Follow the instructions carefully and stop spraying after the buds open.
Grubs
Asiatic garden beetles (Maladera formosae), European chafers (Amphimallon majale), masked chafers (Cyclocephala spp.), May and June beetles (Phyllophaga spp.), and vine weevils (Otiorhynchus sulcatus) all feed on fir roots during their larval stage.
The grubs live in the soil and feed on roots, sometimes for years, until they mature and emerge as adults.
Root feeding leads to stunted growth both above and below ground. In seedlings, heavy infestations can cause lasting damage or even death.
If you spot adult beetles and your fir appears weak or stressed, grubs are likely present. To confirm, dig around the roots and look for the larvae.
You can help deter infestations by removing weeds and avoiding dense ground covers near the base of the tree.
For control, apply beneficial nematodes in spring or summer to target the grubs. When adults are active, treat with a pyrethrin-based spray, such as Monterey Take Down Garden Spray.
Monterey Take Down Garden Spray
You can find Monterey Take Down Garden Spray available at Arbico Organics in 32-ounce ready-to-use spray or as concentrate.
Spider Mites
The two-spotted spider mite (Tetranychus urticae) is perhaps the most common pest of Fraser fir, especially when conditions are warm and dry.
These sap-sucking tick relatives draw out the sap from the needles and branches. As they do, the needles turn spotty yellow and will eventually drop from the tree.
If you see yellowing and needle drop, look closely for fine webbing and signs of the mites, which are about the size of the tip of a needle.
Check out our guide to controlling spider mites to learn more.
Weevils
The Pales weevil (Hylobius pales) targets many conifers, including Fraser firs. Adults are oval, nearly black, and about half an inch long. They overwinter on the forest floor and emerge in spring to breed.
Females lay eggs on the roots of trees and the emerging white grubs tunnel into the roots to feed.
By late summer or early fall, the new adult weevils emerge, which have brown heads and cream-colored bodies.
The adults feed on tender bark and exposed roots. If enough weevils attack a young tree, they can girdle branches or even the trunk, causing serious damage or death.
Look for signs like girdling, oozing sap, browning foliage, and fungal cankers at the base. The latter may signal Procerum root disease, which often follows a weevil infestation.
Control takes a two-pronged approach. First, you want to tackle the grubs and weevils using beneficial nematodes applied to the soil.
Triple Threat Beneficial Nematodes
Something like Triple Threat Beneficial Nematodes, available from Arbico Organics should be applied as directed in the spring.
In the summer, when the adults are active, spray with a pyrethrin-based product.
Disease
There’s only one disease that can be a major problem, and it’s a doozy. You might also rarely see armillaria root rot on trees infested with adelgids, but it’s not a problem otherwise.
Armillaria
If your tree is infected with armillaria, the trunk and roots will rot away, and you might see yellow fungi at the base of the tree. There’s nothing you can do to save a tree at this point.
Phytophthora Root Rot
Phytophthora root rot (PRR) is a serious and increasingly common disease that can destroy a tree, turning it a sickly orange in a matter of weeks.
Commercial growers anticipate that they’ll lose up to a third of their trees each year to this disease.
It’s caused by a pathogen called Phytophthora cinnamomi, which is an oomycete or water mold. This water mold can be carried in water, soil, or even on your shoes or tools, so it can spread rapidly.
Once it’s in your soil, it’s almost impossible to get rid of and can live for decades. That’s why prevention is so important.
Right now, researchers are working on breeding PRR-resistant Fraser firs, but until that happens, it’s something you’ll have to be vigilant about.
If your tree is infected, all or part of it will wilt, and the needles will take on a gray-green hue, and not in a pretty way.
You’ll also see dead branches, needle drop, delayed bud break, and slow growth. Sometimes only half of the tree will be symptomatic or it might be the whole specimen.
If you were to dig down and look at the roots, they’d be a rusty cinnamon color with black or white tips, and they might lack the fine hairy roots.
The first step in avoiding it is to always buy or take seeds, plants, and cuttings from reputable sources or healthy looking plants. If a plant looks sick, avoid it at all costs. It might not have PRR, but better safe than sorry.
Set your plant in appropriate space with appropriate drainage and soil. Heavy clay retains water, and water is P. cinnamomi’s best friend.
If you know the disease is present in your area, water using treated culinary water or well water. River water or irrigation might be carrying the pathogen.
You should also spray your tree preventatively with a fungicide that contains copper.
If your tree is infected, there’s no cure, but you can try and support the specimen with products products that contain phosphorous acid, hydrogen peroxide, citric acid, or the beneficial bacteria Bacillus subtilis or Streptomyces lydicus WYEC 108.
I’m a particular fan of CEASE, which harnesses the power of B. subtilis to kill fungal spores.
You can find this product at Arbico Organics in one- or two-and-a-half gallon jugs.
You can also use the conventional fungicide Subdue MAXX.
Embrace the Fabulous Fraser Fir
I was on one of those drives, you know the kind where you’re bored out of your mind and staring out the window, checking the GPS every two minutes to see how far away you are from your destination.
Forehead against the window, I was watching the rural landscape fly past when we were suddenly smack dab in the middle of hundreds of Christmas trees.
For a second, I wondered if I’d fallen asleep and was having holiday-themed dreams. Turns out, we were just driving through one of Oregon’s many Fraser fir farms.
If you want a fragrant, beautiful conifer with soft needles and classic Christmas tree shape, you can’t find a better option.
It’s the only conifer I keep near my patio because I can’t get enough of the scent when I walk by, and I don’t have to worry about being stabbed by a million needles if I brush against it.
What is it that draws you to this tree? And how do you plan to use yours? Let us know in the comments section below!
And to learn more about growing conifers in your landscape, check out these guides next:
