Mule Palm Question

[nitsua0895]

I'm noticing that the petioles of the newest fronds on my Mule palm are turning a bronze color. I'm pretty sure it's not cold damage because I can remember seeing it as far back as September. Do I just need to fertilize it well once spring begins?

Besides the strange coloring, the palm is growing very fast and looks completely healthy everywhere else. 

 

[atlantisrising]

I see this occasionally also on various species where the petiole 2-3 leaves down from the spear has browned. I suspect it is either a fertilizer issue when that leaf was formed or a fungus issue. As long as the spear is healthy the tree has probably grown past it while we were unaware of the problem. A few occasions it has heralded the beginning of the end but usually nothing to worry about. Most lethal problems show progressively from the bottom leaf up or the spear leaf down. I would suggest hydrogen peroxide mixed 50/50 with water poured down the crown to make sure no fungus is working. Do that once a week for a month.

[nitsua0895]

Unfortunately it appears a small part of the spear leaf is bronze colored as well so I'll go ahead and start using the hydrogen peroxide/water mixture on it tomorrow. Thanks for the advice! 

[nitsua0895]

The spear leaf has grown more and is starting to look pretty bad. There's a white/gray color with moldy looking black spots mixed in. I imagine this isn't a good sign at all.

Should I try and apply some fungicide along with the peroxide?

 

[atlantisrising]

I'm still not completely sure what causes a leaf to form with necrosis like this, but my three suspects are: 1. not enough water, 2. fertilizer problem, 3. fungus in the bud or crown. If you are watering regularly and there are no other signs of fertilizer issues which I don't see in the photos (looks nice and green and spear is definitely pushing) then fungus tops the list. I would definitely keep up the peroxide treatment and adding fungicide is a good idea, A relatively affordable one that works on two types of fungus is called "Banrot", I paid $60 for 2 Lbs., that amount will last a long time if all you are treating is container plants.  I use that weekly for a month along with the peroxide. Treat the crown and also the roots, it is taken up thru the roots too. This worked for me recently with my Clinostigma samoense. Best wishes.