Hi Tui, my dwarf nectarine has a jelly-like substance on the branches. What is this? And what do I need to do to clear this up? Thanks.

Hi Helen, the jelly substance could be natural sap from the tree, or, it could be bacterial canker, the jelly substance is called gummosis. It is caused by bacterial infection which is prevalent in cooler wet weather, so early spring when buds are emerging. It can form in emerging buds and pruning wounds, and is spread by unclean cutting tools. The disease overwinters in buds and the bark of the tree, in spring when the weather is cool and wet the bacteria is spread by rain.  Emerging buds give an opening to the infection to enter the plant. Avoid overhead watering, water around the base of the tree, make sure the tree is regularly watered in the growing season, mulched and fertilised to keep it actively growing. Improve air flow around the tree by thinning out branches, and apply a copper based fungicide spray in spring and autumn. Avoid fertilising the tree late in summer, as new growth does not have time to harden off and so is more susceptible to disease. Bacterial canker can cause branches to die-back. Remove the infected branches approximately 10cm below the wound and die-back. Use clean, sharp cutting tools, clean the tools thoroughly after use with methylated spirits to prevent the disease spreading. If it is the trunk of the tree that has the gummosis, the tree may not be as salvageable, and may need to be removed. By leaving the tree to see if it recovers, there is a greater chance of the disease spreading. The Tui Team.