The volume of flame, however, is increased by inert gas, and there is a proportionate diminution of the heating effect. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 Various. Nitrogen by itself is an inert gas, colorless and uninflammable. Scientific American Supplement No. 819 Various.
Tomato Spotted Wilt Virus. The tomato spotted wilt virus (TSWV) causes dark brown, purple or black spots on leaves. The spots can spread to the stems, causing cankers and streaks. The foliage begins to wilt once the disease spreads, and the leaves become stiff.
Overview. If your roses are displaying black spots and yellow leaves, the plants are infected with a fungal disease called black spot.Though the disease is referred to as black spot, other symptoms of the underlying problem, like yellowing of leaves, become apparent.f your roses are displaying black spots and yellow leaves, the plants are infected with a fungal disease called black spot.