Digital Image Analysis System for Determining Tissue-Blot Immunoassay Results for Ratoon Stunting Disease of Sugarcane. J. M. Shine, Jr., Florida Sugar Cane League, Canal Point 33438. J. C. Comstock, Agricultural Research Service, U.S. Department of Agriculture, Sugarcane Field Station, Canal Point 33438. Plant Dis. 77:511-513. Accepted for publication 19 January 1993. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1993. DOI: 10.1094/PD-77-0511.

A digital image analysis system (DIAS) was evaluated for enumerating colonized vascular bundles (CVB) from membranes resulting from the tissue-blot immunoassay (TBIA) of sugarcane clones being screened for resistance to ratoon stunting disease. Fourteen sugarcane clones were inoculated, transplanted to the field, grown to maturity, and sampled in a prescribed manner for TBIA. Tissue blots were developed, and immunoassayed membranes were counted by both DIAS and the standard visual method. The correlation between mean CVB for clones determined by DIAS vs. visual counting was statistically significant (r = 0.90). DIAS is quicker than visual counting and eliminates problems related to operator bias and fatigue. The number of samples evaluated during an 8-hr period was 1,200–1,350 using DIAS vs. 450–600 using visual counting techniques.