Lawn army grub control without spraying

Controlling army grubs without spraying and 3 steps to a great winter lawn

Last week when i was mowing the lawn i noticed some small 3cm sized grey moths flying up out of my lawn, disturbed by the lawn mower and not wanting to be turned into garden mulch they took off. This didn’t surprise me as it is autumn and autumn is lawn grub season. You guessed it these were adult lawn grub moths heading for a new lawn to lay their eggs in.

A few days later i decided to take a closer look at the patch of lawn the army grubs had set about destroying. Armed with a bucket of soapy water, warm is best, i headed back to the area where all the moths were sited. From a distance the area the caterpillars had attacked looked to be reasonably green and still healthy which surprised me.

Approaching a little closer i noticed a small swarm of 4cm long red/brown wasps numbering 30 or 40 hovering and dancing right over the effected turf area. I also noticed the lawn looked better than i had anticipated. Approaching a little closer i poured on the soapy water and as I suspected up came a few lawn grubs.

How to recognize natures lawn grub control, sorry you cant see the pests in the youtube version of my video!

Lawn grubs again i thought….every autumn in my Lake Macquarie home we seem to get them.

Thoughts of past encounters where i had ignored army worms and ended up with over 50% of my Shade Master buffalo lawn dead right before the winter growth slow down crossed my mind. That was it i will spray the grass in the morning i thought, i dislike spraying as much as the next person but have learned the hard way that spraying is better than looking at bare patches of grass all winter.

Day 4 i was looking up at the lawn grub effected lawn and these wasps were still zooming about only now around 50-60. I knew of the wasp and that it was parasitic to lawn grubs but had never seen them in these numbers. The best news was that the grass was still looking ok after 4 days of lawn grub attack.

2 weeks on and the wasps are still there, the grass looks good, no one has been stung by a wasp and i have not had to spray this area of lawn. The wasps seem indifferent to me and my regular lawn inspection visits and not aggressive.

How to avoid the 3 most common lawn care mistakes

Autumn is an easy time to make mistakes when caring for your lawn. Following a wet summer early autumn your lawn will often be lush, dark green and flourishing.

Autumn lawn care mistake number 1: Ignoring the signs of lawn grub.

Unless you have been lucky as i was in Autumn this year and get a hand from mother nature with your lawn grubs unfortunately there is a good chance you need to control an unwanted visit from the army worm. Thick flourishing leaf growth from your well kept Autumn lawn is the favorite place for the adult lawn grub moths to lay their eggs.

Lawn grubs are the lawn damaging caterpillar larvae of a small grey moth. The lawn grub moth is active after dark when they hatch from a neighboring lawn or nature strip. Mating and laying their eggs into the most lush lawn they can find. Being a winged insect travel from lawn to lawn is not a challenge. Your lawn can be grub free one week and infested the next. Moths are easily seen in your cars headlights approximately 3cm long and dancing around lawns in your street after dark.

These grub sightings are often the first clue it is time to be vigilant when checking for lawn grub damage in your lawn.

See what lawn army grub damage looks like…this is time to spray

Damaged lawn can appear in two ways. Early attacks will look like sunken patches where surrounding areas of grass have longer leaves, the area often roundish in shape to start with. In buffalo lawns like Sir Walter, Shade Master and Sapphire buffalo grass types it often looks like you have dropped the mower onto an area set too low then started the mower leaving a round sunken patch.

Badly infested lawns will look stripped of leaves , with nothing but stems and runners left. The small sunken patches start to join together.

Identifying army grub

Using the warm soapy water technique mentioned earlier, pour this mix over affected areas preferably on the edges where there is still some unaffected grass. The small caterpillars will come to the surface. These caterpillars are smooth and olive green or brown and range in length from 2cm to 6cm long. You only need to find a few to have a problem.

Controlling army grub

Once discovered in your lawn rarely will you get the wasps in big numbers as i mentioned in my story.  My advice is if it is Autumn or late summer is to control the lawn grub with a lawn grub specific spray as soon as possible. Applied late in the day these sprays cover the leaf surface in wait for the lawn caterpillars night time attacks. One spray with a suitable insecticide should be enough.

Autumn lawn care mistake 2: Not feeding in autumn

Autumn lawn feeding is the most important feed of the year, so important that i will often feed twice in autumn and skip a summer feed. Autumn is your last chance to get strong spreading growth from the commonly used warm season lawn types so popular in Newcastle and Hunter valley homes. Warm season grasses include Kikuyu, Couch and the buffalo group of grasses. Covering growth of any dead spots caused from summer dry outs and autumn lawn pest attacks will be much more difficult as winter sets in and the soil temperature drops below about 15 degrees Celsius.

If you only feed once it is best done towards the end of autumn while the soil is still warm say no later than mid May. This one feed will provide your lawn with enough nutrients to get it over winter.

Growth response from a fast acting fertilizers like Green up or No 17 will be more steady in autumn saving on mowing.

Grasses like Sir Walter, Shade Master and Sapphire buffalos will keep a dark green color and avoid unsightly purpling off in the coolest part of winter.

Autumn lawn care mistake 3: Stop watering as it cools off

Cooling weather and shorter days will put less demand on the amount of water your lawn needs to keep it in a steady healthy state. This step is for those with lawns like mine, less than perfect and could always do with an improvement.

Lawns that have bare patches from drying out in the summer heat or pest attacks will not grow if the soil is too dry. Active growth that covers and re-thickens will only occur in good conditions where nutrients and moisture are readily available. Small consistent doses from a soaking sprinkler are the most effective way to get the moisture into the soil below the lawn.  My favorite technique is to use a small metal sprinkler and a simple tap timer, 10-12 minutes per area, simply wind the tap timer on and forget about it until you are ready to move the sprinkler.

These small consistent doses keep the costs of watering very low and make the most of the last days your lawn will grow until spring each water releasing a small amount of fertilizer to the plants roots.

This summer we found really challenging to keep our home lawn healthy. Having just moved to a home where no underlay soil was used in preparation when the grass was laid. Check out this link on the absolute minimum water your lawn can survive on in the summer heat for how we kept the lawn from going backwards in the near record heat stint of 40 days over 33 degrees Celsius in a row with out rain.


Autumn is great time for lawns especially if we have had a wet summer,  don’t be fooled by your lawns good looks lawn grubs are more likely to attack the best lawns.

Checking for lawn pests in Autumn is a must each year with times to be extra vigilant after rain or extra humid wet Autumns. Keep checking for moths at night right through Autumn until the weather turns cold.

Don’t spray for lawn grubs if you have a healthy lawn wasp population. If spraying is needed ask at your local garden advice centre for an effective single dose lawn grub control. Saves time and money! Some of the best lawn grub killers can also kill spiders, cockroaches, termites and fleas.

Feeding your lawn in Autumn is the most important time to feed, feeding twice is a good idea especially for modern buffalo lawn turf types.

Watering is important especially when you are looking for active spreading lawn growth to cover dry dead patches or pest damaged areas.

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  1. Huw Ellis 2 years ago | Reply

    A very helpful article about army grubs. I had a small section of my lawn affected but managed to prevent further invasion. Unlike the area outside the back fence which is reserve, and was really badly affected. However the grass seems to have greened up a bit again. I will follow up your advice about feeding of the lawn at this time of year.. I would be interested to talk one of your staff about the so called “wasps”. I destroyed a nest last week with’ Blitzem Wasp Killer and Nest Destroyer. It worked very well. The jet reaches up to 4 metres.
    However the “wasps “are still very prevalent on next doors, frangipani tree flowers. And I never did see them on the lawn.
    I am not much of a photographer but I think I have identified a plant called “Agave Parryi”. We never planted such a thing although we have had plenty of common agave. We have lived here 40 years, and it was amazing to see this agave type plant shoot up to about 2.5 metres,
    get all sorts of green sprouts on it and in the last few days these sprouts are turning in to yellow flowers. Would welcome your comment
    And if you are interested you are welcome to view it. I have never seen such a plant!

    • Cherry Road Nursery 2 years ago | Reply

      Hi Huw thanks for your positive comment on the article much appreciated. The wasps on your neighbors Frangipanni im not sure about. I have tried a few times to photograph the good wasp that attacks the lawn grubs but they wont sit still. The wasp nest you destroyed most likely was a paper wasp which are most definitely not friendly around the home.
      With your Agave plant it is not just a common Agave attenuata with a flower spike you are talking about? These are a meter taller than the plant when they flower.
      I looked up Agave Parryi online as we have never sold it and it looks to have a distinct leaf with a sharp point so im sure if you have one of these it would be easy to identify by these features.
      Thanks Matt

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