Symptoms
In some cultivars, the phosphorus deficiency appears as small brown dots which develop interveinally on the lower leaves.
Additionally, starting from the leaf margin, chlorotic and subsequently necrotic areas progress. The necroses may have a brown or a dull, dark olive, colour.
Reasons
Phosphorus deficiency on the leaf.
Deficiency symptoms can also be found when soil P content is sufficient, but the tomato plants are grown at too low temperatures since phosphorus uptake is inhibited under these conditions.