Pheromones & Apple Pests

by Catherine Haug

This article was sent to me by John Holbrook, from Missoula Extension service, on a test project regarding apple pests in Missoula.

While the test project was conducted in Missoula, the same project could be tested for use in Flathead orchards and neighborhoods.  However, it is important to note that this treatment:

  • Won’t work for just a few trees; it takes at least 100 trees (current test is for treed neighborhoods in 5-block radius).
  • Only works on apples and pears, NOT on cherries, peaches, apricots or plums.

I will contact Flathead and Lake County Extension offices to see if a similar project could be done in Flathead valley neighborhoods.

Missoula Neighborhoods Fruit Tree Pest Management Project

Missoula County Extension Office Plant Clinic is testing a method for codling moth pest management.  The larvae bore into apples and pears, and eat their way out into adulthood.

Benson’s Farm apple orchard was used to test the experiment in “mating disruption” in 2008 with good results.  Extension agent Helen Atthowe experimented with a method using twist ties soaked in a synthetic pheromone which are then attached to the fruit tree.  This pheomone confuses the male moth into thinking the females are everywhere and thus has difficulty in locating them.

This method is proving to be nearly as effective as spraying in some cases, where at least FIVE ACRES of fruit trees (approximately 500 trees) have pheromone twisty-ties applied to them.  Benson’s raised the cleanest apples they have ever produced using the mating disruption method, in which 3 -4 twisty ties impregnated with maint pheromone were tied onto each of Benson’s 150 trees, for a total of 400 pheromone twisty ties.

Pheromone is a bit like insect perfume.  If it is put on one or a few trees, it actually attracts codling moths.  But if it is applied in high concentrations (on a least 100 trees) it disrupts mating so baby worms don’t end up on apples and pears.

The pheromone twisty ties can be aplied to any kind of frit or shade tree in order to get the concentration high enough to disrupt codling moth mating.  But the pheromone only owrks on the codling moth, which is a pest of apples and pears.  It is not effective on pests of cherries, apricots or plums.

Benson’s also targeted the two codling moth worm hatches in Missoula last year with 2 organic sprays (spinosad).  For completely worm-free apples and pears, Missoulians will probably still have to apply 1 or 2 sprays.

You can check ut Pest Alert Phone line at (406) 258-3820 for weekly pest updates and best spray timing during the spring and summer.

Missoula Neighborhood Experiment

Neighbors are being asked to come together and participate in this project as an opportunity to produce fruit without the use of toxic herbicides [sic].  There is the opportunity to assist neighbors who have fruit trees or an orchard even if you do not.  In order for the project to be effective, about 100 trees are required in a five-block radius to saturate the air with the scent.

The Plant Clinic is developing a database of interested folks.  They will be contacted in late April to participate in the project for a cost database of interested folks.  They will be contacted in late April to participate in the project for a cost of about $5.00 per tree.  For more information or to be included contact Helen or Sandi at (406) 258-4213 or email plantclinic(at)


Comments are closed.