Deniliquin Pastoral Times

Locusts risk listed as ‘moderate’


With bumper crops on the horizon for much of the state, landholder­s are being urged to be on the lookout for locust activity this spring and report any sightings immediatel­y.

Adult plague locusts usually lay eggs in harder loamy red soils, favouring compact roads next to crops, tree lines and farm buildings, especially those built on higher ground such as ridges.

NSW Plague Locust Commission­er Scott Charlton said while fewer reports of locusts had been received than in previous years, landholder­s west of the ranges should still be vigilant and expect sporadic outbreaks.

‘‘Despite warmer weather and high rainfall forecast across much of the state this spring, we have received very few reports to date of locust activity,’’ Mr Charlton said.

‘‘We are still encouragin­g landowners in the upper Western and far Northwest to monitor for any activity, as this will help control teams with their response efforts and limit further spread of locusts.

‘‘Locust hatching is still expected in the northwest of the state throughout September as temperatur­es increase, while outbreaks throughout the lower western Riverina may not occur until October.

‘‘On-ground treatment by landholder­s once locusts begin to ‘band’ is by far the best and most effective treatment option and will help limit new swarms.’’

In its September bulletin, the Australian Plague Locusts Commission said there is a ‘‘moderate risk of a widespread infestatio­n developing during spring’’ in the Riverina and Murray regions.

‘‘Surveys in early March identified a widespread adult population, with higher densities up to low-density swarm in the Hillston, Hay and Jerilderie areas,’’ the September bulletin states.

‘‘An area of fifth instar Sub-Band density was detected in the Jerilderie district and a few instances of present, numerous-density of nymphs were identified in other areas.

‘‘Surveys in mid-April identified a decrease in adult numbers in this region, with consistent scattered to numerous densities of adults but no nymphs detected.

‘‘Surveys in early May indicated further decline in adult numbers, only occasional numerous-density was detected among isolated to scattered densities of adults, with no nymphs identified.

‘‘Surveys in early June did not detect any locusts.’’

LLS officers confirmed a hatching report in Barellan in mid-March, and a small third instar band in Leeton in addition to two test drillings in the northwest of Jerilderie in early April.

The university of NSW insect monitoring radar in Hay detected a significan­t locust migration on the night of March 12 to 13.

‘‘March rainfall ranged from nil in the west to over 100mm in the east (Hay 14.6mm, Narrandera 98 mm, Yanco 122 mm), which represents average to very much above average falls.

‘‘April rainfall was very much below average in most areas, less than 10 mm at most, while the May total was from 5 mm in the west to less than 50 mm in the east, which was below average to about average.’’

As a result of those findings from earlier in the year, the Australian Plague Locust Commission is forecastin­g that overwinter­ing eggs are likely to hatch from late September onwards.

It says the formation of localised bands are ‘‘possible’’.

‘‘Locust population levels could reach high density in some areas. There is a low to moderate probabilit­y of migration from and to adjacent regions in the spring,’’ the bulletin said.

If you suspect you’ve got Plague Locusts, contact your nearest Local Land Services office on 1300 795 299.

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