Narcissus: Alternatives to the use of formaldehyde in HWT tanks for the control of stem nematode and Fusarium basal rot

A preliminary review (BOF 61) showed that several biocides were suitable candidate replacements for formaldehyde, and the fungicide Bravo 500 also appeared to be suitable for use in HWT to control basal rot spores.  Changes to the standard HWT regime (increased temperature, increased duration of exposure) also appeared to offer some promise.  In this study, preliminary laboratory testing of a range of products was carried out.  The most effective of these were FAM 30 (which killed both stem nematodes and basal rot spores) and Bravo 500 (which killed basal rot spores only).  In growing-on tests no crop safety issues were recorded in the bulbs treated with either of these products.

The loss of formaldehyde has prompted a search for an alternative method of dealing with stem nematodes and Fusarium basal rot during HWT.  The purpose of the work described in this report was to test the candidate alternative treatments to the use of formaldehyde in HWT so that the best treatment could be adopted by the bulbs industry when it was no longer permissible to use formaldehyde in HWT.