Despite recent low temperatures favouring a slow down in botrytis development, Certis’ Morley Benson has urging strawberry growers to be vigilant as temperatures rise again.

Mr benson said, “The relatively warm winter promoted disease sporulation during January, but while the recent cold snap helped curtail its spread, inoculum has remained.” He advised growers to take measures to pre-empt the fungus Botrytis cinerea before it establishes and infects new growth to avoid an impossible control situation.

“Botrytis cinerea, or grey mould, is one of the top two diseases, along with powdery mildew, faced by protected strawberry crops, and is historically the number one disease for outdoor production,” he said. As well as vulnerability to grey mould, this year’s fruit crops are likely to suffer the effects of water scarcity as much of the UK’s strawberry growing regions are set to be affected by drought this springtime.

As a saprophyte Botrytis has the ability to survive within the structure of a young strawberry fruit as a latent infection. “First entering wounded plant tissue through access points created by dead and decaying plant petals, the fungus then develops a spore tube that ensures its survival within the plant until the fruit begins to swell and ripen,” Morley explained.

He continued, “Given conducive still and humid conditions, disease sporulation takes place and the infection is visibly expressed as fluffy grey fungal strands around the fruit. By this time nothing can be done to rectify the problem. The fruits are inedible causing significant yield loss, and in some instances, death of the entire crown.”

Morely advised, “Prompt removal of dead and decaying plant material is an effective means of cultural control,” but warned that in extreme cases it may be necessary to apply preventative fungicide. He stressed that maintaining ventilation and air flow around the plant is also important to prevent a moist, still microclimate developing and favouring the spread of the disease.

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