Lethal temperature-time dosages for the cotton root knot nematode (Meloidogyne incognita), stunt nematode (Tylenchorhynchus spp.) and non-plant parasitic nematodes.

摘要

Constant temperature-time dosages were applied to soil infested with cotton root knot (Meloidogyne incognita) (Mi), stunt ( Tylenchorhynchus spp.), and a mixture of non-plant parasitic nematodes (NPPN). Nematodes in soil were extracted after heat treatment (E1), and again after a six-week period from soil (E2) and roots (E3) exposed to experimental soil; and root galling (RG) was also assessed. Observed LD₁₀₀ values for Mi in RG were 5040, 1440, 60, 22, 15, and 5 min for 39, 42, 46, 50, 60, and 70°C, respectively. NPPN LD₁₀₀ values were >10080, >2880, >480, >240, >60, and >40 min, for 39, 42, 46, 50, 60 and 70°C, respectively. The observed LD₁₀₀ values for the Tylenchorhynchus spp. were >10080, >2820, 120, 30, 10, and 10 min for 39, 42, 46, 50, 60, and 70°C, respectively. Tolerance to heat was NPPN > stunt > Mi. The E2, E3, and RG ratings showed longer time requirements to achieve LD ₁₀₀ than E1.