Impact of cover crops on population density of the root-lesion nematode Pratylenchus penetrans.

Abstract In Belgium and worldwide, agriculture has been under threat from plant-parasitic nematodes. Root-lesion nematodes (Pratylenchus spp.) cause yield loss in many vegetable, arable and horticultural crops. Increased use of cover crops can affect population build ups. This study evaluated the reproductive potential of Pratylenchus penetrans on different cultivars of cover crops both, in pot tests and field experiments. Twenty three different cultivars were evaluated against P. penetrans at low (10 P. penetrans per 100 cm³ soil) and high (100 P. penetrans per 100 cm³ soil) initial inoculum density in a pot experiment under glasshouse conditions. Based on their reproductive factor (Rf) after 8 weeks, they were classified under five different categories: Non-host, Poor host, Maintenance host, Good host, and Excellent host. At low Pi, fodder radish 'Defender' and 'Doublet' and birds foot trefoil 'Lotar' were poor hosts. At high Pi, birds foot trefoil 'Lotar' and 'Franco', fodder radish 'Doublemax', 'Maximus' and 'Contra', black oat 'Pratex', phacelia 'Natra', Italian ryegrass 'Meroa' and 'Fedra', rye 'Dukato' and 'Matador' reduced the P. penetrans population. Under field conditions, fodder radish 'Doublet', Japanese oat 'Delux', yellow mustard 'Chacha', Phacelia 'Natra', Italian ryegrass 'Fedra' and Tagetes patula reduced the root-lesion nematode population. The infectious process of P. penetrans on some of these cultivars proven to be poor host was screened using Cone tainers™. Penetration, development and multiplication of P. penetrans was assessed. The information opens possibilities for further resistance breeding. Based on our results we can conclude that with proper choice of selected cultivars of cover crops, P. penetrans can be controlled but that further breeding efforts are needed.