This year we’re growing three Andean tuber crops down on Plot #59: Oca, Yacon and Ulluco. It could also be the last year that we grow the third of that trio. DEFRA – the government’s Department for Environment Food & Rural Affairs – have issued a biosecurity warning, because some Ulluco tubers imported into the UK may be infected with several non-native viruses.
The situation is a serious one: the viruses could potentially infect plants of three major families: Amaranthaceae (spinach, beets, chard etc.) Cucurbitaceae (squash, pumpkin, courgette, etc.) and Solanaceae (potatoes, tomatoes, etc.) so that’s a number of our major food crops. I double-check with the head gardener where I work – Lindsay Berry, M.Hort – and she confirmed that yes, this sort of warning should be taken very seriously indeed.
Frustratingly, DEFRA haven’t updated their website with their own biosecurity alert, so I can’t point you straight to the source, but Emma at the Unconventional Gardener blog has posted details of the warning, along with a copy of the DEFRA document that was issued to tuber suppliers and sent on to me by the folks at Incredible Vegetables, from whom we bought our tubers this year.
This is the relevant section of the DEFRA document, with instructions to Ulluco growers:
- Ulluco should only be harvested for personal consumption and should not be sold or transferred to other sites (and all tubers should be removed from the soil).
- Tubers of ulluco should not be saved for planting in the following year.
- If potatoes and species of Amaranthaceae, Cucurbitaceae and Solanaceae are also grown nearby to ulluco, these should only be harvested for personal consumption and any seed/tubers should not be saved for planting in the following year.
- Any remaining waste from the vegetables, including peelings, can be disposed of in general waste bins to go to landfill and should not be composted.
- Remaining plant material (leaves and stems) of ulluco, should be destroyed following harvest, either by incineration (burning on site), via deep burial (to a minimum of 2 m) or bagged and disposed of with waste for land fill.
- Remaining plant material or potato and species of Amaranthaceae, Cucurbitaceae and Solanaceae, which you have grown, should be destroyed following harvest, either by incineration (burning on site), via deep burial (to a minimum of 2 m) or bagged and disposed of with waste for land fill.
- The planting area should be cleared of all plant material, including weeds.
- If any ulluco and potato plants regrow in the following year, they should be destroyed as for the plant material above.
- The viruses are potentially transmitted mechanically (on people, clothes, equipment etc.), so hygiene best practice should be followed:
- Wash hands with soap before and after working on a crop.
- Clean any tools and equipment which have been in contact with ulluco thoroughly to remove all plant material and soil.
Once again, rather frustratingly, there’s no information on how to spot signs of a definite viral infection, or whether the viruses are likely to persist in the soil next season, which of course would prevent growing any crops from potentially infected species. Although, as DEFRA hasn’t told us to immediately destroy all Ulluco crops and remove the soil, it would seem that the viruses in question might need a living host to persist?
In any case, because of the potential risk for mechanical transmission, I spent an unpleasant couple of hours on Sunday dragging half-decomposed vegetable matter out of our large compost bay – to which for the past few weeks I’d been adding the foliage from this year’s squash plants, which had been growing right next to the Ulluco – then bagging it up and taking it to the municipal tip.
So that’s an entire year’s worth of compostable material destroyed, because DEFRA haven’t specified the precise conditions under which the viruses can persist. Still, better safe than sorry, eh? I’d rather loose a year’s compost than risk a future year or more’s potato, tomato, squash and beet harvest.
I just hope we have a decent Ulluco crop this year, to make up for all the hassle.