Snow gums are experiencing dieback in Kosciuszko National Park, largely because of the impacts of the native longicorn (or ‘longhorn’) beetle. These beetles prefer to lay their eggs on moisture-stressed trees and, in warmer weather, the longicorn beetle can hatch and grow up to 75% faster.
According to work published in the Resort Roundup winter 2019 edition (produced by the NSW government), ‘reduced snowfall, high summer temperatures such as January 2019 where temperatures at Thredbo top station were 4.4oC above average, and a reduction in autumn rainfall mean that snow gums are under much greater moisture stress than in the past.’ This means that larger beetle populations are causing more frequent dieback of some snow gum trees.
The SOS Snowgum program is asking people to log instances of dieback in mountain areas.
Help add to knowledge on longicorn wood-borers associated with Snow Gum forest dieback. You can log dieback or sightings of longicorn beetles via the SOS Snowgum website here.
There is background information on the issue available here.