Well-sealed growing rooms are essential in order to exclude phorids and sciarids flies! Using chemical or biological control agents makes no sense at all if there are all manner of entry and exit routes still open to phorids and sciarids. If a room or tunnel is well and truly sealed, then you won’t even need any control agents. Once a pest has invaded a growing room, it stays there and cannot get out again. When harvesting is finished, you can cook out the growing room and avoid the risk of infecting other growing rooms.
Do you have a new farm? Go into a growing room and close the door behind you, but do not switch on the lights. Look at the bottom of the back door. Can you see any beams of light? If the answer is yes, then the door is not closing properly. Go to the rear of the room, right up to the door. Carefully look up and to your left and right. Can you see any signs of light around the door? Seeing light is a bad sign. Now return to the front of the growing room and do the same check with the door to the corridor. Adjust any doors that are not closing properly. Or fit new rubber seals around the doors to solve the problem.
Small gaps in the ceiling often occur at the point where cables run through the ceiling. Tug gently on these cables: if they move easily, there is too much play around the cable. Applying adhesive around the cable can do wonders. You also often see cracks where the walls and the ceiling join. The best way to seal these cracks is to use a special flexible coating.
The drains are sealed by a water trap. Air pressure can lift the lid off the drain, or the water may evaporate later on in the flush. Seal the drain with a cap, and only open it manually if necessary.
The climate unit is often overlooked, but I advise you to check the flexible hoses running between the fan and the unit. After 10 – 15 years, these hoses often start to crack or tear, which means they can intake soiled air. The installation is fitted with water drains, with a water trap. Check whether they are still working properly. When you replace air filters, run some tape around the edges to prevent any unfiltered air being drawn into the growing room.
Polyurethane foam (PUR) and adhesive
PUR is sometimes the only solution on certain farms. It is cheap, readily available and can be applied quickly. The only place it cannot be used is on the door used to enter the growing room every day. Instead, coat the edges of the door and the door post with a sticky adhesive that doesn’t dry out to trap phorids fly and sciarids fly. Do watch out for your clothes and hands each time you use the door!
Bron: Mushroom Blog – Mark den Ouden