Aphids
This problem spreads through handling, insects or soil rather than the weather, so there is no live forecast risk — focus on prevention below.
When it strikes
About
Aphids are soft-bodied sap-sucking insects that multiply explosively in warm spring and summer weather on almost every crop, weakening plants and spreading viruses as they feed.
Symptoms
Clusters of tiny green, black or grey insects on new growth and leaf undersides; curled, distorted leaves; sticky honeydew and black sooty mould; ants tending the colonies.
Organic Treatment
Blast off with water, squash colonies, spray insecticidal soap or neem, and encourage ladybirds, lacewings and hoverflies. Avoid excess nitrogen that fuels soft growth.
Chemical Treatment
Pyrethrin or systemic insecticides for heavy infestations, used sparingly to protect beneficial insects.
Prevention
Encourage natural predators, avoid over-fertilising, inspect new growth regularly, and use reflective mulch and row cover on vulnerable crops.