FAQ

No one group can afford to carry out a foliage protection program against spruce budworm as occurred during the 1970s and 1980s. The total cost of that program, which spanned approximately 13 years in New Brunswick, was around $175 million. A comparable program today would likely cost between $50 and $100 million per year for 8 to 12 years. The increase in cost is one reason all partners share interest in developing an early intervention strategy.

The Healthy Forest Partnership was formed in response to the threat of a spruce budworm outbreak. The partnership consists of Atlantic Canadian and Maine governments, landowners, industry and scientists. The goal is to develop better approaches to managing a spruce budworm outbreak and work to prevent a widespread severe spruce budworm outbreak from occurring.

Yes. In Atlantic Canada, the government departments responsible for the management of natural resources, environment, and health have all been consulted and have had input on the early intervention strategy research project.

The funding, provided in part by the Atlantic Canada Opportunities Agency, is to support research associated with developing an early intervention strategy. The research is focused on understanding how spruce budworm outbreaks start, so that tactics can be developed that will limit or possibly prevent a widespread severe spruce budworm outbreak from occurring. Only the province of Québec is currently engaged in a foliage protection spray program.

In Budget 2018, the Government of Canada announced funding of $74M over four years and $750,000 ongoing, for the Spruce Budworm Early Intervention Strategy Phase II.  The program leverages an additional $50M from the Provinces of New Brunswick, Nova Scotia, Prince Edward Island, and Newfoundland and Labrador, as well as industry, for a total of $124M. Managed by Natural Resources Canada, the EIS is a research program investigating a novel approach to spruce budworm management. EIS management involves treating smaller areas or “hotspots”, i.e., areas where populations are still low, but are increasing. The objective is to keep populations low enough to limit or prevent an outbreak from occurring, with minimal or no damage to forests, and therefore no impact on wood supply or the economy.

We know from fossil records and from tree-ring analysis of very old trees that spruce budworm outbreaks have occurred for hundreds of years. There were major budworm outbreaks in the 1870s, 1910s, and 1950s. Current silviculture practices have only been in place since the 1970s or 1980s.

We also know that spruce budworm outbreaks occur in areas where there isn’t intensive silviculture practices. Planting spruce to replace the more vulnerable balsam fir is one of the main ways to reduce tree mortality during budworm outbreaks.

As part of this research, we are continuing to study how forest composition might influence outbreak intensity.

Growth loss and tree mortality during a spruce budworm outbreak vary with its duration, severity, tree species and age. Balsam fir is the preferred host of the spruce budworm. The most severe epidemic will kill 80 to 90 percent of mature balsam fir and 30 to 50 percent of mature spruce trees.

Spruce budworm populations have been increasing in northern New Brunswick and northwestern Newfoundland for several years. However, these populations are much lower than in Québec. The early intervention approach to control spruce budworm populations that started in 2014 appears to be working, as very little defoliation has occurred in New Brunswick.

The first indication of a spruce budworm outbreak is red spruce and fir trees. The reddening of trees is the result of spruce budworm feeding on new buds causing the needles to die. In addition, there will also be a smell of decaying tree needles. You can expect to see red trees from the beginning to middle of July.

Spruce budworm larvae eat the new buds, current-year foliage, and sometimes older needles of balsam fir and spruce trees, often for several years. The defoliation causes growth loss and if defoliation continues for 4-6 or more years, the trees usually die.

It is unknown how outbreaks start. Some researchers have suggested that an excess of over mature host trees in a given area can contribute to the rapid rise of spruce budworm. It has also been suggested that climate and “release” from natural enemies (predators such as birds and spiders, as well as insect parasites) may play a role.

A successful early intervention strategy will result healthy forests with reduced losses in wood supply and a reduction in the cost of forest protection. The research may also result in a major shift in insect management strategies from “keeping trees alive” to “targeted intervention to alter the course of pending outbreaks.”

The impact on wood supply from a spruce budworm outbreak would persist for 30 to 40 years.

The spruce budworm outbreak in Québec is similar to the severe outbreak scenario analyzed for the direct logging and sawmill sector and the indirect effects on all economic sectors in New Brunswick (Chang et al., 2012). The study indicated that total output in the New Brunswick economy over the 2012 – 2041 period under an uncontrolled moderate to severe spruce budworm outbreak, would decline in present-value by CDN $3.3 billion and $4.7 billion.

References:

Chang,W., Lantz, V.A., Hennigar, C.R., MacLean, D.A., 2012. Benefit-cost analysis of spruce budworm (Choristoneura fumiferana Clem.) control: Incorporating market and non-market values. In Journal of Environmental Management, Volume 93, Issue 1, Pages 104–112.

A model of an uncontrolled moderate to severe spruce budworm outbreak in the Atlantic region done by researchers at the University of New Brunswick predicts job loss could be between 46,000 and 56,000 person-years of employment over 30 years. This represents 1,500-1,900 person-years each year.

All products are federally registered and approved safe for use by Health Canada. The research project is regulated by requirements of the Federal Pest Control Products Act and provincial acts and regulations relating to use of pesticides. All provincial permits and product label conditions are followed to ensure safe and responsible use.

Btk is a naturally-occurring soil bacteria and is not harmful to humans or other mammals, bees, birds, or fish when used according to label conditions. Foliage treated with Btk must be eaten by the caterpillars for the product to be effective.

When eaten, tebufenozide imitates a natural insect hormone that causes the developing caterpillars to molt prematurely. The caterpillars then quickly stop feeding and die. It is harmless to humans or other mammals, bees, birds, or fish when used according to label conditions. Here is a link to a detailed fact sheet about Mimic.

Pheromones are used to lure or attract insects to traps and can be used to disrupt mating cycles. They occur naturally, are unique to each insect, and trigger behavioural changes in members of the same species. Spruce budworm pheromones do not kill insect, and pose no risk to humans, other animals or the environment.

Tebufenozide (Mimic or Limit) must be added to water and mixed. This mixture is then aerially applied at a rate of 1 to 2 litres per hectare. The tebufenozide portion of this mixture is fixed at 290 ml per hectare; this is less than the contents of a can of soda. Nozzles on the aircraft break the liquid mixture into small droplets (atomize) so that when the drops land on foliage they are small enough to be eaten by spruce budworm.

The upper canopy of the forest is where the spruce budworm is most often found. Therefore, it is also the best location for droplets to be deposited. Because the forest canopy acts as a filter, few droplets reach the ground. Research conducted by the Canadian Forest Service has shown that 90-95% of the spray is deposited in the forest canopy (Kreutzweiser & Nicholson, 2007). The portion that reaches the ground stays in the upper 5 cm (2 inches) of the soil and leafy debris and does not leach away. It is broken down over time by soil microbes, sunlight, and moisture (Sundaram, 1997; Thompson & Kreutzweiser, 2007). Research has also shown that any tebufenozide that reaches the ground is not harmful to soil invertebrates (Addison, 1996).

Tebufenozide deposited on the shoots and needles of the spruce and fir trees must be eaten by the budworm larvae. The larvae stop feeding almost immediately and die within a day or two. Tebufenozide deposited in the canopy is relatively rainfast and is not easily washed off by rainfall (Sundaram, 1995).

Water bodies are identified on maps and are excluded from all treatment areas during the planning phase: there is no targeting of visible water bodies. Based on research conducted by the Canadian Forest Service, tebufenozide that lands on water has no noticeable environmental impact. Even if a water body were to be unintentionally sprayed, research scientists have studied the effects of tebufenozide on aquatic invertebrates and found no significant harmful effects on most organisms at concentrations expected after aerial spraying. (Kreutzweiser & Nicholson, 2007. Kreutzweiser et. al. 1994; 1998).

The most recent review of tebufenozide states: “No adverse effects on birds, mammals or aquatic species are likely to occur from exposure to tebufenozide” (US Department of Agriculture, 2012).

References:

Addison, J.A. 1996. Safety testing of tebufenozide, a new molt-inducing insecticide for effects on non-target forest soil invertebrates Ecotoxicological Environmental Safety 33, 55-61.

Kreutzweiser, D, and Nicholson, C. 2007. A Simple Empirical Model to Predict Forest Insecticide Ground-Level Deposition from a Compendium of Field Data. Natural Resources Canada, Sault Ste. Marie Ontario Canada P6A5M7. In Journal of Environmental Sciences & Health Part B, V 42, pg. 107-113. USA.

Kreutzweiser, D., Capell S., Wainio-Keizer K., and Eichenberg, D. 1994. Toxicity of new molt inducing insecticide (RH-5992) to aquatic macroinvertebrates. Ecotoxicological Environmental Safety 28, 14-24.

Kreutzweiser, D.P., Gunn, J.M., Thompson, D.G., Pollard, H.G., and Faber, M.J. 1998. Zooplankton community responses to a novel forest insecticide, tebufenozide (RH-5992), in littoral lake enclosures. Canadian Journal of Fisheries and Aquatic Sciences 55:639-648.

Sundaram, K.M.S. 1997. Persistence & Mobility of Tebufenozide in Forest Litter and Soil Ecosystems under Field and Laboratory Conditions, Natural Resources Canada, Sault Ste. Marie Ontario Canada P6A5M7 in Pesticide Science V 51, 115-130. UK.

Thompson, D., and Kreutzweiser, D. 2007. A Review of the Environmental Fate and Effects of Natural ‘Reduced Risk’ Pesticides in Canada. In K.D. Racke and A. Felsot (editors), Crop Protection Products for Organic Agriculture: Environmental, Health, and Efficacy Assessment, ACS Books, American Chemical Society, Washington. pp 245-274.

Sundaram, K.M.S. 1995. Photostability & Rainfastness of Tebufenozide Deposits of Fir Foliage.  Natural Resources Canada, Sault Ste. Marie Ontario Canada P6A5M7. In American Chemical Society, 0097-6156/95/0595-034. USA.

US Department of Agriculture – Forest Service. 2012. Gypsy Moth Management in the United States: A Cooperative Approach. Final Supplementary Environmental Impact Statement V 1, pg. 11. USA.

In an uncontrolled moderate to severe outbreak, it is estimated that losses in wood in the Atlantic region would be between 2.4 million and 3.3 million cubic metres of wood per year for the next 30 years.

Water bodies are identified on maps and are excluded from all treatment areas during the planning phase; there is no targeting of visible water bodies.

If Btk or Tebufenozide does reach a water body, research indicates that the risk of harmful effects is very low. Both products were studied extensively by government scientists and regulatory officials before being allowed for use in Canada.

Pheromones have no harmful effects on aquatic systems. Directions for use on the label of pheromones are approved by regulatory officials from Health Canada and allow the product to be applied up to water’s edge.

If conifer-dominated stream buffers or watersheds suffer high mortality from budworm outbreaks, their ability to deliver and regulate clean water supplies will be reduced. The biodiversity in those watersheds that depend on healthy forests will be affected. These kinds of impacts from budworm defoliation can last a decade or more.

Tree growth is affected as long as defoliation continues, usually 8-10 years. If the tree survives, growth begins to recover soon after defoliation ceases and is back to normal about 5 years later. The effects on forest growth are much longer lasting because of the loss of productivity in forest stands killed or salvage harvested during the outbreak. Wood supply projections for New Brunswick are counting on major increases in wood supply in about 2040 and 2060, the result of silviculture investments. A severe spruce budworm outbreak without foliage protection has been projected to reduce wood supply by 25 percent for 10 years after the beginning of the outbreak and to remain below expected levels for over 40 years.

References

Hennigar, C.R, Erdle, T.A, Gullison, J.J, MacLean, D.A. 2013. Reexamining wood supply in light of future spruce budworm outbreaks: a case study in New Brunswick. For. Chron.  In The Forestry Chronicle, 2013, 89(1): 42-53.

In an uncontrolled moderate to severe outbreak, the estimated losses in wood supply in the Atlantic region are predicted to be between 2.4 million and 3.3 million cubic metres of wood per year over the next 30 years. A detailed wood supply analysis for alternative future scenarios for New Brunswick is presented in Hennigar et al. 2013.

References

Hennigar, C.R, Erdle, T.A, Gullison, J.J, MacLean, D.A. 2013. Reexamining wood supply in light of future spruce budworm outbreaks: a case study in New Brunswick. For. Chron.  In The Forestry Chronicle, 2013, 89(1): 42-53.

Success is defined as spruce budworm populations returning to low levels. Researchers will assess populations in the treated areas using branch and trap sampling methods. If the treated areas have lower population levels or a lower proportion of positive samples and are not re-infested, then the treatments will be considered successful.

Spruce budworm populations are estimated using several methods during surveys conducted by the Partnership. Aerial surveys are used to locate defoliation in mid-July, when the effects of budworm feeding cause trees to turn red. The areas are mapped to define the spatial distribution and severity (nil, light, moderate, severe classes) of defoliation. Spruce budworm moths are also trapped using either pheromone or light traps. This method is used to inform managers about the general level and annual trends of spruce budworm populations.

Branch sampling is a method to count caterpillars that are overwintering on tree branches. This method is used to estimate the level of the population that will cause defoliation in the stand the next spring. Scientists can monitor spruce budworm at all life cycle stages depending on what they want to know about the population.

The researchers in the Partnership work for Canadian universities or for government departments such as Natural Resources Canada’s Canadian Forest Service. Results are presented annually by the researchers at Healthy Forest Partnership workshops. At these open sessions, researchers answer questions about their results and findings. The research results are published in scientific publications so they can be reviewed by a wider range of scientists and the public.

The focus of the early intervention project is to avoid a large scale treatment foliage protection program. The goal of the research is to understand how outbreaks begin and to develop new tactics that would minimize the area of our forest requiring insecticide.

Traditional spruce budworm management focused on foliage protection during outbreaks. The objective of foliage protection was to keep trees alive until the outbreak ran its course and insect populations declined due to natural enemies. Research by Dr. Jacques Régnière (Canadian Forest Service) and others indicate that at very low population levels, mating success of budworm moths is low because male moths have difficulty finding females. This research is the foundation for this new approach to managing spruce budworm populations.

Early intervention research is happening across eastern Canada and Maine. The current treatment program is focused on northern New Brunswick and northwestern Newfoundland where spruce budworm populations are being closely monitored. Please refer to our map section for treatment updates.

Aerial applications do not occur over residential areas. However, aircraft sometimes do have to pass near homes when on their flight paths. We work hard to minimize this as much as possible.

Spruce budworm treatments typically occur in the early mornings and evenings in late May and June. Treatments normally require 1 or 2 applications. Public notices (printed ads) and signage at normal entrance points to treatment areas are placed in advance of aerial application. The insecticides used (Btk and tebufenozide) are not harmful to the health of humans or other animals and only affect larval insects (such as spruce budworm).

We do apologize for any disruption this may cause and appreciate your patience.

An early intervention strategy against spruce budworm is intended to interrupt or delay low-density budworm populations from progressing to outbreak levels. By understanding the processes occurring in a rising spruce budworm population, researchers may be able to develop new targeted approaches that could keep low density budworm populations from progressing.

Of the very few insecticides available for aerial use against spruce budworm, considerations that can determine what treatment is used and where it is used include its application cost, government regulation, logistics, the life stage of the insect, weather, timing, effect on natural enemies, and size of the hotspot (increasing population).

The insecticides used (Btk and tebufenozide) are not harmful to the health of humans or other animals and only affect larval insects (such as spruce budworm). Health Canada has determined that there is no health concern associated with eating berries or edible plants (e.g. blueberries, raspberries) treated with either insecticide during forestry applications. As for pheromones, they only interfere with the communication behaviour of spruce budworm and are not harmful to the health of humans and other animals. Moreover, treatments are targeted to spruce/fir forests, so open areas where berry crops grow are less likely to be treated. Public notices (printed ads) and signage at entrance points to treatment areas are placed in advance of aerial application. Signage stays up for a minimum of 7 days after treatment. Btk and tebufenozide treatments typically occur in late-May and June, while pheromone treatments occur in early July.

Tebufenozide must be added to water and mixed. This mixture is then aerially applied at a rate of 1 to 2 litres per hectare. The tebufenozide portion of this mixture is fixed at 290 ml per hectare; this is less than the contents of a can of pop. Nozzles on the aircraft break the liquid mixture into small droplets (atomize) so when the drops land on foliage they are small enough to be eaten by spruce budworm.  The research areas designated for tebufenozide require one spray treatment only, unlike Btk which usually requires two.

The upper canopy of the forest is where the spruce budworm is most commonly found. Therefore, it is also the best location for droplets to be deposited. Because the forest canopy acts as a filter, few droplets reach the ground. Research conducted by the Canadian Forest Service has shown that 90-95% of the spray is deposited in the forest canopy (Kreutzweiser & Nicholson, 2007). The portion that reaches the ground stays in the upper 5 cm (2 inches) of the soil and leafy debris and does not leach away. It is broken down over time by soil microbes, sunlight, and moisture (Sundaram, 1997), (Thompson & Kreutzweiser, 2007). Research has also shown that any tebufenozide that reaches the ground is not harmful to soil invertebrates (Addison, 1996).

Tebufenozide deposited on the shoots and needles of the spruce and fir trees is eaten by the budworm larvae. The larvae stop feeding almost immediately and die within a day or two. Tebufenozide deposited in the canopy is relatively rainfast and is not easily washed off by rainfall (Sundaram, 1995).

Water bodies are identified on maps and are excluded from all treatment areas during the planning phase: there is no targeting of visible water bodies. Based on research conducted by the Canadian Forest Service, tebufenozide that lands on water has no noticeable environmental impact. Even if a water body were to be unintentionally sprayed , research scientists have studied the effects of tebufenozide on aquatic invertebrates and found that there were no significant harmful effects on most organisms at concentrations expected after aerial spraying. (Kreutzweiser & Nicholson, 2007. Kreutzweiser et. al. 1994; 1998).

The most recent review of tebufenozide states that ‘No adverse effects on birds, mammals or aquatic species are likely to occur from exposure to tebufenozide (US Department of Agriculture, 2012).

References:

Addison, J.A. 1996. Safety testing of tebufenozide, a new molt-inducing insecticide for effects on non-target forest soil invertebrates Ecotoxicological Environmental Safety 33, 55-61.

Kreutzweiser, D, and Nicholson, C. 2007. A Simple Empirical Model to Predict Forest Insecticide Ground-Level Deposition from a Compendium of Field Data. Natural Resources Canada, Sault Ste. Marie Ontario Canada P6A5M7. In Journal of Environmental Sciences & Health Part B, V 42, pg. 107-113. USA.

Kreutzweiser, D., Capell S., Wainio-Keizer K., and Eichenberg, D. 1994. Toxicity of new molt inducing insecticide (RH-5992) to aquatic macroinvertebrates. Ecotoxicological Environmental Safety 28, 14-24.

Kreutzweiser, D.P., Gunn, J.M., Thompson, D.G., Pollard, H.G., and Faber, M.J. 1998. Zooplankton community responses to a novel forest insecticide, tebufenozide (RH-5992), in littoral lake enclosures. Canadian Journal of Fisheries and Aquatic Sciences 55:639-648.

Sundaram, K.M.S. 1997. Persistence & Mobility of Tebufenozide in Forest Litter and Soil Ecosystems under Field and Laboratory Conditions, Natural Resources Canada, Sault Ste. Marie Ontario Canada P6A5M7 in Pesticide Science V 51, 115-130. UK.

Thompson, D., and Kreutzweiser, D. 2007. A Review of the Environmental Fate and Effects of Natural ‘Reduced Risk’ Pesticides in Canada. In K.D. Racke and A. Felsot (editors), Crop Protection Products for Organic Agriculture: Environmental, Health, and Efficacy Assessment, ACS Books, American Chemical Society, Washington. pp 245-274.

Sundaram, K.M.S. 1995. Photostability & Rainfastness of Tebufenozide Deposits of Fir Foliage.  Natural Resources Canada, Sault Ste. Marie Ontario Canada P6A5M7. In American Chemical Society, 0097-6156/95/0595-034. USA.

US Department of Agriculture – Forest Service. 2012. Gypsy Moth Management in the United States: A Cooperative Approach. Final Supplementary Environmental Impact Statement V 1, pg. 11. USA.

Yes. None of the insecticides will have any impact on the health or quality of game meat.

No. None of the insecticides will have any impact on the health or quality of fish.  Even if some spray residues reached water bodies (the likelihood of this is very low), the insecticides do not accumulate in fish tissue and will not harm anyone who eats those fish.

Permits issued by Provincial departments require setbacks or buffers on properties or other non-target areas. The research areas maps are uploaded into the GPS guidance system of the aircraft. A computerised system guides the pilot back and forth across the treatment area and controls when the spray system is activated. This ensures that only the approved research areas are treated. The permits also specify some of the weather thresholds to help minimize risk.  Pilots and crews are trained and licensed in the application of insecticides.

Permits issued by the Provincial departments specify that public notices (in newspapers) and signs (at access points) must be posted prior to aerial application. Please refer to our map section for more information on the location of research areas.

Aerial treatments using tebufenozide or Btk occur when spruce budworm caterpillars have grown to a specific age class. Treatments can begin as early as late May or early June.  Pheromone treatments begin about three weeks later, when the adult moths are starting to fly.