Best Practices for Removing Avocado Suckers
California avocado grove maintenance includes removing diseased trees and thinning the orchard — but growers often are faced with an additional challenge having completed those processes: avocado suckers. Suckers that emerge from a stump might, initially, look like a new, robust avocado tree but it’s difficult to know whether the emerging tree is a scion variety that will produce marketable fruit or is simply regrowth from the rootstock.
So, how do you eliminate suckers? Drs. Ben Faber and Brad Hanson address this topic in their latest blog post. First and foremost, growers are advised against using glyphosate or triclopyr “cut stump” systemic herbicide treatments. These treatments, which are painted/poured/sprayed on stumps, will work their way through the stump’s roots and can be absorbed by the roots of nearby healthy avocado trees. When this occurs – the surrounding healthy trees may die. California avocado groves usually exhibit root grafting (tree-to-tree root connections), so growers should avoid using systemic herbicides to eliminate suckers.
Growers have several other options. One of the most cost-effective is to cut the tree down as close as possible to the soil. Suckers can then be knocked off during routine grove inspections. You also can cover the stump and surrounding area with a thick, black plastic sheet, or score the top of the stump and apply 10 pounds of salt per stump (urea or magnesium sulfate). Contact herbicides can be applied to the suckers and are most effective when they are less than a foot tall. In most cases, these products will need to be applied each time new buds or suckers erupt.