Trachycarpus phomopsis canker - anybody got experience ?

[Nigel]

I guess most of us have experience with the mystery disease that deforms and rots the base of trachycarpus princeps. It is a canker that spreads across the basal plate, the plant starts to lean and leaves become progressively smaller. Often a new shoot will appear from the side of the plant. Small patches of grey blue can be seen that produce clouds of spores when tapped.

It has been identified as a Phomopsis canker.

I am interested to know if any growers have experience with the control of this disease with systemic fungicide, and which fungicide is effective..

[Mauna Kea Cloudforest]

Well, you know something that most of us don't, I had no idea it was Phomopsis canker. This canker is actually quite prevalent in California. I've sold a few princeps and my advice is to treat them like cacti and grow them on 2-3 inches of gravel at the base like a cactus. That will go a lot further in preventing disease. You can also use redwood bark mulch which has strong anti-fungal properties. And most of all, keep all irrigation away from the base. The fungus is most active during the growing season.

[Mauna Kea Cloudforest]

I forgot to mention one other very basic trick: this is a palm that grows on lime rock and can handle very high pH. Fungus hates high pH, it needs acidic soil in order to thrive. You can use azomite and other pH raising supplements to inhibit fungal growth. And let the top soil dry out completely between waterings.

[DoomsDave]

That's an interesting explanation.

I have a two-headed princeps that might indeed have gotten the canker. I'll go home and look when I leave the Dark Tower.