Investigation of the chlorophylls and flavonoids content in apple leaves under conditions of various scab protection systems

As part of the study of the effect of fungicides on the development of apple scab in an orchard in the Solnechnogorsk district of the Moscow region, changes in the optical parameters of apple leaves depending on protection systems and varieties were studied. The effectiveness of the express method using the Dualex chlorophyll meter has been proven. This method has the same effectiveness as the traditional spectrophotometric determination of the chlorophylls a and b, but it is faster and easier. The choice of the method of working with the N-tester is justified. Leaves 5-9 of average age, located in the middle of the shoot, were selected as plant samples. They are considered to be the most optimal for assessing the state of the nitrogen status of plants. It has been experimentally proven that the treatment of plants with fungicides based on captan, dithianon, trifloxystrobin and ciprodinil has the positive effect on increasing the plant nitrogen balance index (NBI). The greatest effect of an increase in the NBI index was observed on the Mantet variety, the most susceptible to the development of scab in the conditions of the experiment.