Potential use of arugula (Eruca sativa L.) as a trap crop for Meloidogyne hapla

In the absence of resistant cultivars, the impending loss of methyl bromide (MBr) and few sustainable alternatives available, managing the northern root-knot nematode, Meloidogyne hapla, is a challenge in temperate vegetable and nursery production systems. Many brassica plants, including arugula, Eruca sativa, possess biofumigant and trap crop qualities, and thus have been gaining popularity as potential alternatives to MBr. As part of a project to develop alternatives to MBr, this study was conducted to determine the effects of arugula cv. Nemat on three glasshouse populations of M. hapla from Rhode Island (RI), New York, Geneva (NYG) and Michigan (MI). In two glasshouse experiments conducted at 20 +/- 2 degrees C and 28 +/- 2 degrees C, arugula and Rutgers tomato (standard susceptible) seedlings were inoculated with either 0 (control) or 3000 eggs of 67-85% undifferentiated stages of the three populations. Experiment I was terminated at 20 days and Experiment 2 at 28 days after nematode inoculation. At 20 degrees C, 200 and 280 degree-days (DD, base 10 degrees C) were accumulated, while 360 and 504 DD were accumulated at 28 degrees C in the respective experiments. Total numbers of nematodes recovered from roots varied by host and by nematode population over the course of the study, but the numbers of females in roots did not vary significantly. This suggests variability in reaching the adult female stage. Egg and egg mass production was normal in all nematode-infected tomatoes, but no eggs were produced in more than 80% of arugula plants, and less than 17% of the arugula samples had fewer than five loose eggs and no egg masses. The results show that arugula interferes with development and reproduction of populations of M. hapla and thus has potential as a trap crop to control M. hapla.