Following trials in the USA, HDC commissioned work to investigate chlorine dioxide, a biocide widely used in fruit and vegetable processing and to treat drinking water. It is easy to use and has no harmful environmental impacts. This was the first time it was tested in the UK as a hot-water treatment additive.
In project BOF 070, chlorine dioxide was tested at 4-5ppm in commercial hot-water treatment tanks. Several systems for monitoring concentration were compared. Treated bulb stocks ('Mando' and 'Quirinus') were planted along with other batches where recommended bulb dip treatments FAM 30 and Bravo 500 (chlorothalonil) had been the additives. BOF 070a monitored growth and development during a two-year growing cycle.
Target doses of chlorine dioxide were achieved and, of the monitoring tested, the ChloridoXense meter was most reliable. Chlorine dioxide appeared to have no adverse effects on crop performance compared with FAM 30 and Bravo 500. 'Mando' actually produced more stems, with better stem length, higher flower count and faster shoot development.
There was no significant difference between treatments in the performance of 'Quirinus'. However, until definite bulb yield data is available from a fully randomised, replicated trial, growers should continue to rely on FAM 30 and Bravo 500.
Horticultural Development Company
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