An on-farm bioassay for assessing Meloidogyne hapla infestations as a decision management tool

A simple, visual soil bioassay was developed to assess Meloidogyne hapla soil infestation levels in order to facilitate the implementation of management practices on an as-needed basis. Generally, four composite soil samples were collected per target field, planted with lettuce (Lactuca sativa) seedlings and maintained in a greenhouse for this study. After 4-6 weeks, the root systems were washed free of soil and scored for root-galling severity by counting the total number of galls that developed or estimating the percentage of root system galled. Crop-specific thresholds or the presence or absence of galls are then used in part to make M. hapla management decisions. This bioassay was simplified and adapted for on-farm use by growers and has already been successfully utilized in making nematode management decisions. (c) 2007 Elsevier Ltd. All rights reserved.