Molecular identification of date palm root rot fungal diseases and control with metal nanoparticles in Egypt

Abstract

Date palms (Phoenix dactylifera L.) are the most important crop in New Valley Governorate, Egypt, with approximately two million trees and 60,000 tons of fruit. Date palms in Egyptian conditions are infected with various diseases caused by many soilborne pathogenic fungi, resulting in significant root rot of offshoots and trees. The most virulent fungus recorded in Egypt was Fusarium oxysporum, which caused date palm root rot, followed by F. moniliforme, F. solani, Thielaviopsis paradoxa, Botryodiplodia theobromae and Rhizoctonia solani. The survey, samples collected, disease incidence and severity percent of date palm root rot diseases were conducted in five districts (Kharga, Baris, Balat, Dakhla and Farafra) each with five sites in New Valley Governorate. The highest DI and DS percentages were 42.67 and 14.27% in Dakhla District, while the latest DI and DS percentages were 19.37 and 6.62% in Farafra District. Molecular identification of sixteen pathogenic fungal isolates (including eight fungi first detected on date palms in Egypt) was performed using Internal Transcribed Spacer (ITS). The highest pathogenic fungus was Fusarium oxysporum, the last was Marasmius palmivorus. CH-NP was most effective in vitro at 100 ppm, while SiO2 was least effective. The most effective nanoparticle treatment in the greenhouse was CH-NP, while the lowest treatment was ZnO before soil infestation. Although CH-NP was the most effective treatment after soil infestation, SiO2 was the least effective treatment. To our knowledge, this study is the first report of the association of eight new fungi with date palm root diseases in Egypt.