‘Lawn Grub’ is a common name for surface dwelling caterpillars. They may also be called sod webworm, army worm and cutworm that feed on the lawn leaves then become moths after their pupae stage.
Traditionally lawn grubs appear more regularly in the warmer months of Victoria during October to March. This is when your lawn is at its greenest and healthiest which is when Lawn Grubs love to attack! Lawn grubs effect all lawns but they especially love Couch, RT Fescue and Kikuyu varieties, if you have Sir Walter Buffalo then we normally find that the damage is minimal and the lawn quickly recovers.
Symptoms of Lawn Grubs
Increased bird activity on your lawn
One of the most easily spotted symptoms is an increase in bird activity on your lawn. These grubs make a great snack for the local birds and you’ll find them popping over to your place for lunch!
Small, greyish brown moths fly around looking out for the healthiest lawn to leave their eggs on, giving their larvae the best chance of survival. Moths are generally seen flying around your lawn during dusk at the end of the day.
Once moths have laid their eggs in your lawn, within 2–5 days these eggs become grub larvae. These caterpillars are the critters doing the damage as they spend between 18–24 days chewing through your beautiful lawn before becoming pupae and around 5–8 days later moths and so the cycle begins again!
Brown patches in your lawn
During the Spring months as your lawn is recovering from the cooler winter temperatures, especially after your spring fertiliser, you may notice brown patches that remain brown. You can lift some of the grass in the patched and if lawn grubs are the culprit you’ll find that the grass will roll up like a carpet, as it has no roots.
How to treat Lawn Grubs
So how can I get rid of lawn grubs? If you suspect you have lawn grubs there are treatments available. There are plenty of pest controls available on the market. It’s good to keep in mind that it can take a while to break up the cycle so you want to look for something that is going to remain in the soil, for this reason Lilydale Instant Lawn recommend LSA Grub Guard. With other treatments a second application may be necessary.
Black or African Lawn Beetle
Black Lawn Beetles a shiny jet black scarab beetle up to 15mm long with serrated front legs, with a larvae which are white to creamy-white. soft bodied curl grub up to 25mm long.
Black Lawn Beetles are often blamed for damage to lawns but often is not the cause. As Black Beetles feed, they will continue to move throughout the soil, never staying in a single place too long. Lawn Beetles are active at the same time as the lawn is most active in it’s growing cycle. When the lawn goes dormant over Winter, so do the beetles and their grubs.
If however Black Lawn Beetles and their grub offspring are ever found in concentrated very large quantities then this feeding can cause damage to the lawn and only then should treatment be considered.