Scottish Rock Garden Club Forum
Cultivation => Cultivation Problems => Topic started by: ian mcenery on June 14, 2009, 03:36:17 PM
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I have a couple of these plants and last year Jaqueline Postil got this disfiguring of the leaves and now Gurkha also has the problem have sprayed with the usual insecticide but the new growth seems stunted. Last year this led to poor flowerbud formation. Does anyone know what is wrong??
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No. My plants leaves are always healthy but I'll go outside now for a look.
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Ian, when I see such damage I first think of Thrips or mites.
This time of year you might often see this damage and if it is no mite then mostly it's Privet Thrips.
On your leaves I see some silvery spots, which is typical.
I'm no expert and had to google a bit on the website of the research station in Holland to make myself clear about how to explain.
I see it here in my garden too and when damage is little, I pick some leaves off and throw them in the dust bin..
But when it's more damage some spraying with a stronger insecticide is the only way, I'm afraid.
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The ragged holes that are developing on the leaves could be due to capsid bug damage.
They do the damage when the leaves are very small, and it only becomes apparent as the leaves expand (by which time the pest has moved on).
- so you may not find any insects on the plants now, and insecticide is therefore not of help at this stage with this pest.
It's a case of spraying early (when the damage may not be apparent) but the insect can be seen if you look out for it.
Most insecticides are effective (eg bifenthrin).
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Ian, when I see such damage I first think of Thrips or mites.
This time of year you might often see this damage and if it is no mite then mostly it's Privet Thrips.
On your leaves I see some silvery spots, which is typical.
I'm no expert and had to google a bit on the website of the research station in Holland to make myself clear about how to explain.
I see it here in my garden too and when damage is little, I pick some leaves off and throw them in the dust bin..
But when it's more damage some spraying with a stronger insecticide is the only way, I'm afraid.
The ragged holes that are developing on the leaves could be due to capsid bug damage.
They do the damage when the leaves are very small, and it only becomes apparent as the leaves expand (by which time the pest has moved on).
- so you may not find any insects on the plants now, and insecticide is therefore not of help at this stage with this pest.
It's a case of spraying early (when the damage may not be apparent) but the insect can be seen if you look out for it.
Most insecticides are effective (eg bifenthrin).
Luit and Giles thank you for your advice I have sprayed the plant again and hopefully await a satisfactory outcome this time :-\. Thanks again to you both