This is such a large and complex subject that the best we can hope for is to give a brief summary of the main points. Just because we grow the plants in containers it dont mean that they wont suffer from any of the pests and diseases,when you consider that the majority of them come from countries with different climates to our own, its hardly surprising they surcome. If you catch the problem in its early stages, the remedy is usually easily delt with useing environmentally friendly measures. One way to limit the pest attacks is by companion planting(planting alongside suitable neighbours) and in the ideal situation for the plant (dont put sunlovers in the shade) or visa versa. You should only resort to the use of chemicals as a last resort. It is now recognised that chemical treatments kill as many benificial insects as they do pests. Some of the diseases you may find among your plants are listed below with the symptoms and treatments.
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mosaic disease | Leaves specled with yellow.then distorted growth disorders | No treatment available.Destroy the plant |
FUNGAL DISEASES | ||
Powdery mildew white coating on leaves,flowers,buds,&branches |
stunted growth and deformed leaves | remove affected parts. spray with field horsetailbroth. fugicides |
Rust. litlle yellow or brown postules on leaves |
leaves fall prematurely,growth weakend | remove leaves. dont use on compost heap. fungacides |
Sooty mould. sticky black sooty coating on leaves |
leaves turn yellow and drop prematurely and plant weakens | collect and destroy leaves. fungicides |
Stem/root rot. rot begines in roots tubers and rhizomes |
poor show of blooms then plant dies off. | destroy affected plants,improve soil, fundicides |
Grey mould. grey velvety coating on leaves and flowers |
plant rots and wilts, buds fail to open. | remove diceased parts, improve ventilation,reduce watering,avoid nitrogen rich feeds. |
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Aphids. green,grey,or black sucking insects |
puckered leaves,shoot tips die off,plant weakens,sooty moulds form. | extract of wormwood,pyretyrum spray,insecticides |
Leafbugs. not all are pests |
leaves have holes and deformed,flowers deformed | pick off by hand. insecticides |
Leaf miners. caterpillars of leaf mining moth |
misshapen passages eaten through leaves | remove affected leaves. |
Red spider mites. small usually red-coloured mites |
leaves drop as sap is drawn off. | put plant in shade and sprinkle with warm water, insecticides |
Whitefly, tiny mothlike insects on underside of leaves. |
damage to leaves from sap removal, sooty moulds tend to form. | hard to treat,sticky insect sheets, insecticides |
Thunderfly/thrips. small black flying insects |
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pyrethrum spray if attack is severe. |