Lychee:

I am doing my first dormant oil/copper sprays right now, taking advantage of the first real window of good weather that we have seen for many weeks. I will do another just before or at bud break in about two weeks, weather permitting, and if it doesn't permit I wait until it does.

Don Yellman, Great Falls, VA

Thanks Don. Also, can I combine the copper (kocide) with a broad fungacide (mainly to combat bacterial spot) so that I can do both sprays in one go, or will the two sprays interfere with each other?

LL, I do my dormant copper at pink -- as late as possible gives the most bang for the buck.

Right now I am up to my ears in pruning needing doing due to the snow-induced backlog, and I don't like to spray before pruning because its a waste to spray all that pruned wood. So, my main goal now is to get the pruning done before pink hits.

Scott

I just did a dormant spray of Chlorothalonil (daconil)
for peach leaf curl. This was Cornell's recomm. Anyone try It?
MM

I just applied Daconil to my peach last weekend as the buds are near to swelling. Last fall I did a Kocide app.. Never tried the Daconil before and relied on a spring Kocide app instead with no problems. Why the switch? To help deal with shothole and not add any apps. in the process.

Michael, I prefer copper for shothole since it stays on longer. Only after leafing out would I consider using daconil for shothole since at that point copper is phytotoxic. Daconil has a 60-ish-day PHI so its useable til shuck split or so. I in fact never use daconil since copper at leaf fall in fall and pink in spring has kept me out of shothole touble.

Scott

As the thread is talking about two different diseases, I thought I'd offer a clarification for anyone trying to decide on timing.

Leaf curl is best treated before bud swell. When the bud scales start to loosen, the fungus is washed in the bud scales and makes control harder. Since the primary infection comes from the fungus residing in microscopic crevices on the tree, a dormant application of a good fungicide is designed to kill the infection on the tree before it can wash into the bud scales, or emerging leaves. I surmise fungicides for leaf curl are recommended in the fall precisely for this reason. However, under the right conditions the fungus can regrow, so another spray just before bud swell is recommended in wet winters (which works well here). Here is a link on leaf curl.

Fungal shot hole was also mentioned. While both leaf curl and shot hole can be treated in fall dormancy, the spring treatment is a bit different. Where leaf curl is another dormant treatment in the spring, shot hole is best treated at bloom. I suspect Scott's method of treating at pink is a happy medium to treat both diseases.

However, if you're only battling leaf curl, dormant sprays are your best control.

Here is a link that might be useful: A link on shot hole

LL, Olpea is right that you should spray earlier for curl. I didn't notice that in your question. I have some years done a pre bud swell copper but I don't think its doing much for me since I have no curl problems. For bacterial spot which is my problem you need to have a layer of copper down before leaves come out since the rains will wash the disease onto the new leaves. The CA schedule you link olpea is not very useful for the east coast I don't think, since they don't have the rains like we do. The schedule I follow the most is the one below. Usually I do a couple spring copper sprays, e.g. pink and a couple weeks later at a dilute dose, plus leaf fall. If the disease is bad I spray more and if its not visible then there will be no sprays after the dormant spray.

Scott

Here is a link that might be useful: NCSU peach spray guide

Scott - thanks for link -seems to answer my question-ncsu states ferbam daconil copper in order of effectivness for PLC

Scott,

I thought you were talking about fungal shot hole, because you mentioned using Daconil, and Daconil has no effect on bacterial shot hole.

If we're talking bacterial shot hole, I agree, Davis isn't going to be much help. I don't even think they have bacterial shot hole in CA.

Thanks for the responses. One aspect of my question that I dont believe was answered, is whether it is ok to combine the kocide with a general fungacide spray so that i can obtain broad coverage with one spray. is this ok? or will the two different chemicals interfere with one another.

also, when is Peach tree bud swell in NY. what exaclt am i looking for to determine that bud swell is about to occur and i need to quickly get a copper spray for PLC

Olpea, this fungal vs bacterial shot-hole is a complex issue. My belief is that both varieties are common in the east (and, I have been told this by some experts). However, people seem to only talk about the bacterial kind and it is the only thing listed in spray guides. So, my feeling is they are sloppily viewed as one disease in the east, and this greatly confuses the treatment recommendations. I am almost positive that I have the fungal form in my orchard since the holes tend to be more round-edged with that. I think I have some of the bacterial version as well but am not completely sure. In terms of overall spray recommendation I follow the west coast idea of a leaf fall spray for fungal spot but which east coast people do not mention, but I believe the repeated spring sprays of the east coast guides are good for either kind of shot-hole since rain events are horrible for either of them -- my round-holed shothole propagates like crazy onto the new leaves after a rain, and if there is no rain the new leaves stay clean. The west coast recommendations for fungal spot are not taking into account heavy spring rains since they don't have them.

I am guilty of abusing this terminology myself since its a pain to go into a lengthy explanation each time, but most of the time the treatment is similar so I don't feel too bad about it. However you are correct that fungonil is only useful for the fungal kind.

LL, I don't see any problem with that mix.

Scott

With weather variables thrown in, what's best? I think I've heard 48 hours without rain and temps above 40F is best. Is this true and if overnight lows dip into the 30's but stay above freezing is this OK? Kocide & oil is what I'd be spraying. I did get a spray in last fall after leaf drop, but don't want ANY PLC this season.

Thanks!

Here is a link that might be useful: bud development stages

Thanks to Scott and Olpea for the detail. FWIW, my spray regimine until last fall was only a late dormant app. of Kocide at the 9lb. rate mixed w/spray oil. There has been no PLC and progressively more shothole as the years go by but still not a serious problem. This year I plan to see what I can do with the SH before it gets worse. The other reason is it can be very difficult to get in a Kocide app. during this time of year so making one in the fall seemed to make sense.

Of course if there is one thing that many folks know it is that the weather can wreak havoc on the best planned spray schedule. For the shothole control attempt this year, the plan is to do the just pre-budswell spray (done) in case the bloom app gets rained out to what is to be the last at 1-2 wks post petal fall. That could easily all change with the weather.

One puzzling thing to me, and perhaps the OP also, is if you aren't certain PLC will infect a tree should one spray for it? It seems, like other diseases, to be potentially anywhere at any time. My tree has yet to show symptoms yet it would seem unwise to take a chance with PLC as destructive as it can be.

Michael, I don't spray for PLC unless I see it; it is pretty easy to completely eradicate as I have had two "invasions" and both times I had them pounded into submission within a year. Shothole is a different matter, I don't think you ever get rid of it you only reduce its impact. There are lots of ornamental plum cherry etc trees which keep shothole going whereas curl sticks to peaches which does not have ornamental trees around here; that may be a factor.

Scott

Thanks Scott: I'm can't wait to see if my controls have any effect on the shothole.