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.
Tomato stems and leaves. Tomato plants are also susceptible to late blight, and the foliar symptoms are similar. Like potato, infected tomato plants (Figure 12) may be rapidly infected and destroyed by P. infestans.White sporulation (sporangia and sporangiophores) (Figure 13) may be visible in humid weather.omato stems and leaves. Tomato plants are also susceptible to late blight, and the foliar symptoms are similar. Like potato, infected tomato plants (Figure 12) may be rapidly infected and destroyed by P. infestans.