Drop your guard at crops' peril

There's quite a bit of black spot, rust and mildew on roses at present, and once they have a foothold, no amount of fungicidal spraying will resolve the problem. The best you can do is contain it.

Sunday, 28th August 2016, 9:00 am
Gooseberries are ripe for picking, but don't thin out branches yet. Picture by Tom Pattinson.

Prevention is better than cure. If you must spray, start at bud burst in spring and continue regularly.

Gooseberries and grapes can be prone to mildew too. If you fail to prune the former, it becomes congested with stems and air cannot penetrate to the centre of the bush – ideal conditions for the disease. We’ve just picked a good crop ahead of wasps becoming interested. But now is not the best time to thin-out branches. Once the leaves fall, a clear picture of the framework emerges – that’s when to prune.

Never take a healthy grape vine for granted. Keep all the vents open to encourage air flow through your greenhouse and maintain a moderate temperature.

Neither can you afford to drop your guard on the pest front.

Cabbage white butterflies keep inspecting the fine mesh netting that covers our winter greens. They’re looking for a chink in the armour and any part of a leaf touching it will receive a cluster of eggs.

Two rabbits that brazenly graze on the front lawn are also nibbling at the bedding plants. Luckily, they’ve not discovered raised vegetable beds in the back garden yet.

Craftiest of all are the slugs and snails that wander freely, damaging plants under cover of darkness.

Here the control options seem endless. Do we surround plants with a barrier of gritty material or copper to give them a shock? Are pitfall traps filled with beer the answer? Or should we introduce parasitic nematodes to the soil?

Poisonous baits, such as slug pellets, are out for us because we have three species of animal friends on patrol. God bless the song thrush, and toads and frogs.