Efficacy of hot water drenches of Anthurium andraeanum plants against the burrowing nematode Radopholus similis and plant thermotolerance

Hot-water drench treatments were evaluated for disinfesting roots of potted anthurium Anthurium andraeanum of the burrowing nematode Radopholus similis. A continuous drench of roots and media in pots with 50degreesC water for 5 to 20 min eliminated or reduced nematode populations to < 1 g(-1) of dry root. A second hot water drench, 2 months after the first drenching, tended to increase the efficacy of the heat treatment. A few survivors persisted in the roots and/or stems of a few plants 2 to 4 months after heat treatment. Non-treatment of the shoots and possible migration from stem to root tissues are probable causes of nematode survival. Drenching potting media and roots in pot were as effective against R. similis in the roots as hot water dipping bare-rooted plants. Plant response to hot-water drenching varied among cultivars, but most exhibited tolerance to the heat treatments. Visual inspection of the plants showed little difference between treated and untreated plants in the heat tolerant cultivars. However, all heat-treated 'Marian Seefurth' plants, especially hot water-dipped bare-rooted plants, appeared to suffer some degree of growth reduction as measured by lower root and stem dry weights when compared to untreated plants 3 months after treatment. Conditioning anthurium plants with hot water or hot air prior to hot water drenching did not benefit plant quality when compared to unconditioned, heat-treated plants.