What are Grub Worms?:
This is an insect that you will find in the soil of your lawn or landscape year round. The only time they feed enough to kill the lawn would be starting at the end of August up until the end of December (give or take a week or two). The grass will start yellowing in an area or areas, then it will turn light brown and then die. If you catch the problem early it can save you a lot of grief, money and your whole lawn (watch my video showing how to check for grub worms and what they look like) This insect has potential to kill the entire lawn costing you hundreds and potentially thousands of dollars. You must treat with insecticide labeled for grub worms or whatever insect you may be treating for. It is important to read the label when you apply (or you can hire a professional).
How to check for Grub Worms in your lawn:
The roots of your grass are dangling down into the soil, the grub worm is down in the soil cutting across the roots and cutting the roots in half (imagine holding a shoe string and cutting it in half with scissors) that is what they are doing to the roots of your grass. The grass will pull up like picking up carpet off the ground (very easily). Early in grub worm season, when pulling up on the grass, you may see grub worms just underneath the carpet of grass. Further into the season they go deeper into the soil and you may not see them (this doesn’t mean they are not feeding on your lawn). Remember they don’t stop feeding until the end of December (give or take a week or two).
How to get rid of Grub Worms:
1) Treat as soon as possible with an insecticide labeled for grub worms (read the label or hire a professional).
2) Fertilize your lawn to get the areas that are stressed out healthy again, treat consistently.
3) Aerate the lawn to allow deeper water, nutrient and root penetration and also lateral growth from the roots, this will help areas fill back in.
4) Water properly
Don’t take out dead grass just yet, if you catch it in time after treating you may see St. Augustine start to recover in areas that have been damaged. After treating give your lawn seven to twelve days to see if it will start to recover, healthy grass will start to peek up through the damaged areas. Keeping St. Augustine healthy around stressed areas will help it repair itself during spring and summer. Fall and winter areas may take longer to repair themselves due to the soil temperatures and the temperature outside. Weeds and Bermuda grass will naturally fill in dead spots when St. Augustine dies or is stressed. It may take up until spring or summer to make a full recovery.
Grub worms, Sod Webworms, and Brown Patch Disease can all three be active at the same time of year. I have seen areas as small as a trash can lid to the size of a house fill back in with good, healthy St. Augustine grass, as long as areas were treated properly. Understanding Grub Worms, knowing when they start to feed, recognizing the signs, and taking the proper actions can save your whole lawn from dying and possibly save you hundreds or even thousands of dollars.