Globodera rostochiensis and G. pallida are the principal nematodes affecting potato in subtropical regions and are responsible for considerable yield losses; Meloidogyne spp. and Pratylenchus spp. are of local importance. The tolerance limit of potato to both cyst nematodes is 1.3-2.1 eggs/g soil and the relative minimum yield at high nematode densities ranges from 0 to 40%. Short-cycle potatoes planted in summer and harvested in the fall minimize nematode reproduction and yield loss. Long-cycle potatoes planted in the fall and harvested in spring suffer greater yield loss than short-cycle potatoes and allow a significant proportion of the nematodes to reach the cyst stage. Potato crops sown in spring and harvested in summer suffer the heaviest crop losses and allow maximum reproduction of the cyst nematode (39-65 x). Nematode population buildup is influenced by the number of generations completed per year, the length of the potato growing season, and the soil temperature. Thus, appr
