Hi Leslie!  Good timing -- you can take action now to help address your grub situation.  Due to all of the rain & moisture we've experienced, the grub population is having a banner year.

There are different kinds of grubs and I am inferring that you are referring to one of the species that you can find in your lawn.  

Fortunately, our UVM Extension entomologist, Margaret Skinner, has written a fact sheet that provides information about managing common grubs:

https://www.uvm.edu/sites/default/files/Extension-Community-Horticulture/Resources/WhitegrubsinsoilJune2023.pdf

Though it might take you a few minutes to read this three-page summary, it helps to understand the life cycle of pests -- methods for managing them follow towards the end of the article.

Note, in particular:

• Cultural Practices to Minimize Grubs:
  • While we can't control the weather, we can set our lawn mowers higher; if you are not already doing this, it's a step you can take in the future.  A healthy height to aim for is in the 3" range.
• Monitoring:
  
  • You can still lift a square of sod for sampling -- but you are running out of time as the season cools.  Good idea to do so soon if you have not done so already
• Management:
  • I hope you will give the organic options due consideration. 
  • If you are battling Japanese Beetles and are tempted to put up Japanese Beetle traps during the height of the season:  we find that some home gardeners mistakenly place the traps near the plants they are trying to protect.  Since the pheromones in the bait trap attracts the pest....this practice may be serving as a welcome mat where you least want to invite more Japanese Beetles.  Placing the traps far away from your plants MAY help (well: they will at least give you a sampling/count....they may also attract your neighbor's Japanese Beetles....)
    • Nematodes are a great target-specific solution that won't harm people, pets and beneficial insects....but they need to be applied while the soil temperature is between 60-93 degrees Fahrenheit.  So the window here is closing.  (Note that soil temperatures stay higher than the air -- if you find live, large grubs in your soil sample and the soil temperature's over 60 degrees:  it's a good time to apply nematodes.)  Here's a link for succinct "How to Apply Nematodes" info:  https://ipm.ucanr.edu/PMG/GARDEN/CONTROLS/applicationtips.html#:~:text=Nematodes%20are%20highly%20perishable%20and,%C2%B0%20and%2093%C2%B0%20F.    Be sure to click on the "Application Tips in Turf" link if that applies to your situation.
    •  Milky Spore treatment:  all of the benefits listed above apply to Milky Spore treatment (and the ideal time to apply is spring and/or fall when the soil temp is in the 60-70 degree range and grubs are large & abundant) -- the differences are: 1) This solution targets Japanese Beetles specifically (great if this is the form of grub you wish to control) and 2) There's a running debate about whether Vermont's too cold for this solution to work effectively.  I had terrific success with Milky Spore when I bought a home in Beverly MA several decades ago that was in USDA Zone 5 (then...).  With global warming, I find that my lawn in Shelburne (down near the lake) ranges between zones 4-5 now. So depending upon where you are in Chittenden county & what your climate zone is:  you might want to consider this solution.
    • If you decide to take a pesticide approach: confer with a trusted local garden center for their recommendation(s) and be sure to read all of the directions carefully.  Weigh the risks of harming other living organisms carefully, as I trust you will.

To close with another positive thought: most of the management solutions require watering in the nematodes/milky spore bacillus/insecticide....and it doesn't seem that you'll have trouble keeping your lawn watered if trends continue.  (On the other hand: if your lawn tends to actually flood with water pools that don't drain: that's too much water for the organic, living solutions.)

I hope this helps and that your grub population is now facing a decline,

- Robilee Smith