Orchard Tip: When Ants Attack Fruit Trees{32}

western thatching ants fruit trees

Western Thatching Ants chowing down on my pear tree buds.

I’ve always kept a healthy distance from ants. The notion of strength in numbers is not lost on me. If the Lilliputians could secure one colossal Gulliver, I fear a robust colony of wee ants could serve up a napping Neanderthal like me quite handily given the chance. My wariness of ants came at an early age in the South, when I knew any contact with the aptly named fire ant would lead to high kicks, screams and tears in a matter of seconds–not a pretty display for any child flailing under the confines of peer-driven coolness and conformity. Lucky for me even grown men reacted the same way when on the receiving end of fire ant’s bite.

western thatching ants in tree

It takes a colony…to take down a tree

Here in the Pacific Northwest, we have the Western Thatching Ant, a slightly more genteel cousin, but one that packs a punch if provoked or crossed. This species of ant builds formidable hills, easily the size of a half-buried mini cooper. The warmer temperatures of spring awaken Western Thatching Ants like a call to the mess tent. As voracious diners, they consume both insects and plants depending on seasonal preference and availability. While they are considered a beneficial insect that cleans up the forest floor of buggy riffraff and plant debris, they also treat my orchard like a vertical buffet of tender emerging buds.  When ants attack fruit trees, they can denude it of the flower buds needed for fruit development and production. I love my pears, apples and cherries too much to give them up that readily to legion of opportunistic arthropods.

close-up pear blossoms

Note the chewing holes in the flower buds

Since I don’t spray my orchards with pesticides, I have to outwit this legion of bud munchers and look for a solution that is mechanical in nature, one that would prevent the ants from climbing into the trees in the first place. My solution was to create a trunk roadblock using a product called Tanglefoot. The idea is to wrapped the trunk in a stretchy plastic flagging tape and then coat it lightly with a sticky substance that keeps the ants from crossing. Here’s how you do it.

tanglefoot ants tape

A no-go: The ants circle, then retreat.

When Ants Attack Your Fruit Trees

How to keep them away from the buds and fruit.

Materials:

  • Flagging tape (a non-adhesive tape used to mark boundaries)
  • Tanglefoot
  • Disposable paint brush

Instructions:

  1. Start in the morning before ants become active
  2. Shake the tree to knock off any ants that may be there already.
  3. Wrap trunk with flagging tape (which stretches) just below first branches
  4. Wrap it around going upward to create an overlap.
  5. Wrap tape around enough to create a three to four inch band around the trunk.
  6. Pull the final end of tape under the last loop and pull tightly to cinch.
  7. Coat flagging tape with thin layer of Tanglefoot.
  8. I use an old shaving brush, but a disposable paint brush works fine.
  9. Be careful not to get any Tanglefoot on the bare trunk
  10. Leave top and bottom edge clean.

Caution:  You never want to apply the Tanglefoot directly to the tree.  I did do this once and it badly sunburned the bark and caused it to become callous and split. I suspect this continuous practice would girdle the tree trunk eventually.

I found the tanglefoot needs to be reapplied after a couple months, especially when fruit begins to ripen, which brings the ants out for dessert.

tree tape tanglefoot.jpg

Start from the bottom of the trunk and wrap upward.

taped tree trunk

Take the top end, and pull under the top loop to tighten on itself. Trim excess.

tape

Tanglefoot is the consistency of creamed honey, but brushes on nicely thin.