Root exudates impact attraction of the root lesion nematode, Pratylenchus penetrans, to non-host plants

Pratylenchus penetrans is a root lesion nematode that feeds on healthy cells within carrot taproots. Pratylenchus penetrans has a wide host range so farmers have a hard time finding proper management (Collins, 2016). Cover crops can be a way for growers to lower populations during offseason, also provides other benefits to soil fertility. Cover crops should be non-hosts to root lesion to prevent population growth of the pest. In this study, we aim to determine how nematodes respond to oilseed radish root exudates. Determining if root lesion nematodes are attracted to, unreactive, or repulsed by oilseed radish root exudates can help us understand how these crops can be used for management. Previous research from the Applied Nematology Laboratory indicates that some varieties of oilseed radishes are poor or non-hosts to root lesion nematode (Darling et al., pending). Investigating how nematodes respond to root exudates can help determine if plant-parasitic nematodes are initially attracted to nonhosts or repulsed by them. We examined four treatments, a positive control – Carrot, and three oil seed radish varieties Select, Concorde and Defender. The trial was conducted in a Petri dish, where 100 root lesion nematodes were inoculated on one side, and the root exudate was placed on the other. Six- and 24-hours post inoculation, the number of nematodes within each region was counted. Each treatment had five replicates and the trial was repeated twice.