Hot Water Tuber Treatments for Management of Meloidogyne arenaria in Caladium Cultivars

Hot water treatment was evaluated for its efficacy in controlling Meloidogyne arenaria on caladium. Caladium tubers pre-infested with M. arenaria were immersed in hot water at 50°C for 0 min, 30 min, and 45 min before being planted into 16.5-cm pots filled with sterilized sandy soil. Two caladium cultivars Florida Sweetheart PP 8526 (SWT) and Postman Joyner (PJR), each with three tuber sizes [#3 (<1.5 inch), #1 (1.5–2.5 inch), and Jumbo (>2.5 inch)], were evaluated. Ninety days after the first shoot observation, the number of nematode eggs in roots and second-stage juveniles in soil were significantly reduced, but not eliminated, in both 30 min and 45 min treatments; the 45 min treatment had better results than the 30 min treatment. The efficacy of hot water treatment was affected by caladium cultivar, but not by tuber size. The treated PJR tubers had lower nematode numbers than those of the cultivar SWT. The difference in nematode number between the two caladium cultivars might be related to the morphological characteristics of caladium tubers, as the scale-like tissue on SWT tubers might provide refuge for root-knot nematodes from heat damage. Further research needs to be conducted on determining heat-tolerant thresholds for different Meloidogyne spp. and different caladium cultivars, which will help improve nematode management strategies for caladium growers.