CROP-ROTATION MINIMIZES LOSSES FROM CORKY ROOT IN FLORIDA LETTUCE

The severity of corky root disease (Rhizomonas suberifaciens Van Bruggen et al.) increases with continuous lettuce (Lactuca sativa L.) cropping and exerts a negative impact on the quantity and quality of the lettuce produced. Experimental data from commercial fields were used to analyze profitability outcomes resulting from various management strategies, including cultivars, locations, and field cropping history, to control corky root. Regardless of the field cropping history, net returns were not negatively affected when resistant cultivars were planted. For susceptible cultivars, even when considering land development costs, producers maximize net returns by planting lettuce following sugarcane in land not previously cropped to lettuce. After the first crop of lettuce following sugarcane, yields slowly decreased but remained profitable for three to four crop cycles.