Seasonal changes in the numbers and stages of Ditylenchus dipsaci (Kühn) Filipjev, in soil and host plants in Portugal

Abstract

The stem and bulb nematode Ditylenchus dipsaci (Kiihn) Filipjev is widely distributed in Portugal where it attacks several crops. Most work on this species has been concerned with the relationships between the nematode and its environment or on the influence of temperature, moisture and soil type on its distribution in soil (Seinhorst, 1956; Lewis and Mai, 1960; Wallace, 1961 and 1962; Sayre and Mountain, 1962; Webster, 1964; Miyagawa and Lear, 1970). Tseng et al. (1968) and Yeates (1972) studied seasonal fluctuation in an alfalfa field and a Danish beech forest, and Caubel (1973) fluctuations in crops of clover and onion plants. The objective of our work was to study population changes in crops grown under Portuguese conditions.