On January 5, 2023 18 plants each of LB8-9xS13-15-16 and UFR-5 were potted in 10x10x30 cm containers with autoclaved Astatula sand:ProMix (3:1). Half of the pots of each rootstock were inoculated with 210 sting nematodes in 10 ml water and the remaining half with 10 ml of nematode suspension filtrate from which nematodes were removed by passing repeatedly through a 25µ seive. The plants were maintained in a greenhouse until July 5 when they were removed from pots, separated into tops, tap-pioneer roots, fibrous roots, dried (70o) and weighed. Sting nematodes in 250 cm3 soil from each pot were recovered by sucrose centrifugation. The trial was designed to compare the resistance (nematode reproduction) and tolerance (of nematode damage) between two UF rootstocks that performed best and worst in the mass-screening-tolerance assays reported previously. It is not possible to attribute nematode reproduction to any rootstock in the latter assay, because all lines are grown together in the same large tank. The top weights of UFR-5, and LB8-9xS13-15-16 plants were reduced by 18% and 36% (P=0.05), respectively, in the pots with nematodes compared to the non-nematode pots. Fibrous root density was reduced by nematodes by 10% and 48% (NS due to high variability in the damage) in the respective rootstocks. Two of the LB8-9xS13-15-16 plants died during the trial. The average nematode density in pots with UFR-5 was 535 (all stages) and in pots with LB8-9xS13-15-16 was 378. The trial demonstrated that while UFR-5 exhibited greater tolerance to sting nematodes compared to LB8-9xS13-15-16 in the tank-tolerance assay, the line is not resistant to nematode reproduction. UFR-5 also showed somewhat greater tolerance to the nematode in the pot study than did LB8-9xS13-15-16; however, more pronounced damage in pots compared to that in the tank (Figure 1 in accompanying MS Word document) suggests that the relative rootstock tolerance under more stringent conditions such as the field, where the nematode is not presented with a choice of rootstocks (as in the tank study), remains unresolved. Additional resistance trials with these and additional rootstocks are scheduled to run in tandem with the ongoing and remaining tolerance studies.