Western Australia
May 21, 2008
Source:
GRDC's The Crop Doctor
According to Dr Gary Fitt, Deputy
Chief of CSIRO Entomology, Australia, invertebrate pests cost
Australian broadacre agriculture, not including horticulture and
forestry, about $500 million per year in lost production.
The GRDC funded National Invertebrate Pest Initiative (NIPI) was
set up to bring together entomologists from around Australia to
foster grower adoption of integrated pest management (IPM)
practices for invertebrate pests in the grains industry.
Such integrated approaches, using natural and cultural factors
to limit pest populations and only supplementing with
insecticides, are gaining momentum.
Growers recognise that sole reliance on chemicals for insect
pest control is leading to resistance problems. IPM advocates
“justified” strategic spraying, rather than “prophylactic” or
insurance spraying, which is not a sustainable practice.
PestFax, a free email information service, provides weekly
alerts to the WA grains industry of reported pest threats to
crops and pastures and advises growers on pest identification
and management.
The service commenced in WA by the Department of Agriculture and
Food WA (DAFWA), has been running for more than 12 years. The
same service is now available in SA/Western Victoria and
Victoria/NSW, where it’s known as “PestFacts”.
PestFax Editor, NIPI member and GRDC Seed of Light winner, Peter
Mangano said the more frequently a pest population is exposed to
a chemical, the higher the selection pressure and the more
quickly resistance is likely to develop.
He indicated the availability of low cost insecticides had
accelerated this process.
GRDC supported DAFWA entomologist, Svetlana Micic, said that to
successfully conduct IPM, many factors must be addressed.
Correct pest identification is critical, particularly as it’s
easy to misidentify species such as mites, due to their small
size, she said.
Ms Micic recommended accurate monitoring at key times, including
after ‘break of season’ rain in autumn, before sowing and during
seedling emergence and early plant establishment.
Cultural control options, such as intensive spring grazing of
pasture to reduce feed on offer levels below two tonnes per
hectare, can reduce pest numbers and their carryover potential
between seasons.
Also, having fallows where no green material exists in paddocks
for at least two weeks before sowing crops, is a useful
strategy, she said.
Cropping rotations must be considered, with trials showing that
pest susceptible crops, such as canola, have reduced pest
pressure, especially from mites, when following a cereal
rotation, than when following pasture, Ms Micic said.
According to Mr Mangano, grower attitudes to pest management
vary enormously, from the risk-averse who spray insurance
sprays, unaware of actual pest presence, to those who won’t
spray, even with moderate numbers of pests, but choose to
continue to monitor until threshold levels are reached.
He suggested reduced spraying and choosing softer insecticides
that are target specific and assist the natural beneficial or
“good” insects in their work.
These beneficial insects feed directly on, or are parasites of,
the pests. Parasitic wasps, for example, will decrease aphid
populations, if the wasps are allowed to build up to sufficient
numbers.
www.grdc.com.au/pestlinks
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The Crop Doctor is
GRDC Managing Director,
Peter Reading |
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