well in Brisbane last week there was a lot of media coverage about the army lawn grub. I even did an interview for an hour that was cut to 5 seconds for a news report.
What they don’t tell you but you need to know is:
- It is a seasonal pest.
- It is prevalent this year as in drought not so many insects emerge, they wait for a better season with higher humidity and rain.
- It is almost always present on new turf and this should be treated at the time of laying
- Populations can explode if new gardens are installed in old gardens
- It does cross property boundaries
- Birds eat lawn grub and they do have natural predators
- If you spray chemicals and then you cause unexpected deaths of natural predators and other incidental deaths occur
How to identify the grub early
The grass looks great one day and the next day you notice a small patch of lawn looks “off”. The colour is duller and bluer rather than green and shiny and it sags a little. THe grass is easily detached form the roots if you pull at the blades and they come away in the hands. A dead patch emerges, often irregular in shape and various patches of dead brown lawn emerge over the next few days. Now is the time to get active.,
To check if you are not sure, lay a piece of old towel or a bag over the lawn near the patch at nigh and lift it in the morning and look closely near ground level for grubs that may be brown, black, slightly greenish in colour or striped about a cm long or so. This is the culprit! I have seen infections so bad you can see them crawling along the fence and pathways. I used soap this time I think. Many years ago now.
Cultural problems that encourage lawn grub
Chemical controls create new problems so don’t go there You don’t really need to go that far.
- Straw necked Ibis love lawn grub and work the fields in a very methodical fashion so they are actual free labour or control
- Magpies and Butcher birds are also in this group of gurb eaters
- There is a predatory wasp for the lawn grub that lays eggs in the larvae underground that leads to an explosive and ugly end for the grub
- Old farmers used to use detergents to use in the pastures when under attack.
Bacterial controls are available and I have been recommending these for at least 15 years. Basically you mix the product (Dipel 20) in water (with dishwashing detergent to make it sticky) and spray it on the lawn in the late afternoon if possible but most importantly when the lawn is dry. The grub emerges to feed on the leaf blades, seeds and stems in the night time and goes buck underground to eat lawn roots during the day. Therefore if you spray in the late afternoon you get “good contact”. The infection spreads through the host population and then the lawn grub dies out naturally and then so does the bacterial infection as there is no longer a host for the infection to rest on.
You can tell as the grub goes black when infected and dead. It doesn’t kill birds, bees, affect pets or people it just gets the grubs. It probably works on most soft bodied grubs but I want the ones on the garden plants because I love butterflies.
So don’t panic just relax and keep a few birds around by feeding and supplying drinking water and they will be there to give you a helping hand right back.
Go forth and love nature- we can work together, no need to dominate, just participate