|Molybdenum deficiency in a young cauliflower|
The main symptoms of molybdenum deficiency are stunting and failure of leaves to develop a healthy dark green colour. The leaves of affected plants show a pale green or yellowish green colour between the veins and along the edges. In advanced stages, the leaf tissue at the margins of the leaves dies. The older leaves are the more severely affected. In cauliflowers, the yellowing of the tissue on the outer leaves is followed by the death of the edges of the small heart leaves. When these develop, the absence of leaf tissue on their edges results in the formation of narrow, distorted leaves to which the name whiptail has been applied. Affected leaves are usually slightly thickened and the leaf edges tend to curl upwards, especially in tomatoes.
For small greenhouse or family garden, apply molybdenum fertilizer at 4g (0.14oz) per each 11kg (25lbs) of mixed fertilizers.
Phosphorus and sulphur are often deficient under the same conditions that bring about molybdenum deficiency, so increasing the supply of molybdenum through fertilizers wiil produce only negative crop response until the phosphorus or sulphate fertility levels are increased adequately.