Submitted to: International Society of Sugar Cane Technologists Pathology Workshop
Publication Type: Abstract Only
Publication Acceptance Date: 11/8/2005
Publication Date: 11/9/2005
Citation: Comstock, J.C. Ratoon stunt and yellow leaf effects on sugarcane yields. International Society of Sugar Cane Technologists Pathology Workshop.
Technical Abstract: Separate trials were established to determine the effects of ratoon stunt, caused by Liefsonia xyli subsp. xyli (Lxx) and yellow leaf, caused by Sugarcane Yellow Leaf Virus (SCYLV), on sugarcane yields in plant and first-ratoon crops. In 1-m long plots, responses of eight cultivars were tested for ratoon stunt, and five cultivars were tested for SCYLV. For ratoon stunt, two trials compared the yields of healthy plants to Lxx-inoculated plants and one trial compared healthy to verified Lxx-infected plants. In the yellow leaf trials healthy and SCYLV-infected plants were compared. In each of the ratoon stunt trials, combining the data of all the cultivars (CP 70-1133, CP 72-1210, CP 72-2086, CP 80-1743, CP 80-1827, CP 84-1198, CP 85-1491, and CP 89-2143) yields were significantly reduced ranging from 3.5 to 15.8 % loss of sugar per plot. Statistically significant losses were not obtained for each cultivar in the individual trials; however, the infected plots consistently had lower yields with only a rare exception. For SCYLV, plot weight and kg sugar per plot for all cultivars (CP 72-1210, CP 80-1827, CP 84-1198, CP 85-1382 and CP 89-2143) combined were higher for healthy than for SCYLV-infected. Again statistical differences were not always significant in the yields of individual cultivars although the majority of yield parameters were higher in the SCYLV-free plots. The disease incidence must be taken into consideration when extrapolating yield trial results to crop yield. In Florida, the incidence of ratoon stunt varies between zero and 100 % in commercial fields but is not usually extremely high. Since the incidence of SCYLV is usually 85 % or higher in commercial fields, total commercial losses due to yellow leaf in Florida are probably higher than ratoon stunt.