The effect of temperature on hatch and activity of second-stage juveniles of the root-knot nematode, Meloidogyne minor, an emerging pest in north-west Europe

Abstract

Summary -Meloidogyne minor is a serious threat to turfgrass in north-west Europe, and has a broad host range that includes other economically important plants. The species was described only recently and little is known about its biology. This study examines the effect of temperature on hatch and motility of second-stage juveniles (J2), and records hatching from egg masses collected from golf greens in different seasons. Eggs were present throughout the year and a high percentage hatch (46-88%) was recorded when they were incubated at 20 • C. When egg masses were incubated at constant temperatures, J2 hatched between 15 and 25 • C, with limited hatch (<1%) at 10 and 30 • C. The percentage hatch was lower at 15 • C (43%) than at 20-25 • C (63-76%). J2 hatched fastest at 23 • C, with an average duration to hatching of 7 days compared to 17 days at 15 • C. The range of temperatures at which J2 was active was broader than that at which they hatched. J2 were active from 4-30 • C, with greatest activity between 15 and 25 • C. The addition of grass root extract temporarily increased J2 activity at 10-20 • C, but not at lower temperatures.

Life cycle and damage of the root-knot nematode Meloidogyne minor on potato, Solanum tuberosum

“…J2 of M. minor were able to survive in water at 4°C for more than 12 weeks (Wesemael et al, 2012). Morris et al (2011) showed limited activity (movement) of J2 of M. minor at 4°C and 100% activity at 10°C. This supports our choice for 5°C as T^ for development.…”

“…Therefore, the females they observed in the tubers were probably second generation females. In east Ireland, egg masses of M. minor were detected during the whole year on creeping bentgrass (Morris et al, 2011), but the mean number of eggs per egg mass peaked in May and September. The total degree days (base 5°C) per year in east Ireland is 1631, based on monthly average soil temperatures at 10 cm depth from the period 1981-2010 (data from Casement weather station, MET éireann).…”

“…Hence, more research on this aspect is required. Morris et al (2011) demonstrated that hatching of J2 was less than 1% when egg masses were incubated for 63 days at temperatures below 10°C. The optimum temperature for hatching was determined at 20-25°C and the optimum temperature for activity was 15-25°C (Morris et al, 2011).…”

“…Morris et al (2011) demonstrated that hatching of J2 was less than 1% when egg masses were incubated for 63 days at temperatures below 10°C. The optimum temperature for hatching was determined at 20-25°C and the optimum temperature for activity was 15-25°C (Morris et al, 2011). Our experiment to determine the life cycle duration of M. minor was performed at 22.3°C which is in the optimum temperature range for activity.…”

Spatial and temporal dynamics of Meloidogyne minor on creeping bentgrass in golf greens

“…Meloidogyne minor J2 were absent from soil between November and February, despite the constant availability of egg masses from which J2 hatched when incubated at 20°C (Morris et al, 2011). A large number of hatched J2 was present in March, when average daytime temperatures at a depth of 10 cm approached 10°C.…”