The importance of a leaf test was driven home when AgFirst’s Dean Rainham was called to advise on a very sick G3 block. The leaves were cupped downward, small, shoot growth stunted, very chlorotic, white at the margins.
It was the 15th Oct and flowering was about to start. A full crop load was at stake. A correct diagnosis was critical. Herbicide damage or nutritional imbalance was suspected. Leaf tests were taken; one for herbicide residual and one for a full nutrient analysis. We received the nutritional results back on the 19th Oct.
The problem was identified; an acute Manganese deficiency. The foliar product Trace-it Manganese N, which is a Manganese Nitrate formulation, was recommended and applied at 4 L/ha on the 20th Oct. Quick action was needed so Manganese Nitrate was chosen because it is highly soluble and readily absorbed by the leaf. The results were stunning. Chlorophyll returned to the leaves and they started expanding, shoots started growing and quickly a healthy green colour returned to the vines.
A follow-up leaf test was analysed on the 9th Nov, 3 weeks after application, to confirm the recovery.
Never underestimate the value of a timely leaf test. We recommend at least three leaf tests on Gold3; Nov, Dec & Feb. It’s a high value crop and needs a proactive management regime.