|One of my apricot trees has yellowish leaves, with brown tinges around the edge of leaves. Then the leaves turn crispy and fall off. Another apricot tree within 20 feet of this tree is green leaved and healthy as other apricot trees. Can you tell me why?
When leaves completely dry out, the problem is often salt burn. This is common in our area with low rainfall, alkaline soil and water high in salts. Browning usually occurs on the old leaves first. This excess salt accumulates in the leaf edges, where it kills the tissue and the leaf dries out and turns brown. It's important to water deeply, slowly and infrequently. At least once a month, water deeply enough to "leach" or push salts below the root zone. Frequent, light "sprinklings" allow salts to accumulate in the top layers of soil, where the roots are, which is bad news.
Since only one tree is showing symptoms, it seems that salt buildup from watering would be a more likely culprit. Are your trees on drip irrigation? If so, check the emitters. Make sure it's getting a deep, slow watering out past the tree's canopy, where new roots are growing. Soak it slowly now to leach out potential salts.
Similar symptoms occur when too much fertilizer has been applied. When fertilizing, moisten the soil well before and after application. Follow package directions exactly. (A little bit more is never better!) Fertilizing during the hot weather isn't a good idea because the potential for burn is increased. Good luck!