Phosphite and nutrient applications as explorative tools to identify possible factors associated with Eucalyptus gomphocephala decline in South-Western Australia

摘要: Tree declines are increasingly being reported around the world. Since 1990’s Eucalyptus gomphocephala (tuart) has suffered a significant decline in Yalgorup region, approximately 100 km south of Perth Western Australia. The complexity many tree makes diagnosis difficult. Robust tools needed to help identify factors contributing declines. Two experiments tested effect trunk applied phosphite, nutrients and combined phosphite nutrient treatments on wild declining E. gomphocephala. Treatment efficacy was as management option mitigate crown an explorative tool determine disease causality. Experiment 1 assessed injections different concentrations, implants compositions treatments. 2 concentrations. In 1, together with treatments, increased average condition by 21 %, measured using health score (CHS) averaged over 4 years, greatest improvements evident 6 months after application. Injection 25 g phosphite/L 0.3 zinc sulphide gave increase. 2, application 75 375 CHS compared control treatment, trees injected 150 phosphite/L. Foliar analysis for confirmed uptake all increase flushes new growth resulting from highlight possible involvement Phytophthora species decline, known be controlled Further work applications, particular emphasis zinc, is required understand potentially decline.