Which symptom is a sign of nitrogen deficiency in tomato leaves?

• A. Pale Yellow Older Leaves
• B. Marginal Leaf Scorch and Curling
• C. Interveinal Chlorosis
• D. Leaf Burn from Salt Toxicity

Answer: (A)

Nitrogen moves within the plant to support new growth, so when it’s short, the plant taps nitrogen from the oldest leaves first. That makes the older leaves turn pale yellow while new growth stays comparatively greener, a telltale sign that nitrogen is lacking. In tomatoes, you’ll usually see this yellowing begin on the oldest leaves and spread as the deficiency worsens, often with slower overall growth.

The other symptoms point to different problems: marginal scorch and curling is more typical of potassium deficiency or environmental stress; interveinal chlorosis is commonly linked to iron or magnesium issues; and leaf burn from salt toxicity comes from too much fertilizer or saline conditions. So the pale yellowing of older leaves best indicates nitrogen deficiency.