The Geometric Mean. In this video, I show how to find the geometric mean of two numbers and show what that number means in relation to the numbers that you started with.1  Education. 2  Standard YouTube License.he Geometric Mean. In this video, I show how to find the geometric mean of two numbers and show what that number means in relation to the numbers that you started with. 1  Education.
Symptoms often appear first on older leaves. If weather conditions are moist and temperatures are low, masses of gray to violet fungal spores envelop infected leaves, which become girdled, collapse, and die. The dead leaf tissue is rapidly colonized by purple blotch, which is dark in color and obscures downy mildew. Downy mildew seldom kills onion plants, but bulb growth may be reduced. Bulb tissue, especially the neck, may become spongy and the bulb may lack keeping quality.
2. mildew-a fungus that produces a superficial (usually white) growth on organic matter. powdery mildew-any of various fungi of the genus Erysiphe producing powdery conidia on the host surface. downy mildew, false mildew-any of various fungi of the family Peronosporaceae parasitic on e.g. grapes and potatoes and melons.