Answer: Fungus gnats breed in wet soil, so the easiest control is to cover the soil surface with some coarse sand. The sand will dry out quickly after watering the plant and stop the fungus gnats from breeding. (It will take a week or two for the adults to disappear once you have broken the breeding cycle.) Another option is to use an insecticidal soap soil drench such as Gnatrol. Read and follow the label directions. Finally, take care that you are not overwatering the palm - the soil surface should not be constantly wet.
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