What or who is killing San Miguel's trees?

Though the landscape now is a brilliant Irish green, thanks to about 14 or 15 inches of rain so far this season, there are dozens, probably hundreds of white cedars and certain types of pines all over San Miguel and in our ranch that are turning up dead, as if struck by lightning. 

Hey, has anyone noticed the trees in front died?

At our ranch we've had to cut down about nine or ten tall trees, a shame indeed because this land was practically moon-like barren when we bought it, and over the past ten years we have planted at least 150 trees of all sizes and types. It's inevitable to lose a tree once in a while, but such large loss of mature trees is really sad. 

Elsewhere, the losses are most visible in front of the municipal office center, where a stately row of a dozen or more pine trees, probably about 20 feet tall or more, are now dead. I miss those trees because they helped hide the exceptionally ugly mustard-colored exterior of the building.

The die off in our ranch probably began sometime in February or March, but we didn't notice it because during the dry season most vegetation  looks pretty much dead. But it became more noticeable when the rainy season began, around May, and the dead trees stood like brown question marks amid the green surroundings.  

Sad sight.

Then a neighbor reported that several of his cedars and pines had died too, and when they'd chopped them down had noticed that the roots were infested with slimy, white, two-inch-long worms that Mexicans call gallinas ciegas or "blind hens." I believe they would be regarded as some sort of grub in the States.

We consulted with the headman at "El Surco" a vendor of fertilizers and pesticides, but he hadn't heard about dead trees or have a clue. But he recommended to excavate lightly around the roots and apply an insecticidal powder for treating gallinas ciegas, followed by a good watering, in case that was the cause. 

Félix went at this task like a crazy man and treated all the trees, sick or healthy, cedar, pine or whatever. Since he planted most of the trees, I think Félix takes their demise personally.

At this point, we haven't noticed any more dead trees, but the ones that are brownish are not getting any greener. It seems, however, that the gallina ciega grub might be the culprit. 

We've planted a few replacements though none of them cedars of pines: a couple of grevilleas which have done well elsewhere in the ranch, and two green oaks, based on their being planted in the median of San Miguel's libramiento. I figured that if they can survive in that mess of traffic and and truck fumes, they'll survive just about anywhere. Plus a fraile tree, which doesn't seem too happy. 

I've continued my research into the death of the trees, but haven't found any conclusive answer. I've been told to spray for mites, paint the trunks white, or water them even more, which sounds crazy in this super wet rainy season.

Félix's latest brainstorm is that muérdago, or mistletoe, a deceptively beautiful parasite plant with yellow flowers that attaches itself to the branches of the trees, is the killer agent. He says he's found gooey bird droppings on the dead trees, which is how muérdago spreads. Except that with birds everywhere, there's also bound to be poop everywhere, and so far we haven't noticed any of the telltale yellow flowers. 

Meanwhile, at the Botanic Garden no one answers the phone and the Ecology Department referred me to someone at City Hall, who hadn't even noticed that most the trees in front had died. 

By far the most interesting hypothesis came from my friend Gerardo, who worked in the recent, and failed, mayoral reelection campaign of Luis Alberto Villareal. Gerardo said that he'd heard about the dead trees and had proof that Mauricio Trejo, the opposing and winning candidate, was responsible. 

Security cameras at City Hall had caught campaign workers for Trejo, Gerardo said, injecting the hapless trees with some sort of poison late at night. 

Of all the theories I've heard, that one left me speechless.   

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Hmm, the plot thickens: Félix came in with this picture of a branch of dead pine tree, with something that looks like a parasitic plant attached to it.  Maybe conclusive proof of muérdago?