Chrysanthemums in Aberdeen
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UK Directory of
Common
 Chrysanthemum
Ailments

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Common Pests:
-
Aphids
- Thrips
- Leafminer
- Earwigs
- Slugs 
- Whitefly
- Capsid Bug
- Caterpillars
- Red Spider Mite
- Vine Weevil
- Sciarid Fly
- Stool Miner

Common diseases: 
- White Rust
- Verticillium Wilt
- Powdery Mildew
- Crown Gall
- Chrysanthemum Rust
- Botrytis

Common disorders:
- Nitrogen 
- Phosporus
- Potassium 
- Magnesium
- Manganese
Boron
- Copper
- Iron
- High Salt levels

Suggested settings:
- Monitor
-
Printer

Webmaster:
- contact me

Date last updated: 
24 June 2008

 

Red spider mite (last updated 24 June 2008 )

Small mites (Acarina Tetranychidae) up to 1mm long. Colonies develop on leaves, stems and flowers, usually containing all stages from egg to adults. They feed by extracting sap and cell contents, producing characteristic mottling and other discolorations. 

Red spider mites traditionally are not a serious pest of chrysanthemums, however since the weather has become dryer and warmer they have become a problem in dryer areas.  Greenhouse Red Spider (Tetranychus urticae) is more of a problem because of the dry conditions under glass which they like. There is also the Carmine spider mite (Tetranychus cinnabarinus) which is also troublesome under glass.


Red spider mite
Symptoms.
They first show as fine light speckling, or pale yellow spots on the upper surface of the leaves. Examination with a hand lens will reveal colonies of mites. As the colony increases severe damage to plants occur. June to September is the worse time for severe infestations. Hibernating females of Tetranychus urticae turn red in the autumn and stop feeding.

Biology.
Female red spider mites live for about a month and lay about 100 eggs on the undersides of leaves. Eggs hatch in 3 days in hot weather and up to 30 days in cooler weather. There are 3 nymphal stages  before they become adults, during this time the nymphs feed continually, this can take 8 days to 2 months depending on temperature.  The carmine spider mite continue feeding through the winter whereas the greenhouse spider mite hibernates, only to reappear next spring.

 

Left: attack by Red Spider mite showing characteristic webbing

Controls
Misting twice a day will control the pest, however this is not always possible because of fungal attack to the plants.

Unfortunately most amateur products give very little control.

Some of the newer insecticides for the professional grower give quite good control. These include:-

Tebufenpyrad.
Abamectin.
Petroleum oils.
Fatty acids.
Spiromesifen


Other information 

 

Website designed and published by Paul Barlow with input from Ivor Mace
Copyright 2008 Paul Barlow.