Sick Macadamia?

[Fiddler]

I've become alarmed at the clusters of brown leaves suddenly showing up on my Beaumont Macadamia. For years, this tree has been healthy, productive, and growing like a weed. Now this. Any ideas what could be wrong?

[achetadomestica]

I have a couple newly air layered macadamias I got a few months back.
Mine are very yellow? I gave them 8-4-8 with micro fertilizer and one died fairly quickly.
I have been giving them a  small handful of sulpher every month. I also have been giving them
Epsoma holly tone

How often do you water your tree?
What fertilizer are you using?
Do you know the PH of your soil/water?

[Fiddler]

Haven't needed to water it lately because of our crazy Florida rainy season. I apply that "citrus and mango" fertilizer from Home Depot about 4 times a year. Don't know much about PH, but for the last fifteen years my mango, lychees, jujubes, and macadamias have seemed pretty happy. Other types of fruit trees don't do well in my yard. My pomegranate, atemoya, and fig never did thrive. Black sapote and saphodilla don't do well here, either.

[Fiddler]

Well folks, two developments since I last posted. The tree is looking worse today, and I did a google search and found that some sort of fungal disease seems to be the problem. According to what I read, this is fatal and there's nothing I can do about it. I hope I'm wrong, but my photo exactly matches photos of the dying macadamia trees I saw.

[ScottR]

Macadamia are in Prpteaceae family and they need low-phosphate fertilizers too high of phosphate can kill them!!
Of all proteaceae macadamia can tolerate low slow release phosphate the best.

[NateTheGreat]

That lawn is awfully green. Just been fertilized?

[Johnny Eat Fruit]

You need to cut back on the "P" phosphorus on your Beaumont.  Excessive amounts can damage the Tree. Use an organic 6-2-4, avoid chemical fertilizers with Macadamia trees. Also, make sure the Ph is below 6.5.

Enclosed is a photo of my (9) year old grafted Beaumont Macadamia Tree.

Johnny

[Fiddler]

That lawn is awfully green. Just been fertilized?

No, it must be the sun's angle. This photo was taken at sunrise. I don't fertilize the lawn or water it in dry season.
   

[achetadomestica]

You need to cut back on the "P" phosphorus on your Beaumont.  Excessive amounts can damage the Tree. Use an organic 6-2-4, avoid chemical fertilizers with Macadamia trees. Also, make sure the Ph is below 6.5.

Enclosed is a photo of my (9) year old grafted Beaumont Macadamia Tree.

Johnny

Hey Johnny
What exact fertilizer are you using? My trees are very yellow but they are growing fast.
I guess it's a PH issue. I have been putting a handful of sulpher every month and when I planted
I put allot of lambert peat mix in the hole. The lambert works for jabos? My soil was 6.3 when I had it
tested what are you doing for your PH. Aren't you around 8?

[Johnny Eat Fruit]

I use Down to Earth Fertilizer but any good organic should do.  I lightly apply sulfur twice a year to my tree to keep the PH in check. The soil in my area tends to have a higher PH naturally. Also, I water regularly. Macadamia Trees do much better if the soil is moist and love to be watered but not oversaturated.

When I plant a tree in the ground I never place any organic material in the hole. I feed the plant from the top. Put your organic material on top and water. This will feed the tree naturally.

Johnny

[Malia]

@Fiddler, what is the outcome? Did your macadamia survive?
My Beaumont did almost nothing (maybe 1 flush) for 3 years, then died. Originally was a 3-gallon nice sapling.
I wonder if I should even bother with buying a new one... Or go for another mango 

[Fiddler]

No, it didn't make it. I pulled it out and burned it. Then I sprayed fungicide into the spot where it used to be. Reading your post sorta makes me wonder if there might be some kind of genetic defect in the Beaumont variety that makes it vulnerable to fungal disease. I have four other macadamias on the property and they're not sick.

[Malia]

Well, I am quite a layman, but fungus means sth visible to me. My Beaumont simply dried out. Leaves browned then dropped, dry branches.
I was suspecting nematodes and wanted to pull out the tree. With nematodes should go easily. I pulled hard and the trunk broke without even bending it. I catapulted and bruised my butt. I had to use a shovel to dig out the root. It looked perfect for me. No trace of any parasites, nothing. I will take a picture later.
Very silent death, I would say.

[Johnny Eat Fruit]

Strange Your Beaumont Macadamia Tree died. Mine grew very well here in California in 2021. Could be your climate is not as well suited for this type of nut tree. Hard to say.

Johnny

[Malia]

The root is perfect, no issues. But the wood is super dry.
@Johnny Eat Fruit, there are already 2 Beaumont macadamia trees that followed the same symptoms and died. Fiddler might be correct about the disease. I hope it will not spread to California.

[agroventuresperu]

Here in the high jungle, we have lots of trouble with ours. They are among the most stunted of all the species of tree we planted. In September we added about 1kg of chicken manure with rice hulls, and 1kg of guano de isla, as well as 1kg of dolomite per tree, and a number of them did not like that cocktail for whatever reason. They started getting the brown leaves and dying. Some are OK though, but the growth rate hasn't improved much in any case.

[Jack, Nipomo]

Proteoid roots in the macadamia are characteristic of most species of the Proteaceae.  These are highly efficient roots evolved to survive in very poor soils.  The addition of fertilizer can overwhelm the plant and simply be toxic.  Of my 40 or so trees of different varieties, they rarely see any fertilizer.  Their soil is just old beach sand (with a slight acidic flavor)

[Malia]

@Jack, that makes sense. I fertilized the tree. On the other hand, @Fiddler says that only Beaumont died. Other did not.

[agroventuresperu]

Proteoid roots in the macadamia are characteristic of most species of the Proteaceae.  These are highly efficient roots evolved to survive in very poor soils.  The addition of fertilizer can overwhelm the plant and simply be toxic.  Of my 40 or so trees of different varieties, they rarely see any fertilizer.  Their soil is just old beach sand (with a slight acidic flavor)

In our context, I had originally assumed aluminum toxicity due to the low pH of our soil here, hence the addition of dolomite. We have some areas that are clay, fertile and less problematic with lots of humus, while some other areas are pretty soggy/slightly swampy yet sandy at the same time. We started out with just a small amount of compost mixed with the native soil when we originally planted them. We planted roughly 100 from seed-grown plants started in a nursery. They were planted all over the property in a variety of different locations and soil conditions. No pattern emerged to suggest why some might have survived whereas others did not. They were all pretty healthy in the nursery before planting. When we transplanted to the field we achieved the following results: Most died, lots have shown extremely slow growth, and only a couple have shown moderately slow growth. I don't think our problem here was overly fertile conditions, as our original soil analyses before planting indicated pretty typical nutrient deficiencies that one might expect of deforested jungle turned to cattle pasture for 1 or 2 decades.

If Macadamia grow well in coastal central California on sandy soil, I'm guessing they might require better drainage than avocado. We had a lot of Avocados die on our property, but we also have plenty that have shown excellent growth at different places on the property. I'm not familiar with Macadamia's native growing conditions in Australia.