Meloidogyne minor is a root-knot nematode reported in Belgium, Ireland, The Netherlands, Portugal, United Kingdom, Chile and the United States. It is found in sport fields and golf courses where it causes the yellow patch disease. However, M. minor has also been detected in potato fields in The Netherlands and the UK and may pose a threat for potato cultivation. Therefore, the life cycle and damage of M. minor on potato cv. Bintje were examined under controlled conditions. To assess its life cycle, young potato plants were inoculated with freshly hatched second-stage juveniles (J2). The developmental stages of M. minor were recorded at weekly intervals after inoculation until second generation J2 were detected. One week after inoculation, only vermiform juveniles were found in the roots. All juveniles were swollen after 3 weeks and the first adult females were observed. Egg masses were seen after 6 weeks together with second generation J2. The number of degree days for M. minor to complete its life cycle was calculated using a base temperature of 5°C (DD5); between 606 and 727 DD5 were needed to complete the life cycle. Damage development of M. minor on potato was examined in a pot experiment with different inoculation densities. Symptoms (galling on the tubers) were similar to those caused by M. chitwoodi and M. fallax. At initial population densities (Pi) of 10 J2 (100 cm3 soil)−1 and more, tubers showed galls. Severely damaged potato tubers were observed at Pi >= 50 J2 (100 cm3 soil)−1 and a damage threshold of 41 J2 (100 cm3 soil)−1 was calculated. An in vitro test showed that five, commonly grown, potato cultivars were good hosts for M. minor. Based on our results, M. minor is able to develop on potato and cause severe damage at low initial population densities. Therefore, further spread of this nematode in agricultural fields should be avoided

Summary Problems with plant-parasitic nematodes remain a major challenge in most field vegetable crops worldwide. In agricultural fields in Belgium, these problems have increased in recent years. A major problem is the quarantine root-knot nematode Meloidogyne chitwoodi. The host plant status of the most commonly grown cultivars of spinach (Spinacia oleracea) and the damage threshold for M. chitwoodi were determined in a climate-controlled glasshouse and in a naturally infested field. The yield data with the final population densities were fitted to Seinhorst’s yield and population dynamic models, respectively. The damage threshold values (T) for the relative fresh weight yield were 0.14, 1.08, 11.53 J2 (100 cm3 soil)−1, minimum yield (m) of 0.84, 0.64, 0.52 and maximum yield () of 12.51, 12.44 and 9.60 for ‘Gnu’, ‘Meerkat’ and ‘Whale’ spinach cultivars, respectively. The maximum multiplication rates (a) were 3.81, 2.38 and 2.72, whilst the maximum population densities (M) were 563, 916, and 922 J2 (100 cm3 soil)−1 for ‘Gnu’, ‘Meerkat’ and ‘Whale’, respectively. Meloidogyne chitwoodi had an impact on the spinach yield. The higher the nematode density the lower the yield and vice versa. The tested cultivars were all hosts for M. chitwoodi but differences between cultivars occurred. ‘Kolibri’ and ‘Rhino’ were tested as the least sensitive cultivars for M. chitwoodi during the host screening test and bring opportunities for resistance breeding. This is the first report of spinach as a host for M. chitwoodi.