There are biological insecticides available to kill grubs in your lawn. But be aware that trials have shown inconsistent results: ● Parasitic nematodes are microscopic roundworms that release a bacteria that kills the grubs. Apply in the evening and water thoroughly. ● Bacillus thuringiensis galleriae (Btg) is a strain of bacteria that produces a toxin that affects adult beetles and grubs. Be careful when applying, as it may cause eye and skin irritation.