how can I keep beetles off my lily’s
You are likely talking about the notorious Lily Leaf Beetle. This bright red pest is native to Europe and can completely devastate your lily beds if you don’t keep a close watch.
The adults emerge from the soil early spring and will lay clusters of orange eggs on the underside of lily leafs. Monitor closely during this period (early morning is best because they are sluggish in the cool weather) and bring a bucket of soapy water with you, wear your garden gloves and get picking! Look closely for the eggs and squish any that you find. It is the larvae that are the voracious feeders so don’t let those eggs hatch. Neem oil can be effective on the larvae and eggs. Many of the chemicals available may be harmful to beneficial insects, such as honey bees, and should be used with caution. The adult beetles are resistant to sprays and hand picking is ultimately the best way to go.
The Cooperative Extension at UNH has a detailed information sheet on the Lily Leaf Beetle. Visit the pdf HERE.