40 citrus trees

Asked May 8, 2013, 8:03 PM EDT

We just bought a foreclosed house in Aug and we inherited 40 citrus trees (grapefruit,limes,lemons ans different oranges) in the backyard.We watered the plants everyday and even asked someody to install a drip system to assure regular watering.
A few weeks ago,I saw the leaves are turn yellow starting from the outer part of the leaf and still green on the main veins, some trees have leaves turning yellow with tiny black spots and some have leaves that are turning brown like burnt. Some leaves are rolled and misshapened.
I don't know if it is connected with our putting fertilizers on the soil( Twin Pine 16-16-16) and miracle grow spray plant feeder. We have aphids and some leaves have ashlike-grayblack covering too.
We want to save them. they are all mature around 35 yrs old. Its really sad since they have a lot of small fruits.
Any suggestion on at we should do? Maybe insecticides/fungicides and how to best do it.
Thank you for having this website available for helping first time gardeners like us.

We live in Glendale , Los Angeles County,California.

Los Angeles County California

1 Response

Your citrus trees are exhibiting several different problems.
The twisted and gnarled leaves are infested with citrus leafminer, so review information for control of that pest in California.
One picture is classic magnesium deficiency (leaves with green christmas tree pattern within the leaf). Magnesium deficiency may be temporary--if subsequent flushes continue to show problems, correct with magnesium sulfate (Epsom salts).
Other leaves appear to be pale from nitrogen deficiency and watering incorrectly (too much or too little).
You also describe aphids and sooty mold (fungal complex resulting from honeydew deposited by aphids).

So you need to address insect problems, nutrition and watering.
Citrus trees need regular watering throughout the year, but over-watering can create significant problems as well.
A year-round fertility program should be maintained, supported by soil testing for deficiencies and pH problems.

This eXtension Ask the Expert program does not locate a counterpart in California for you, so you will need to go directly to http://ucanr.edu/ to locate experts and informational resources pertinent to California conditions for growing citrus.