Grains Research and Development

Date: 04.05.2015

IPM encourages natural enemies at Illabo

Author: Alistair Lawson

Image of two men in a paddock

NSW grower John Hopkins (left) and GRDC high-rainfall zone RCSN member Phil Bowden.

PHOTO: Alistair Lawson, AgCommunicators

An inclination to do the ‘right thing’ by nature and to reduce input costs in his cropping program are the driving forces behind John Hopkins’s interest in integrated pest management (IPM) and pest-suppressive landscapes.

Mr Hopkins, who farms with wife Nicole, encourages plant diversity across his 1040-hectare property near Illabo, New South Wales, where they operate a mixed enterprise. They crop up to half the farm to wheat, barley, lupins, canola and oats, operate a self-replacing Merino and prime lamb flock and a Simmental cattle stud.

With other nearby landholders whose total property area spans about 8000ha, Mr Hopkins is taking part in an IPM project on pest-suppressive landscapes, which aims to build on previous GRDC-funded work carried out by CSIRO. The project is part of the cross-property planning led by Murrumbidgee Landcare and GRDC High-Rainfall Zone Regional Cropping Solutions Network member Phil Bowden with funding from the Australian Department of Environment Biodiversity Fund and NSW Environmental Trust.

Mr Bowden says there is a need for more neighbouring landholder groups to cooperate to encourage beneficial insects, such as wasps, lady beetles and hoverflies, and many other predators and parasites that work on pests on a broad landscape scale.

“Some broad-spectrum insecticides kill all species, and sometimes growers have no choice but to use them; however, if they have an option to select ‘softer’ chemicals that do not harm the beneficial insects then this is preferable,” Mr Bowden says.

Mr Hopkins describes himself as a naturalist and he sees IPM as exciting and an opportunity to work with nature, not against it.

“I believe as grain growers we sometimes do things the wrong way,” he says. “When we spray for unwanted pests we also have the potential to take out beneficial insects.”

Some pests that are of particular concern in Mr Hopkins’s area include Rutherglen bugs, redlegged earth mites and lucerne flea. The GRDC-funded pest-suppressive landscape work found that such pests are harboured by weeds including Paterson’s curse, scotch thistle, goosefoot and capeweed.

Beneficial insects that Mr Hopkins and Mr Bowden are trying to encourage in the area include various wasp species, lacewings, hoverflies and predatory beetles.

To try to encourage beneficial insects, Mr Hopkins has planted sections of his property to eucalypts and understorey shrubs and is also regenerating creek beds with native flora, fencing them off to prevent stock damaging the understorey.

CSIRO’s pest-suppressive landscapes work found that native vegetation in good condition with few weeds and an intact understorey may reduce the number of pest insects and support beneficial insects. However, it can also harbour some crop pests.

Mr Hopkins takes a cautious approach when and if he has to spray insecticides. He seeks independent advice on the best product to use to minimise effects on beneficial insect populations.

He focuses on longevity of pastures – at least six years in a rotation – before they return to crop.

“We have ‘shotgun’ mixtures in our pastures – a mix of several different cultivars with different growth habits, which includes grasses, phalaris, clover and lucerne,” Mr Hopkins says. “As I understand it, lucerne acts as a buffer in those pastures and brings in a lot of beneficial insects that are good for the rest of the program.”

Mr Hopkins acknowledges there can be risks associated with an extensive focus on using native vegetation in pest management.

“It does increase our risk of fire danger, which is something I’m fully aware of after having the property burnt-out twice,” he says. “It can create habitats for unwanted pests, including feral cats, foxes and rabbits, and it can be expensive, with the cost of fencing, as well as the fact that we’re giving up land for tree plantings.”

While Mr Hopkins has not yet quantified the full economic benefit, he believes it is a good opportunity through which growers can gain an advantage in pest management.

“It’s money for jam as I see it,” he says. “We can encourage more beneficial insects to take care of pests naturally while reducing input costs because we’re not spraying as many insecticides.”

 Name Description
Pests hosted
Table 1 High-risk weeds that harbour pests in the southern grain-growing region.
Paterson's curse
Annual or short-lived perennial that germinates in autumn and winter and produces characteristic purple flowers. Earth mites such as redlegged earth mites and blue oat mite, lucerne flea, Rutherglen bugs, thrips and leafhoppers.
Capeweed Annual species found in cropping and pastures. Germinates in autumn and flowers in spring. Earth mites such as redlegged earth mites and blue oat mite, lucerne flea, Rutherglen bugs, thrips and leafhoppers.
Scotch thistle and other thistle species
Annual to biennial weed. Seeds can germinate at any time with a flush in late autumn or late winter to spring. Earth mites such as redlegged earth mites and blue oat mite, lucerne flea, Rutherglen bugs, thrips and leafhoppers.
Goosefoot or mintweed (small crumbweed)
Annual or perennial herb that germinates in spring or summer. Found in pastures, remnant native vegetation and disturbed areas. Native to Australia and can be a weed of pastures. Earth mites such as redlegged earth mites and blue oat mite, lucerne flea, Rutherglen bugs, thrips and leafhoppers.

SOURCE: GRDC Pest-suppressive landscapes fact sheet

 Name Description
Predators hosted
Table 2 Native plants that support beneficial insects in the southern grain-growing region
 White Cyprus pine
Fire-sensitive native conifer
Spiders, brown lacewing adults, ladybird beetles and spiny shield bugs.
 Paperbark tree
Spring-flowering shrub to tree with papery bark. Spiders, brown lacewing adults, ladybird beetles, spiny shield bugs and damsel bugs.
 Wattles Shrub to tree that flowers sporadically in response to rainfall. Spiders, brown lacewing adults, ladybird beetles and spiny shield bugs.
 Eucalyptus Native trees that are a feature of open box woodlands. Spiders, brown lacewing adults, ladybird beetles and spiny shield bugs.

More information:

John Hopkins
0427 102 748

hopkinspastoral@bigpond.com

Phil Bowden
0427 201 946
philbow54@gmail.com


Next:

Eyespot alert for new season crops

Previous:

GM expansion around the globe

GRDC Project Code CSE00051

Region National, South, North