|I have had somebody tell me my mature lemon tree has borers because it has a sap like substance coming out of the trunk. What can I do to save the tree?|
|Citrus tree borers are a huge problem in New Zealand but not in southern California, according to University of California at Davis. So, the problem of oozing sap may not be associated with borers but instead with a fungal disease called phytopthera. Until we know for sure, don't apply any insecticides or fungicides. With a fungal disease you will notice a sticky substance coming out of the tree's trunk. Keep the base of the trunk dry; clear away any soil, mulch, grass, or weeds that might be holding moisture at the base; trim and clean any oozing wounds; and remove decayed bark to a point where no discoloration is visible. If water hits the trunk from sprinklers, that can trigger the fungus as well. Make sure water does not stand in a basin around the trunk during winter rains.
For a positive diagnosis you may need to hire a professional arborist to visit your property and inspect the tree.