TeddyGreenFingersStrawberry crown and root rot
Phytophthora cactorum · Podridão da coroa do morangueiro
What you see
A plant in full growth wilts and dies in a day or two, often with fruit still on it. Cut the crown across and instead of white tissue you find a firm reddish-brown discolouration through the middle.
Conditions
Waterlogged or compacted ground, especially after heavy rain on a flat bed. Spreads in surface water, so it runs downhill through a row.
Treatment
Remove dead plants with their crowns and surrounding soil. Nothing will cure an infected crown. Improve drainage before replanting.
Prevention
Plant on ridges or in raised beds so crowns sit above standing water. Use certified runners. Never replant strawberries into ground where they just died - move the bed.
Months: April, May, June, October, November
The thing people get wrong
The sudden collapse of a healthy fruiting plant is so abrupt that people assume a vole or a severed root. Cut the crown - the red-brown core is diagnostic and it tells you the real problem, which is drainage, not the plant. Strawberries planted on the flat in heavy ground will keep doing this every wet spring until the bed is raised.