Spread of Fungal Powdery Mildew and Rust Diseases among Large Plants in the Denov Arboretum - a Case Study in the Surkhandarya Region of Uzbekistan

Present study reports on the spread of 142 different Micromycetes infecting 125 large plant species preserved in southern Uzbekistan. Over 22 among those belonging to 16 families and 19 genera were found to be susceptible to powdery mildew (Erysiphe spp.) caused by 21 species and 4 forms of those fungi. We have observed their distribution chiefly among the following plant families: Rosaceae-3 species, Oleaceae-2, Salicaceae-2, Fagaceae-1, Juglandaceae-2, Sapindaceae-1, Ulmaceae-1, Fabaceae-2, Convolvulaceae-1, Platanaceae-1, Polygonaceae-1, Moraceae-1, Vitaceae-1, Bignoniaceae-1 and Grossulariaceae-1. We also noticed the spread of this fungal genus to some other fruit and ornamental plants, prominently including Vitis vinifera, Quercus robur, Robinia pseudoacacia. and Platanus orientalis, found to be highly susceptible with powdery mildew. From the results of our research, 8 species of rust causing Micromycetes fungi were also detected infesting the tall plants of the Denov Arboretum, damaging 5 different types of higher plants belonging to 3 families and 4 genera in the Arboretum. Consequent to this study, we have recommended appropriate control measures, including application of the fungicide “Score 250 EC” (difenoconazole) 0.15-0.2 L/ha, for effective (77.4-89.9%) prevention of damage and subsequent spread.