Eco-Friendly Management of Penicillium Fruit Rot of Citrus

Citrus, the third most important fruit crop after mango and banana, suffers significant post-harvest losses due to Penicillium species, particularly P. digitatum. A survey (Jan-Apr 2021) in Dudia Talav market, Gujarat, identified Penicillium rot as the predominant issue, with peak incidence in mid-February. Diseased fruits were sampled, and the pathogen was identified based on cultural and microscopic traits. On potato dextrose agar, P. digitatum formed fast-growing, olive-green, velvety colonies with irregular margins and pale-yellow pigmentation beneath. Mycelium was hyaline, septate, and branched. Conidiophores were terverticillate, and conidia were smooth, green, ellipsoidal to cylindrical (6.0-12.5 × 3.5-6.0 µm). Among biocontrol agents tested, Pseudomonas fluorescens showed the highest inhibition (93.13%), followed by Trichoderma harzianum (86.18%) and T. viride (79.83%). Turmeric was the most effective plant extract, inhibiting pathogen growth at all tested concentrations (5%, 10%, 15%), followed by garlic. Edible chemicals viz., sodium bicarbonate, potassium metabisulphite, and calcium chloride completely inhibited mycelial growth at 750 ppm both in vitro and in vivo.