Download “Investigations into the Causes of Bract Browning in Waratahs” Investigations-into-the-Causes-of-Bract-Browning-in-Waratahs.pdf – Downloaded 1 time – 21 kB

Bract browning of waratahs reduces their market value and export potential as a cut flower crop. Many environmental factors such as light, water stress and localised calcium deficiency have been implicated in the  development of bract browning. Potted waratahs of cultivars ‘Olympic Flame’ and ‘Sunflare’ grown under 50% shade cloth had significantly lower bract browning scores than those grown in full sun. Frequent irrigation was less important, but responses differed between cultivars. Although calcium sprays to the affected area have been found to reduce necrosis attributed to localised calcium deficiency in other species, definitive
results for calcium sprays have not yet been obtained for waratahs. Experiments in the 2001 growing season indicate that shade cloth and other means of protection have the potential to significantly reduce bract browning.