Adatok az uborka asvanyi osszetetele, hozama es lisztharmat-ellenallosaga osszefuggesehez.
1990
Nagy Gy.Sz. | Kadar I.
In nutrient solution experiments, plants grown in a distilled water control or on 5-10 times the normal concentration of Hoagland solution gave low yields. The largest number of powdery mildew colonies was generally found in the case of a double concentration of standard Hoagland, where the plants were the tallest and had the highest yields and the greatest number of leaves. In N, P and K experiments the optimum concentrations were equivalent to 1.3-2.0 times the normal concentrations of Hoagland solution. The optimum concentrations of Ca and Mg were a tenth and a third, respectively, of those recommended in standard Hoagland solution. Judging by the mineral composition of 10-week-old cucumber plants, the optimum nutrient supplies in treatments giving the greatest shoot mass were: 2.5-3.5 N, 0.4-0.6 P, 3-5 K, 2-2.5 Ca, 0.5-0.8 Mg. Too high a concentration of standard Hoagland solution or an over-supply of N reduced both plant yields and the number of powdery mildew colonies. The better condition the host plant is in, the more susceptible it is likely to be to powdery mildew.
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