Leafcutter bees, widely used in North America and Argentina to produce high seed yields in lucerne, are being trialed in Australia.
Denis Anderson of CSIRO Entomology has, with the Australian Quarantine Inspection Service, developed protocols that allow the importation of leafcutter bees into Australia.
This importation is important given lucerne’s ability to lower watertables and its general value in dryland farming rotations.
Health and stamina for the bees are part of the protocols. Initial trials with iodine to kill fungi the bees might have been carrying did little for their health status and few survived. When the treatment was changed to sodium hypochlorite, survival rates improved but not to the satisfaction of Dr Anderson.
He then sought and found an area in Canada, Peace River, which is free of the fungal bee disease, chalkbrood, and is now able to import leafcutter bees without them having to be treated with chemicals.
(Chalkbrood is a major fungal disease of bee larvae.)
Dr Anderson said that, after other quarantine measures were met, 300,000 leafcutters were released into lucerne at five sites in southern NSW and the ACT last year.
“There has been a build-up in numbers which has been promising,” Dr Anderson said, “and we will be importing another 1 million this year. Given that you need about 60,000 leafcutter bees per hectare, to do the lucerne-pollinating job properly, it will be a few years before there are sufficient numbers for general lucernepollination activities.”
In terms of the native ecology, Dr Anderson said that lucerne flowers don’t attract a lot of insects, so there is not much competition with the leafcutters. The researchers are checking the effects on native bees and also checking that the leafcutter bees are not moving off the crop with trap-nests around the sites (this is an Environment Australia requirement) with no problems observed to date.
Contact: Dr Denis Anderson 02 6246 4148