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| Aphids |
What are Aphids?
Aphids are small pests that infest shoot tips and flower buds and suck the sap of plants.
They are generally 1.5mm long, with soft bodies.
There are hundreds of aphid types, the most common of which are greenfly on roses, and blackfly on broad beans and nasturtiums
They all do damage to plants and can also infect them with virus diseases.
Symptoms include distorted shoot and leaf growth, sticky foliage from the honeydew the aphids excrete, which encourages the growth of unsightly sooty moulds.
Both young and adult aphids feed almost continuously.
Colonies are commonly found on leaves, buds, stems, roots and flowers, some species attack a wide
range of plants, others are host specific.
How to Detect Aphids;
Whitefly (indoor) Whitefly (Outdoor) Blackfly Indoor infestation Outdoor infestation Blackfly are easy to see but the presence of other types is often first recognized by the damage they cause.
Look inside rolled up leaves for cherry aphid, under cabbage leaves for mealy aphid and in the fluffy lumps on fruit bark for woolly aphid.
If lettuce turns yellow and wilts, suspect root aphids, and if plants are sticky with honeydew, or black with sooty mould, look on the leaves above for pests.
How to Control Aphids;Prevention is the first method of control.
Healthy plants are less likely to be attacked by aphids, so, pay attention to correct feeding.
Walk around the garden daily and pick off infested leaves.
alternatively , rub off aphids between thumb and forefinger without damaging the plant.
Use insecticides as little as possible.
Avoid blanket spraying of the whole plant as this can kill beneficial insects such as the Ladybirds, Lacewings and Hoverflies that prey on aphids.
Ladybird Ladybird larvae Lacewing Lacewing larvae Hoverfly
Sticky yellow cards are an environmentally friendly way of controlling greenhouse aphids.
The colour attracts them away from plants and the adhesive acts like fly-paper.
Feed birds in bad weather and they will repay you by eating aphids in summer.
A family of blue tits can eat over 100,000 aphids a year.
Keep weeds under control. Aphids often feed and live through the winter months on common weeds.
Insecticides;
There are three types of man-made chemical insecticide for aphid control:
Contact insecticides; When applied as spray or dust kills only the aphids it touches.
The natural plant extract insecticides pyrethrum and derris, and horticultural soft soap, are examples of tried and tested contact insecticides.
Tar oil wash; Is used only on dormant, deciduous (leafless), shrubs and trees, and kills both hibernating aphids and their eggs, which are hidden in cracks in the bark. Systemic insecticides; Are taken up by the plant and kill aphids that suck the sap as well as those directly sprayed.
They can even reach aphids hidden in curled or tightly packed leaves.
Natural predators; Aphidius colemani, Aphidloletes aphidimyza, Lacewings, Ladybirds
There are no glasshouse fumigants licensed for use by the amateur gardener during the growing season
Caution!
Garden insecticides, both organic and artificial, are considered safe for plants, pets, people and the environment provided you follow the rules.
The law requires you to read and follow the instructions on the label.
Check that the insecticide used is recommended for aphids, and that it is safe for your plants before you start spraying.
Apply before damaging populations build up.
Examine plants frequently, especially during March to October.
Protect beneficial insects by spraying in the evening and treating fruit trees only before and after flowering.
Spray only where there are pests.
All-over spraying is dangerous to wildlife, causes pollution and wastes money.
Plant Treatment;
Apple; Tar oil winter wash on dormant trees, and systemic insecticide after flowering Broad bean; Pinch out growing tips to deter blackfly and / or spray with contact insecticide Cabbage; Rub off small infestations, and / or pray under leaves with contact insecticide
Cherry; Blackfly use systemic insecticide to reach aphid rolled within leaves. Lettuce; Root aphids: drench soil with contact insecticide. Lupin; Spray with contact insecticide as soon aphids are seen or destroy plant to prevent spread. Nasturtium; Rub aphids off, or pinch out infested tips, and / or spray with systemic insecticide. Rose; Soap insecticide very effective, and / or systemic insecticide on heavy attacks. Viburnum; Tar oil winter wash on deciduous types, and / or systemic insecticide in severe cases Conservatory plants; Wipe off smooth-leaved plants. Place systemic insecticide sticks into compost.
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