This page collects information on spruce budworm control. Comments are active, so feel free to respond below.
[Note: this was originally published May 13, 2013, but has been updated and reposted.]
Protocol
Aerial spraying of Bt is not a risk-free proposition, particularly for immune-compromised individuals. Overspray can be carried over large areas. (See discussion below.)
As a basic courtesy, please let your neighbors know when spraying is to occur, so that they can take precautions. A phone call, visit, or note in the mailbox is probably best, but many residents would also appreciate a note to the canyon email list. (If your message bounces, send it to tom at metasd dot com and I’ll post it.)
Bt information
Former BCPOA Director Joan Cory compiled this summary of the state of Bt knowledge, when aerial spraying was planned in 2007:
The short version is that Bt is widely regarded as safe, but has not been well studied, and poses a risk to humans and pets in some conditions. Resistance and collateral damage to beneficial species are to be expected. A crucial bit is:
SAFETY CONSIDERATIONS. NOTIFY YOUR NEIGHBORS if you are going to spray. Studies have shown that Bt can be quite widespread outside of aerial spray zones and can be a concern for certain groups of individuals (see below). Because of the potential for infection of humans and other organisms, it is reasonable to inform your neighbors so that they can stay inside or evacuate to town for a period of time around the spraying.
In 2007, we used the email list to to distribute notice the evening before Boyd Morgan was to fly – we could easily do that again this year.
Comment from Matthew Broughton 3 Fiddles Farm
Matthew Broughton here of 3 Fiddles Farm-the only organic farm in Bridger Canyon
I want to preface my comments with the fact that I attended MSU’s Masters Program in Entomology in the early 2000’s, I was a research associate at MSU for 7 years studying, specifically, plant-insect interactions and biological-control, and I am an ardent Organic Farmer. I know that Bt is currently allowed for organic production, which I feel is a mistake. Natural balance needs to be obtained, not heavy handed controls. I am sad to hear that canyon wide spraying is being planned. This posses a huge risk to all beneficial Lepidopteran (moths and butterflies, including caddis flies in the stream.) and will impact the whole ecosystem, including the predators of the budworms.
This will not eradicate the Budworm, it will only be a short term control measure. This is also setting up the dangerous treadmill of continuous control measures, year after year. Be aware that some of the advice being given to you is by the companies and people who profit from the sale of the product and should be dubiously accepted.
A quick review of Colorado Extension Service advice for controlling Budworm outbreaks is as follows.
Control
Budworm populations usually are held in check by a combination of predators, parasites, adverse climatic conditions, or inadequate food supply. Spiders, insects and a variety of birds are important predators. Adverse weather conditions, particularly sudden freezes in late spring, may kill large numbers of larvae. A major factor in ending long-term outbreaks appears to be starvation from inadequate or nutritionally poor food sources. However, this may not be a factor in urban situations. Cultural practices such as thinning, watering and fertilizing, which promote tree vigor, may help trees better withstand repeated attacks.
I also want to point out that there are wide spread suspicions that Bt exposure has many negative health effects for humans and vertebrates, including leaky gut syndrome, inflammation(resulting in a myriad of diseases) and genetic damage from exposure. Little studies have been completed due to pressures on the EPA and FDA to allow its use, and thus there are no long term and real human health studies, just a few low number preliminary studies. There are many dangerous data gaps on the safety of this product. As a result of the minimal short-term toxic exposure risks, this “natural” product was exempted from long term studies. I would like to point out that many “natural” products are quite dangerous long term i.e. asbestos, lead, uranium, tritium, etc.
On our property we have several spruce trees that were affected by the budwroms and we increased their watering, and the trees recovered and resisted damage. A cheap, easy, and safe fix.
Assessment of 2010 spraying at Bridger Bowl
This USDA Forest Service report documents the results of Bt spraying at Bridger Bowl in 2010:
BB spray assess stelprdb5400238.pdf
An excerpt:
On September 12-13, 2011 we returned to Bridger Bowl to evaluate the effectiveness of
the B.t. treatment. Ocular defoliation estimates showed that trees that had been
sprayed had significantly lower percentage of their foliage consumed by budworm.
There was approximately a 1/3 reduction in defoliation for the treated trees when
compared to trees in the nearby untreated area. Percentage of buds with evidence and
damage from budworm was also significantly lower in the treated trees compared to
nearby untreated trees.…
The establishment of a younger size class in both pine and fir-dominated stands is
critical to the success of forest resiliency over time. Currently, most of the forests at
Bridger Bowl are mature and over-mature stands of pine and fir that are not sustainable
over the long-term.Although western spruce budworm is a native insect that has co-evolved with western
spruce-fir forests, extensive damage and mortality from budworm can occur especially
during drought periods and in areas where fire has been suppressed. Suppression
actions such as spraying B.t. at Bridger Bowl may become necessary again if defoliation
from budworm is severe and occurs over multiple years. Protecting foliage with B.t. is a
temporary solution to reducing defoliation, growth loss, deformation, and tree
mortality. Silvicultural treatments that reduce stocking density, number of canopy
layers, and increase individual tree vigor and species composition are the only long-term
solution to budworm management. The need for spraying in the future should be
greatly reduced if silvicultural treatments continue to be implemented at Bridger Bowl.
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Budworm infestations, just like most other biosystems, wax and wane in cycles by year. It is true that bt will ‘work’ when sprayed for that year, but it will NOT get all the budworms, will not be a long term solution and does nothing to encourage conifers to become robust and healthy so they can withstand infestations. In fact, spraying just increases the toxic chemicals in our water, air and soil and over the years the build up accumulates in our human bodies.
Budworm infestations are just one of the “costs of doing business” in Bridger Canyon where we live; I’d rather see some budworm die off, knowing that forests evolve, than have another layer of toxins added to my ecosystem! We humans need to stop thinking that a chemical or a pill are the answers to all problems.
Susan Kendrick, BCR
I agree with Mr. Broughton.
Achieving a natural balance is more important, even if its a bit painful to see some of your trees die.
About 7 years ago we “managed” our trees by having them thinned to about 30 feet between each and none of the branches touching. We have only lost a couple trees since then and the thinning opened up the forest beautifully. After a couple years we had more flowers, grasses and animals than ever. We even made a little money on the deal it it has become a more natural, old growth-like forest where the trees don’t have to compete so hard with each other so they grow stronger and can resist bud worms on their own.
Lets hope for a moist summer,
Geoff Baumann
Point taken in general, but Bt is a biological control (bacillus thuringiensis), so it can’t bioaccumulate and isn’t a chemical threat. There are surely side effects though, including harm to beneficial insects and predators.
There may be no long term solution, other than forest succession, because climate is an important driver of pest outbreaks. There’s a noticeable warming trend in Montana, and that’s likely to accelerate, so major changes are in store for us. Natural balance is over. Judicious use of pesticides may be useful in managing the transition, though on the whole I think they’re overused already.
I sprayed Bt aerially in 2007, and it helped, and I’ve spot-sprayed a few trees each year since. This year I’ll probably focus on thinning, and maybe try to identify something useful to plant (limber pine?). I’ll also spot-spray more trees than in the past, but not do the aerial thing again.
Thank you to all those who have taken the time to offer information about BT. I have given BT a lot of thought and have finally resolved that very careful thinning, mulching, watering where prudent (or possibly (rain collection?), and a very aggressive planting program are the best use of money, over a five, ten, fifteen year time period.
An acquaintance of mine succeed in planting 1000 trees in two years by himself. If we coordinated as a community and made a plan, the cost for spraying would go a long way for procuring and planting seedlings. We have experts within our community to advise us as to the wisest array of trees, best locations, efficient care (water being in short supply) and we are good at team work, organizing, and when needed, getting things done.
We need a long range Community plan. If we want human and other animal populations to handle the drought years, we need to be thoughtful about what we plant, how and where. Big machines might be damaging, for example.
Clear cutting has been practiced by logging companies at times. We should know exactly where, be proactive about assessing the impacts, and insist on selective cutting as per wise practice for soil erosion prevention, tree growth, animals etc. We have knowledge of the drier and moister soils and native plants and trees that would do best and we should instruct the logging companies as to replanting.
Grey water is a huge loss of water for all Americans. There is no reason we can’t, as a Community, invent/devise water collection and dispersement devises that are both sustainable and effective to provide drip irrigation to tree plantings. A little ingenuity and collective effort are our tools for increasing challenges of our changing climate impacts so we might as well start working together now to meet these challenges. Collective spraying engages the spirit of this but I strongly believe these other efforts use our time, money and energy better.
It appears we are headed for many years of water constraints. Trees will get more stressed. Spruce trees will increasingly be stressed. Supporting soil water retention, very cautious thinning (tree canapies are important for shading soils and thus limiting evaporation), doing a widespread ecologically sound diversity of plantings, reducing our human uses of water, as part of a 15 year plan for our community at large are all doable, practical and cost effective efforts yielding longterm positive results which spraying, in comparison, does not achieve.
I suggest we make a decision at the 5/21 meeting that we will have a comprehensive plan by the end of summer which advises as to appropriate trees etc. to plant, where and how, resources for doing so, and for forming teams of people to plant seedlings this fall. Obvioiusly this is a private landowner decison to engage or not engage, but if resources, help and advice are available, those interested can proceed on their own land this fall. It may seem daunting, but in fact, Bridger Canyon is not so big. Helping our trees stay or become more healthy in a longterm way is practical and necessary and a better use of money resources than short-term results from spraying which also has some negative impacts including harming useful insects. Ellen Trygstad
Some comments via email:
We will have a 1 month old grand baby at the Three Fiddles Farm (all organic) and absolutely are opposed to spraying. If it happens we want notice so we can protect the baby, its parents, ourselves, our cattle, and wish we could cover all the crops.
The Broughtons
10663 Bridger Canyon Road
We absolutely want to know if and when any spraying will take place in the area, we are expecting a grand baby this summer and would not want his tiny lungs in the area at such a time.
Thank you,
The Thornbroughs
6007 Sunny Hillside Lane
Happy Memorial Day.
We feel the same way as we prefer not to have kids and dogs exposed.
Thank you,
Calio/Coleman Clan
Bridger Woods Rd
We definitely want to know in advance re. any spraying planned for this summer.
Howard Davis
why is there not a canyon wide tree thinning going on in Bridger…this desperately needs to happen..forget the spraying…it is a bad bandaid…the forests for the most part are unhealthy and wood is mostly pulp…get Northwest Management to come and clean out the forest…Call Greg Ellison…He did ours up in Aspen Meadow along with John Sacket and Jim Huffman. In my humble opinion it’s the only answer to the controlling of the spruce and pine bark beetle…
Thanks for facilitating the communications. We’d like advance notice too as we have livestock and gardens. Last year, the airplane flew incredibly close to and at my house and I found this VERY disconcerting. I think a calm day was picked, which was appreciated as I watched the sheets of spray fall on my neighbor’s property.
Does anyone know what other insects are affected by the spray? What is the decay period, if any, of the potency and does this have implications for insect eating animals such as birds?
Thank you. E. Trygstad
More via email:
We DEFINITELY want to be notified if there is going to be spraying in our area (7886 Bridger Canyon).
We agree with Mr. Broughton. When we moved to the canyon over thirty years ago, the hillsides and fields were abundant with wild flowers. With the subdivisions came wide spread chemical spraying which killed most of the flowers in our area. I shudder to think of all the other things the chemicals may have killed.
Thank you for notifying us,
Baird Godvin
I would not recommend spraying. Developing a comprehensive Forest management plan is important with the goals of improving health of the forest, improving wildlife habitat and reducing fire risk is the way to go. Careful thinning is a major part of this and both MSU and UofM have great resources. This has protected our trees from insect damage very well. Spraying is only a bandaid.
The spraying that was done in 2007 and 2013 was worse than a waste of money. We did no spraying and the results can be seen here:
http://bclodge.com/2013/q3/Extras/index.htm
The spraying kills all moths and butterflies, not just the budworm. As a result, the predators (birds, etc) that would feed on them either die or go elsewhere. Money is better spent thinning the forests to make them more healthy and able to withstand this cyclic threat. Things like BT should only be used on a very limited basis (i.e. hand-spray individual trees) to protect landscape trees near homes.