Many plants, both indoors and outdoors.
Just a few of the outdoor plants affected.... Aucuba, Alder, Azelea, Bay laurel, Beech, Box, Camellia, Cedars, Ceanothus, Cotoneaster, Currants, Cypress, Cytisus, Dogwoods, Eleagnus, Elms, Euonymus, Gooseberry, Heathers, Holly, Hydrangea, Horse chestnut, Ivy, Japanese maples, Juniper, Lilac, Magnolia, Malus, Pyracantha, Rhododendron, Skimmia, Sycamore, Viburnum, Weigela, and Wisteria.
Many of the indoor plants affected by soft scale (Coccus hesperidum) seem to be those with glossy evergreen leaves such as Citrus, Grape vine, Ficus, palms and ivies. Schefflera (Umbrella Tree). Jasmine and asparagus ferns are also prone to scale.
All year round. Early summer being a time they are most noticable on outdoor plants.
Scale insects in their various forms on stem and leaves, photo / picture / image.
Appearance of damage.
Infested plants exhibit disk-like waxy bumps or scales on their stems and the underside of leaves. These scales are normally brown or grey-white, and are often found along the centre vein of leaves.
A sticky substance known honeydew may be produced by the scales and deposited on the foliage as a sticky sheen. Under damp conditions the honeydew can be taken over by a black fungus known as sooty mould, causing a really unpleasant look to the plants.
Sooty mould on a leaf caused by the honey of the scale insect, photo / picture / image.
The cause is scale insects, which depending on the species can be anywhere from 1 to 10mm long.
Female scale insects (usually brown) remain still beneath the scales or shell-like covering over their bodies, but underneath they feed on the juices of the plant. The scales slow moving to further feeding areas of the plant are rarely witnessed by the gardener as it is done so gradually.
The males are really hard to see, approx 1mm in length, resembling a tiny midge.
The females are able to reproduce without the males, either laying their eggs under the scales or in the case of Pulvinaria scale the eggs are deposited outside the scale under a mass of white cotton wool-like fibres, which is the egg sac.
The young of the scale insect known as nymphs crawl all over the plant and spread the infestation of scale.
White cotton wool-like fibres trails, which are the egg sac of the scale insect, photo / picture / image.
They suck sap from plants resulting in weak, stunted, yellow foliage, and a general lack of vigour .
Sooty mould may build up, causing a really unpleasant look to the weakened plants.
On occasion they can kill plants, if numbers are great.
Organic or cultural control.
Do not over-fertilise your plants with materials high in Nitrogen, as Scale thrive on plants with lush growth, which is full of sap.
If one house plant in a group is infested, then move it away from the other plants to a shed or garage, a quarantine to prevent transferring the pest. If one is heavily infested, consider discarding it to prevent other plants becoming infested. Don't forget to check any plants you bring into the house or garden for evidence of scale.
If just a few scales exist, they can be scraped off using your fingernail or other blunt scraping implement.
Wash the plants with soapy water (water + squirts of unscented washing-up liquid), rubbing off scales with a tooth/nail brush as you go.
A make-up pad, cotton ball or cotton bud lightly dipped in methylated spirits can be used on the scales and to generally wipe over the leaves to kill the males and young. Repeat about a week later.
If certain leaves are badly covered in scales meaning that they would end up looking pock-marked after cleaning, it would be best to prune the leave itself off. Pruning off the scale infested leaves prevents the females laying more eggs which eventually become more scale insects.
Garden centres also offer organic pest killers which can be quite effective, for example fatty acids, insecticidal soaps and horticultural oils. all of these work by suffocating the pest. These are less effective when the scale shell has formed, working best on the young, and applications must be repeated weekly to work well. However they are quite safe to use on fruit trees and bushes.
If you can't get your hands on any fatty acids, insecticidal soaps or horticultural oils, you can make try a homemade version of these sprays. Mix one part unscented washing-up liquid with five parts cooking oil in twenty parts water and apply by sprayer.
For deciduous fruit trees and bushes in the winter you can treat them with a winter wash to prevent over-wintering scale. Tar oil washes are no longer available so you will require a wash based on plant oils such as "Growing Success Winter Tree Wash".
The parasitic wasp, Metaphycus helvolus is a biological control can be employed during the summer in glasshouses. Metaphycus helvolus can be ordered through garden centres or online.
Please note: Some plants may be adversely effected by soap or methylated spirits, so test a leaf or two to see the reaction beforehand.
Because of the hard outer coating of the scale, many contact insectides will struggle to have an effect. Instead you may have to opt for a systemic insecticide which taken into the plant through it's leaves, poisoning the pest as it feeds on the plant. The majority of these insecticides are not permitted for use on edible fruit plants/trees.
BugClear Ultra or BugClear Ultra Gun, a systemic insecticide manufactured by Scotts contains acetamiprid which effective on scale.
Provado Ultimate Bug Killer (imidacloprid) also manufactured by Scotts has been found to be very effective as a systemic insecticide against scale in the UK. However it is currently without a licence for the Irish market.
Please note: Chemical insecticides should not be used in conjunction with the biological control of Metaphycus helvolus. If spraying, do so at dusk to avoid damage to pollinating insects, and to avoid the spray solution plus hot sun burning the plants leaves.
Video. A Bay laurel affected by scale insects and how these gardeners are dealing with the problem.
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DISCLAIMER: The control methods are suggested here as a matter of general information. Under Irish and EU law it is illegal to use any preparation as a pesticide/fugicide/herbicide that is not approved for such use. The author and the website accepts no responsibility for how a user may mix, use, store, or any effects the mixture or its elements may have on people, plants or the environment. The information here is for reference only and does not imply a recommendation for use. If you disregard this warning and make any of the preparations, you do so entirely at your own risk.
Jeffrey W. Lotz, Florida Department of Agriculture and Consumer Services, Bugwood.org
Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org
United States National Collection of Scale Insects Photographs Archive, USDA Agricultural Research Service, Bugwood.org
Whitney Cranshaw, Colorado State University, Bugwood.org
www.forestryimages.org _________________ Gardening books.
Joined: 17 Jun 2009 Posts: 188 Location: Kenmare, Co. Kerry
Posted: Sat Jan 23, 2010 11:33 am Post subject: Natural insecticide use herbs
Richter's herbs http://www.richters.com/Web_store/web_store.cgi?product=X4760-400&show=&prodclass=C003&cart_id=6691883.13594 has a wonderful selection of natural homeopathic remedies for ailments using herbs and also for insect control. I remember back in the old child labour days - picking the potato bugs off the spuds and drowning them in the jar of water at the end of the row like rambo. Or worse still, not spotting the green worm in the cauliflower until it was boiled already in the pot. There was always one!
Anyways, this is a rich site filled with information on germination times, ease of sowing, healing qualities, good price comparison, home remedies, may ship international.
Just look at the varieties of basil? Did you know that adding marigold to chicken food produces more yellow yolk?
Also, of note, ever notice how those hybrid seeds and gm seeds don't self seed? Well, another reason to buy good seed that is open pollinated and can be traded and bartered with friends.
Yes, that may cure those itchy fingered, night creeper plant snippers!
I've got a problem with some bay trees and was wondering if you might have any idea what it is - could it be a a result of scale insects?.
The bays were bought as pyramid shaped trees and planted spring/ early summer 2010. The bed had been dug out from the drive area which was packed rough stone/gravel. We put reasonable top soil from a pile stored on site in the bed to about 2-3 ft deep. The leaves started to get brown spots in the autumn (before any frost) and I sprayed them with a seaweed/comfrey foliar spray to try and give them a general boost.
Now the trees are practically all brown with darker spots on the leaves and some with black marks or thin black lines a couple of mm long.
looks more like a fungal infection to me calendula. like a bay tree version of rose black spot. first thing I would do is collect any fallen leaves and burn them then skim off the top inch of soil and dispose of that as well. all to prevent the carry over of fungal spores. _________________ ______________________________
thank you Blackbird. Will do that. Am planning to trim them back once I am sure the spring has sprung (radio was talking about snow on Paddy's day this morning). So I will burn all the trimmings and give them a foliar spray.
I dug up the smallest one after a night of heavy rain as someone had suggested waterlogging but there was no sign of that.
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