I have recently been on several farms where the level of hygiene looked good. There was great organisation, everything was neat and tidy, the concrete aprons almost sparkled and any suspect mushroom was covered in salt. In fact, if Verticillium showed its ugly head the whole bag was covered, just to be sure, to be sure. The salt wasn’t showered on, that might have sent the spores flying. Instead a wet but not dripping tissue was gently lowered onto the Verticilliumand then this was covered to some depth using coarse salt.

However, there was one weak link. The aprons were not very wide and just off the apron the hard fill was covered in spillage of spent compost and casing! In wet weather a grower might just about get away with this, but a few hot dry days and there is potential for a mini dust storm. If the grower was unlucky enough for that windy day to coincide with a casing day a ‘disaster’ could result. I was told such areas were ‘sprayed’, but even the best disinfectants are neutralised by a ‘depth’ of organic matter, such as found in a lump of casing. Soil with grass growing on it would have ‘absorbed’ the spillage better. Concrete is expensive but so is wasted potential yield if disease strikes. Perhaps a thin skin of concrete that was clearly marked as a no go area for vehicles might be a compromise?

Talking of casing, some growers may not realise that the large bags that it comes in are not made from a continuous plastic sheet. It is a woven material that allows the casing to ‘breath’. Dust can penetrate it. As a consequence, it is highly advisable to store casing away from possible contamination, ideally in a ‘cool’ dust free area.

Another point is that the waste skip is a serious potential source of contaminated dust. Even if it is empty, or just has some reject mushrooms and stalks in it, it is still highly suspect.Bags of casing should not be ‘parked’ near to it and it should be well out of the way on a casing day.