Avocado Trees, Mites, and Gophers

Question: I’m on a fast mission, quite desperate. I’m pulling my hair out. I have an avocado tree that has mites and is definitely languishing. Too much rain, and even though I composted loads before planting, not enough to balance out the clay. Pray I don’t get/have root-rot. Went around with a 1 inch pvc pipe and created 10-12 holes which I added aged horse manure and coir to maybe suck up some of the excess water. Plugs were definitely wet. Checked your book for ideas, County suggests toxic sprays… that’s a no go. Should I pull off the leaves? New leaves are healthy so far, loads of flower buds. Thoughts??

Answer: The avocado you showed me in the photo looks as if if has been beset by a gopher. When gophers eat the roots of avocado this is what happens. It’s classic.

But gopher damage usually is just one or two branches up in the tree, caused by dying roots on one side where the gophers ate the roots. Your photo shows root damage on all sides of the tree, probably due to roots dying in water logged soil. Avocados are very sensitive to drainage. Must have good drainage or they succumb to root rot.

It may be wet soil, but mites don’t do what you showed me in photo. Mites hit plants that are already in bad shape from some other cause.

Comments

  1. Kathryn Willetts

    Dear Pat,
    My yard is beset by gophers, I’m about to plant a pair of avocado trees in a single hole, and I just read your comments about gophers eating avocado roots.
    Should I not plant the trees to save myself the grief & expense? Or, if you think it OK to plant the trees, what is an effective way to win a war with gophers?
    Thanks for this great web-site!
    Kathryn

    • My advice is to plant the trees in a large wire basket. In the area where I live there is a man who traps gophers and only charges for the dead ones. I suggest burying the dead body back in the hole he came from. The best trap I have ever used is the Black Hole trap. This really works if you follow directions. I used to catch many gophers with this trap. My son-in-law caught a gopher in 20 minutes with this trap. (don’t buy the black box trap. It doesn’t work! A grower I knew broke wine bottles with a hammer and buried the sharp glass in the planting hole and in a wide circle further out. I have never done that since I thought of what might happen eventually: Innocent gardeners living there later might get hurt or even children.

  2. Kathryn Willetts

    Hi again Pat,
    Thanks for the quick response. We’ll certainly get the Black Hole Trap, but I’m confused about the advice to plant the avocado in a wire basket. I’ve learned that avocado trees have roots only within the top 3″ of soil and spread about 30′ outward from the trunk, so I’m wondering how a wire basket lining the planting hole would deter future gophers? Am I misunderstanding the recommendation?
    Kathryn

    • Thanks for writing back. Frankly I think you’re right to be concerned about the idea of planting in a wire basket. I apologize to you since though i am normally persnickety and super-correct in my answers, I think I answered you too hastily this morning before hurrying out to be on time for an appointment. I didn’t devote enough time to thinking about your question—not my normal habit.

      The advice I gave you was the same advice given to me by a famous tree man, whose name I had better not mention here. I want to apologize for handing on the self-same advice to you because, despite the fact that the wire basket idea was repeated like a religion for many years, I never used this system myself and the man who suggested it to me not only sold these baskets but was the same grower who buried crushed glass himself—which kind of proves he didn’t believe in the baskets.

      Here is a true story that happened in my family and it has given me a creative idea of how to use a different kind of “wire basket” that would stop gophers while doing no damage to the roots of your tree. First the story: About 30 years ago a son-in-law of mine told me he was going to install a Santa Ana bermuda-grass lawn from sod in his back yard but that all his neighbors’ lawns were riddled with gopher holes. He asked me how to prevent this from happening. I suggested preparing the area for planting sod, purchasing rolls of chicken wire and unrolling them flat on top, overlapping the edges by 4 or 5 inches, and laying the sod on top. (This advice would have been even better had I suggested using plastic-coated wire.) Nonetheless, my son in law followed my advice and never had a gopher problem during the 15 years they owned that house. Evidently the wire lasted long enough because the current owners have never had a gopher problem either Most of the lawn was surrounded by a poured concrete edge to prevent the bermuda-grass from invading flower beds. However, one side bordered a horse corral. Gophers dug under this edge for 6 or 8 feet and then would try to make a mound, come up for air and hit the wire. Then they gave up. My son-in-law never had a single gopher mound on his lawn.

      So here is what I suggest: Plant the trees and cover, let’s say, a 20-foot-wide circle with “gopher wire” instead of chicken wire. This would make a safer space for at least that much of their future root run. (Gopher wire is available by the roll at garden supply stores.) Twenty feet out from the trees, dig a trench about 18 inches deep and 6 inches wide surrounding your circle of wire, install gopher wire upright in the trench with four inches on the bottom bent outward and the top edge wired to the sheet of wire lying flat. Finally, cover the entire area with mulch. This will prevent gophers from invading the root zone of your trees. Other than that your only solution is trapping the gophers or finding a service to do the job for you, as I have done. By the way, after trapping many gophers in my large garden, I now once again have none. Not sure why but we did bury their dead bodies back in the holes from which they came.

Leave a Reply