Effectiveness of a Hot Water Drench for the Control of Foliar Nematodes Aphelenchoides fragariae in Floriculture.

Effectiveness of a hot water drench for the control of Aphelenchoides fragariae infesting hosta (Hosta sp.) and ferns (Matteuccia pensylvanica) was studied. Drenching with hot water at 70 degrees C and 90 degrees C in October reduced (P < 0.05) A. fragariae in the soil but not in the leaves relative to the control (25 degrees C) 300 days after treatment (DAT). Plants drenched with 90 degrees C water had lower numbers of nematode-infected leaves per plant than those treated with 25 degrees C and 70 degrees C water (P < 0.05). Hot water treatments had no adverse effect on the growth parameters of hosta. Boiling water (100 degrees C) applied once a month for 3 consecutive months (April, May, June) consistently reduced the number of infected leaves and the severity of infection relative to the control 150 DAT in hosta but not in ferns (P < 0.05). Boiling water (100 degrees C) caused a 67% reduction in A. fragariae population in hosta leaves, 50% in fern fronds, and 61% to 98% in the soil over the control 150 DAT. A boiling water drench had no effect on the fern growth but caused 49% and 22% reduction in the number and size of hosta leaves, respectively, over the control in 2002. We conclude that 90 degrees C water soil drench in the autumn or early spring could prove effective in managing foliar nematodes on hosta in nurseries and landscapes.