Alys Fowler

Controlling pests and disease in your garden

A healthy garden has pests and diseases, sometimes lots, sometimes just a few. Many things that are pests to us are food for something else. They are part of the ecosystem and a healthy garden can sustain them without damage.

Slugs and snails are necessary, their eggs and babies are food for many beetles, some birds and the odd hedgehog. Their slime is an important glue, helping to bind soil together and if they weren’t around to eat all the rotting organic matter we’d be drowning in it. Of course, when they nibble your prize cabbage or a whole row of lettuce, it’s hard not feel mad at them.

Acting as a predator is no bad thing and it makes sense to destroy something that is destroying something you want to eat. But I think there needs to fair rules for this game.

Employing chemicals, namely pesticides to do this, isn’t fair game. It harms far more than the ecosystem and is costly in many ways, the plastic bottles, the manufacturing, the water use and then despite all the claims, there’s always a lingering effect long after the pesticide and the pests are gone.

Slug pellets only affect about 10% of the population in your garden. Big slugs need to eat a fair few pellets for them to be affected, however they are also smart. They eat one, get a stomach ache and remember that. They have around a 30-day memory for things they don’t like, thus scattering slug pellets everywhere isn’t that useful. More importantly anything that goes on to eat the slug (and that’s you too because once they die they return to the soil which your food grows in) ends up with the pesticide residue in them.

Many pests can be kept off plants and crops with netting. Fine mesh netting such as Enviromesh is not cheap, but it lasts for years and if carefully weighed down and if necessary, you can bury the edges in the soil. It will keep butterflies, sawflies, leaf miners, flea beetles, carrot flies and pigeons off; whilst still allowing good air circulation and the rain through to the plants. It’s rather good at keeping frost off too, so once you own some you’ll find you use it all year round.

Attracting predators and beneficial insects that feast on pests and diseases (there are beetles that eat fungus for instance) makes a lot of sense too. Many beneficial insects have a predatory stage when young, such as ladybird larvae who love to eat aphids, but are vegetarian as adults. They need nectar and protein, so plants such as poached egg plants, Calendulas, Asters, Sedums, and green manures such as Phacelias and mustards will feed the adults you need to encourage into your garden.

Plenty of garden birds feed their young soft bodied insects such as caterpillars, sawfly larvae, snails and small slugs (very few things eat big slugs, because the slime is hard to digest). Attract them to your garden means feeding them all year round so that they see you as a one stop shop for dining. This means keeping your bird feeders full not just in the cold months, but in the Summer too and have a clean source of water for them to drink and bathe in.

It makes sense with common diseases, moulds, mildews, blight, leaf spots and the like, to grow plants that are known or bred to be disease resistant. It will often say on the seed pack or plant label if a particular variety has these benefits and it saves on a lot of work. Nearly all diseases do better if there is poor air circulation between plants, it just means the disease can travel rapidly from its point of origin to the whole plant. If you find you get a lot of downy mildew, either try moving the plant to a spot in the garden which is more open or cut back or take out plants around it that might be crowding it out.

Finally, pest and diseases only tend to take down unhealthy plants, if your soil is healthy, has a fine structure and plenty of organic matter, it’s amazing how many plants will grow out of a problem. The simplest solution to this is to make your own garden compost. It’s free, saves food waste going to landfill and does absolute wonders to the soil. You should try and spread well-rotted compost around your plants every Spring and Autumn. In Autumn the compost will protect the soil from the worst of the Winter weather and slowly rot in time for Spring growth. In Spring the compost will rot down into the soil much quicker because the soil is heating up, but as it does this is will suppress weeds and lock moisture, whilst also feed any plants around it, so that by Summer if you do get any problems, your plants should be good measure to handle the issues.