https://www.canr.msu.edu/news/how_to_choose_and_when_to_apply_grub_control_products_for_your_lawn
PREVENTIVE insecticides that will prevent grub damage next fall (2020) and following spring (2021)
These products are used to prevent future grub problems, not to control the grubs present in the lawn in the spring. They will not work on grubs found in the lawn from the middle of October through the middle of May. However, when applied in June or July they provide excellent protection against the next generation of grubs. So, if you need to apply the preventive insecticide BEFORE the grubs are there, how do you know if you need to use an insecticide or not? If you confirmed grub damage the previous fall or spring, meaning you found lots of grubs, then you may want to use a preventive insecticide for one or two years to build a more dense turf that will be tolerant of grubs. If you have treated for several years and you do not see evidence of grubs in your lawn or in the neighbor’s lawn, it may be time to stop treating. There is an erroneous philosophy being perpetuated that because we have European chafers and Japanese beetles in the area, it is necessary to treat every year or your lawn will be damaged by grubs. This is not true.
Preventive products are the most effective. Products containing imidacloprid, thiamethoxam, clothianidin or chlorantraniloprole will not control grubs in the spring.
1. Scotts Grub-Ex – Granular chlorantraniliprole 0.08%
- Apply between April 15 and May 15 for best results.
2. Bayer Advanced Season Long Grub Control and Turf Revitalizer – Granular imidacloprid 0.25% and fertilizer
- Apply between June 1 and July 15 for best results.
Make sure to irrigate the lawn with at least 0.5 inches of water* and allow the grass to dry before allowing anyone or pets into the treated area. Irrigation is essential for the chemical to be most effective.
