How to Control Cutworms in Your Lawn

What are Cutworms?

Mature Cutworms are plump, smooth caterpillars often with longitudinal lines and brown to black spots on their back and sides.

They vary in colour from dark grey to greenish brown or black and can be 1-2mm long at hatching but quickly grow to about 40mm.

Cutworm larvae pupate into a moth which is attracted to light and lays clusters of eggs at night in your lawn.

Resting moths fold their wings along their body.

How to Kill Cutworms in Your Lawn

Regular monitoring for pests should be part of your lawn care schedule year-round.

In the case of Cutworms, watch out for the presence of moths in spring and early summer.

Birds pecking at the ground can often be a sign that something is amiss.

Look out for insect-eating birds such as the Common Myna (also known as the Indian Myna), Magpies, Pied Currawongs and Butcher Birds which consume both Cutworm larvae and adult moths.

Signs of larval feeding damage appear as small yellow or brown patches and the grass may feel spongy underfoot.

There will often be a brown spot up to 50mm across with a hole in the middle where the Cutworms hide during the day.

These pests can be managed using either insecticide or a chemical-free method of control.

Using an Insecticide

Always wear the appropriate protective equipment – gloves, safety glasses etc… – and read the product label before using any insecticide.

Check whether the product is suitable for Cutworms and that it is safe for use on your grass type.

Look for products containing the active ingredients Bifenthrin or Chlorantraniliprole for long-term residual control.

Recommended Products

Indigo Rumbler 100SC 1L

Acelepryn GR 10kg

Acelepryn 750ml

When to Apply Insecticides

Best results are obtained from treating the problem before pest numbers explode.

Plan to treat your lawn about 14-21 days after moth numbers peak.

Spray only in the early morning or at night to avoid killing Bees that forage in flowers during the day.

How Long do Insecticides Take to Work?

Some products must be watered in after application and can act as both a knockdown and a preventative treatment.

It will take a few days for many products to work.

Wait three days before using the soapy water flush test to see if it’s working and repeat treatment if necessary after a 10-14 days.

Killing Cutworms Without Damaging your Lawn

Poor lawn maintenance contributes to Cutworm problems from year to year.

Follow good mowing practices and dethatch and aerate regularly to help keep insects at a minimum.

Lawns mown too short are at greater risk of damage because they are already under stress.

How to get Rid of Cutworms Naturally

If you suspect Cutworms are chewing away at your lawn, an easy way to be sure is to spread a wet hessian bag – use a potato sack or buy hessian by the metre from some garden stores – over a patch of lawn.

Leave the wet hessian bag overnight on the lawn and the grubs will attach themselves to the hessian, ready for disposal in the morning.

Where the lawn has died after the roots were nipped off, dig into the soil underneath to uncover the culprits.

Collect grubs, beetles and moths and feed them to your chickens, if you have any, or toss them onto a paved area for wild birds to eat.

You could also drown the Cutworms in a bucket of soapy water before putting them into a plastic bag and in the bin.

For more information about managing pests in your lawn, and to browse our range of lawncare products from leading brands, visit myhomeTURF’s online store.