Lawn Care: Success with Nematodes


We’ve all found them at one time or another, crawling and living in the soil of our lawn or garden. There’s no mistaking their bright white bodies and distinct orange face. White Grubs! Here in the province of Ontario, as with most of the rest of Canada, there really are only two ways to get rid of them.

Getting rid of grubs

The first way to remove them is letting the skunks, racoons and other rodents looking for a meal, tear up your lawn and dig them out. Though this can be highly effective, it can also be highly distructive, and this really isn’t something we want; however, sometimes one doesn’t have a choice, and early spring digging is the first sign to some homeowners they have grubs.

Second, apply nematodes. Nematodes are microscopic, parasitic worms which live in the soil. If you’ve ever dug in your garden, you’ve come into contact a nematode. There are many types of nematodes and some, like the ones you purchase for white grubs, are species specific. Once applied, these neamtodes will hunt out a host to infect and multiply.

Nematodes are best applied in the fall beginning around the third week of August. If you’ve got a major infestation, more than 5 grubs per square foot on average, you should also be prepared to apply them again in the spring. Remember, nematodes are not a preventitive measure. If you don’t have any, they will starve and vanish from your soil, and you will have spent all the time and effort for nothing.

When purchasing nematodes, they often come packaged in a ball or pouch, containing upwards of 10 million nematodes. Each package covers approximately 3000 square feet. Be aware of where you pick up your package of nematodes. As nematodes are living creatures, they should be kept on the sales floor in a fridge. This slows the life cycle of the nematode and helps ensure their health and viability when it comes time to apply them. If you haven’t already, be sure to pick up a nematode applicator. This needs to be clean and free of any chemical residue, like fertilizers.

How to apply nematodes to your lawn

Applying nematodes is fairly simple, however it does require your attention over a short period of time to ensure they reach their destination. The best time to apply them is the evening when the sun is nearly eye level on the horizon. This will help minimize evaporation of the water they’re suspended in by the wind and sun.

Water your lawn for 30-40 minutes: Nematodes travel in the soil through water. If the soil is too dry, you’ll limit their mobility and effectiveness. Left too long without food, they will perish.

Prepare the nematodes: While you’re sprinkler is watering your lawn, follow the instuctions on the package on how to dilute the nematodes properly. Some application systems require you to mix the nematodes first and then place them in the applicator, while others have you simply drop them into the applicator and mix them there.

Water in the Nematodes: Attach your applicator to your hose. Begin applying your nematodes in any location white grubs are known to be, ensuring the nematodes find the grubs. After a thorough application to the infested areas, any left over may be applied to the remainder of the lawn.

Water your lawn for another 10 minutes: This last watering will make sure any nematodes in the water left on the grass get washed down into the soil where they can do their work.

Dont’ forget to water: Make sure you maintain the moisture level of the upper inch of lawn area for the next 3-5 days. This allows your nematodes to travel through the soil to find your grubs.

White grubs are unfortunately a fact of life when it comes to having a lawn. Even the thickest, greenest lawns have one or two grubs in them. No matter what our lawn goals are, establishing and maintaining a healthy lawn care program, which fits into your lifestyle, is key to creating the emerald oasis of your dreams.

written by Matthew Dressing, C.H.T.
horticultural technician – landscape technician – landscape designer

© Matthew Dressing and Natural Affinity Designs, 2018. Unauthorized use and/or duplication of this material without express and written permission from this site’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Matthew Dressing and Natural Affinity Designs with appropriate and specific direction to the original content.

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