Effect of Interaction of Inoculum Dose, Cultivar, and Geographic Location on the Development of Foliar Symptoms of Bacterial Ring Rot of Potato

Abstract

Proportional hazards models were used to estimate hazard and survival functions for both the onset and maximum incidence of foliar symptoms of bacterial ring rot in three potato cultivars (Norchip, Norland, and Russet Burbank) grown at seven locations across the United States (Colorado, Maine, New York, North Dakota, Oregon, Washington, and Wisconsin) over the period 1988-1990. The models predicted a minimum of 50 and 82 days after planting for survival probabilities of P<0.95 and P<0.05 for symptom onset and maximum disease incidence, respectively. The time frame predicted for these events was affected by cultivar, location, and cultivar by location interaction. There was no proportional increase in the relative hazards for symptom onset and maximum disease incidence due to increased inoculum dose [...]