Answer: Since you have only one drip emitter on the tree, I suspect that it isn't receiving enough water. What is the flow rate on your emitter? The most typical is one gallon per hour. A very common problem is assuming that if a drip emitter runs for awhile, the plant has been watered sufficiently. One gallon of water, for example, would not be nearly enough to moisten a tree's root system. With a newly planted tree, make sure the water penetrates 2 feet deep. Soil should be consistently moist for about 4 weeks while the root system is establishing. After that, you can probably water deeply about once a week through summer. As the tree matures, water should be 3 feet deep. Use a pointed stick or piece of metal to push in the soil. It will move easily through moist soil and stop at dry soil. At least once a month, water deeply enough to "leach" or push salts well below the root zone. Frequent, light "sprinklings" or short time spans with drip irrigation, allow salts to accumulate in the top layers of soil, where the roots are, which is bad news. This excess salt accumulates in the leaf edges, where it kills the tissue and the leaf dries out and turns brown.
Similar symptoms occur when too much fertilizer has been applied. Research shows that it is s generally not advisable to fertilize trees for one year after planting. Plant roots often "burn." I hope this info helps.
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