Studies Showing the Effectiveness of Verbenone

Most studies concluded that treatment with Verbenone or SPLAT paste had a very high efficacy rate.



Here are some studies that detail the effectiveness of Verbenone in controlled studies conducted by and for several Towns

Studies were implemented that used Verbenone in both integrated situations and non-integrated situations . ie:

  1. Properties without "green attack tree" removal and WITH removal of trees as soon as pitch tubes were evident.
  2. Properties that used Verbenone tested against Control properties that did not use Verbenone.

Most studies concluded that treatment with verbenone pouches at roughly 16.5 yd centers is a useful tool for protecting trees from attack by the mountain pine beetle provided that Verbenone is used as part of a multi-year integrated pest management program that also includes disposal of all infested trees on the area to be protected.

cut infested trees
cut infested trees

Tips for Keeping your Trees Protected:

  • Monitor you trees closely. Rusted tops can be sometimes seen as early as late September.
  • Watch for white pitch-outs where beetles have attacked.
  • Keep your trees healthy. Water thoroughly and regularly.
  • Remove green attack: trees that are carrying larvae but are not dead; this is critical to your success.
  • Dispose of infested trees properly. Burning or chipping is the most common.
  • Thin your trees. Reducing "basal area" (average amount of an area occupied by tree stems) to less than 100 sq ft per acre is recommended.
  • Use Verbenone each year to prevent recurrence.

Operational Success of Verbenone Against the Mountain Pine Beetle in a Rural Community September 2007

Attack around trees treated with Verbenone was substantially lower than around both pheromone-baited and untreated control trees, amounting to just 13.5% overall. Our results confirm that verbenone is an effective deterrent to attack by the Mountain Pine Beetle. However, they also confirm that the effect of verbenone is not absolute.

Read this Study: Report on Mountain Pine Beelte Activity and Effectiveness of Verbenone at Panorama Town Site (.doc format)

The attack rate in untreated stands was roughly three times that of treated stands in both California and Idaho, even at this low application rate.

Operational Success of SPLAT Verbenone Against the Mountain Pine Beetle: Most studies concluded that treatment with SPLAT paste had a very high efficacy rate.

  • According to a blog on Feb 3, 2016: Throughout a two-year USDA-funded research project, SPLAT Verb consistently achieved a 100 percent rate of protection when applied to individual lodgepole pines, even when bark beetle infestation rates were shown to be high. For example, in a 2012–2013 study, 28 out of 30 untreated control trees fell victim to the beetle plague, whereas all SPLAT Verb-treated trees within the same vicinity remained healthy and un-infested a full year after treatment. In addition, these studies showed that SPLAT Verb can produce a protective “halo effect” that repels MPB from the trees up to 11 meters from the one it was directly applied.
  • In an article titled, "Applied Chemical Ecology of the Mountain Pine Beetle" by Robert A. Progar, Nancy Gillette, Christopher J. Fettig, and Kathryn Hrinkevich, Fettig et al. (2012d) began evaluating SPLAT formulated with verbenone (“SPLATVerb”) for protecting individual P. contorta from mortality attributed to D. ponderosae in Wyoming in 2011.

    After being deployed in the field for 23 days, dollops of SPLATVerb (Figure 5) still contained 40% of their original concentration of verbenone, and it was not until 12 months in the field that trace amounts of chrysanthenone, a compound with no known effects on bark beetle behavior (see Chemical Stability in the Forest Environment for related issues), were detected (C.J. Fettig, A. Mafra-Neto, and A.S. Munson, unpubl. data, Jan. 15, 2013).

    Although this research is in the early stages of development, SPLATVerb appears promising for individual tree protection as 100% tree protection was observed, whereas 93.3% tree mortality occurred in the untreated control. (C.J. Fettig, A. Mafra-Neto, and A.S. Munson, unpubl. data, Jan. 15, 2013).

  • In another recent study, on SPLAT Verb efficacy on individual lodgepole pines, there was a zero percent mortality rate on trees treated with SPLAT Verb, compared to a 93% mortality rate in untreated trees. In small stands, treatment with SPLAT Verb proved nearly twice as effective as an alternative verbenone product and reduced tree mortality compared to an untreated control by a factor of 6.

  • 09/01/13 to 08/31/15: Results from the Stanislaus National Forest and Yosemite National Park indicated that SPLAT® Verb was efficacious in protecting sugar pines from MPB attack. All SPLAT® Verb treatments were considered extremely efficacious; within the Stanislaus National Forest, less than 5% of trees died as a result of D. ponderosae colonization within the highest dose group and within Yosemite National Park, no trees were colonized or killed by D. ponderosae.

It is very difficult to find current studies using Verbenone on Southern Pine Beetles. Most were produced before Verbenone was widely used or even approved for use.

Operational Success of Verbenone Against the Southern Pine Beetle: This study concluded that treatment with Verbenone had a high efficacy rate against SPB when used in a strong program of forest management.

  • Results showed that Treatment with (S)-Verbenone at 8 ml per tree in combination with felling all freshly attacked trees worked best to control the onslaught of SPB.
  • Spot growth in all five tested infestations treated with this application was completely halted with few or no additional trees being attacked.
  • Read the study here

In a Journal of Forestry article entitled, "A Scentsible Approach to Controlling Southern Pine Beetles: Two New Tactics Using Verbenone", results of an early study using systhetic beetle pheromones for controlling southern pine beetle infestations - verbenone - were introduced.

  • The techniques, verbenone-only and verbenone-plus-felling, reduce tree loss by disrupting infestation growth. In three years of field tests, the verbenone-only tactic completely suppressed 69 percent of the treated infestations, and the verbenone-plus-felling tactic suppressed 86 percent. The tactics provide much-needed alternatives to current control techniques and will allow suppression of infestations where tree felling is restricted or prohibited.
  • Read the study Here