Strawberry disorders and diseases
Good quality products are free from diseases and disorders! Customers will not buy strawberries with rots or with damaged skin. There are dozens of different diseases and disorders and these are not always easy to recognize. However, a good diagnosis is important. By recognizing the symptoms of a disease or disorder, it can be linked to the cause. If you know the cause, you know what measures can be taken to prevent the disease or disorder in the future.
Disease management
A range of postharvest diseases can occur in the strawberry supply chain. Both pre-harvest factors (e.g. plant spacing) and postharvest factors can contribute to less disease infestation. Care should be taken to keep diseased or wounded strawberries out of trays at harvest, as strawberry diseases could easily spread from diseased to nearby healthy fruits. Fungal rots after harvest can be controlled by fast cooling of harvested fruit and avoidance of bruising and injuries. These mechanical damages will reduce appearance, but also increase water loss (weight loss) and respiration, which can speed up firmness loss and senescence.
Frequently occurring disorders and diseases
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Handling damage. Photo by WFBR Handling damage
Careless handling can easily lead to damage, in all parts of the supply chain. Especially a good picking procedure is extremely important for the strawberry quality later in the chain. Mechanical damage or skin injuries will reduce appearance, and often lead to secondary rot development. The presence of dirt from the field can aggravate this problem with rots. -
Senescence. Photo by WFBR Senescence
Senescence is associated with loss of texture (soft tissue) and flavour. Fruit tissue can become brown. The strawberries with senescence symptoms have been stored under suboptimal conditions such as too high temperature or are simply stored too long. -
Shrivelling. Photo by Ray Bernoff/Shutterstock.com Shrivelling
If the air around the strawberries is too dry, water will evaporate from the strawberries and they can become soft and shriveled. The green calyx can dry out and lose its fresh green colour. During storage at 0 °C, it is therefore recommended to target a relative humidity of 90 to 95%. -
Botrytis. Photo by WFBR Botrytis
The major postharvest disease of strawberries is grey mould, caused by Botrytis cinerea. Infection can occur already in the field or later in the postharvest phase. It becomes visible as a grey mycelium on the strawberry surface. The diseased tissue has no distinct border and can spread over the total fruit and neighbouring fruits. The fungus growth is inhibited by lower temperatures. Further meausures are avoidance of wet fruit, and avoidance of fruit injuries and bruises. -
Rhizopus. Photo by Catherine Eckert/Shutterstock.com Rhizopus
Rhizopus soft rot is caused by the fungus Rhizopus stolonifer. Unlike Botrytis, leakage of juice can occur. This disease is usually associated with handling damage, and especially overripe fruits are susceptible. This fungus will not grow at low temperatures and therefore temperature management is the simplest method of control.