Scale season
Scales are sap-sucking insects that come in many shapes and sizes, but they all share one characteristic – the adults build a coating that disguises and protects the pest beneath.
Generally, scales fall into two groups. Soft scales are the most easily seen, as they have a thicker coating that’s clearly obvious. Hard scales are smaller and less noticeable but can often cause more damage to the plant.
Some of the most common soft scales are white wax scale, pink wax scale and soft brown scale. Soft scales are often seen clustering along the mid-rib of the leaf. As well as sucking sap from the plant, most of these soft scales produce honeydew, a sticky substance that spreads out over the leaf. A black fungus called sooty mould (pictured) can grow on this layer. As well as looking ugly, this interferes with the plant’s ability to function.
Soft scales are easiest to control at this time of year because it’s their breeding season. The immobile mother scale lays her eggs under the protection of her scaly covering. After the babies hatch out, they head off to find a part of the plant where they can settle down and begin their sap-sucking life. They’re at their most vulnerable in this mobile stage.
Hard scales, which are flat and more difficult to control, don’t produce honeydew. Some hard scales (such as California red scale on citrus, rose scale and white louse scale) can cause accompanying dieback or discolouration on leaves or stems. They breed at any time of year, so it’s more difficult to catch them in their vulnerable juvenile stage.
Controlling scales:
- Remember, summer is the best time to treat soft scale. Use Yates Scale Gun or PestOil because both form a layer of oil that smothers the scale (especially the young ones). Choose a cool day – never use oil when weather’s hot. Scale Gun also contains pyrethrum natural insecticide, which increase its effectiveness.
- Confidor is also suitable for controlling soft scales. Spray once, then wait a few weeks and give a follow-up spray.
- In the early stages, most scales can be removed by gently scrubbing with a soapy brush.
- Ants love honeydew, so they’ll encourage scales and drive away scale predators. Hence, controlling ants will help to reduce scale numbers. One simple way to do this is to wrap a sticky band around the trunk of scale-infested plants. Do this at the end of the day and the ants won’t be able to climb up and get to the scales next morning.
- Some hard scales can be controlled with a winter application of lime sulphur.
- Sooty mould will gradually flake off once the scales have died.
Comments (11)
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brigitta
Yates site member
09:22, 06 January 2010
How do I treat scale on a maiden hair fern? I am in qld and it is hot weather. So it sound like white oil is out of the question and maiden hair ferns seem so delicate
Jennifer
Yates site member
09:22, 06 January 2010
I’ll try the sticky tape around the trunk to deter ants, thanks.
Chandra
Yates site member
09:50, 06 January 2010
I use “Malathion & White Oil” Insecticide and find it very effective on any thing which is affected with Scales,Aphids and other insects. I use it on my Vegetables,Fruit trees and Ornamentals.
Linda
Yates site member
10:06, 06 January 2010
I use the old fashioned method of soapy water before I try chemicals and it usually works.
Jackie
Yates site member
10:19, 06 January 2010
“Sticky band” would that be sticky tape around the trunk of the tree or another product or way of doing it? Would the sticky tape effect the tree or do you just leave it on for a day and replace the following day? I have a real problem with ants and their protection of the scale so if I can fix this it would be good. I also have small children so I cannot use poison near the base of the trees. If anyone can help me I would appreciate it. Thank you.
Ailene
Yates site member
14:25, 06 January 2010
Instead of sticky tape, perhaps a good dollop of vaseline would also do the trick, especially for small trees.
Beris
Yates site member
14:54, 06 January 2010
I have hard scale on my roses what can be used in the summer to control these if white oil cannot be sprayed in the heat.
Magdalena
Yates site member
11:10, 08 January 2010
On another problem where THINGS climb or slide up the stem of a plant I found a solution by accident. I had a problem with snails ruining my calla lillies. I couldn’t find the vaseline and used Vicks vaporub instead. I rubbed a 2cm wide line around the pot approximately 2cm from the top. The plant flourished and no more leaves were eaten. It worked perfectly and for a log time with one application.
Teri
Yates site member
04:15, 15 January 2010
Tanglefoot is a non-toxic sticky goo that really stops ants.We used it to stop ants stealing seeds from seed traps in experimental work. Yates should carry Tanglefoot! Available via web. Hard scales on a small ornamental easily removed by hard thumbnail, follow up with soapy water. Be very careful handling anything with malathion in it: the concentrate is dangerous and readily skin-absorbed.
Dr.Arunadevaraj
Yates site member
17:06, 09 August 2010
There is heavy infestation of white scales on my Gymnema Creeper. I sprayed vermi oil to clear it on a cool day.
Dr.Arunadevaraj
Yates site member
17:07, 09 August 2010
Thank you. Great!!
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