Results and Discussion
Soil samples from the top 10 cm were collected from six randomly selected points on each bed, just before transplanting from the nursery, and combined into one composite sample per bed for the initial count of FC and helminth egg populations in duplicates. Samples were also taken from nearby plots with no previous history of vegetable production to serve as controls. Six lettuce heads were aseptically collected from each bed four weeks after transplanting, after which they were randomly combined into three composite samples containing two lettuce heads. The samples were kept in a refrigerator at 48C and analysed within 24 hours for FC and helminth eggs using standard methods.