"Star like" disease of persimmon (

Area of Science:

• Plant Pathology
• Mycology
• Horticulture

Background:

• A novel corky, star-like symptom was observed on young persimmon fruitlets along the Mediterranean coast.
• These cosmetic lesions significantly impacted fruit marketability, affecting up to 50% of the crop.
• Symptoms were consistently correlated with the presence of attached, wilting flower parts.

Purpose of the Study:

• To identify the causal agent of the observed corky star symptom on persimmon fruitlets.
• To fulfill Koch's postulates to confirm the pathogenicity of isolated fungi.
• To characterize the identified fungus using morphological and molecular methods.

Main Methods:

• Fungal isolation from symptomatic persimmon fruitlets and attached flower parts using potato dextrose agar (PDA) with tetracycline.
• Pathogenicity tests (Koch's postulates) involving inoculation of healthy persimmon fruitlets with isolated fungi.
• Morphological characterization of fungal colonies and conidia, and molecular identification using ITS, RPB2, and BT-1 gene sequencing.

Main Results:

• Two fungi, Alternaria sp. and Botrytis sp., were isolated; only Botrytis sp. caused similar symptoms upon inoculation.
• Molecular analysis confirmed the isolate as Botrytis cinerea, with high sequence identity (99.80-99.87%) to known strains.
• The identified Botrytis cinerea isolate produced characteristic gray-brown colonies and elliptical conidia, with microsclerotia formation.

Conclusions:

• Botrytis cinerea is identified as the causal agent of the "star like" corky symptom on persimmon fruitlets in Israel.
• This study provides the first report of B. cinerea causing this specific symptom on persimmons in the region.
• The findings highlight the importance of managing attached floral debris to mitigate cosmetic damage and economic losses in persimmon cultivation.