Effect of Time, Temperature, and Inoculum Density on Reproduction of Pratylenchus thornei in Carrot Disk Cultures.

Reproduction of Pratylenchus thornei on carrot disk cultures at different time periods after inoculation, temperature, and initial inoculum density was studied. At 25 C and with an initial inoculum of 25 females per disk, the final nematode population increased with increasing time after inoculation, although the populations after 25 and 50 days were not different. Nematode numbers increased by 1,255-fold and 3,619-fold at 75 and 100 days, respectively. Over 35 days incubation at 15, 20, 25, and 30 C, the nematode multiplied 1.8, 8.4, 10.5, and 0.4 times, respectively. The optimum temperature for reproduction was between 20 and 25 C, and the nematode life cycle was completed in about 25-35 days. Increasing nematode inoculum (25, 50, 100, 500, 1,000 nematodes per disk) increased the final nematode population but did not increase reproduction rate, the highest being 25.3 at an initial inoculum density of 100 nematodes per disk.