INFLUENCE OF CHILLING AND FREEZING TEMPERATURES ON INFECTIVITY OF MELOIDOGYNE-INCOGNITA AND MELOIDOGYNE-HAPLA

  • 1 January 1978
    • journal article
    • research article
    • Vol. 10  (2) , 177-180
Abstract
Egg masses and 2nd-stage larvae of M. incognita and M. hapla in soil were exposed to temperatures ranging from 20 to -8.degree. C. Temperature was lowered in 2 day intervals to 16, 12, 8, 4, 0, -4 and -8.degree. C, and the nematodes remained at 4, 0, -4 or -8.degree. C for 18, 14, 10, or 6 days, respectively. Unhatched larvae of both species were more resistant to low temperatures than were embryonic stages. Within the eggs of M. incognita, 7.5% of embryos and 48% of larval stages survived 14 days at 0.degree. C; 9% of embryos and 90% of larval stages in the eggs of M. hapla survived 10 days at -4.degree. C. Second-stage larvae of both species remained infective [to tomato, Lycopersicon esculentum] in soil at 4 or 0.degree. C, but were injured at -4 and -8.degree. C. Infectivity of these larvae was lower in saturated soil than in soil at 51 cm moisture tension at all temperatures.