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nafex - Re: [NAFEX] the apple/dogwood borer and how to fight them

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  • From: <dmnorton@royaloakfarmorchard.com>
  • To: "North American Fruit Explorers" <nafex@lists.ibiblio.org>
  • Subject: Re: [NAFEX] the apple/dogwood borer and how to fight them
  • Date: Thu, 2 Apr 2009 17:09:36 -0500

It is very important to distinguish between the various types of borers, since those affecting apples trees can be from the moth or beetle families. Round headed apple borer is a beetle whereas both the dogwood and apple bark borer are clear winged moths. The moth species seldom, if at all, bores all the way into the heartwood as does the round-headed apple borer. I can see where Lorsban may not be able to penetrate all the way into round headed apple borer canals that have reached into the heartwood, but it is rare that the moth species will eat beyond the cambium where Lorsban can effectively penetrate. If anyone is uncertain what type of borer they may have, there is some good info at http://bugguide.net/node/view/30033/bgimage, http://www.ipmimages.org/search/action.cfm?q=dogwood%20borer, http://www.omafra.gov.on.ca/english/crops/facts/apborers.htm and at http://www.umext.maine.edu/piscataquis/gardening/2004/vol2iss7/apple.htm. For a great close up of RHAB go to http://www.ipmimages.org/browse/detail.cfm?imgnum=3066002. 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: <david.maxwell@dal.ca>
To: <nafex@lists.ibiblio.org>
Sent: Thursday, April 02, 2009 2:07 PM
Subject: Re: [NAFEX] the apple/dogwood borer and how to fight them


I have been fighting Rounded-Headed Apple Borer (Saperda candida) for years (in Nova
Scotia, Canada). The commercial growers didn't know what it was, and the extension folk
knew very little about it, (because their regular cover sprays killed it off). Like you, I have
tried wires, drills, knives and curses. None of these work.
My current approach (started last summer, so can't verify effectiveness), is 1) paint the trunks
with a mix of lime and latex paint. Supposedly this creates a barrier to oviposition. I am not
at all sure it does, BUT what it does do is make any active infestation immediately apparent,
because the frass from the holes shows up on the light surface. 2) Here is the sneaky bit:
having found a hole, inject a strong insecticide solution into the hole with a syringe and 21
gauge needle. The beasts usually have several opening to the surface, and I keep injecting
solution until it comes out the other holes. I figure that way I have filled the chambers
completely with neat insecticidal solution. Even if the insecticide (and I suspect it doesn't
much matter which one one uses) doesn't kill them, maybe the buggers will drown!

My suspicion is that painting Lorsban on the trunks (or spraying it - or indeed any other
insecticide - is going to be a lost cause. The beasties are safely under the bark; your
Lorsaban isn't going to get them. (It may kill the females trying to lay new eggs, but it won't
stop the ones already there from girdling your trees.) The grubs live under the bark for up to
3 years before emerging, so if you have them in the trees, you are going to have to either
expose them or attack them in their burrows directly.







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