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.
Blossom End Rot. A small, watery-looking spot on the blossom end of young tomato fruits may be blossom end rot. This black spot may remain small or it may enlarge to engulf as much as half the fruit. Blossom end rot does not spread from plant to plant and may not affect all tomatoes on the same plant.