A field study on the host status of different crops for Meloidogyne minor and its damage potential to potato

For several years, a new species of root-knot nematode, Meloidogyne minor, has been reported from parts of The Netherlands, Belgium, UK and Ireland. So far, this species causes most problems on golf courses but has also been reported from a potato field in Zeijerveld (The Netherlands) where it caused strong growth reduction on potato plants, but no damage to potato tubers. As The Netherlands is a potato-producing country, field experiments were set up to evaluate the potential risks this species poses. We tested the host status of some common crops for M. minor under field conditions and, more importantly, also tested its potential to harm potato production in terms of quantity as well as quality. In a 2-year field experiment (2007-2009), the host status of potato (cv. Bartina), rye, annual ryegrass, sugar beet, and maize was tested in the first growing season. Afterwards, these plots were used to evaluate the damage potential of M. minor on two commonly cultivated potato cultivars (cvs Astérix and Markies). In general, only potato seemed to be a good host for this nematode species with a Pf/Pi-ratio about 1.5. Reproduction was observed mostly on roots but also on tubers, which increases the spread of M. minor by seed potatoes. However, there was no reduction in potato production, neither in yield nor in tuber quality. No significant reproduction could be observed on the other plants (Pf/Pi values close to zero). From these results one might conclude that this nematode will not become a major threat to European agriculture. However, care has to be taken as within additional glasshouse experiments potato tubers were susceptible for damage caused by M. minor. Thus, further studies on the general biology and ecology of M. minor are needed to make a better risk assessment on this new nematode pest