When to tolerate, when to act, and what never to spray

Tolerance is a skill you develop over seasons. A few aphids on a rose in April are not worth worrying about. By mid-May the ladybirds will have found them. A cabbage with twenty caterpillars on it in June is a different matter; pick them off or lose the plant. The question is not 'Is there a pest?' but 'Is the damage accelerating, and will it cost me the harvest?'. Minor cosmetic damage — a few notched leaves, some surface chewing — is normal and ignorable. If new growth is being destroyed faster than the plant can replace it, act.

Some battles are not worth fighting. If your broad beans are black with blackfly in late May despite pinching out the tips, pull the plants and compost them. The pods lower down are already swelling; you will still eat. If your lettuce is riddled with slugs every spring, grow it in pots on a table or switch to rocket and mizuna (less palatable to slugs). If lily beetle strips your lilies every year and you cannot face picking them off twice a week, stop growing lilies. Gardening is not about mastering every pest; it is about choosing plants and methods that suit your patience and your garden's ecology.

Never use neonicotinoids (banned for outdoor use in the UK but still in some old shed stocks). Never use insecticides containing deltamethrin, lambda-cyhalothrin or cypermethrin near water, flowering plants or anywhere bees forage. Even organic options come with limits: pyrethrum (from chrysanthemums) kills everything including ladybirds and lacewings; use it only as a last resort on isolated infestations, and only at dusk when pollinators are inactive. Insecticidal soap is gentler but still disrupts soft-bodied beneficials; spot-treat rather than drench. The least harmful option is always the one you choose first.