Thursday, May 30, 2024

Pest and Diseases

Horticultural pest and diseases

Red imported fire ant (Image: Jesse Rorabaugh)
Pest and Diseases

How invasive insect pests spread

By Denis Crawford

Several invasive insects currently of concern to the horticultural industry have something in common – the ability to travel long distances in horticultural material.

If reading a newspaper recently might make you think that we are under threat from invasive insects from all points of the compass, you would be right.… Continue reading

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Imperial jezebel feeding on grasstree flower (image supplied by Denis Crawford)
Pest and Diseases

Bushfires can devastate some insect populations

By Denis Crawford

Conventional wisdom tells us that the bush will recover after fire, and that the wildlife will return. It’s not that simple.

I’m not likely to forget February 13th 2024. It was the day a bushfire descended on my local town of Pomonal, destroyed 45 homes, many sheds and other structures, kilometres of fencing, and over 2700 hectares of bushland and private land.… Continue reading

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Typical tomato spotted wilt virus symptoms on fruit
Pest and Diseases

Insects that transmit plant diseases

By Denis Crawford

Insects that spread plant diseases are known as vectors of that disease. It’s important to know that some insects are more efficient vectors than other others.

Insects which transmit plant diseases are mostly sap-sucking insects of the insect order Hemiptera.… Continue reading

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Butterflies have more than aesthetic value in gardens (image supplied by Denis Crawford)
Pest and Diseases

Where have all the butterflies gone?

By Denis Crawford

Butterflies are desirable in gardens because they are indicators of a healthy environment. Unfortunately, they are under threat from climate change.

People enjoy seeing butterflies fluttering around their gardens and in bushland. Butterflies are considered to be harmless, perhaps with the exception of the cabbage white butterfly (Pieris rapae), and they are often quite large, colourful, and aesthetically pleasing.… Continue reading

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Stalked lacewing eggs (Image by Denis Crawford)
Pest and Diseases

Every insect has an enemy

By Denis Crawford

We all know about the natural enemies of pest insects, but did you know that beneficial insects also have their enemies?

I have often said “for every insect out there, there is probably another insect that wants to feed on it or breed in it”.… Continue reading

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Free pollination by feral bees may decline (Image supplied by Denis Crawford)
Pest and Diseases

Flies as pollinators

By Denis Crawford

With European honeybee populations under pressure from varroa mite it is time to take another look at alternative pollinators.

The need for pollinators that are complementary to, or an alternative to, European honeybees has never been more critical.… Continue reading

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Typical antlion pit (Images supplied by Denis Crawford)
Pest and Diseases

Some insects are tool users

By Denis Crawford

Most people are familiar with mammals and birds that use tools, but they may not be aware that some insects also use tools.

I first became aware of animals using tools through the work of Jane Goodall in Africa during the 1960s.… Continue reading

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Male red and blue beetle (images supplied by Denis Crawford)
Pest and Diseases

Overlooked predatory insects

By Denis Crawford

We are all familiar with predators such as ladybird beetles and lacewings, but some of the less familiar predators are just as important.

Ladybird beetles are certainly the most well-known predators and common species are instantly recognisable with their bright colours and dark spots.… Continue reading

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She may have lost her wings, but he hasn’t (images supplied by Denis Crawford)
Pest and Diseases

The benefits of having wings

By Denis Crawford

Insects are the only invertebrates that can fly, and flight has allowed insects to dominate most terrestrial ecosystems.

Insects first took to the air 350 to 400 million years ago, but like most evolutionary developments, it didn’t happen overnight.… Continue reading

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This tiny weevil is helping pollinate these Thryptomene flowers (image supplied by Denis Crawford)
Pest and Diseases

Weevils are not all pests

By Denis Crawford

Think weevil, think pest? Think again. Weevils are incredibly diverse, and some species are plant pollinators.

With about 400,000 species worldwide, the insect order Coleoptera (beetles) accounts for about 25% of all animal species on earth. 20% of those beetles are weevils of the superfamily Curculionoidea.… Continue reading

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Tiny Trichogramma wasps are mass reared to control caterpillar pests (image supplied by Denis Crawford)
Pest and Diseases

Insects as livestock

By Denis Crawford

There is a long and fascinating history of mass rearing of various insects, and it seems that the practice is set to expand somewhat.

There has been a lot of press in the last couple of years about farming insects for human consumption.… Continue reading

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Wireworms have a distinctive form (Supplied by Denis Crawford of Graphic Science)
Pest and Diseases

What grub is that?

By Denis Crawford

Insects that have life cycles of complete metamorphosis have larvae that come in a variety of forms.

A life cycle of complete metamorphosis (holometabolous) means hatching from an egg into a larval stage, then pupating, and later emerging as an adult.… Continue reading

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This caterpillar has three pairs of true legs and four pairs of abdominal prolegs (Supplied by Denis Crawford of Graphic Science)
Pest and Diseases

Identifying insects

Many insects are instantly recognisable but what do you do when you find an insect you’ve never seen before?

If I described an insect as having a triangular head with large eyes, spindly hind legs and grasping raptorial forelegs, I reckon most of you would have an image of a praying mantis in mind.… Continue reading

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Gumtree scale ladybird feeding on scale (Supplied by Denis Crawford of Graphic Science)
Pest and Diseases

Ants abound, but is that bad?

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

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Control Helicoverpa larvae with an IPM program (Supplied by Denis Crawford of Graphic Science)
Pest and Diseases

Alternatives to pesticides

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

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Damselfly eggs are not safe underwater
Pest and Diseases

Tiny wasps are the best pest control

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

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Native bees are not affected by varroa mite (Supplied by Denis Crawford of Graphic Science)
Pest and Diseases

The impact of varroa mite

By Denis Crawford

Varroa mite, the invasive parasite of European honey bees, has been detected in NSW. The current outbreak is very concerning but is there possibly a silver lining to this outbreak?

At the time of writing this article, the NSW outbreak of varroa mite (Varroa destructor) appears to be contained.… Continue reading

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