Application of Environmentally Safe Inducers of Resistance in Apple Orchards
The aim of the research was to determine the efficiency of application of preparations with immunostimulating effect against scab on leaves and fruits. The research was carried out in a commercial orchard of I.V. Michurin Federal Scientific Centre in 2014-2016. The objects of the research were apple trees cv. Zhigulevskoe and Bogatyr, grafted on 54-118 stock, which have different scab resistance (weakly resistant and relatively resistant, respectively). The least development of scab under conditions of 2014 and 2015 on leaves and fruits of Zhigulevskoe was noted at the application of Immunocytophyte (8.4 % and 0.93 %, respectively); for Bogatyr variety the most efficient preparation was Emistim (3.6 % and 0.84 %). In 2016, the least development of scab was observed in trials with the use of Nartsiss. The best biological efficiency on leaves and fruits in 2014-2015 was demonstrated by Immunocytophyte: for Zhigulevskoe it was from 67.4 % to 87.6 % and for Bogatyr it was from 76.7 % to 88.6 %. Under conditions of 2016 Emistim was the most efficient (up to 69.7 % for Zhigulevskoe cultivar and up to 79.2 % Bogatyr cultivar). The similar tendency was also characteristic for the yield: for Zhigulevskoe cultivar it was higher by 1.8-7.9 kg relative to the control, for Bogatyr cultivar - it was higher by 2.4-8.1 kg. According to the index of photosynthetic activity (Fv/Fm), it was noted cultivar selectivity of responsiveness to the treatment, depending on the preparation. For Zhigulevskoe the use of Emistim was the most effective (the average vegetation value Fv/Fm was 0.72 relative units, in other variants it was not higher than 0.7 relative units); for Bogatyr cultivar Immunocytophyte application was the best (the average vegetation value Fv/Fm was 0.74 relative units, in other variants it was not higher than 0.71 relative units). There was observed a sufficiently low level of Fv/Fm variance on a single plant at the application of inducers: for Zhigulevskoe it was 0.0016-0.0029 relative units in the experimental variants and 0.0049 relative units in the control; for Bogatyr cultivar it was 0.0011-0.0023 relative units and 0.0047 relative units, respectively.