We noticed a tremendous amount of grub damage and large grub populations during fall aeration and seeding 2010. I don’t know if the flood contributed to the large population, but is was the most grub activity I have seen in 15 years! The grubs feed on the turfgrass roots leaving an area the appearance of “drought conditions”, even if you have irrigation. The turf would peel back when we tried to aerate and grubs would be near the soil surface. Mature grubs remain at the soil surface until about the first frost. They overwinter deeper in the soil and re-emerge when soil temps warm in spring. Most adult grubs will emerge as June Bugs or Japanese beetles in late spring/early summer. The best time to control grubs is during June and July using a systemic insecticide like Merit. Systemic Insecticides target the grubs that are feeding on the turf and their offspring. They work slowly (about 3-4 weeks to start), but can control grubs for up to one year. This is the first year I will recommend all my irrigated lawns take a grub control this summer. Otherwise, they will continue to multiply and damage the turf. We will leave more information and an estimate for grub control during our 2nd application visit in 2011.
****Although moles do feed on grubs, a grub application is in NO way marketed as “mole control”. Moles also feed heavily on earth worms(which are beneficial to the turf and soil) and Merit will not harm the earthworms!!! Therefore, controlling grubs will reduce a portion of the food supply for moles, but does not determine whether a mole stays or leaves your lawn. I recommend a grub application to stop the damage the grubs due to turfgrass roots and consider reducing a moles food supply as only a side benefit.
If moles are damaging your lawn, call Keith Burgess @615-496-7004. He gets the moles!!!!!!! He also can tell you by the damage if the moles are feeding on grubs and/or earthworms.