Laevigatum death

[Mickeyjaytee]

Hey guys n gals,

I have a few laevigatum stock that im growing out and I’ve had a sudden issue that affected one and now has moved onto another, concerned it may move yet again to the rest.

Plants are otherwise healthy, watered daily and fertilised.

I had noticed ones leaves start to pale. Over some time it’s definitely died and now have a second that’s starting to pale too. Just curious if anyone could know the cause?

I can see some leaf damage on the lead growth so I’m thinking some pest is into it. Can’t directly see a pest though. I’ve linked some photos. I seem to have a problem with my Kunzeas in the garden too. I’m thinking thrips.

Any help would be great

[Mickeyjaytee]

It’s on 2 different lepto hybrids which I’ve attached and also a pic of the kunzea in the garden. I do believe the black spots are frass as opposed to scale.

The leptos all have quite a pale yellow new growth which, I have given them trace elements this year so I don’t think it’s a lack of iron or magnesium. There’s also a bit of dead new growth but, they have been kept watered.

There’s definitely something going on

[Raniformis]

Pull it out and look at the roots, daily watering is pretty excessive for a young plant.

[Raniformis]

Assuming you use a balanced nutrient and the soil pH is within a range that the plants can access those nutrients the next things to look at are light, roots and humidity.

Chloroplasts capture photons, photons trigger respiration and respiration triggers transpiration. Should one of these processes suffer, the other processes can't perform efficiently and all the symptoms look the same.

Weakened plants then become susceptible to insects and disease.

[Mickeyjaytee]

Pull it out and look at the roots, daily watering is pretty excessive for a young plant.

Thanks for the reply! So watering daily can be much but, I am in Perth and when I water, they’re always dry (the ones in pots which are quite small pots). The others are in the ground (definitely not watered daily). Considering they all seem to have been hit at once makes me think more of a pest other than humidity, light and roots etc. Soil pH is neutral.

The plants are in the same positions as last year so nothing significant has changed.

Thanks!

[Raniformis]

Coolio. Well that sucks, I'm good at keeping stuff green and alive but not so good when things go bad, most of my effort goes into preparation. When in doubt I usually resort to a foliar feed.

Hopefully someone experienced with the species has more than generic answers for you.

[Mickeyjaytee]

Coolio. Well that sucks, I'm good at keeping stuff green and alive but not so good when things go bad, most of my effort goes into preparation. When in doubt I usually resort to a foliar feed.

Hopefully someone experienced with the species has more than generic answers for you.

No worries. Thanks for the input! Hopefully someone has had a similar issue or can recognise what’s going on.

[shibui]

When I see pale and distorted leaves I immediately think mites. Spider mites are tiny but suck sap and can quickly build up numbers to decimate plants.
I haven't had them on natives but we do see them on other species.

Most pest mites are only just visible to the naked eye and only if you have great vision.
Very fine spider webs under and around the leaves is another sign of mites.
Shake or tap a branch over white paper to dislodge some. Sometimes you can spot the mites moving on the paper or spot tiny black spots of mite poo.
Otherwise check under the leaves with a magnifying glass. Mites have 6 legs so not insects.
Most insecticides do not kill mites. Look for something that lists mites on the label.

[Sno]

Don’t you love it . It could be a number of issues but the first thing that came to me when I saw the first photo was it had been ‘cooked ‘. You guys over in the west have been having a warmish summer so I would say this is the most probable cause . Your potting mix has probably dried out enough that it became hydrophobic which will lead to death .
I have a really open mix so I can’t miss a watering ( up to 3 times a day depending on the day ) and I don’t experience your heat . It works for me because my mix can’t get hydrophobic but some trees are still in ordinary potting mix which are growing on . They don’t need as much water as my ‘ bonsai mix ones’ but they are the ones you have to watch out for because the centre can dry out . With out a good soak it will stay dry and you may think a regular water will be enough but if the tree is actively growing it will want even more water .

[Mickeyjaytee]

When I see pale and distorted leaves I immediately think mites. Spider mites are tiny but suck sap and can quickly build up numbers to decimate plants.
I haven't had them on natives but we do see them on other species.

Most pest mites are only just visible to the naked eye and only if you have great vision.
Very fine spider webs under and around the leaves is another sign of mites.
Shake or tap a branch over white paper to dislodge some. Sometimes you can spot the mites moving on the paper or spot tiny black spots of mite poo.
Otherwise check under the leaves with a magnifying glass. Mites have 6 legs so not insects.
Most insecticides do not kill mites. Look for something that lists mites on the label.

Thanks for chiming in Neil, I appreciate it. I did the old whack a branch on a page and nothing. 2 weeks ago I gave it a shot and there was 1 thrip. That was off the kunzea. The laevigatum hmmm, it kind of is a bit different. It seemed to pale all over at once. I removed the survivors and sprayed them and they’re in quarantine. I might keep an eye out for some mite spray just to be on the safe side. Do you know if initiator or malathion works on mite? I hate using the stuff and it’s a last resort. I will get a mite spray otherwise.

Don’t you love it . It could be a number of issues but the first thing that came to me when I saw the first photo was it had been ‘cooked ‘. You guys over in the west have been having a warmish summer so I would say this is the most probable cause . Your potting mix has probably dried out enough that it became hydrophobic which will lead to death .
I have a really open mix so I can’t miss a watering ( up to 3 times a day depending on the day ) and I don’t experience your heat . It works for me because my mix can’t get hydrophobic but some trees are still in ordinary potting mix which are growing on . They don’t need as much water as my ‘ bonsai mix ones’ but they are the ones you have to watch out for because the centre can dry out . With out a good soak it will stay dry and you may think a regular water will be enough but if the tree is actively growing it will want even more water .

Thanks for the reply Sno. I think you’re right in that it does look like it’s been cooked. Sadly this spring just gone was nearly nonexistent and I did lose a pretty good laevigatum to drying out. That said it hasn’t been as warm lately. I pulled out the dead one yesterday and it was wet through, no signs of hydrophobia. I got everything through all the 44 degree days luckily and it’s been much cooler lately. They were repotted in spring so the soil is fresh and they had bounced back and were happily sending out new growth.

I think it could be possible to have a wilting bacteria in the soil (for the laevigatum). Earlier this year in another part of the garden a potted Correa of mine contracted it in the soil somehow. It wilts and dies and more water just increases the bacteria. I certainly hope it’s not that. It was removed and disposed of months ago though.

I have a couple of the laevigatum ‘foreshore’ and strangely one of them decided to kill back most of the plant before sending out new growth and it looks nice and healthy again. I couldn’t find a reason for that either. Oddly the hybrids are doing much better than the parent species

Still unsure of those yellow damaged areas on the laevigatum leaves though. Definitely some kind of damage.

I didn’t think bonsai would be this tough! I’ve had so many pests/diseases this year and failures. It’s been crazy.

Thanks for the help!

[Mickeyjaytee]

Well I spoke too soon. My laevigatum foreshore has started showing signs. New growth is wilted, discolouration has begun. I’d love to know what’s doing this!

A couple of notes. This has happened extremely fast. Yesterday I thought its colouring may have paled a little. Today it was definite and the wilting had begun. Soil is not dry and there’s no signs of hydrophobic soil.

A horticulturalist suggested thrips but, do they move that fast? I whacked a branch on white paper, nothing… I have 2 rhaps sending out new growth and they’re always hit hard by thrips, they haven’t.

Baffled

[Mickeyjaytee]

Sorry another update. I have a few burgundy peppermint trees and it looks like they’ve been smashed by thrips. I’ve attached pics of the bugs I found.

The laevigatum do not seem to have any frass though and, I wouldn’t expect the whole plant to discolour and die all over at once. Any thoughts?