Continuously wet conditions will allow this rot to progress and cause fruit drop. Life Cycle Sclerotia are special structures formed by this fungus within cavities of infected blossoms and on the surface of infected fruit. Sclerotinia allow the fungus to survive in the soil through the winter months. Dry conditions at the soil surface will delay apothecia emergence. Apothecia can survive for several days or weeks depending on the prevailing environmental conditions, and can be revived with rainfall, after being dry and shrivelled.
Ascospores are the primary inoculum for all Sclerotinia infections and disease.
The process of spore release from apothecia is called 'puffing' . This active ejection of ascospores enables them to travel the short distance from the orchard floor into turbulent air. Little is known about the daily or seasonal fluctuations in ascospore numbers or their dispersal and survival in kiwifruit orchards. Several years ago, data were obtained from a spore trap operating in a Te Puna orchard for the purpose of Botrytis research . This data indicates that spores were present on most days from late November to early May, although there was considerable fluctuation from day to day.