Root-knot nematode

Microscopic soil worms that form knobbly galls on roots, so plants wilt and starve despite adequate water and feeding. Worse in sandy soils.

Plants wilt in the heat and yellow despite care; pulled roots show lumpy swellings and galls (forked, stunted carrots).

Remove and bin affected plants (do not compost roots). Solarise beds over summer and rest heavily infested soil.

Rotate crops, grow a mustard or marigold green-manure, and build organic matter to support beneficial soil life.