Pest and Diseases

By Denis Crawford

Many ants are beneficial, but some ant species can be pests in some situations. When is that?

This Pest Files is inspired by some recent encounters I had with ants. In late January 2023 I noticed several species of ants climbing the trunk of a young roadside gumtree (Eucalyptus obliqua).… Continue reading

By Denis Crawford

Biological control may not be an instant pest solution, but it is a pest control option well worth pursuing.

Large parts of eastern Australia have just been through a very wet spring and early summer. That period of warm wet weather meant a boom time for mosquitoes, they were everywhere in huge numbers.… Continue reading

By Denis Crawford

The arrival of an exotic herbivorous insect in an environment dominated by only a few plant species can be a recipe for disaster.

When an insect is introduced into an area with few natural pathogens, parasites and predators, that insect may become a severe pest.… Continue reading

By Denis Crawford

Given the recent debate in the media about the future of pesticides in some parts of the world, it’s time to look at the alternatives to pesticides.

A recent series of articles in The Guardian“Toxic nation: Australia’s pesticide problem” highlighted several issues with pesticide use in Australia.… Continue reading

By Denis Crawford

Tiny wasps that are barely visible to the naked eye are important biological control agents for various pests. If the wasps are so small, how do you know they are present?

I recently did some photography for a Queensland integrated pest management company that needed photos of Trichogramma pretiosum, a tiny wasp less than a millimetre long.… Continue reading

By Denis Crawford

I wrote an article in March 2009 titled ‘Why do we have pests?’ The main themes of that Pest Files were monoculture, invasive insects, suppression of beneficials, and resistance to pesticides. What has changed in the last 13 years?… Continue reading

By Denis Crawford

There is more than one type of insect life cycle. Understanding the life cycles of insects can help when managing pests and/or encouraging beneficial insects.

In Pest Files of April this year I described the insect life cycle of ‘complete metamorphosis’ or holometabolous development, from egg to larva to pupa to adult.… Continue reading

By Denis Crawford

Biodiversity in gardens means growing a variety of plants, which are likely to attract a variety of insects. That might sound alarming to some, but it’s actually a good thing.

Biodiversity can be a bit of a buzzword, but the way I look at it, is insects are the foundation of biodiversity.… Continue reading

By Denis Crawford

Sap-feeding insects may be quite small, but they usually leave signs of their feeding activity.

I had a couple of speaking engagements at the Melbourne International Flower & Garden Show (MIFGS) this year. I was always on the lookout for insect specimens to show people, either the insects themselves, or the damage they cause, or other signs of their activities.… Continue reading

By Denis Crawford

For insects which go through a lifecycle of complete metamorphosis, the pupal stage is a critical one. But sometimes the pupal process is not smooth sailing.

Only insects which pass through a lifecycle of complete metamorphosis (holometabolous) have a pupal stage.… Continue reading

By Denis Crawford

The populations of some insects can vary dramatically in size from one year to the next. Why does that happen?

As I write this Pest File my garden is a-flutter with clouds of cabbage white butterflies (Pieris rapae).… Continue reading