First Report of Gray Mold Caused by Botrytis cinerea on Dragon Fruit (Hylocereus undatus) in Mexico

The dragon fruit is native of Mexico, and Puebla is the third-largest producing state (SIAP 2023). In June 2023, field sampling was conducted in El Paraíso, Atlixco (18° 49' 5.275" N, 98° 26' 52.353" W), Puebla, Mexico. The mean temperature and relative humidity were 20 °C and 75% for seven consecutive days. Dragon fruits cv. 'Delight' close to harvest with gray mold symptoms were found in a commercial area of 2 ha, with an incidence of 35 to 40% and an estimated severity of 75% on infected fruit. The symptoms included necrosis at the apex, which later spread throughout the fruit, along with a soft, black rot covered in abundant mycelium and sporulation. The fungus was isolated from 40 symptomatic fruits by disinfesting pieces of necrotic tissue with 3% NaClO for one minute, rinsing with sterile distilled water (SDW), plating on Petri dishes with potato dextrose agar, and incubating at 25 °C in the dark. One isolate was obtained from each diseased fruit by the hyphal-tip method. The colonies were initially white with a growth rate of 1.15-1.32 cm per day and turned gray after 10 days; the mycelium was dense and aerial. Spherical and irregular sclerotia were formed, measuring 0.9-1.4 × 0.6-1.1 mm (n = 100). Each Petri dish produced 56-278 sclerotia (n = 40) after 11 days; these were initially white and gradually turned dark brown. Brown to olive conidiophores were straight, septate, and branched, measuring 1075-1520 × 10-21 μm, with elliptical hyaline to light brown conidia of 6.6-11.5 × 5-8.1 μm (n=100). The isolates were tentatively identified as