Event Reports 2025

February 2025

A Rogue’s Gallery of Pests and Diseases

Sally Nex gave a most informative talk at the March meeting of Sampford Brett Gardening Club. Sally is a peat free advocate, grows organically and, even though pests can be extremely annoying, likes nature in all its forms!

She adopts a ‘Mind your Ps and Qs’ approach to resisting pests and diseases – P for PREVENTION and Q for QUICK ACTION.

PREVENTION

A barrier is the most important to protect brassicas etc. and she recommends ‘Environmesh’ – more expensive but it doesn’t shred and is plastic free.

Re slugs – circle plants with bran which swells when wet which makes life difficult for slugs. For plants in pots, stand the pot on feet in a large saucer full of water and, hopefully, the slugs and snails are not good swimmers!

Look for disease resistant varieties of plants and carry out good garden hygiene, especially in the greenhouse where all detritus should be removed (don’t store pots there as they make good hiding places) and use a palette knife to clean under the glass.

Bacterial canker is very infectious so ensure that your tools are regularly cleaned with disinfectant.

Aphids reproduce at a phenomenal rate so tolerate a low level which then encourages the ladybirds and thus keeps numbers down. Frogs and toads should also be encouraged as they eat slugs’ eggs.

Brightly coloured flowers and herbs confuse insects and help protect from carrot fly.

QUICK ACTION

The RHS book od Pests and Diseases is very helpful reading.

Be attentive!

Use natural sprays to guard against lupin aphid, willow aphid – just jet wash two to three times a week.

Chilli water and garlic water are also effective and good against red spider mite.

Biological controls such as nematodes are effective but expensive and only last for about six weeks.

According to a recent study, the top five pests are:

1)       Slugs and Snails – interestingly there are about 20,000 slugs in an average garden but only 86% are harmless to plants. For further prevention, slugs don’t like parsley and parsnips so spread theses among other plants. Also red plants seem to be less attacked. If you turn the soil in the autumn, you also disturb the eggs.

2)       Vine Weevil – Grubs eat the roots so take plant out of pot, wash the roots and repot. Birds love the grubs. A biological control can be used in late July.

3)       Box Tree Moth Caterpillar – avoid clipping plants to closely and use nematodes.

4)       Ants – not a real pest but if they nest in pots, tip out, clean and repot.

5)       Woolly Aphid – feed through the bark of a tree and create entry points for other infections.

The top five diseases:

1)       Honey Fungus – look in the soil for black bootlaces and under the bark for white fungal growth.

2)       Pear Rust – overwinters on juniper trees so plant pears well away.

3)       Bacterial Canker – only on stone fruit. Symptoms are clear ooze and sunken patches on the bark. Prune in the summer – the trees will heal quickly.

4)       Rose Blackspot 0 once a rose has blackspot, it will always have it and even disease resistant roses will succumb in time as the disease mutates. Rosa rugosa and other species roses are not affected.

5)       Bracket Fungus – once you see fruiting bodies on a tree, call in an expert!

One last tip re sowing seeds, don’t be tempted to sow too early as the seedlings grow towards the light making them leggy and weak when light levels are low.

Sally was a fount of knowledge and what is written here is but a snapshot of her talk!