Biological control of Alternaria and late blight of potatoes

Infectious diseases, such as Alternaria and late blight, caused by the microorganisms Alternaria solani and Phytophthora infestans, often reduce potato yields and quality. Disease control involves the intensive use of chemical pesticides, which leads to pathogen resistance and various environmental challenges. Therefore, it is vital to investigate safe methods of plant protection. The purpose of the present study was to evaluate the effectiveness of various combinations of biological products against Alternaria and late blight of potatoes. The experiments were conducted at the Ukrainian Research Station of Plant Quarantine of the Institute of Plant Protection of the National Academy of Agrarian Sciences. Biofungicides based on micromycetes of the genera Gliocladium and Trichoderma and bacteria of the genera Pseudomonas and Bacillus were used for the study. The use of combinations of different products included pre-planting treatment of tubers and three sprayings of vegetative plants at different stages of their growth and development. The use of biological products on potatoes reduced the spread of Alternaria by 38.7-51.2% and reduced the intensity of the disease development by 19.1-24.2% compared to the control. The technical efficiency ranged within 70.0-88.6%. The most effective combinations for disease control were Biospectrum BT + Vitastim BT, Bactofit BT + BioHibervit BT, Bactofit BT + Vitastim BT, which provided technical efficiency of 82.0-88.6%. The studied biological products also reduced the damage to plants by the pathogen of late blight. Technical efficiency under different variants of application of the preparations ranged from 61.6% (Trichopsin BT + BioHibervit BT, Fluorescin BT + BioHibervit BT) to 84.9% (Bactofit BT + Vitastim BT). The biological products had a positive effect on plant growth, yield formation, and overall productivity. The highest yield increase was observed in the variants with the use of Bactofit BT + BioHibervit BT, Trichopsin BT + Vitastim in Biospectrum BT + Vitastim BT. The studies confirmed the potential of biological products in the management of potato diseases