Pilidiella

Pilidiella is a genus of ascomycetous fungi that acts as a significant plant pathogen, known for causing necrosis, fruit rot, and stem lesions. The most notable species, Pilidiella diplodiella, is widely recognized for causing white rot in grapes, which can devastate vineyards in humid, warm climates if left unmanaged.

The disease primarily targets the fruit and vegetative parts of the plant. Unlike some fungal pathogens that enter through natural openings, Pilidiella typically exploits wounds caused by hail, insect punctures, or mechanical damage from agricultural machinery. Once the pathogen gains entry, it rapidly consumes the host tissue, leading to structural breakdown.

Host crops for this fungus include grapevine (Vitis vinifera), strawberry (Fragaria ananassa), and certain ornamental shrubs. In grapes, the infection often leads to sudden fruit collapse and mummification. In strawberries, the fungus can infect the crown and petioles, resulting in wilting and sudden plant death, which is often mistaken for root rot.

Symptoms are distinct in advanced stages. Infected grape berries turn from green to a bleached, pale, or whitish color, appearing water-soaked before shriveling. Small, black, pimple-like structures called pycnidia eventually emerge on the surface of the infected tissue. These structures contain thousands of conidia, which are easily splashed by rain or wind to adjacent healthy plants.

Favorable conditions for development include high temperatures and high humidity, which are common during summer months. The pathogen survives the winter in the soil as sclerotia or within dormant pycnidia on old vine canes or fallen debris. Effective management relies heavily on minimizing inoculum sources through rigorous field sanitation and preventing mechanical wounds.

• Remove and destroy all infected plant debris to reduce overwintering spores.
• Apply protective fungicides after severe weather events or physical damage.
• Improve canopy management to ensure air circulation and reduce humidity levels.
• Monitor vineyards and fields for early signs of bleaching or tissue necrosis.