Beware of the Apple Borer!
In many parts of central and northern New England the roundheaded appletree
borer (Saperda candida) is the number one enemy of young apple,
crabapple and quince trees. If you are growing young apple trees in these
locations, you must protect your trees from this pest. Farther south and north
the borer may not be a pest. If you don’t know if they are a problem in your
area, check with any grower near you: they’ll know. Otherwise, err on the
side of caution. The borer does not endanger other fruit trees or ornamentals.
The borer beetle lays its eggs under the bark near the base of the tree. The
developing larvae tunnel through the wood, eventually weakening the tree
until it crumbles and falls over. The trouble sign is small deposits of orange
sawdust, called frass, at the base of the tree, usually appearing in June or
July. Left unchecked, borers usually mean death for your trees.
Borers thrive in shady moist warm environments. Keep grass back at least
6" from the tree base. Activity is most prevalent in June and July. Keep a
lookout for the frass. Locate the hole or soft spot in the trunk and insert a
wire until you locate and kill the larvae. Cut away soft, spongy pockets with
a knife. Even serious carving is less harmful to the tree than leaving the
larvae alive inside.
After years of experimentation, I think that painting is the best deterrent.
I’ve tried a number of recipes and this is my favorite. It’s easy and requires
no hard-to-find ingredients. Mix white interior latex paint with joint
compound. (The stuff you smear on sheet rock joints and nail holes—you
can buy a small tub at any hardware store. Some exterior paint formulations
contain ingredients that can harm the underlying phloem.) The consistency
should be thick but still quite easy to paint, not glob on. Repaint periodically or each year
as needed. This mix will help deter borers. It will also make for
easy detection of any infestation you may have. Look for the
frass! Using the paint method, you will also need to put some sort of screen
or plastic rodent protector around the trunk during the winter months
Suzanne Lefebvre wrote:Last summer was a terrible year here for apple borer damage. Anyone have guild/companion plants for apple to deter borer? Moved to a beautiful property with LOTS of wild apple trees. Have grafted several and trying to plant guilds around them.
Sorry never had one in our orchard. Know people who are plagued by them. They ended up putting screening around the base of the tree 0-3' to keep them from infesting.