Pluot gumming can be from borers, sunburn
Question: We planted a pluot this past spring along with four peach trees of different varieties. The pluot just started oozing sap or gumming on the lower truck. All of the trees were planted as bare-root trees. The trees have a bermed area for holding water with wood chips for mulch. I am watering two to three times a week and frequently check soil moisture around the roots with a very long screwdriver.
In peach, gumming or sap coming from the trunk or limbs is frequently due to borers. In both plum and apricot (the parent trees of pluots), gumming can happen without borer problems. Frequently it is a sign of stress.
Make sure the trunk and limbs are in the shade of their own canopy to reduce sunburn from direct sunlight. Sunburn damage can cause this as well.
Paint the trunk and limbs with diluted white latex paint to reduce sun and heat damage to these areas.
Dilute white latex paint with an equal amount of water and spray it or brush it on. This will reduce the surface temperature of these areas about 5 to 6 degrees. We normally do this in the winter when we don’t have to fight with the leaves and after pruning is done.
Bob Morris is a professor emeritus in horticulture with the University of Nevada and can be reached at extremehort@aol.com. Visit his blog at xtremehorticulture.blogspot.com.