4 colony-forming units per mL of Monilinia fructicola, placed in a growth chamber at 138C and rated for rot at 8 and 11 d after inoculation. The response of cultivars or selections varied from year to year. In 2000, 10 of 14 cultivars had disease incidences of over 50% by day 8, whereas, in 2002, only 2 of 19 cultivars had disease incidences greater than 50%. Staccato TM , Stardust and Sweetheart were in the least susceptible category, that is, the percent rot infection was significantly less than the mean of all genotypes in 2 of the 4 yr. Santina, Skeena, and 13N-07-32 were in the least susceptible category in 1 of 4 yr. The level of resistance to brown rot was not very high. For the least susceptible cultivars such as Staccato TM , Stardust, or Sweetheart, the level of resistance was not high enough to grow the crop without fungicide applications.