Large numbers of pest species Cochchafer beetles are expected to be seen in the coming weeks and the Department of Primary Industries and Water (DPIW) wants dead specimens sent to its laboratories.
The redheaded cockchafer beetle is a shiny black beetle 15 mm long and half as wide. It is related to the Christmas beetle and dung beetles and can cause damage to pasture.
DPIW entomologist Lionel Hill said before 1987 the pest, a native insect, was restricted to the north of Tasmania and parts of interstate. Since then it has turned up in patches in the south and this year, with mass flights in Hobart and East Coast, it is spreading.
Mr Hill said the DPIW pasture pest database was being updated and the public could send beetle specimens to DPIW to update the department's distribution database records. He said to kill the beetle by freezing it and then post it in to either New Town labs or Devonport.
The beetle itself does not feed or otherwise injure plants, but has a grub which lives in the soil and eats the roots of pasture grasses. Because it stays underground it is not susceptible to sprays (unlike the blackheaded cockchafer grub which eats the grass foliage and can be poisoned).
It has a slow, 2-year life cycle so that years of abundance tend to be alternate. The beetles fly during spring, lay eggs in the soil and grow slowly as grubs in the soil. By late autumn and early winter they are large grubs which do a lot of damage. After that they progress through a couple of non-feeding stages of development occupying the second winter and do not re-emerge until the second spring of the cycle.
Mr Hill said there was a natural fungus treatment for this pest which is a granule drilled into the soil. The other control is to sow more resistant grasses than the popular ryegrass.
Mail the beetle specimens to either:
Dr Cathy Young, DPIW Entomology, 13 St Johns Avenue, New Town 7008 or
Lionel Hill, DPIW Entomology, P.O. Box 303, Devonport 7310.
