RELEASE THE BUGS
TRY BIOLOGICAL CONTROL IN YOUR GARDEN
For the first time in 31 years, my large Japanese maple (Acer palmatum) has been invaded by a sap-sucking army of aphids this spring.
I first noticed a coating of a sticky, shiny material on plants grown beneath the tree a couple of weeks ago, looked up to see most, if not all, leaves and soft twigs covered in these pesky insects.
I’ve taken the hose to them a couple of times, knocking them off with a strong jet of water, but they’ve returned.
This got me to thinking about enlisting some beneficial insects to deal with them, and that back in 2018, I penned an article on these little saviours.
Here is an amended version of that article: Humans have recognised the beneficial qualities of some insects since somewhere around 300AD, 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, cacao, 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 largescale 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 while 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.
Here’s a list of the beneficial insects bred by Bugs For Bugs in Toowoomba.
1. 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 500 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 to provide food 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.
2. An exciting newer predator being bred in Toowoomba is the spotted ladybird beetle (Harmonia conformis). 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 among the colonies. Their larvae will appear about two weeks later and will also start to feed on the unfortunate aphids in their vicinity.
3. If you have soft scale or mealyb ugs 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 giveaway. 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.
4. One of their tiniest predatory insects is no longer than 0.5mm, the Trichogramma wasp. This wee wonder targets the eggs of the helicoverpa 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 seven 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, or a domestic/garden pack, containing 12,000 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 Hypoaspis, a soil-dwelling predatory mite which simply loves to feed on fungus gnats (those annoying little black flying insects that inhabit your indoor plant potting mixes) and thrips. Bugs For Bugs also specialise in fruit fly control products, and are actively researching better ways to deal with these very pesky native flies.
Visit bugsforbugs.com.au for more information.
GARDEN CUTTINGS
Say g’day on my Facebook page: Mike Wells – Wellsley Horticulture or email your gardening questions (or article suggestions) to: wellsleyhorticultural@gmail.com.