Pests & Diseases

I suppose it’s inevitable you are going to get the odd pest and disease in your garden but on my evening garden walk of deadheading and watering I’ve identified rather a few.

You can go the chemical control route but I generally try to let nature take its course or if things are really getting out of hand I try to organically control them, here are a few on this weeks hit list:

Black bean aphid (Black fly) – Symptoms: dense colonies of black insects, 2mm long, living on the shoot tips and undersides of the leaves of broad beans; globe artichokes; nasturtiums; dahlias and poppies.

The aphids are managed by ants that farm them and milk the sticky honeydew that they produce.

Control: inspect plants regularly and remove by hand as soon as they appear. Pinch out infected tips or spray with a strong jet of water to keep numbers down.

Powdery mildew – Symptoms: white, powdery patches of fungus on the surface of leaves of apple; blackcurrant; gooseberry; grapes; courgettes; marrows; cucumbers & peas. Control: watering and mulching makes the plants less prone to infection.

Take out infected shoots as soon as you can. In autumn, destroy infected leaves as they fall to reduce the amount of infectious spores in spring.

Rust – Symptoms: a fungal disease brought on by wet summers causing yellow or orange spots on leaf surface and reddish brown pustules on the underside. Leaves can fall prematurely.

Plants commonly affected are antirrhinum, bluebell, box, chrysanthemum, fuchsia & hollyhock.

Control: pick off and dispose of infected leaves not on the compost heap, avoid excess use of nitrogen fertiliser as this encourages leafy growth which rust loves. Look for rust resistant cultivars.

Black spot – Symptoms: another fungal disease mostly affecting roses reducing plant vigour with enlarging black spots on the upper leaf surface. Control: collect and destroy fallen leaves in autumn.

Prune out all affected stems in spring before leaves appear. Choose disease resistant cultivars.

Now excuse me I’m off to squish a few aphids...

My Plant of the Week

This has to be Knautia macedonica, looking so pretty in my garden at the moment.

This no fuss clump-forming herbaceous perennial has a succession of scabious-like flower heads from mid-summer. It seems to thrive in my very dry, exposed gravel garden liking the south facing aspect on well-drained soil growing up to a height of 75cm.