Answer: I'd start by hosing the plant off completely, especially the undersides of the leaves, to see if you can wash away the critters. Allow it to dry then assess the situation. If there are still insects present, the green worms can be controlled with a spray of bt (bacillus thuringensis) and the little black bugs may respond to insecticidal soap. (Both are botanically derived and shouldn't cause any harm to humans or to pets.) As for the fungus gnats - they live and breed in moist potting soil. You can cover the exposed soil with gravel or sand to exclude them. Be sure to read and follow the label directions - you may need to apply the bt or insecticidal soap, wait 15 minutes and then rinse it off so the foliage isn't affected. Best wishes with your schefflera.
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