Pestalotiopsis Leaf Spot of date palm ( Phoenix dactylifera L. ) in Saudi Arabia

Abstract

Symptoms of Pestalotiopsis leaf spot of date palm trees starts as tiny black spots, which gradually enlarge in size and may reach more than 5 cm. in diameter. Old lesions were somewhat white with black borders and may contain spore clusters in the center. Lesions found on leaf blade or on the rachis tissues. Culture of Pestalotiopsis palmarum ( Cooke ) steyaert isolated from leaves of date palm was maintained on Potato-Dextrose-Agar ( PDA ) at room temperature. Acervulus-like spore clusters were formed at the edges of mycelia within 10 days after inoculation on PDA. Pathogenicity test of P. palmarum on four cultivars of date palms ( 3 years old ) was carried out under greenhouse conditions ( 27 oC / day, 18 c / night ) at the college of Agriculture, King Saud University. The wounded rachis tissues of all tested date palm cultivars ( Barhee, Zagloal, Minify and Medjool ) were susceptible to the fungus.