Pest and Diseases

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

By Denis Crawford

Most cultivated plants are attacked by a mixture of introduced and native insect pests. You may be surprised which pests are the native ones.

I recently found some caterpillars chewing into the leaves and stems of my climbing guinea flower, Hibbertia scandens.… Continue reading

By Denis Crawford

The arrival of insects en masse can cause alarm, but as you will see an ‘invasion’ may not necessarily result in an infestation requiring management.

Just as our borders were reopening post-COVID, there were some arrival flights of a different kind in my region.… Continue reading

By Denis Crawford

Aphids thrive in warm, moist conditions so they are often the first insect pests that we notice in spring. Most of the aphids that cause problems in Australia are introduced from elsewhere and it’s likely they are here to stay.… Continue reading

By Denis Crawford

The value of night pollinating insects has long been overlooked, but recent studies show just how important nocturnal insects are for horticultural production.

Information about crop pollination is nearly always dominated by the European honey bee (Apis mellifera) and how vital that particular insect is to the food that we eat.… Continue reading

By Denis Crawford

It’s been a while (May 2019) since I wrote about the biochemical arms race being waged between plants and insects, and how some insects co-opt certain plant chemicals for their own purposes. Recent research has uncovered some particularly intriguing adaptations.… Continue reading

By Denis Crawford

Serpentine leafminer is an invasive leafminer fly that has spread through many regions of the world and was detected in Australia late last year for the first time.

Serpentine leafminer (Liriomyza huidobrensis) was first detected in Australia in the Sydney basin in October 2020 on field-grown vegetable crops.… Continue reading

By Denis Crawford –

Galls are abnormal growths that can form on just about any part of a plant. Why do galls form and do they harm the plants they form on?

Galls form in response to a variety of organisms entering plant tissue in some way.… Continue reading

By Denis Crawford –

Recent media reports demonstrate how seemingly minor changes can have profound unforeseen effects down the track. A bit like the butterfly effect in chaos theory.

I don’t pretend to be an expert on chaos theory in general, or the butterfly effect in particular, but the way I understand it, the idea centres on how “small, nearly imperceptible changes can have massive implications in complex systems”.… Continue reading

By Denis Crawford –

The immense diversity of insects has led to some amazing adaptations and mutual relationships with other organisms.

You might have read in the news recently about an environmental battle to prevent the clearing of 2000 hectares of native vegetation on a Cape York station.… Continue reading

By Denis Crawford –

Rachel Carson’s book Silent Spring, published in 1962, detailed the impact of pesticides on wildlife. The book was one of the factors which led to the phasing out of DDT. Unfortunately, recent reports show some of the pesticides we use today also have unintended impacts on wildlife.… Continue reading