COMPOST
5) Dirty air is sucked into the tunnel through this dry siphon.
6) Air is blown directly out of the mycelium growth tunnels through the gaps around the doors into the clean spawning hall..
We all know the importance of good hygiene in preventing Trichoderma infections However, it is too simple to say: ‘tighten up the hygiene standards and the problem is solved’. Controlling Trichoderma was easier in the past. Even in situations with sub-optimal hygiene and less attention to hygiene, fungicides such as Carbendazim acted as a safety net, making it still relatively easy to manage any infections. However, in many countries, effective fungicides have now been banned so hygiene is the only weapon available. In addition, various effective disinfectants such as formalin have already been banned. This does not make the battle against Trichoderma any easier. Hygiene is therefore the keyword, although we should consider hygiene in a broader sense than in the past.
Trichoderma can infiltrate a site in many ways, including via spores on spawn bags, mycelium on wooden pallets (photo 4), broken spore filters, contaminated spray water, overpressure that drops during spawning, unfiltered compressor air used for humidification, undisinfected supplement, poor pasteurisation, etc. I could
discuss each of these themes at length. Once an infection has gained a foothold and hygiene practice is inadequate, the infection pressure increases rapidly. At each successive spawning cycle the problem grows and can reach serious proportions within three weeks. On the other hand, with good hygiene standards, especially during spawning, any Trichoderma infection will slowly disappear. This does not eradicate the problem of identifying the entry point of the infection, otherwise it will reoccur in the short term.
The source of internal cross-contamination can originate from many links in the chain at the composting yard. It goes without saying that the spawning hall, machinery and the empty tunnel that is filled with spawned compost must be thoroughly clean and disinfected. Some of the things I come across in my role as an external expert tasked with critically examining hygiene still amaze me. This is just a small selection of my experiences: inadequately cleaned machinery, overpressure in a hall that is not properly filtered, insufficient overpres- sure, underpressure in the space housing the fans (causing one tunnel to suck in air from another), damaged flexible connections, dry siphons (photo 5), damaged tunnel walls, central air ducts with malfunctioning valves, pulling winches used for both spawning and phase III compost, compost residues in condensation trays, air ducts and air conditioning systems, leaking tunnel doors (photo 6) and cook-out tunnels with a far too low temperature (photo 7), et cetera.
7) Insufficient air circulation during cook-out in the tun- nel means only 64.5°C is reached.
20 MUSHROOM BUSINESS
So, I hear you say: what about compost yards that spawn outdoors? I know some of those yards and it works well there too. The question you should always ask is how high the infection pressure is in the
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