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

Abstract

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 ºC and 90 ºC in October reduced (P 0.05) A. fragariae in the soil but not in the leaves relative to the control (25 ºC) 300 days after treatment (DAT). Plants drenched with 90 ºC water had lower numbers of nematode-infected leaves per plant than those treated with 25 ºC and 70 ºC water (P 0.05). Hot water treatments had no adverse effect on the growth parameters of hosta. Boiling water (100 ºC) 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 ºC) 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 ºC water soil drench in the autumn or early spring could prove effective in managing foliar nematodes on hosta in nurseries and landscapes.