how old and how big are your trees?

have you looked very closely for tiny pests?

i'm leaning towards root rot/wet feet. instead of getting water every morning, they should be watered deeply about once per week.

this spring we had rain 2-3 times per week for about 6 weeks straight, and one of my potted citrus showed the exact symptoms, leaves started to yellow, curl up and fall off. most of the branches turned brown and had to be pruned off. i repotted with dry mix and it was able to sprout a few new branches on the lower/mid part of the trunk. my two inground navels showed some signs too but didn't suffer as much leaf/branch losses.

What do the citrus specialists at your local extension office say? They, more so than any of us on this or any other forum, are the professionals you should contact when it comes to serious concerns with your citrus.

In a major citrus producing state, extension resourses are readily available for backyard growers as well as commercial.

I'd second too much water as the likely cause. Just because it's worked in the past doesn't mean it's a good practice to water every day especially if your soil is somewhat slow draining.

I would do what Rhizo suggested without hesitation and with no time to waste.
Hello everyone else. Enjoy your day :)

Sounds like Phytophera, which is quite common is Northern California; and is made worse by keeping the soil too wet.

Phytophera is commonly expressed as collar rot or root rot... both usually kill the tree, or weaken it to the point it would be better replaced.

Commercially, Phytophera in N.Calif. is the result of flooding from rivers or overwatering with river water.

Thanks for all the responses. Most of the trees are 8-10 years old. They are all dwarfs -- none of them is more than four or five feet tall.

I don't know who my local ag extension agent is or how to get in touch with him/her, but that's a good suggestion -- I'll look into that.

The consensus of all the comments seems to be root rot caused by overwatering. It would be hard to overemphasize how dry it is here in the summer. It hasn't rained in a couple of months and normally doesn't rain from about May 1 through Thanksgiving. The irrigation I provide every morning is minimal. It's true that I have been giving some of these trees an extra shot of water in the late afternoon recently -- because the ground is so dry as to be almost lunar. Maybe that extra water created the problem. But that doesn't explain why citrus trees to which I haven't been giving extra water are showing the same symptoms. Plus, we had a rainy spring and they loved that.

The affected trees are a pink grapefruit, a Meyer lemon, a navel orange (which has already died), a Valencia orange and now a Bearss lime.

Over the weekend, I'm going to try (1) cutting out the affected branches; (2) spraying thoroughly with bug killer, (3) taking affected leaves to the local garden center and (4) looking up the county extension agent. If anyone has any other ideas, please share them.

Thanks,

Nimzo

Nimzo, I also am thinking this is Phytophthora causing root rot due to overwatering. Watering your citrus every day is way too much water. You're better watering once or twice a week, for a longer period of time. Over the last 3 years, we've had ample winter rains, so and in combination with our temperatures in the spring, it is a "perfect storm" for Phytophthora. Here's a couple of links for you:

http://www.ipm.ucdavis.edu/PMG/C107/m107bpleaftwigdis.html
http://www.ipm.ucdavis.edu/PMG/r107100111.html
http://www.ipm.ucdavis.edu/PMG/r107100411.html

Please don't spray your tree with "bug spray". I seriously doubt you have bugs. You most likely have a soil fungus. All you're going to do is kill off your beneficial insects. To reach your local extension office, contact your local Master Gardener's organization. They are affiliated with your local county extension office. Take many, many photos, up close (well focused) as well as the entire tree. Send them to the MG association and ask them if they can help you diagnose your trees for sure.

Patty S.

Nimzo, click on your county in the attached link for get the contact information of your local county office.

Here is a link that might be useful: click here for Extension information

Heres some good pictures descriptions. But its no substitutes for you extension office.

http://www.ipm.ucdavis.edu/PMG/C107/m107bpleaftwigdis.html

You are wetting a very small area twice a day so of course the rest of the soil is lunar dry in that climate. You need to wet a much bigger area less often.

I agree. Wet a larger area, deeper, and less often.