Plan spraying to protect dung beetles
09 July 2018
Dung beetle field day 2018 with Bernard Doube
With the break in the season and the regrowth of pastures, landholders might be noticing the emergence of Redlegged Earth Mites, a major pest of pastures, crops and vegetables in southern Australia.
Redlegged Earth Mites (RLEM) can be controlled effectively using insecticides. However, graziers need to be aware that these broad spectrum pesticides will also kill beneficial insects such as dung beetles. Studies have shown, for example, that 100 per cent of dung beetles died after being exposed to insecticides five days after application (Dung down under: dung beetles for Australia. 2014. Dr Bernard Doube and Tim Marshall.)
Dung beetles benefit both agriculture and the environment by burying livestock and horse dung. In effect, they reduce pasture fouling, improve soil nutrient levels, increase water permeability in soil and build soil carbon, amongst a host of other benefits.
If you have dung beetles on your property, you can help protect them and still use insecticides to control RLEM with some simple planning.
As our region’s dung beetle population is active at this time of year, it’s best to avoid spraying altogether until the end of September. Fortunately, spring is also the most effective time to spray to control RLEM. A free online tool from CSIRO called TIMERITE™ will help predict the best date to spray your property.
Red legged earth mite
If you have recently sown new pasture which is very vulnerable to these mites, your only option may be to apply insecticide now. But before you decide to spray, it’s best to get out in the paddock with a magnifying glass and check emerging seedlings to see if mites and mite damage is actually present. If there is a low amount of damage, spraying may not be necessary.
To reduce the impact on dung beetles, do not graze a paddock for two months before or after insecticide has been applied. This will reduce the beetles’ food source and discourage adult beetles from moving into the sprayed paddock.
One newer option which may avoid the need to spray newly-sown paddocks are insecticide treatments for seeds. These protect newly establishing pasture seedlings and prevent damage from RLEM. The CSIRO have also developed three new sub-clover varieties that are much more resistant to RLEM damage.
While a spring insecticide application is by far the best option for established pasture, it will still have some impact on dung beetles and other beneficial insects. Careful close-up monitoring of pastures prior to spray application is very important.
It is also worthwhile noting that some drenches will kill dung beetles. The safe drenches to use are the older white and clear drenches and those in the moxidectin group.
Always seek professional advice on chemical applications appropriate for your property.
If you’re interested in finding out more about dung beetles, a new page on this website has instructional videos and resources to help you support a healthy dung beetle population on your property.