Answer: It's hard to say what happened to your orange and grapefruit trees. If you overfertilized then I would think the lemon would have met the same fate. It could be a soil borne insect, disease or nematodes effecting the root system. Dig around the roots and see what you find. If you water them well, the trees hopefully will come back if it's just shock from overfertiliztion.
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