives no better control than plain water, and micronized copper sulfate tribasic formulations (Microcop, etc) only give about 90% with the very best results, usually not that good more like 75%, and believe me, you DON'T want to be applying copper around your garden on a regular basis. You can't get rid of it and it can cause endless grief in micronutrient land.
Note that this is NOT what most references will say, but field trials clearly showed that lime sulfur and oil was vastly better than any other treatment.
The simplest and oldest solution is the most effective. Most curl problemsreally come from not getting out there at all to spray.
It is really more of a twig disease. The young, unhardend leaves, and only those leaves, get infected as they push past the spores overwintering in the scales. It only grows when the average daily temperature is within a certain range. So you don't "cure" it by picking off all the bad leaves. The leaves produced under warmer conditions will be free of it anyway. And I haveactually seen it come back when cool conditions returned. And it can kill twigs and young branches when it gets bad and you don't treat it from year to year. And the spores can last several years resting before they activate and infect. And so you have to spray EVERY year, you will never get rid of it.
Good luck, and have fun!
The above followup was added by Luen on November 06, 2002 at 11:58 pm PST.
I will say that Indian Free is acknowledged to have some resistance, but its progeny seem lacking. Sometimes I have had fruit that taste good, usually it is more of a novelty.
The above followup was added by Luen on November 07, 2002 at 0:00 am PST.
lime sulur & oil
where do i get lime sulfur & oil...is it safe?
The above followup was added by dave on November 07, 2002 at 1:31 am PST.
I will have to try it this year
My old peach tree which came with the place, gets it realy bad, but my new one is not quite so. It does not seem to bother the fruit on any of my trees, except to make them look really bad.
Last year I tried a dilute solution of lemon juice and hydrogen peroxide, it had some effect, but not enough, but too only put it on at pink bud. I have a real hard time using even the lime foliar compound, they are quite harsh as well.
I have thought of using Tea Tree oil, it is anti: bacterial, fungal and such, but expensive, at least $8.00 for 1 fluid oz. But if it worked, maybe it would be worth it. I have no idea how much it would even take, I guess experimentation would be in order, maybe it would not require a strong concentration, and really be that expensive. Has anyone tried it?
The above followup was added by David, Waterford CA, zone9 on November 07, 2002 at 6:01 pm PST.
Certainly some varieties have good genetic resistance to peach-leaf curl. Frost, Q-1-8, and Indian Free all are thought to be in this category. None of these are low-chill, so they're not so suited to my climate. And I haven't been impressed with the taste of Frost (either grown in my climate, where it was astringent-- and seemed a shy bearer because of lack of chill presumably-- or grown in good climate where it was a typical peach). Indian Free is kind of an interesting fruit grown in good climates. It's not very sweet until quite ripe, but it's got interesting and kind of unique flavor and looks cool. But I personally prefer other peaches. I've never eaten Q-1-8. But any peach fully tree-ripe can blow away supermarket fruit, so if you don't want to spray, these are good bets. I had a Frost peach at my folks' place, with other peaches and nectarines grafted onto it. If I was a slacker and didn't spray, or sprayed late etc, the other varieties would have curl, and the Frost would not. So the 10-year trials in Washington showing it has curl resistance are valid, I'd say.
Interesting thoughts from Luen on different spray effectiveness. I've found that lime-sulfur controls peach leaf curl well for me. Timing is critical-- if you wait until you can see the bud scales starting to swell, you're too late. And spraying right before rain (even with spreader/sticker) seems to make it less effective. And many peach/nectarine varieties that I had would hang onto their leaves almost entirely through the winter, so doing a first spray in the November period didn't work unless I mechanically stripped leaves, which only works on tiny trees unless you use chemical defoliants. (These are a clever trick employed by cherry growers among others to fool the tree into thinking it is geting more chill than it actually is.) I usually try to get in 3 sprays, but sometimes only do 2.
Lime sulfur is very widely available-- any nursery should have it. Old, safe, no effect on bees-- what's not to like?
Anyway, there's a lot of info on leaf curl out there-- try UC Davis IPM site: http://fruitsandnuts.ucdavis.edu/crops.html
The above followup was added by Tom A. on November 07, 2002 at 6:36 pm PST.
Tom, I agree with you, there ARE resistant varieties, but except for Indian Free, that was my point, who has heard of Frost or Q-1-8? You should select a peach for its flavor then go from there. If you absolutely can't abide by spraying, there probably are some out there with resistance if you look hard enough, and looks like you did and found two more.
If there are 10 year trials in Washington to attest to that fact, I believe. But as far as the ones people want, it remains just a wish. There is no secret list of commonly available outstanding varieties that don't get curl.
If you want Late Elberta, Rio Oso Gem, Heavenly White, or any of the other ones that make you go semiconscious with delight when you bit into them, you just have to spray.
I have had Indian Free from real hot areas, it got sweet enough that I liked it okay. It would never beat a Late Elberta or better varieties. Along the coast it is sprightly, I think that would be the word, maybe "refreshing" too. Acid and astringent. Striking color.
Also, it was determined by the study I mentioned that a primary weak link was the leaf scar left by the dehiscing leaf and the scales of next year's buds. The best control was when they were able to spray the scar before it hardened up and get spray on the buds before they shrank back into the stem in hard dormancy in late December and January. If you are in an area where the tree doesn't want to defoliate, you may have more problem. Their recommendation was to spray early rather than late, and tests with only late sprays gave poor results, even with lime-sulfur.
I would also be interested in seeing if heavy spray oil (Volck, which was actually developed in Watsonville believe it or not, and was one of the first and still most effective insecticides ever developed) works better than Stay Stuk, Triton B-1956, or other resin-based sticking agents. It wouldn't surprise me if it did. And I agree, I think it might take a couple of days of dry weather to really get it to dry down completely and keep it on well.
But last year I sprayed just a few hours before a rain storm in early December and I still got excellent control with only a single spray. I only saw traces of disease. And in our area it is usually severe on unsprayed trees.
I think peaches and especially nectarines are as good as the very best subtropical fruits. They are well worth taking the time to spray one time per year with a safe, non-toxic agent that I believe is approved for use in commercial organic gardening. I think lime sulfur is formed simply by combining sulfure and lye.
The above followup was added by Luen on November 08, 2002 at 1:00 am PST.
Citrus Gall Wasp & Curly leaf
it's that time again! I've been using the copper based spray for my stonefruits to prevent leaf curl - but it hasn't been very successful - does anyone have any secret remedy?
I also need to find a solution for the citrus gall wasp - I can't cut back new growth every year - defeats the purpose of havinf a FRUIT tree!.
I know I've read somewhere that there is a natural predator for this bug - anyone know what it is & where I can get it in Melbourne??
The above followup was added by dave on July 08, 2003 at 0:08 am PST.
What spray shold I use for Curly Leaf on lemon trees?
The above followup was added by Ann Wrighton on April 18, 2005 at 3:32 am PST.
Please note that you are viewing posts from the vintage Cloudforest forum. These are un-moderated posts made by un-registered users. Every effort has been made to clean up the old archives, but we cannot guarantee the contents. If you find an offensive post, please bring it to our attention and we will remove it.
It is not possible to post to the old archives. If you wish to follow up on one of the posts in the archives, please make a reference of the post URL and start a new topic in the Fruits, Rare Fruits and Exotics forum.