Hi there,
This appeared on my hedge out the front (black powder on the leaves, white bits in the creases), rubs off pretty easily & doesn't seem to be harming the plant but I'm wondering whether it's preventable. Thanks, any ideas or help on this would be great!!
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Desert rose
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- Location: Queensland, Australia
Peculiar black powdery stuff on hedge leaves
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applestar
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Those "white bits" on the stems and leaf creases are sucking insect -- I'm thinking scale though they don't look familiar ...but I see you are from Australia so you probably have different kinds than what I'm used to seeing.
When sucking insects feed, they produce/excrete sticky sugary substance called "honeydew" and the black powdery stuff you are seeing is what's called "sooty mold" that grows on the honeydew.
If your season is going into cooler temps and winter, you could probably use horticultural oil to help control/kill the scale? But I'm going to let others provide the best answer since I'm not all that familiar with how to treat such a significant scale infestation on large outdoor shrubbery.
I would use soapy (NOT DETERGENT) solution to eliminate the sooty mold -- you may need to actually wash/wipe individual leaves with soft cloth and maybe toothbrush for tight spaces -- they may not come off just by spraying and rinsing off. This will help to get the immature scale off but more mature ones are likely resistant and will need stronger measures.
When sucking insects feed, they produce/excrete sticky sugary substance called "honeydew" and the black powdery stuff you are seeing is what's called "sooty mold" that grows on the honeydew.
If your season is going into cooler temps and winter, you could probably use horticultural oil to help control/kill the scale? But I'm going to let others provide the best answer since I'm not all that familiar with how to treat such a significant scale infestation on large outdoor shrubbery.
I would use soapy (NOT DETERGENT) solution to eliminate the sooty mold -- you may need to actually wash/wipe individual leaves with soft cloth and maybe toothbrush for tight spaces -- they may not come off just by spraying and rinsing off. This will help to get the immature scale off but more mature ones are likely resistant and will need stronger measures.
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rainbowgardener
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Agree with applestar. And you do need to get rid of this stuff. The scale insects (yes those blobs that never move are insects, look them up) will multiply and the continued sucking of the juices will eventually weaken the plant, making it vulnerable to diseases.
If you just have one plant like this, a good way to get rid of the scale is to touch each one with a cotton swab soaked in rubbing alcohol, but that would get very tedious if you have a whole big hedge like this.
If you just have one plant like this, a good way to get rid of the scale is to touch each one with a cotton swab soaked in rubbing alcohol, but that would get very tedious if you have a whole big hedge like this.
