Interactive lesson

Protection and harvest without chemicals, step by step

Interactive lesson: prevention first, the sprayer last — downy and powdery mildew of vines, copper and sulphur by the rules, protective gear, bird netting and picking at the right time.

Free sample Chapters 1 and 2 (8 steps) are free. The full lesson comes with the Protection and harvest without chemicals module. Already bought? Unlock

This lesson is general guidance, not professional training. Local regulations and expert advice always take precedence. Read our disclaimer.

The whole lesson as text

1. Prevention first

Protection without chemicals is not "doing nothing". It is a sequence of steps from the cheapest towards a product.

Resistant variety — The first step is a resistant variety and healthy planting stock, in the sun, with air movement and on free-draining soil.
Drip and mulch — Drip irrigation instead of a sprinkler: leaves and fruit stay dry. Mulch under strawberries: the fruit doesn't touch the soil, so less grey mould.
An open vine and row — Canopy work on vines, a narrow raspberry row and strawberry spacing. Leaves dry quickly, and any spray reaches the bunch.
Hygiene and helpers — Take diseased leaves, fruit and wood out of the planting. Hedges and bird and insect boxes bring in beneficial creatures.

Why: With strawberries, raspberries, currants and aronia you solve most problems through the choice of site and variety, spacing, pruning and frequent picking. A product comes only at the end, at the right time and as the label says.

Resistant varieties: PIWI vines, Invicta gooseberry, Titania and Ben blackcurrants. Less spraying or none.
Birds, ladybirds, lacewings and parasitic wasps keep aphids and caterpillars down by themselves.

2. Downy mildew of the vine

Downy mildew is the most dangerous vine disease in a wet climate — and the UK, Ireland and the eastern US are wet.

The three tens rule — Shoots 10 cm long, a daily average of at least 10 °C (50 °F) and at least 10 mm (0.4 in) of rain in 1–2 days. When all three coincide, the first infection is possible.
Copper before rain — Symptoms appear only 5–18 days later. Copper does not cure, it stops spores germinating, so protect again once 20–30 mm of rain has fallen or 7–10 days have passed since the last treatment.
Oil spots — On top, yellowish, greasy spots, translucent against the light. Underneath, in the morning after a damp night, a white downy growth.
Bunch and berries — The young bunch bends into an S shape, turns brown and dries up. Berries turn grey, then brown and shrivelled, and drop.

Why: In a rainy year it can destroy leaves and bunches within two weeks. It overwinters in fallen leaves on the ground, and in spring rain splashes it onto the leaves.

The most vulnerable period is from shoot growth to bunch closure, roughly June–August in the UK.
Advisory services in the UK and Ireland and Cooperative Extension in the US publish disease-risk warnings for vines: follow them.