Amateur Gardening – 29 June 2019

20 AMATEUR GARDENING 29 JUNE 2019

with Lucy Chamberlain, AG’s fruit and veg expert

Check the health of your plot, says Lucy

Fo cu s o n...Fungal diseases

I

T’S irksome when everything in the

edible garden is looking picture-

perfect, and then, over a matter of

days, leaves become discoloured,

distorted and finally die. I think the

scientists feel our pain by giving these

pathogens derogatory names such as

blight, scab, canker and mildew – what

a motley crew! But with a bit of savvy

thinking we can outwit garden fungi,

so let me explain how.

When it comes to plant disease our

armoury of control is diverse (see my

checklist, right) and this is the secret to

success. Identify what weak point your

specific fungus has, and then strike. For

example, gooseberry breeders have

developed some excellent varieties with

strong resistance to American

gooseberry mildew – job done. Peach

leaf curl fungal spores need moisture

to germinate, so cloaking trees in

polythene or moving potted plants

under cover in late winter and spring as

leaves emerge prevents any damage

occurring. Powdery mildews affect

plants that are drought-stressed, so

laying mulches and irrigating regularly

keeps them at bay.

Combined approach

I’ve focused on three particularly

annoying diseases in the panel below,

and you’ll see that applying multiple

prevention and control methods is key.

It’s like you’re bombarding the fungi from

all sides! Cultural control methods,

fungicides, resistant varieties – with all

these options at your fingertips you can

see that, once you know your enemy,

you can maintain a healthy plot.

All photographs TI Media unless otherwise credited

Grow resistant varieties if diseases

are a problem, such as Tomato

‘Losetto’ and Potato ‘Sarpo Shona’.

Break the life cycle (use peach leaf

curl covers, for instance) and avoid

any weaknesses (keep courgettes

well watered).

If you plan to use fungicides, do so

at the earliest signs of infection by

monitoring crops for symptoms.

Rotate susceptible crops wherever

soil-borne diseases are a known

problem (onion white rot, club root).

Reduce humidity and stagnant air

by wider crop spacings, removing

surplus foliage and avoiding shade.

Remove and dispose of all signs

of infected crop debris to prevent

problem fungi overwintering on

your plot.

Lucy’s tips

Best ways to thwart fungi

How to tackle three key garden diseases

1

Late blight: Strikes tomatoes and

potatoes. Grow varieties that show

resistance or have tolerance to attack

(such as tomato ‘Crimson Crush’,

above). Grow under glass to keep

foliage dry, and cut back affected

potato foliage to prevent tuber damage.

2

Powdery mildew: Attacks many fruit

trees, grapes and cucurbits. Mulch

and irrigate to avoid drought, and prune

off affected foliage immediately.

Choose less susceptible varieties (like

gooseberry ‘Invicta’). Non-organic and

organic sprays are also available.

3

Club root: Affects brassicas

(cabbages, cauliflowers). Rotate

crops to avoid soil build-up, lime soil to

at least pH8, and add organic matter

to deter waterlogging. Grow resistant

varieties such as Brussels sprout

‘Crispus’ (above) and swede ‘Marian’.

Suttons

Lucy

Fungal diseases

Early stages of peach leaf curl (Taphrina

deformans), a fungal disease that causes

leaves to fall prematurely

Regularly check crops vulnerable

to disease, like gooseberries

Main photograph and top inset: Alamy

strong resistance to American

Keep your courgettes well

watered to maintain plant health

Gooseberry ‘Pax’ has

good resistance to

gooseberry mildew

as well as leaf spot

Don’t

forget!

DT Brown