The relationship between feeding and fecundity of females of heterodera avenae

A continuing supply of food was found to be necessary for maximum egg production by Hetero-dera avenae. In glasshouse experiments a minimum of 28 days on the host was necessary before egg production; females allowed to feed longer produced more eggs and formed larger cysts than starved females. On intact root systems of defoliated plants some egg production was possible; young females on detached root pieces or freed from roots had sufficient food reserves for limited egg production. Changes in host physiology associated with anthesis did not affect fecundity, and there were no differences in egg contents of females from a very early maturing host and from one which remained vegetative throughout the nematode life cycle.