South Milford & Lumby

North Yorkshire

Garden Hints for August 2009

I wouldn’t say that pests and diseases are a speciality of mine but it’s certainly an interesting subject. There are thousands of pathogens out there ganging up against us gardeners; from pigeons and mice to fluffy fungi and vicious viruses.

A night class group looking at 30 or 40 crop threatening organisms raised the question recently, asking how far to go to protect vegetables fruit and flowers? Lily beetle, spectacular in appearance does little damage and can be removed by hand picking. Capsid bug’s knawing at my broad beans. Disfiguring? Yes, but not over damaging. Sucking the sap has done little harm. As the leaves develop and expand they tear and develop holes.

On the other hand cabbage white butterfly larvae and gooseberry sawfly stripping a plant in 2 or 3 days demand immediate attention. A pesticide spray is useful here with larvae of all sizes smothering the plant. The trouble with spraying is you also kill beneficial insects. Take care!

Ladybirds, hoverflies, centipedes, parasitic wasps, lacewings, ground beetles, tiger or shield beetles, devil’s coach horses, frogs, hedgehogs and toads, even spiders; all help in the garden. Yes, a lot of beneficial insects and organisms reduce plant parasites. Some you can encourage simply by having your own pond, however small, for dragonflies, damselflies, frogs and toads. Encourage birds into the garden as thrushes and blackbirds really enjoy slugs and snails.

The environment or microclimate in the garden may cause problems. Shelter and shade is a real bind. I have a Leyland cypress by my vegetable plot; a huge obstruction. With competition from its roots, it encourages thin, rank growth and reduces fruit and vegetable production. Shade promotes red thread disease in turf, mildew on gooseberries and currants plus canker on fruit trees and ornamentals like roses. Good air circulation can prevent chocolate spot on broad beans planted wider apart.

Early sown carrots subject to carrot fly may be covered with fleece, you might erect low netting or plant french marigolds to attract pest predators.

Hygiene is critical, because many pests and diseases live on plant remains, completing their lifecycles; hence a good winter clean-up. Putting down organic matter as mulch retains moisture, improves soil structure and adds soil nitrogen, growing stronger plants; building pest and disease resistance.

A little more adventurous? Try chemical free control. Yes, that could mean a walk in the dark with the torch, hand picking slimy enemies! Funny the noises you hear when night comes; even the rasp of a slug as it eats away at a row of prize cabbage. Beer traps carefully placed for wasps, slugs and snails and pheromone traps have a sticky sexual attractant into which codling moth, plum moth and carnation tortrix fly. Sticky bands and traps applied in the autumn catch wingless female winter moths, ants, earwigs and adult vine weevils as they climb up the tree. Leonard the bowler in Monk Fryston has a wild card up his sleeve for leather jackets and cockchafer grubs. He discovered that eelworm watered on his lawn had remarkable results!

Yorkshire Landscape Gardens

dave@daviddmitchell.co.uk