What's the most effective way of killing Grass grub?

The best time for treating grub worms is in late summer or early fall while the grub worms are still small and close to the surface. Grub worms are less susceptible to treatment in the spring, as they are too large and no longer feeding. For this reason, insecticides are less effective. Spring rains can also make this difficult, as applications may be washed away. When choosing insecticides for lawn grubs, it’s important to consider the various types. For fall treatment, Dylox is the most effective and fast acting available. However, two products worth consideration for use early in the season, Merit and Mach-2, can be helpful for prevention. These target the pests before they lay their eggs, killing them and any hatchlings before infestation occurs. Always read and follow instructions carefully when using these types of product

Read more at Gardening Know How: Lawn Grubs – How To Get Rid Of Grub Worms https://www.gardeningknowhow.com/plant-problems/pests/insects/get-rid-of-grub-worms.htm