Lettuce Anthracnose in Victoria: Use of Field Runner to Analyse Spatial Pattern of Disease

The incidence and distribution of anthracnose, caused by Microdochium panattonianum, was monitored at 3 sites at Werribee South, Victoria, in 1985, by Field Runner, a stratified random sampling programme, installed on a portable microcomputer. The incidence on Winterlake lettuce increased from 6.1% on 11 Aug. to 25.5% on 9 Sep.; the incidence on Black Velvet increased from 5.3% on 20 Aug. to 19.1% on 2 Sep. Disease severity on the majority of infected plants was light (1-30 lesions/plant). The variance/mean ratios, Lloyd's indices, K parameter of the negative binomial and Z scores measured by Field Runner confirmed that lettuce anthracnose was aggregated both within the fields and within rows and indicated epidemics commence from focal points. Field Runner was a useful tool that allowed single handed assessment and analysis of disease incidence, severity, distribution in the field and monitoring of disease epidemics. Australasian Plant Pathology 16(3) 54 - 58 Full text doi:10.1071/APP9870054 © CSIRO 1987