ارزیابی کودهای پتاسیمی در کنترل بیماری آتشک در شرایط آزمایشگاهی

Fire blight disease of pome fruit trees is one of the main factors limiting the construction and cultivation of pear and quince orchards in Iran. Copper compounds, as the only effective substances against this disease, have a contact effect. If they are not used at the right time, they will be ineffective due to the penetration of bacteria into the inner parts of the plant tissue. Therefore, in order to control this disease effectively, it is necessary to examine other compounds. For this purpose, potassium compounds, including Potassium phosphate, Potassium silicate, and Solupotasse, were mixed with irrigation water and used for the base of pyrodwarf pear. Concentrations of 20 ml/L of Potassium phosphate, 200 ml/L of Potassium silicate and 38 g/L of Solupotasse were used according to the manufacturer's instructions. The desired concentrations were mixed with irrigation water every five days in a volume of 100 mL and four weeks before bacterial inoculation and were provided to the seedlings of pyrodwarf rootstock. The isolate of Erwinia amylovora D43 available in the microbial collection of the Agricultural and Natural Resources Research Center of Semnan Province (Shahrood) was used. Bacterial inoculation was done by injection into the tissue at the end of the main stem (50 microliters with a concentration of 108 CFU/mL). The results of the use of the three potassium fertilizers showed no adverse symptoms or disorders, such as burns or color changes, at the concentrations used on pear seedlings. All the potassium compounds used reduced the incidence of disease compared to the control treatment. The highest reduction in the incidence of disease was obtained for Potassium phosphate treatment with a rate of 40.6%. After that, Potassium silicate with 31.2% and Solupotasse with 27.9% disease reduction were ranked next. Therefore, the use of potassium compounds, in addition to reducing the consumption of poisons and preventing the resistance of bacterial pathogens, will reduce spraying costs.