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- From: <dmnorton@royaloakfarmorchard.com>
- To: "North American Fruit Explorers" <nafex@lists.ibiblio.org>
- Subject: Re: [NAFEX] Captan
- Date: Sat, 21 Mar 2009 19:38:12 -0500
Walter, here are the previous
posts in the order in which they were posted. They schedule is in the
second post.
1. A dormant oil spray is predominately for mites and scale. If you
have a
problem with these pests then I recommend a dormant oil spray. Oil sprays are temperature sensitive and must be sprayed between 45+ and 75 degrees. That makes it somewhat difficult to spray in the early spring while trees are still dormant. Because of this, I use Superior Oil - 70 sec because you can change rates and spray it even after 1/4' green if you need to. It allows for much flexibility. A Bordeaux mix can be tricky at best and can create timing issues as well. Bordeaux is suggested for those orchards that have also had fire blight issues as well as insects which is why it consists of copper sulfate, lime and miscible superior oil. It has to be mixed in the proper order and must be agitated continuously. A fixed copper spray of copper hydroxide or copper oxychloride is the other alternative without all the hassle. You cannot apply Bordeaux after 1/4" green like you can Superior oil and Bordeaux mixture residues have many compatibility problems with other pesticides and fungicides like captan. Fixed coppers can be mixed with oils, so that is why I use a fixed copper (specifically Champ) and Superior oil. You cannot use Captan within 2 weeks of a copper spray, so I use an EBDC for my first 2 apple scab sprays. This allows me much flexibility in my timing and if I need to I can mix any of these products I have never seen the need for both a dormant oil spray and a Bordeaux spray. In fact, I only do a dormant oil spray every other season. This season is our year to spray oil. Your choice of one over the other can depend on what you choose to use for your remaining spring sprays. You and I are in almost the same climate zone, but the timing is based on tree phenology and GDD (Growing Degree Days. I use a Bio-intensive IPM program and incorporate biologicals into the program with EPA recommended Reduced Risk chemicals. We have around 12,000 trees and our spray tank holds 500 gallons of product so we can cover the orchard in 4 tanks. Most of the products you would choose depends on the particular pests you have in your orchard. I don't necessarily spray for "every" pest present in the orchard. I monitor the most prevalent each season and then choose products that will provide the best overall coverage of the pests with the least amount of sprays. Our annual budget for spraying is around $20,000 and one orchard spray can cost as much as $4,000, depending on the tank mix I might use. I try to mix as many products as possible based on timing, GDD, pests and weather. 2. The protectants such as an EBDC or Captan are non-systemic and actually kill spores as they germinate before they have a chance to infect the plant. They poison the metabolism of fungal cells at many levels. Since they are multisite (multi-level) and fungi would have to develop multiple mutations to overcome them, resistance is unlikely. So I go for the kill with the first spray since the leaves are just beginning to grow. At green tip, there isn't much leaf there to absorb a systemic spray like an SI. The Strobilurins (Flint/Sovran) have
single-site mode of action and that makes them prone to resistance
development. With Sterol Inhibitors (Nova/Rally) that inhibit different
points in the sterol synthesis pathway, resistance development tends to be
more gradual, but is still possible none the less. Since they are
systemic, they will penetrate the leaf which gives them some "reach back" effect
and I think are better used after 1/2" green.
Right now, Dithane is cheaper than Captan
plus you shouldn't use Captan within 10 days of an oil spray. We always
have issues when we spray oil and try to follow-up with Captan due to the
weather, so that is another reason I choose an EBDC for the first spray in
the years we spray oil. It gives me a bit more
flexibility. Because of the resistance issues, I'm using an
anti-resistant scab management program based on rotating different classes of
fungicides. Here's my timing breakdown:
GREEN TIP - 1 to 2 applications
of an Captan or EBDC (Dithane) at full rate
PREEBLOOM - 1 to 2 applications
of a Strobilurin (Flint or Sovran) or an EBDC or Captan or an EBDC & Captan
(each at 1/2 rate)
PINK & BLOOM - 1 to 2
applications of an SI (Rally - Nova is now Rally) mixed with an EBDC or
Captan (1/2 rate) or EBDC OR EBDC or Captan (full rate)
PETAL FALL, FIRST COVER - 1 to 2
applications of a Strobilurin (Flint or Sovran) OR Captan (EBDC cannot be used
after Bloom)
SUMMER - Classic protectant
except an EBDC such as Captan or Pristine (carboxamide and a
strobilurin)
I'm sure you know all of this, but I went into a
bit more information for the benefit of those who are not aware of the
differences between the various fungicide sprays. I would be interested in
knowing what approach you take in scab management.
I hope this
helps!
Dennis Norton
Royal Oak Farm Orchard Office (815) 648-4467 Mobile (815) 228-2174 Fax (609) 228-2174 http://www.royaloakfarmorchard.com http://www.theorchardkeeper.blogspot.com http://www.revivalhymn.com
|
-
[NAFEX] Captan,
walter6353, 03/21/2009
- Re: [NAFEX] Captan, ROBERT W JUDY A HARTMAN, 03/21/2009
- <Possible follow-up(s)>
-
Re: [NAFEX] Captan,
walter6353, 03/21/2009
- Re: [NAFEX] Captan, dmnorton, 03/21/2009
-
Re: [NAFEX] Captan,
walter6353, 03/21/2009
- Re: [NAFEX] Captan, dmnorton, 03/21/2009
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