Grubs, Grubs, Grubs!

Grubs, what are grubs? What are the symptoms of grubs? Where do grubs come from? What do grubs eat? How do you control grubs?

Let's answer these questions about grubs. Grubs are the larval form of beetles. There are many species of grubs in the northeastern USA. Perhaps the most common species of grubs is Japanese Beetle.

Grubs can be identified, as to species, by looking at the pattern of hairs, called "raster", located on their butts. Use of a hand lens helps to see the raster pattern. Control of grubs will vary according to species present. If multiple species of grubs are present, not all species may be controlled by the same method of control.

You know you have grubs if you have holes torn in your lawn. Birds and animals, such as skunks, dig up turf in search of grubs for food. During dry conditions, patches of turf may brown up as a result of grubs eating off the roots. This may not be evident under wet conditions or irrigation. Try tugging on the turf, if it rolls up like a carpet, the roots have been chewed, you probably have grubs.

Grubs may be attracted to your lawn (rather the adult beetles) by lights, trees, and moist or dry conditions. Again there are variations by species of grubs. In my yard, I have a Purple Sand Cherry that attracts Japanese Beetles like you wouldn't believe. Adults will mate and lay their eggs in the soil.

Grubs, being underground, push soil, organic matter, and all things into their mouths. Grubs derive nutrition from the organic matter, i.e. plant roots. I once collected grubs from a golf course and placed them in styrofoam cups to take back to the lab for identification. The grubs ate their way through the cups.

There are many products to control grubs. Grub control products range from organic to chemical form. Key to controlling grubs is species identification. Grubs are grubs about 10 months out of the year. By knowing the species, one can look up the average life cycle for your area. In my area, July 4 is the average date when adult Japanese Beetles emerge from the soil and start flying. Mating and egg-laying occurs the end of July and grubs begin to grow throughout August until cold weather sets in.

Grubs go deeper into the soil as temperatures fall to overwinter. In the Spring, they move up toward the surface as soil temperatures rise.

Timing of grub control is very important, depending on the type of control you choose. If using a pesticide product to control grubs, always read the label before you buy the product, and before you use the product. Follow the label, in every detail, for safety to you, the environment, as well as effective use of the product.

The strategy you use to control grubs will depend on a number of factors, such as the history of grubs in your lawn, the pressure of grubs (how many grubs per square foot?), the species of grubs, as well as expenses involved. A few grubs per square foot may be less tolerable during a dry year than many more grubs per square foot in a wet year. Pesticide products vary by mode of action, i.e. contact the grubs or do the grubs need to ingest the product?

There are many local professionals who can assist you with your problems with grubs. Contact a REPUTABLE professional or your university cooperative extension for assistance.