Relationships between initial population densities of Meloidogyne ethiopica and growth of vinifera grape in pots
AbstractThe effect of initial population densities of a Chilean population of Meloidogyne ethiopica on the growth of vinifera grape, Vitis vinifera, cv. Merlot Noir, was investigated in a glasshouse experiment using 350 cm3 clay pots containing pasteurized sandy soil. Each pot was artificially inoculated with 0, 0.125, 0.25, 0.5, 1, 2, 4, 8, 16, 32, 64, 128, 256 or 512 eggs and second stage juveniles/cm3 soil (Pi) and planted with one grape seedling. The plants were arranged on a bench in a glasshouse at 26 ± 3 °C for 45 days, with six-fold replication of each Pi. Plant response to Pi fitted the Seinhorst model, y = m + (1 – m)zP-T. Tolerance limits to the nematode were 1.3, 0.6 and 0.45 eggs and second stage juveniles/cm3 soil for height, top weight and root weight of the plants, respectively. Minimum relative yields were 0.2, 0.06 and 0 at Pi ≥ 64 eggs and second stage juveniles/cm3 soil for height, fresh top and root weight of the grape seedlings, respectively. Final population densities and reproduction rates of M. ethiopica were larger at initial population densities of 8-16 eggs/cm3 soil and less at larger Pi. The highest nematode reproduction rate, 34.4-fold, occurred at Pi of 0.25 egg/cm3 soil. Root gall index increased with the increase of Pi.