ABSTRACT
Abiotic disorders are those not known to be caused by a pest or pathogen (biotic cause). Many result in symptoms very similar to those with a biotic cause. This is not surprising as there is a limit to the variety of symptoms that mushrooms can produce. In the future, it is possible that a biotic cause may be found for some although it is likely that most have none. It is helpful for a mushroom producer to be familiar with these problems in order to be able to differentiate them from the others. In general, abiotic disorders do not constitute a regular cause of crop loss but they can sometimes be very significant. They are generally erratic and unpredictable in occurrence. Many occur once only. They are extremely difficult to reproduce in experiments, even when the conditions in which they were found are simulated as accurately as possible. The disorders are described in a crop development sequence, starting with precropping, then cropping (with whole mushroom symptoms, stem and cap disorders grouped), and finally harvesting and post-harvesting.
