Current status of Anchorage Spruce beetle infestation, if spraying is needed and when to do it - Ask Extension
Is spraying still needed in South Anchorage to protect trees from spruce beetles? When should it be done by?
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Current status of Anchorage Spruce beetle infestation, if spraying is needed and when to do it #865895
Asked April 25, 2024, 2:34 PM EDT
Is spraying still needed in South Anchorage to protect trees from spruce beetles? When should it be done by?
Anchorage County Alaska
Expert Response
Hi Michelle,
Deciding whether or not to spray your spruce as a prevention of spruce beetle attack depends on your goals for your yard and the level of risk you find acceptable. The past two summers we have seen a decline in spruce beetle active damage in Anchorage. There still are some pockets of activity around the municipality, but not nearly as much as we were seeing earlier in the outbreak.
Another piece to consider is whether these trees have been sprayed before, and how long ago. Most companies are applying products with the active ingredient carbaryl for spruce beetle prevention, which is 100% effective for two summers when applied correctly. During outbreak when beetle populations are high we do recommend sticking to an every-other spring spray schedule for those high-value trees you don't want to lose. However, as beetle populations decline, some folks are willing to accept a bit more risk, and decide to delay their spray another year. Past studies in Alaska have shown that carbaryl applications are still about 89% effective at preventing spruce beetle attack during that third summer after spraying. For some folks, that amount of risk of losing a tree is acceptable, but for other folks that risk of losing a tree may be too high and they may prefer to re-spray again this year, that decision is totally up to you.
As far as spray timing, we recommend as early as possible in spring, preferably by mid-May. Beetles typically start to fly in search of new host trees in mid-May so ideally the tree would be protected before that flight period starts. If your yard still has a lot of snow cover though that will delay when those sprays can be applied.
For more information about the outbreak status and management options for spruce beetle you can visit our multi-agency spruce beetle website, https://www.alaskasprucebeetle.org/
Deciding whether or not to spray your spruce as a prevention of spruce beetle attack depends on your goals for your yard and the level of risk you find acceptable. The past two summers we have seen a decline in spruce beetle active damage in Anchorage. There still are some pockets of activity around the municipality, but not nearly as much as we were seeing earlier in the outbreak.
Another piece to consider is whether these trees have been sprayed before, and how long ago. Most companies are applying products with the active ingredient carbaryl for spruce beetle prevention, which is 100% effective for two summers when applied correctly. During outbreak when beetle populations are high we do recommend sticking to an every-other spring spray schedule for those high-value trees you don't want to lose. However, as beetle populations decline, some folks are willing to accept a bit more risk, and decide to delay their spray another year. Past studies in Alaska have shown that carbaryl applications are still about 89% effective at preventing spruce beetle attack during that third summer after spraying. For some folks, that amount of risk of losing a tree is acceptable, but for other folks that risk of losing a tree may be too high and they may prefer to re-spray again this year, that decision is totally up to you.
As far as spray timing, we recommend as early as possible in spring, preferably by mid-May. Beetles typically start to fly in search of new host trees in mid-May so ideally the tree would be protected before that flight period starts. If your yard still has a lot of snow cover though that will delay when those sprays can be applied.
For more information about the outbreak status and management options for spruce beetle you can visit our multi-agency spruce beetle website, https://www.alaskasprucebeetle.org/
Thanks for your response. My other concern is the nesting song birds, they are arriving in great numbers now, and since we still have some snow on the ground, I’m concerned that waiting any longer will be harmful to the nesting birds. We noticed a decline in birds in our area after spraying, how does this effect them and their nests/eggs? Thanks again, Michelle
On Apr 25, 2024, at 10:55 AM, Ask Extension <<personal data hidden>> wrote:
Hi Michelle,
For questions about environmental impacts of carbaryl I would recommend contacting the National Pesticide Information Center. This is a university-based program that provides objective, research-based information about pesticides to the public. Their phone number is 1.800.858.7378 and they are available Monday - Friday, 7-11 AM Alaska time. They also have an email address: <personal data hidden>
The National Pesticide Information Center does have a webpage about carbaryl where it lists this active ingredient as "practically non-toxic to slightly toxic" to birds. You can find that information here: http://npic.orst.edu/factsheets/carbarylgen.html#wildlife
For questions about environmental impacts of carbaryl I would recommend contacting the National Pesticide Information Center. This is a university-based program that provides objective, research-based information about pesticides to the public. Their phone number is 1.800.858.7378 and they are available Monday - Friday, 7-11 AM Alaska time. They also have an email address: <personal data hidden>
The National Pesticide Information Center does have a webpage about carbaryl where it lists this active ingredient as "practically non-toxic to slightly toxic" to birds. You can find that information here: http://npic.orst.edu/factsheets/carbarylgen.html#wildlife
