In a laboratory study individual female X. diversicaudatum from a Scottish population had a longevity of c 60 wk on strawberry, Fragaria X ananassa cv. Cambridge Favourite. This result was equivalent to c 5460 day degrees but the reproductive span of the nematode was only c 36 wk, equivalent to c 3276 day degrees. The estimated mean total reproductive capacity was 180 to 200 progeny, with an egg laid every 21 day degrees above a daily threshold of 50C. No periodicity occurred in the production of progeny confirming that plant root production is probably a factor limiting reproduction by the nematodes under natural conditions.