WANT SOME GOOD BUGS?
TRY BIOLOGICAL CONTROL IN YOUR BACKYARD.
BACK in April this year I penned an article about the range of natural predators attacking a plague of aphids on a patch of sweet corn grown for a nutrition trial at our TAFE college.
At that time the aphids were being decimated by a braconid wasp, two varieties of ladybird beetles, and a green long-legged fly.
The result of this full-on assault was an eventual control of aphid numbers, not total eradication.
Despite some damage to the corn flowers and leaves by these sap-suckers, many high quality cobs were harvested, thanks to our beneficial insect friends.
Humans have recognised the beneficial qualities of some insects since somewhere around 300 AD, when weaver ants were reportedly used to protect citrus crops from foliage-devouring insects.
It seems that these ants were traded as a commodity from that time onwards and are still recognised as valuable protectors of crops such as coconut, cashew, citrus, cocao, oil palm, litchi, coffee, eucalyptus and mango.
In 1772, botanist Carl Linnaeus, regarded as the father of modern taxonomy (plant naming), suggested that “predatory insects should be caught and used for disinfecting crop plants”, but it wasn’t until the late 1800s that the first successful large-scale economic control of a crop pest was achieved in southern California.
An Australian pest, the cottony cushion scale, was decimating citrus crops. Two predators were successfully introduced, the vedalia beetle, and a parasitic fly, bringing the scale under control within two years of release.
In the 1920s another successful citrus pest control program was undertaken, this time targeting citrus mealybug in California with a predatory lady beetle, Cryptolaemus montrouzieri.
Now you may be asking “what does large-scale biological control of insect pests have to do with home gardeners?”
It may come as a surprise to many gardeners that predatory insects have been produced here in Queensland for more than 30 years, by a company in central Queensland started by entomologist Dan Papacek.
Bugs For Bugs is a science-based business that had its beginnings in Integrated Pest Management (IPM) in the citrus producing region around Gayndah and Mundubbera.
The company specialises in the production of good bugs to control bad bugs, and whilst primarily supplying bugs for commercial growers of crops such as strawberries, corn, citrus, tomatoes and melons, they also package their bugs in home gardener friendly numbers.
I recently toured their production facility in Toowoomba (their larger, original site is in Mundubbera), and was intrigued by the interesting methods used to breed large numbers of these little marvels.
Here’s a list of the beneficial insects bred by Bugs For Bugs in Toowoomba.
For home gardeners, one of their star predators is the lacewing (Mallada signata). These voracious insects have a pretty eclectic appetite for pest species, and can be used to control aphids, two spotted mites, greenhouse whitefly, scales, mealybugs and even moth eggs and small caterpillars.
Bugs For Bugs produce a home gardener pack which contains 300 lacewing eggs (they are released after hatching and at their second larval stage), six release boxes (which can be suspended on twigs or branches), and two yellow sticky traps for monitoring pest populations.
It’s best to have flowering plants in your garden so as to provide fodder in the forms of nectar and pollen. An interesting lacewing fact is that the larvae impale the remains of their prey on spines on their backs in order to camouflage themselves!
An exciting newer predator being bred in Toowoomba is the spotted ladybird beetle (Harmonia species). These are Australian native insects that simply love munching on your garden aphid afflictions.
Some are also known to feed on whiteflies and psyllids. These little helpers are supplied in packs of 30 beetles, and once released will begin feeding on aphids immediately as well as laying eggs amongst the colonies. Their larvae will appear about two weeks later and will also start to feed on the unfortunate aphids in their vicinity.
If you have soft scale or mealybugs on your citrus trees, then a small army of a beaut little ladybird beetle, Cryptolaemus montrouzieri, may help in their control. You may see these in your garden from time to time, their orange head and black wing covers a dead give-away.
As with the spotted ladybird beetle, their larvae are also predators of these pests. Interestingly, the beetle larvae look like the mealybugs they feed on! Bugs For Bugs supply Cryptolaemus in packs of 100 adults, or 50 and 200 larvae.
One of their tiniest predatory insects is no longer than 0.5mm, the Trichogramma wasp. This wee wonder targets the eggs of the heliothis and cabbage moths, major caterpillar pests of tomatoes, sweet corn, capsicum, French beans, lettuce, strawberries and even citrus and avocados.
They lay their eggs inside the moth eggs, with the emerging wasp larvae parasitising the developing caterpillars inside the eggs. After about 7 to 10 days, the adult wasp emerges to continue their life of predation on these damaging pests. Trichogramma are sold in sheets of parasitised moth eggs, containing about 60,000 wasps!
Other products from Bugs for Bugs include predatory mites (Persimilis, Californicus – for the control of spider mites and other mite species), Chilocorus (a ladybird beetle for targeting armoured scale insects) and Spalangia wasp (a predator of house fly and stable fly). Bugs For Bugs also specialise in fruit fly control products, and are actively researching better ways to deal with these very pesky native flies.
Thanks to Dan Papacek for graciously allowing me to visit the Toowoomba office of Bugs For Bugs. Visit bugsforbugs.com.au for more information.