Characterization and integration of host resistance with a weather-based fungicide scheduling program for control of anthracnose fruit rot of processing tomatoes
Abstract
The relationship between anthracnose resistance of tomato cultivars and disease incidence at various fungicide application intervals (determined by a weather-based scheduling program) was evaluated in field studies in 1992 and 1993. The resistance of tomato cultivars was indexed relative to the disease response of a standard susceptible cultivar in evaluations conducted in a disease nursery. Five different fungicide application intervals, based on action threshold values determined by the TOM-CAST program (12, 16, 20, 24, or 32 daily severity values), were tested on five tomato cultivars that represented a range of resistance currently available in commercial production. Linear regression techniques were used to determine the relationship between application interval and disease incidence of each cultivar. The slope of the regression for each cultivar was designated as a TOM-CAST Anthracnose Coefficient (TAC). TAC values for other cultivars were estimated by substituting resistance indices into an equation describing the relationship between TAC and resistance index values. Estimated TAC values were used to determine cultivar-specific fungicide application intervals. Results indicated that with the TOM-CAST program, resistant cultivars require three to four fewer fungicide applications per year than susceptible cultivars to obtain adequate control of anthracnose.
Degree
Ph.D.
Advisors
Latin, Purdue University.
Subject Area
Plant pathology
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