Fruit is either absent or poorly formed. Do not use within 7 days of harvest. They are common on land that was in sod in the previous year. The grubs feed on the roots of the strawberry plant usually killing it. Flour in warm water controls grubs as it sticks and dries on their soft bodies.
Diatomaceous earth is a contact insecticide, but is rather expensive.
Bacillus popilliae, a milky spore disease, sold under the tradenames of Doom or Japidemic will control grubs for many years. However, it takes time to build up in the soil in order to take effect.