Fungus Monilinia laxa
All stone fruit are affected by blossom and twig blight.
Blossom and twig blight is similar to the more common brown rot, but the symptoms are much more severe on blossoms and twigs. Infected twigs may ooze gum near areas of dead or dying bark. The fungus kills blossoms and twigs and is especially severe in apricots where up to 30 cm of terminal shoots can be killed within one season.
Moist weather during the period from budswell till fruit set favours the incidence of this disease. This disease is far more prevalent in the Barossa Valley than other production areas.
To keep Monilinia laxa out of the Riverland, it is important for growers to take care not to bring diseased trees into the Riverland from the Adelaide Hills or the Barossa Valley.
Methods of control are similar to those for brown rot. Blossom sprays can be critical for this disease, especially in a wet season where up to three sprays may be needed at this stage. In addition to the sprays recommended for brown rot, a spray in late winter is also necessary for effective control of blossom and twig blight.