MCH (Methyl Cyclo-Hexanol) Douglas-Fir Beetle Protection
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Douglas Fir Beetles – What Trees Are at Risk?
Douglas Fir Trees (Rocky Mountain Douglas-fir Pseudotsuga menzeisii var.glauca) is the most common conifer tree species found in the forests of Montana and Idaho. This tree displays an ability to grow across a wide variety of environments. It spreads easily due to its relatively light seed that can catch wind currents and disperse up to 2 miles. Douglas-fir is a hearty and resilient tree that is moderately fire-resistant and can withstand snow, wind, drought, and mild insect infestation. Despite being a highly sustainable tree, Douglas Fir Trees are susceptible to various insects and pests. The most well-known enemy of Douglas-Fir Trees is the Douglas-Fir Beetles.
Douglas-fir Beetles (Dendroctonus pseudotsugae) prefer to first bore into host trees that are large, old, and already stressed or have recently died. The stress can be from other pests such as defoliating Tussock Moths, or Western Spruce Budworms. Trees also may be experiencing stress from different environmental factors such as fire, drought, or disease. While Douglas-fir Beetles outbreaks tend to start in large, old, and stressed trees, beetles are opportunistic and during outbreaks will also attack healthy trees within a stand after stressed trees have reached carrying capacity.
How Douglas-Fir Beetles Damage Trees?
Adult Douglas-fir Beetles (Dendroctonus pseudotsugae) bore through the bark of Douglas-fir trees into the cambium and then lay eggs. When the eggs hatch the larvae continue to spread throughout the cambium damaging tree tissue that is vital to the survival of the tree. While alone Douglas-fir Beetle is unable to kill a host tree on its own, once a beetle has infected a tree other beetles will quickly follow.
How Douglas Fir Beetles Spread?
Many Douglas-fir Beetles simultaneously attacking a tree can quickly overwhelm a Douglas-fir Tree’s natural defenses and kill it. Douglas-fir Beetles coordinate attacks on trees by following chemical signals called pheromones. The pheromone signals can be submitted from the host tree or by beetles that have found a susceptible host tree. Other Douglas-fir Beetles follow the aggregation pheromones (vacancy signal) or an anti-aggregation pheromone (NO vacancy signal) and soon the host tree is overwhelmed and an outbreak has begun within a stand of trees. Peak flights for Douglas-fir Beetles generally is April-May dependent upon weather conditions.
How to Protect Trees from Douglas Fir Beetles?
Management of Douglas-Fir Beetles can take many forms within an Integrated Pest Management (IPM Plan) Plan. Sometimes the best option might be tree removal and thinning, spraying, or preventative synthetic semiochemical pheromone patches that are attached to trees. Preventative pheromone patches called Methyl Cyclo-Hexanol (MCH) is the synthetic version of the Douglas-fir beetles natural anti-aggregation pheromone. This pheromone essentially sends out a “NO VACANCY” signal which tells beetles this tree cannot support additional beetles, effectively stopping an infestation and outbreak before it can begin. Preventative application measures must be taken before peak flight and are most effective when applied in March.
MCH Bubble Caps: Safeguarding Trees from Bark Beetle Trouble?
What Are MCH Bubble Caps?
MCH Bubble Caps have anti-aggregation pheromones and are highly effective in repelling Douglas Fir Beetles and preventing infestation. MCH Bubble caps is currently registered as a bio-pesticide by the EPA. Unlike conventional pesticides that kill insects, MCH is a biological pesticide that only affects the Douglas-Fir Beetles’ behavior.
When to Use MCH Bubble Caps?
Spring Beetle Season: When spring arrives, so do the beetles.
Preventative application measures must be taken before flight and are most effective when applied in early to mid-April. However, if it is applied early in the flight season but after beetles have initiated attacks on some trees, it may still reduce the number of trees that are killed within the treated area as compared to doing nothing.
How Many Bubble Caps?
For maximum benefit, protected areas should be treated every year during an outbreak. For areas greater than 1⁄2 acre, bubble capsules should be applied at a rate of 30/acre. If added insurance against infestation is desired and the cost is not prohibitive, a slightly higher rate may be applied. However, rates higher than 30/acre should not be necessary in most situations and MCH should never be applied at a rate higher than described on the product label.
Where to Put Them?
Strategic Locations: We attach MCH Bubble Caps to trees, snags (dead trees), shrubs, or even fence posts.
We recommend they be applied on the North side of the tree at a height that applicators can easily reach (i.e., 6-8 feet). However, they can be placed higher in areas such as campgrounds or residential sites where it is likely that they may be disturbed. Ladders or a special long-handled hammer, known as a Hundle hammer, can be used to attach bubble capsules at a height where they are beyond reach.
Spacing Matters:
Even Distribution: If the area is smaller than 2 acres, we spread out the bubble packs evenly around the edges.
Imagine drawing dots around the edge of a circle – that’s how we place them.
For larger areas, a combined approach is recommended:
Around the Perimeter: Place bubble packs around the edges.
Parallel Lines: Distribute them in parallel lines across the whole treatment zone.
Maintain a spacing of approximately 15 to 20 feet between each bubble pack. Alternatively, you can create a grid pattern with a spacing of 38 feet between bubble packs.