Effect of seedling age on the susceptibility and early growth of Meloidogyne incognita infested okra seedlings

Abstract

Screen house studies were conducted to test the effect of various seedling ages on the susceptibility and early growth of Meloidogyne incognita (Kofoid and White, 1919) Chitwood, 1949 infested okra Abelmoschus esculentus (L) Moench seedlings. Pure culture of M. incognita infected Celosia argentea L. cv. TLV-13 plant and thereafter subcultured on celosia plants in sterilized sandy-loam topsoil. Zero (0) (i.e. at sowing), 1 (i.e. at emergence), 8,15,22 and 29 day-old okra seedlings were infested with 20,000 M. incognita eggs extracted from the infected celosia plants roots by the sodium hypochlorite (Naocl) method of Hussey and Barker (1973). Six replicates of the treatment were made in a completely randomized experimental design. Heights of 1, 8 and 15 day-old infested seedlings were not significant but statistically lower than the heights of 0, 22 and 29 day-old seedlings after four (4) weeks of growth. Severity of infection was significantly pronounced in 1, 8 and 15 day-old infested seedlings with corresponding higher root/shoot weight values. 29 day-old infested seedlings displayed the highest level of resistance to the nematodes with significantly higher biomass.
Key word: Seedlings age, Meloidogyne incognita, early growth, okra.