AusBonsai

I've had a wave of death pass through some young Grevilleas, mainly the broader-leafed typed - olivacea and and some of its varieties (I think) , victoriae and diminuta. A similar-leafed species in the garden appears to have the same leaf disease, but has bounced back - some fresh new growth compared to the manky older stuff. Any ideas what it is? Any solutions?
Also, two of my four Mel stypheloides young-uns have lumps that look like lignotubers at their base - the other two don't. I thought lignotubers were mainly in Eucs.
Any help appreciated.

Gavin

Hi Gavin,

The disease affecting your Grevilleas is most probably fungal. See http://www.ehow.com/info_8760568_diseas ... lleas.html It can be treated with a copper fungicide like Yates Fungus Fighter. I'd be careful with watering and make sure there is enough air circulation around the trees. Good luck!

Also, two of my four Mel stypheloides young-uns have lumps that look like lignotubers at their base - the other two don't. I thought lignotubers were mainly in Eucs.

Some Melaleucas can still have lignotubers, like the M. squarrosa and M. thymifolia, so maybe the M. styphelioides can too. Maybe Pup knows more. I also found indications on Google for this particular species, but had trouble accessing the info on the websites. Doesn't look like gall swellings to me, on your photo, so I wouldn't worry so long as your young trees look healthy.

Best wishes,

Lisa

G'day Gavin .My landscape grevillea victoriae and diminuta have similar leaves when water stressed.Both these varieties are really drought tolerant when they are used to lack of water . When I have planted them in my garden I water the first year then they are on there own(tuff love). They usually 'sulk' until they adjust and then there is no stopping them. I have maybe 50 or so growing in the garden . It could be fungus but if they have been on the drier side lately, I would consider this. By the looks of the new growth I wouldn't worry
Cheers Craig.

If it helps, my Callistemon and Leptospermum have lignotubers.

Thanks all for the information. The broad-leafed Grevillea bonsai stock are dead and gone - went in a week or two. I'm hoping to save the garden plants though. It hasn't been damp at all, more like drying/hot.

I couldn't work out why only two of the stypheloides had "lignotubers", and two didn't. We'll see what happens in the next twenty years.

Thanks again,

Gavin

There is yet another possible cause of your Grevillea deaths, Gavin, and that is phosphorus. It seems Grevilleas are particularly sensitive to it. One has to watch with blood & bone and chicken manure-based products.
Regatding fungi: these can be soil-borne.
Anyway, here is an article that looks quite useful.http://www.homedesigndirectory.com.au/g ... leas.shtml
Good luck

Lisa