[NAFEX] Captan

dmnorton at royaloakfarmorchard.com dmnorton at royaloakfarmorchard.com
Sat Mar 21 20:38:12 EDT 2009


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
  ----- Original Message ----- 
  From: walter6353 at myfairpoint.net 
  To: dmnorton at royaloakfarmorchard.com ; North American Fruit Explorers 
  Sent: Saturday, March 21, 2009 5:02 PM
  Subject: Re: [NAFEX] Captan


  Dennis,

       I missed your posts with a schedule, just that you did 3 or 4 sprays, which sounds achievable for me. How do you time the sprays?

       Thanks.

                               Walter














  Quoting dmnorton at royaloakfarmorchard.com:

    Walter,

    The application timing would be the same no matter what zone you are in since the timing is based on tree phenology.  You can follow the schedule in my posts or check out the 2009 guide at http://www.virginiafruit.ento.vt.edu/SprayGuide/TreeFruitSprays.html  to get a complete schedule for diseases as well as insects. 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
      ----- Original Message ----- 
      From: walter6353 at myfairpoint.net 
      To: North American Fruit Explorers 
      Sent: Saturday, March 21, 2009 11:59 AM
      Subject: Re: [NAFEX] Captan


      Bob,

         That's exactly what I needed. Anyone suggest an application schedule for scab in VT?

                                Walter


      Quoting ROBERT W JUDY A HARTMAN :

        I don't know if this is what you are looking for but take a look at this information, http://www.aces.edu/pubs/docs/A/ANR-0816/ANR-0816.pdf  It breaks it down to the amount per gallon.

        Bob
          ----- Original Message ----- 
          From: walter6353 at myfairpoint.net 
          To: North American Fruit Explorers 
          Sent: Saturday, March 21, 2009 5:58 AM
          Subject: [NAFEX] Captan





              I plan to do some minimal spraying on old standard apple trees to knock out scab and prevent early defoliation. I have the granulated form of Captan (WG) and a tractor mounted high pressure Rears spray rig with a gun. All of the information I can find gives formulas for per acre application. I need to know at what rate to dilute the granulated powder, as I will be manually spraying individual trees. Can anyone help with this information? What would a suggested schedule be for application? Thanks in advance.





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