Sick Avocado Tree

[ChubbyWorm]

Hi community,

I have a big avocado tree in my yard, newly moved here in January, so I have no idea of its history...
Its leaves started to turn yellow since February, and now it is so much worse. I checked the mite pictures, seems like not a mite issue?
There is an orange tree next to it, has been doing pretty good, but it also started to appear yellow leaves in the recent week. The previous owner has two other small avocado trees in the pots, they both has yellow leaves too and the plants next to them are all doing good.
Does anyone know if this is nutrient deficiency, a fungus problem or some other issues? and any recommended product for it?
Thank you all in advance!!

 

[Marck]

Greetings, welcome to the Forums.

The pattern of damage on the leaves is unusual, but it isn't clear what might have caused it? Have all leaves been affected, or just younger or older leaves, more shaded or more exposed leaves?

If you are certain all the damage is from the last month and a half, what has the weather been like? Were there any frosts?
Has anything else happened that was unusual?

Have you given the plants any particular care? What has precipitation and irrigation been like?

 

[ChubbyWorm]

Greetings, welcome to the Forums.

The pattern of damage on the leaves is unusual, but it isn't clear what might have caused it? Have all leaves been affected, or just younger or older leaves, more shaded or more exposed leaves?

If you are certain all the damage is from the last month and a half, what has the weather been like? Were there any frosts?
Has anything else happened that was unusual?

Have you given the plants any particular care? What has precipitation and irrigation been like?

Thank you Marck for your reply!!

I'll say when I moved in the house, the tree has already started to show some yellow leaves but not this bad. I thought it was cold since it was January, and the night could be 4-6 degrees, but the weather here in Fairfield,CA has definitely been getting warmer, no frost at all in the past month, but the tree is getting worse.

Everything around it is doing great except that orange tree has started to have some yellow leaves too.

Attached is a closer look of the whole tree, I think most of the yellow leaves are older leaves and inside of the tree.

I've just given it some plant food this one here: (https://www.amazon.com/gp/product/B01JIRG2RK/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&psc=1) last weekend since I thought it might because of nutrient deficiency. Been watering it once a week, almost no rain and can be hot and dry at noon. I noticed the soil under it is pretty hard, so I loosened it a little and put on about 1 in of fresh soil last weekend. All of this was done last weekend, didn't give any other special care before (I'm new to gardening too)