Subtropical Fruit Crops Research & Education
University of California
Subtropical Fruit Crops Research & Education

Posts Tagged: diagnosis

What's Wrong with My Citrus?????????????

Hats Off.

The Orange County Master Gardeners have lived up to their name with their website information on citrus. It's a truly impressive information site for not only homeowners, but also growers:

The “Citrus Problem Diagnosis Chart” is especially work perusing:

Orange County logo
Orange County logo

citrus and mountains
citrus and mountains

Posted on Wednesday, June 14, 2017 at 3:22 PM
Tags: citrus (339), diagnosis (2), disease (57), grapefruit (27), horticulture (3), leafminer (1), lemon (100), mandarin (68), orange (69), pests (25), pruning (15), pummelo (3)

Broken Trunk, Dead and Decaying Roots, but Green Canopy? What's the Problem?

I get a call.

He: My trees not doing well.

Me: What's the problem?

He: It's yellow?

Me: Have you looked at the roots? Are there roots?

He: NO

Me: I'll be out next week, but in the meantime, look at the root system.

This is a pretty common exchange and when I got out, you find out that the emitter is clogged, the ground is soggy, there's weed whack damage, there's gopher damage, there's…………………. All kinds of things that pop up and until you see the context that the poor tree is in, it's hard to diagnose the problem. Too much fertilizer, black drip tubing that had water heated in the sun and burned the roots, the trunk buried in mulch, it's hard to imagine all the possibilities. But start with the roots and then go where that leads you.

So, here's the scenario.

You get a call/email.

He: What's wrong with my young tree? It snapped off in the wind. Here's a picture of what's left. Corroded, bulbous graft union. Incompatibility? Extensive decay that indicates a problem of long standing. The leaves are green though, so it means it was hanging in there until the wind blew. Was the trunk buried at planting leading to asphyxiation and crown rot? Is it some sort of wound that started it off? Oh, and about 1% of the planting is like that.

Me: OK, I better take a look at it. I'll get some samples and send them into Akif Eskalen at UC Riverside and bring our plant pathologist Jim Downer out to look at it with me.


So tune in to find out what we diagnose as the problem. In the meantime, if you have an unknown avocado or citrus problem that looks of root origin. You can contact Akif and send him a sample after following the “Sample Submission Form” at:

avocado root rot 4
avocado root rot 4

Posted on Tuesday, January 5, 2016 at 1:29 PM
Tags: avocado (289), Botryosphaeria (13), citrus (339), diagnosis (2), gopher (3), Phytophthora (23), root rot (21), weed whack (1)
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