Further to the discussion on pests and diseases at the April Palm and Cycad Society of New Zealand meeting … Five mature Butias that I shifted three years ago started producing shorter mis-shapen fronds which didn’t open out. Many were ‘accordion-pleated’ as well. It looked abysmal, and was getting worse every month.

Someone said it was Phytophthora, so I looked up the remedies for that. I tried Aliette, and it did nothing. I tried a potassium drench if I remember rightly, and it helped a bit. Then I tried Terrazole. It was a liquid formulation that has since been replaced by powder, but I couldn’t believe the low rates they were recommending. Assuming they would normally be dealing with preventative measures on seedlings or maybe young avocadoes and considering that our palms were already well down the track to oblivion, and very valuable, I felt justified in applying the stuff at 10 times the recommended rate, together with a sticker and Nitrosol liquid fertiliser. The fronds were sprayed, and the ground drenched. In due course I also started drenching the growing tip as well. There seemed to be a more perky look to the plants after a couple of treatments so I kept it up and after two seasons of 2- to 4-weekly applications – many hundreds of dollars worth of spray later – there is a significant flush of healthy growth. Apparently a contributing factor to fungal problems is micronutrient deficiency as a result of loss of root area. Whereas NPK can be taken from old fronds and used by the growing point in production of new fronds, most micronutrients (things like boron, manganese, iron, etc) are less able to be translocated within the plant, and this is what actually causes problems with the new growth. So I have been including a blend of chelated micronutrients in the treatment.

I found out quite a lot in the process of treating this problem. For palms, calcium, magnesium and sulphur are macroelements, that is, they are needed in quantities similar to phosphorous (standard NPK ratios for palms are 3:1:3 or 3:1:2). Most fertilisers contain sufficient sulphates to cover the sulphur requirements but unless you are adding dolomite to your potting mix they may not be getting enough calcium and magnesium.

Apparently there’s another disease attacking Butias, the symptoms of which are dieback of the oldest fronds, progressing rapidly upward to the youngest ones. This is not the problem I had and I don’t know anything about it. The problem I would like to solve is the leaning crown, affecting mainly Kentias, though I do have a Butia suffering from it. I am using Topsin and it may be helping. Any hints would be appreciated. … Brent Hubbard.