As a test to see if you get any improvement, try watering with 1/2 cup of vinegar mixed into two gallons of water. Also, try a couple doses of water soluble fertilizer (like Miracle-Gro) about two to three weeks apart.

Yellowing leaves with darker veins are usually either an iron or nitrogen deficiency. However, a sulfur deficiency can also turn leaves yellow.

20 years ago.. i had 2 across 5 acres .. and they came down with some disease .. and both died within a couple years ...

i was distracted by life.. and never researched it .. nor followed up on it..

hopefully someone else can discuss such ... as there may be something other than a soil issue ...

ken

There is no doubt that it is a soil issue!! Chlorosis is an indication of a nutrient deficiency, in this case I would assume to be pH induced. Insufficiently acidic soils bind iron (the most common cause of chlorosis). Chelated iron should help but adjusting both soil and irrigation pH will provide better results. Shoot for a pH no more than 6.5.