Oils activity against Melampsora epitea on willow

Willow trees cv. Iwa growing in open field conditions in the sandy soil and naturally infected with Melampsora epitea were used. Effectiveness of paraffin oil (Atpolan 80 EC) and plant oils (Olejan 85 EC, rape and sunflower) in the control of pathogen was evaluated. When first uredinia were seen on the lower leaf surface, plants were sprayed 2-times at 7-day intervals with tested compounds at concentration from 0.25 to 2%. Also Surfactant Tergitol (TM) 15-S-9 at conc. 0.3% was added to plant oil suspension. After 2 sprayings a number of uredinia per leaf and number of browned and destroyed uredinia were counted. In the first trial Atpolan 80 EC suppressed uredinia formation about 2-4-times whereas rape or sunflower oil about 1.8 to 3-times. Additionally about 11 to 30% of uredinia were dried. In the next trials effectiveness of tested oils was higher than in previous experiment. After 2-weeks of willow trees protection with Atpolan 80 EC formation of uredinia was inhibited from 7 to 17-times, whereas Olejan 85 EC suppressed their production about 4 to 14-times. Additionally about 9-62% (Atpolan 80 EC) or 10-25% (Olejan 85 EC) of uredinia were browned and dried depend on used concentration. In the third experiment after 2-week-protection of plants with Atpolan 80 EC inhibition of uredinia formation varied from 6 to 10-times. In the case of Olejan 85 EC about 2 to 10-times less uredinia were observed on protected plants than on control, untreated leaf blades. About 48-72% (Atpolan 80 EC) or 17-61% (Olejan 85 EC) of uredinia were dried.