Answer: Without seeing the shrub, it's difficult to identify the problem. It's possible that your shrub has an infestation of scale or mealybugs which attracted the flying insects because of the sticky, sweet exudate from the scales or mealybugs. Or, it's possible that the swarms of flying insects decided to lay eggs on the branches of your magnolia. If you can rub the sticky bumps off, go ahead and do so. If they're egg cases or scale insects, you'll be doing your magnolia a favor.
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