Answer: Aucuba japonica grows best in partial to full shade. Direct sunshine can certainly burn the leaves, but Aucuba is quite susceptible to fungal diseases which will cause the tips of the leaves to turn black. From your description, I suspect that's the problem. The fungus can spread when the spores are ripe and they're splashed by rain or irrigation water to other foliage. You can prune your shrub to remove (and control) the fungus, or you can treat the plant with a registered fungicide. Be sure to read and follow the label directions.
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