Thanks Har. The centers of the spots are all definitely sunken, the edge/rim around the sunken spots are slightly raised, though. A few of the spots also have a slight yellow halo. The more I look at the state of the rootstock, the more I want to get a Neelam scion off it asap.
Any recommendations on forcing it to push new growth? It's getting a monthly time-released fertilizer with micros.
Would girdling the trunk 6" or so below the top do anything?
Going back to Basics: To regulate plants normal vigor.
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1) Sunlight: Needs 6-8 hours of Sunlight
2) Watering: Frequent watering kills more mango trees than less watering. Rely more on rain water than sprinkler or other irrigation systems unless, there is a serous drought going on. For established mango trees watering isn't required.
3) Fertilizers: Try to go with 10-10-10(having primary and secondary macronutrients with micro) to boost vegetative growth, root growth and overall plant health and vigor,1-2 months apart, in a recommended dose. If you have been using 8-3-9, stop that for few months.
4) Pesticides: Use it, depending on the disease condition.
5)Soil condition: Test soil ph and correct it if it is adverse for the growth. Mangoes do like little alkaline soil.