Australia
September 23, 2012
Western Australian growers are encouraged to look out for aphids and caterpillars such as diamondback moth (DBM) and native budworm in their crops this spring, with warm and dry conditions favouring the development of these potentially damaging pests.
“Growers should inspect their crops to determine which insect species are present and assess numbers to determine whether to spray them,” Department of Agriculture and Food (DAFWA) entomologist Svetlana Micic said.
Cabbage aphids on canola
She said growers could access information about aphids and DBM, including spraying thresholds, from Grains Research and Development Corporation (GRDC) fact sheets at www.grdc.com.au/GRDC-FS-DiamondbackMothSouthWest and www.grdc.com.au/GRDC-FS-AphidsandVirusesinPulses
Native budworm information was available in DAFWA FarmNote 184 Management of native budworm in pulse and canola crops in the south-west of Western Australia found by clicking on ‘publications’ then ‘FarmNotes’ at www.agric.wa.gov.au
“Growers who decide they need to control spring insects should think twice about which chemical to use,” Ms Micic said.
“Further applications of synthetic pyrethroids (SPs) to control late season pests can add to the risk of resistance developing in non-target species, such as redlegged earth mites, which are present in the crops being sprayed.”
Ms Micic said aphid species tended to be a problem in crops during dry finishes to the season, and canola crops in particular had increased susceptibility to aphids when drought stressed.
“GRDC supported research conducted by DAFWA has shown that spraying for aphids may be warranted when 20 per cent of canola plants and 50 per cent of cereal plants are infested,” she said.
Ms Micic said generally low levels of diamondback moth and native and lesser budworm were present in some WA crops, including in the Northern Agricultural Region and between Esperance and Ravensthorpe.
“But growers need to be mindful that warm, dry conditions can see their numbers escalate rapidly,” she said.
Ms Micic said growers should also be mindful about locusts, and that information on their identification, management and control - including predicted peak hatching dates – is available at www.agric.wa.gov.au/locust
Significant locust activity is expected during spring in southern and south-eastern parts of WA’s agricultural region with peak hatchings predicted from mid-September to early October.
“Locust control measures by landholders need to occur about 10 days after peak hatching occurs in their region,” Ms Micic said.
Species
