Brown spots - christmas palm adonidia merrillii

[PFranky]

Hi all, first post. I planted 5 x Adonidia Merrillii (Christmas Palm) a few months ago and have noticed recently brown spots showing on existing and new growth.

Located Gold Coast, QLD Australia. 

What are the potential issues and remedies?

• fungal
• pest
• nutrition
• water

Thank you all and I hope I can save these.

[Merlyn]

I'd think it is a potassium deficiency, assuming it is on the older leaves and not on the new spears.  It probably has signs of Magnesium deficiency too.  This sort of thing is common with new plantings.  If it's been a couple of months since planting then I'd give it a good dose of something similar to PalmGain 8-2-12.  I'm not sure what brands are sold in Australia, so just look up the main NPK and pay attention to the micronutrients Magnesium, Manganese, Iron, Boron, etc.  Some timed release just have a bit of Magnesium and are missing the others, but many "palm special" types will include all of them in various amounts.  Here's my notes on deficiencies:

• Nitrogen - Older fronds turn light green uniformly, new fronds remain dark green until deficiency is really severe
• Potassium - Older fronds get translucent yellow/orange or dead spots on leaves, especially at the tips. Caryota and Arenga get random splotched dead spots in leaves. Sometimes tips are curled or frizzled. Always starts at tips of oldest leaves, moving inwards
• Magnesium - Yellow linear bands on leaves but generally transitions to solid green at the base of each leaf. Never causes leaf tip necrosis
• Iron - Many times caused by overly mucky soil and root rot. Starts with new spear leaves with yellow-green or even white, possibly with spots of green.
• Manganese - Lengthwise necrotic streaks in leaves with dead and curled leaf tips. Similar to bands showing Magnesium deficiency
• Boron - Bent or necrotic or distorted leaf tips, distorted or bent spear, bands of dead spots on new fans, spears that won't fully open
• Water - Underwatering brown at the edges first, later followed by yellowing of the whole leaf. Overwatering can be drooping fronds turning yellowish and losing color
• Dolomitic Lime or Azomite - Magnesium Carbonate – slower release and adds Magnesium, helps avoid Potassium deficiencies in Cuban Copernicias. 5Lb per palm on full-size Copernicias and a bit less on Kentiopsis Oliviformis
• Garden Lime - Calcium Carbonate – fast release but works well. 5Lb per palm on full-size Copernicias and a bit less on Kentiopsis Oliviformis

[D Palm]

This year I have discovered if you take Palm Nutritional Spray (has cheleated micro nutrients as listed above) and just dump it on the palm including crown, wonders.

I use to just spray but that took forever and didn’t work w/ some palm that have waxy coatings like Bismarck’s.

it won’t fix the old, but the new will definitely appreciate it. I’ve used the citrus too, works as good for palms if you can’t locate the Palm. I have failed numerous times to grow orange BoP. This is what prompted me, they recovered nicely from 20F and rewarded me with beautiful birds this year. My palms are popping off right now too. 
 

could be cold damage as your coming out of winter.

[PFranky]

Thanks all for the info, this is great, although the spots are occurring on the new growth also.

The response from the nursery I purchased them from was cold damage, however it isn't really that cold in the tropical part of Australia that I am in 10-15deg (50-65deg F) overnight minimums with daily max around 18-25deg (65-75deg F).

I'll keep an eye on it as it starts to warm and keep nutrition up.

[Merlyn]

@D Palm you just dilute the Palm Nutritional Spray to normal levels and then dump it on the whole palm?    I have some but haven't really used it...

As far as cold damage goes, @PFranky you can get cold damage on Adonidia around 40F or so (5C or lower), but I wouldn't expect it if your winter is only about 10C or higher.  But cool nights and days can give palms a fungal infection.  Maybe try squirting hydrogen peroxide in the crown and see if it bubbles up?  If so you've got a fungal infection in the crown.  I use Daconil + H2O2 mix for crown infections, 4tsp mixed into a 32oz bottle.

[Johnny Palmseed]

17 hours ago, PFranky said:

Thanks all for the info, this is great, although the spots are occurring on the new growth also.

The response from the nursery I purchased them from was cold damage, however it isn't really that cold in the tropical part of Australia that I am in 10-15deg (50-65deg F) overnight minimums with daily max around 18-25deg (65-75deg F).

I'll keep an eye on it as it starts to warm and keep nutrition up.

I think the nursery answer is probable. The current temps seem ok but what were they like a few months ago? That is the time frame that the damage likely happened. It really looks like the ones I have seen around here after a cold winter. Yours don’t look bad though, and will probably be fine once it warms up.

[D Palm]

I’ve seen them spot up in low 40F to upper 30F. Doesn’t seem like that’s the case here though.

@Merlyni do about half an ounce for 2 gallons, then dump it into crown, trunk, leaves. I have 2 acres and the sprayer was taking forever. My neighbor thought orange BoP only bloomed in S. FL. She was shocked mine survived the winter and has blooms.

Greens up my citrus leafs too really nice in about 1-3 days after application.

[PFranky]

As an update, the Nursery has also said that their palms have spotted up the same due to the recent winter.

Good to know that it is not necessarily lack of nutrition or fungal/pest issues.

I’ll still keep an eye on them through Spring/Summer and see how it goes.

[Merlyn]

11 hours ago, PFranky said:

As an update, the Nursery has also said that their palms have spotted up the same due to the recent winter.

Good to know that it is not necessarily lack of nutrition or fungal/pest issues.

I’ll still keep an eye on them through Spring/Summer and see how it goes.

Yeah, that seems reasonable.  Sometimes prolonged cold can cause "leaf blights" on sensitive palms.  Most of the time these are cosmetic and not a big concern.  I'd keep an eye on the new spear, and maybe squirt a little hydrogen peroxide in the crown to see if there's an active fungal infection.  If it bubbles up then a once-a-week squirt should help the palm fight off any infection.  If it doesn't bubble up then it's probably just a random "leaf blight" that'll go away when it warms up.