I’ve recently worked over my vegetable garden to plant out my tomatoes and cabbages. During the dig a large number (read 30+) of curl grubs (see photo) were discovered in the 4 square meter garden bed.
Having done a little research, they might be the cause of my problems last season in growing capsicum and pumpkins.
Curl grubs are the larvae of many different beetles that live in your garden. At my house the adults are black and eat the dog poo off my lawn (should I miss a pile). They don’t tend to roll it into balls like the common Dung Beetle, they just hollow the inside of the pile out and leave a dry dog poo shell for me to pick up.
The larvae of the beetles live in the soil in my vegetable garden, presumably all over my yard, and nibble away at the roots of my veggies and other organic material.
These beetles primary role in the environment is to break down organic matter into new soil. They do a great job at this and reducing my dog poo pile is appreciated.
The life cycle of the beetle is as follows.
The life cycle is one year, eggs are laid into soil or compost in spring, newly hatched larvae feed on organic matter while older larvae feed on roots and organic matter.
Larvae spend one winter feeding in the soil and pupate (turn into beetles) in the following spring. They move close to the surface when they are about to pupate (that’s when I get them) and hollow out a chamber to grow. Once they have turned into a beetle, they wait in the soil until they can dig their way out to go and eat and mate then lay eggs.
What to do to get rid of them in the veggie patch?
After looking in some books in the library I found that you can either poison them, dig them up and remove them or introduce some nematodes.
Products like Carbayl and Chlorpiriphos are excellent at killing these buggers off, but at what expense to the soil? I found two earth worms in my garden yesterday, the first since I moved in, and I’m not keen to see them and their family poisoned.
These poisons may be regarded safe to use in the garden, but who really knows what effect they will have on the soil, the plants growing in it and the end user (you!).
Dig and squish:
Each time I cultivate the soil I look for them and put them in a container on the side. By simply removing the bulk of the population I have killed off a generation of beetles to come and lay in the soil. To dispose of them I flush them down the toilet, or if there is a Magpie in the yard I will feed them to it. You could always just jump on them!
The CSIRO in Australia has found that a specific breed of nematode will get inside these beetles larvae and eat them from the inside out. The nematodes don’t eat roots of plants or kill anything else.
For me, I think I’ll stick to digging around my plants to find them and kill them off one by one!
Tags: pests, garden